Music Contract Negotiations & Publishing Essay Example | Topics and Well Written Essays - 750 words

Music Contract Negotiations & Publishing - Essay Example Some of areas may be found inappropriate by the Artiste to promote its musical production (like advertising on hygiene accommodation or etc.). The Artiste also may oppose using some promotional methods (like spread of information the Artiste finds damaging or etc.) (b) This part of the clause brings similar concerns on performing recordings and the Artiste publicly. Areas where the Company will, or will not use the product should be previously mutually agreed within the Contract, or a form of consultation for the areas should be required. Additionally, selling recordings for a commercial, but strange from traditional music industry (for example, tunes for doorbells or etc.) enterprises should require a consultation too (Morley, 2000). Clause 5 recognizes a size of music expected to be produced by the Artiste for each period as one album and one single per period, yet clause 1.1 and clause 1.8 bring a poor notion on what ‘album’ and ‘single’ are correspondently. Therefore, no limits are settled on number of songs, or for a playing time count of a song, making clause 5 unclear. The mutual agreement in the Contract on a minimum/ maximum number of songs is recommended. Clause 6.2 reserves the right for the Artist to give and/ or sell other non-musical production and services independently from the Company, yet the definition of the non-musical activity is very unclear. To escape violation of the Contract in future the types of not allowed artistic activity should be defined by the Company, paying a specific attention on borderline cases (on the example of clause 6.5). In clause 9.1 the Company proposes the Artist to receive 40% of the ‘net profits’, and this may be a point of argument. Commonly small independent labels as the Company is propose a fifty-fifty percent of a ‘net profits to share after the covering of previously agreed recording coasts

Investigate into the Primacy and Recency effect Essay Example for Free

Investigate into the Primacy and Recency effect Essay The aim of this study was to investigate into the Primacy and Recency effect. The study was based on Glanzer and Cunitzs research (1966) who suggested that when remembering words, if given an interference task, the recency effect will be virtually eliminated. It was therefore predicted that when a group of participants were recalling words after having an interference task there would be little, if no recency effect. However it was also predicted that when an interference task was not involved there would be both a primacy and recency effect. The experiment was conducted on two groups of participants, 20 in each group. They were all students between the age of 16 and 18. This was an independent experiment. The findings form this study indicated that there was less of a recency effect when using an interference task then when not. Introduction The aim of this investigation to find out whether people remember material at the beginning of a list better than material at the end. A further aim is to show that when participants take a memory test with the involvement of an interference task there is no recency effect. The recency effect can be defined as the tendency to recall items at the end of the list more readily than those in the middle (about the last 25%). The recency effect occurs due to the last lot of information still being in short term store. A familiar example of the recency effect is the observation that a pop group is only as good as there last hit song. People tend to remember things more clearly if they have happened recently. The recency effect can be measured using free recall, where participants are shown a list of words, and the later asked to recall them. The recency effect is shown by the fact that the last few words in the list are usually remembered better than the middle. However, Glanzer and Cunitz (1966) found that counting backwards for only 10 seconds between the end of the list presentation and the start of recall (thus producing and interference task) virtually eliminated the recency effect, but had no other effect on recall. This can be explained by the fact that the counting backwards interfered with the process of creating memory and so this wiped out the words towards the end of the list. It can be seen that the rest of the list was not affected by the interference task, as they were now in long-term memory store. In Glanzer and Cunitz experiment the participants recalled the first few items in the list much better than those in the middle, this is known as the primacy effect. The primacy effect can be defined as a high level of free recall of the first items in a list (about the first 25%). The primacy effect depends mainly on rehearsal, in that the words at beginning of the list are rehearsed for longer than those in the middle. The primacy effect was shown by Rundus and Atkinson (1970), who asked their participants to rehearse out loud any of the words they wanted to during list presentation. The recency effect is found when the results of a free recall task are plotted in the form of a serial position curve. Generally, this curve is U-shaped, and the recency effect corresponds to the tail of the U on the right. This tail indicates that words presented at the end of a list of to-be-remembered items are better remembered than words presented in the middle of this list. It is called the recency effect because these items were the ones presented most recently to the subject in the memory experiment. The primacy effect is found when the results of a free recall task are plotted in the form of a serial position curve. Generally, this curve is U-shaped, and the primacy effect corresponds to the tail of the U on the left. This tail indicates that words presented at the start of a list of to-be-remembered items are better remembered than words presented in the middle of this list. It is called the primacy effect because these items were the ones presented first to the subject in the memory experiment. The diagram below shows the multi-store model of memory designed by Atkinson and Shiffrin (1968). It shows us how rehearsal is a vital part of the memory system. This model of memory can help to explain why interference will eliminate the recency effect. The recency effect is part of the short-term memory store, in that it is the last piece of information taken in and so, like all information, it goes into short-term store first. What allows us to remember this information is through rehearsal, thus temporarily keeping it in short-term memory store. It is therefore clear to see that if rehearsal is taken away, as it is through an interference task, then there will be no recency effect. Experimental hypothesis If given a list of words to remember, involving an interference task, when recalled there will be a strong primacy effect, and little, if no recency effect. This, one tailed hypothesis was formulated as previous research has indicated the existence of a primacy effect, and the elimination of the recency effect when using an interference task. However when undertaking the same task without interference there should be both a primacy and recency effect. Null hypothesis If given a list of words to remember involving an interference task, when recalled there will be no difference between how strong the recency and primacy effect is. Method Within this investigation there are two groups of participants, consisting of 20 different people in each group. The participants used were all A level students and were asked at random if they willing to take part. Some of these students studied psychology at A level themselves and so may have known what the investigation was about, thus possibly affecting the final results. The type of design being used is that of independent measures. There are two main variables in this investigation, which will later be correlated; these are word number and the total number of times each word was remembered by the participants.

Spike Lee :: essays papers

Spike Lee In 1995 I considered Spike Lee's gritty CLOCKERS one of the year's best films; recently I spotted its video in a clearance bin and picked it up. Upon re-viewing, I am struck again by its complexity. It is the first urban drama to depict inner-city race relations with the intricacy such a pervasive cultural issue demands. On the surface it resembles a whodunit, but its main concern is how drugs and violence contaminate entire communities, dramatized in the collapse of one African-American youth's life. (He chokes up blood the way some of us sweat.) This process is observed by a predominantly white police force that makes hollow attempts to keep order, and refuses to intervene with the community's gradual decline. Instead of characters with overt prejudices and plain racial allegiances-characters that are sterile symbols of bigotry rather than credible humans guilty of it-Lee gives us characters of casual racism. Most representative of this is Harvey Keitel's Rocco Klein, a white detective who cannot understand the culture surrounding him, which is a culture of narcotics, violence, and black-on-black crime. On his beat, drugs are less a problem than a lifestyle, murder resolves the tiniest of disagreements, and young mothers valiantly but vainly battle the influence young dealers have on their sons. Klein views the inner-city with contempt, but deep down he knows all the whores and dealers are human beings, too. Klein is introduced at the scene of a homicide, where the police handle the gruesome death with a clinical sense of detachment, cracking bad jokes and asking the bloodied corpse questions. Is it just a job, or is it racism?

Analysis of A Tale of Two Cities by Charles Dickens Essay -- essays re

â€Å"A Tale of Two Cities† by Charles Dickens is an artfully crafted tale that unabashedly tells the story of the injustice, the horror and the madness of the French Revolution. More than this, it is a story of one man’s redemption, one man who Dickens vividly portrays as being â€Å"a nobody†. This nobody had thrown away his life. â€Å"A Tale of Two Cities† is the tale of Sydney Carton and his full circle redemption. The first impression we get of Sydney Carton is not a pleasant one. â€Å"[Sydney Carton] sat leaning back, with his torn gown half off him, his untidy wig put on just as it happened to light on his head after removal, his hands in his pockets, and his eyes on the ceiling as they had been all day. Something especially reckless in his demeanor†¦gave him a disreputable look.† (p. 57) From this description we get the impression that Carton is a slacker and that he doesn’t care about appearances. We also learn that he is a drunk. â€Å" ‘You have had your bottle, I perceive, Sydney.’ ‘Two tonight, I think.’ † (p.66) Sydney is trying to find the answers for his problems in the wrong places and he has begun to give up hope. â€Å" He resorted to his pint of wine for consolation, drank it all in a few minutes and fell asleep on his arms, with his hair straggling over the table, and a long winding-sheet in the candle dripping down upon h im.† (p. 64) Sydney Carton is in bad shape. He is an alcoholic, he is depressed and he has nothing going for him. Before a chick is born, it must first break free of the shell that encases it. It only begins to chip once it realizes that breaking free is the only way to start a new life. In the same way Carton begins to take a serious look at who he is and what he has become. â€Å" ‘Do you particularly like the m... ...ounters a young, frightened seamstress. Carton takes her hand and commands her to never take her eyes off him. â€Å" ‘ Keep your eyes on me, dear child, and mind no other object.’ † (p. 291) Sydney Carton, had always been the follower, but now, he takes the lead in his own life. Amidst the chaos and the confusion of the crowd, Sydney Carton whispers his final words. â€Å" ‘It is a far, far better thing that I do, then I have ever done, it is a far, far better rest that I go to than I have ever known.† (p. 293) As the chick chips its shell to its final breaking free, Sydney Carton begins the journey of redemption and completely transforms himself. Carton ascends to the plane of heroism, using his death to save the lives of others. His own life thus gains meaning and value. â€Å"A Tale of Two Cities† is truly the tale of the miraculous redemption of one, ordinary â€Å"nobody.†

Mickey and Eddie Essay

As part of our Drama GCSE unit on Blood |Brothers we were requires to use a vast amount of sills and drama techniques in order to improve our understanding of Blood Brothers; in order to do this we completed various exercises to develop our explorative skills. One of the improvisations we had to partake in was the re-enactment of the finale scene in Blood Brothers. As we had already seen the Blood Brothers production, this acted as both an advantage and a hindrance. This acted as an advantage as we had an idea of both characters and therefore an insight into how we could perform this re-enactment, however the disadvantage was that this may prevent us from having our control over the character, this may also prevent us from using our own imagination to interpret the character and their actions as we would have been heavily influenced to mimic what we had already seen. However though we already had familiarity with the production, as it had been a considerable amount of time from when we had seen the production, our drama teachers refreshed our memories by establishing a class discussion on the subject, and the main themes of Blood Brothers. As a group discussed the main themes, scenes and then discussed the finale scene into depth; while doing this we discussed what body language and facial expressions were used and what we all found particularly effective in the scene. Once we had completed our discussion, we were then given a time frame to work towards. Once we had dispersed into our groups we divided the roles in the scene amongst ourselves; Adrian as Eddie, I was Mickey, Tamara was Mrs Johnston and both Zion and Emma acted as the police officers. I felt that this particular exercise was particularly interesting and beneficial for us all; this is as we had a new insight and understanding of Blood Brothers on a higher level. Through the re-enactment of the Blood Brothers production I also found a new knowledge of each character, particular Mickey (the character I played), this is because as you take on the role and you’re in a maximum involvement level you absorb the character and believe in the scene although it is actually happening. This lead to me felling more empathetic towards Mickey as I really felt able to relate to his feelings and his situation, therefore understanding what made him react in the way he did. Mickey reacted in the way he did as he was angry and felt completely betrayed by Eddie, his feelings weren’t helped by what he’d already been through in prison and with him now having to be on medication. Our own re-enactment was fairly accurate to what we had seen in the reduction, however I genuinely feel that we added our own input and originality into the way the final scene was devised and appeared to be (this is inevitable as when you relate to a character, your own feelings and opinions are bound to show through). In our own finale, Adrian (Eddie) opened the scene by thanking the audience for being elected as councillor, while doing so my character then interrupts by running down the stairs and onto the stage. I felt that y my character (Mickey) running down the tiered seating stairs, the audience became more involved in the scene. My character then started pushing Eddie and shouting about his infidelity with Lynda, Eddie then tries to reassure Mickey and justify himself by claiming that both him and Linda are only friends. At this point my character becomes enraged and grabs him by his collar. In our re-enactment there was more physical violence and confrontation on Mickey’s part, I felt that this would portray his rage more effectively. I also took a conscious decision to make Mickey’s tone of voice, behaviour and body language very erratic; this was in order to portray t the audience that he wasn’t in a completely stable state of mind. As b5h character continued in their confrontation, Eddie continues to try and make peace with Mickey and when it reaches the heightened tension of Mickey raising a gun to Eddie’s head, Mrs Johnston shouts stop and runs onto the scene. At this point both police officers run to the bottom of the stage from separate sides, a voice then circulates the room, saying â€Å"we have you surrounded, put the gun down†. At this point my character then starts to look around, suspicious about where the noise is emerging from; at this point I lower the gun. I feel this part of our re-enactment is particularly effective and original as all the other groups used the same approach as the one used in the production whereas in our own improvisation we devised it to appear as though the police have surrounded the building on the outside and are ready to burst in at any time. At this not Mrs Johnston (Tamara) then reveals to both Mickey and Eddie that they are literally ‘Blood Brothers’ as they are twins that were separated at birth, at this point both brothers ask why, at this point Mrs Johnston continues to explain. However in the middle of her explanation Mickey makes his final outburst screaming that because of being with her he’s ended up with no career or money whereas Eddie has managed to become some great councillor; Mrs Johnston then tries to calm Mickey down and t this point his voice raises, as does his hand and gun and he screams It should be me, at this point the gun goes off and Eddie’s killed. Meanwhile at the same point one of the police officers (Emma) emerges on scene and reacts to the sound of the bullet by shooting Mickey. I felt particular sympathy for the police offer that shot Mickey as she only reacted to the gun shot she had heard. I also feel that this particular situation gives the audience a real understanding into how difficult the job of a police officer can really be as they are often put in compromising situations in which quick instinct decisions have to be made. Another improvisation we re-enacted was the ‘kids play’ scene. Our drama teachers explained that the purpose of this is to enable us to lose all inhibitions and feel in essence what it’s like to be a child again. We were then told about Starkravski’s theory on the three essential skills tat needed in order for a person to be a god actor, the most important factor being that of naivatiae. This means to be in a child like state, oblivious to anyone there and t feel completely free, this is as children are extremely nai ve and innocent and with this they can believe in anything, allowing them to have a vivid imagination.

Smart Cards essays

Smart Cards essays Gemplus is maintaining its industry and staying focused on its research efforts. Gemplus employs over 160 engineers in the development of this smart card. Gemplus has recognized the benefits of there research. Gemplus has also researched with various groups such as the British Library, the open University of the Netherlands and Bureau van Dijk management consultants of Belgium to apply the smart card technology for the protection of intellectual property rights. Gemplus has helped us in our efforts to succeed in the development of the Smart card. Smart Card is a new wallet-sized plastic card, manufactured to ISO standards, with embedded microchip. This new card is able to process data, such as user identification codes, at a transaction site. The smart card holds memory it is a microprocessor card, intelligent card with greater data storage and processing capabilities, allowing certain information to be programmed over and over during the usage period. The smart card also has the capability with contactless cards, the newest area of car development, these cards can transmit data without physically being connected to a card reader. Gemplus is the world leader in the production of this conventional plastic card. Smart Card is a credit card with a brain in it. Through our hard work we have made a smart card that has human like intuitions embedded in a small microchip. This card can be programmed to perform tasks and store information, but note the brain is little-meaning that the smart cards power doesnt compare to that of a computer. I know many of you are wondering how is this possible. How can a card be money with a brain? The basic gist is that banks and customers would have public-key encryption keys. Public-keys come in pairs. A private key is known only to the owner for security purposes the signature is for identification purposes. It can also be used for money orders using a private key and cust ...

Replacing a Lost or Stolen Canadian Passport

Replacing a Lost or Stolen Canadian Passport Whether you lose your Canadian passport or if it is stolen, dont panic. Its not an ideal situation, but there are steps you can take to replace your passport, and you may able to get a replacement passport for a limited time. The first thing to do when you discover your passport is missing is to contact local police. Next, youll want to get in touch with the Canadian government. If youre within Canada, call 1-800-567-6868 to report the circumstances of the loss or theft to the Canadian Passport Office. If youre traveling outside of Canada, find the nearest Government of Canada office,  either an embassy or a consulate.   Police or other law enforcement officers will conduct an investigation, which is especially important if youre reporting your passport stolen. It may be a good idea to contact your credit card companies and bank, even if your passport is the only thing missing. Theres the potential for identity thieves to do a lot of damage with a stolen passport, so keep an eye on your financial information until its located, or until you receive a new one. Once the investigation is completed, if authorized,  you can then apply for a replacement passport which may be valid for a limited time until you have to apply for a new passport.   Submit a completed application form,  photos,  fee,  proof of citizenship, and a Statutory Declaration Concerning a Lost, Stolen, Inaccessible or Destroyed Canadian Passport or Travel Document. Canadas Passport Rules Canada shrunk the size of its passports from 48 pages to 36 pages in 2013 (to the consternation of frequent travelers). However, it extended the expiration date, making passports valid for 10 years. Its also important to know that Canada is one of the few countries that dont allow citizens to hold a secondary passport (unless he or she can claim dual citizenship in Canada and another country). What If My Canadian Passport Is Damaged? This is another circumstance when youll need a new Canadian passport. If your passport has water damage, is torn on more than one page, looks like its been altered, or the identity of the passport holder is impaired or illegible, you may be denied by an airline or at a point of entry. Canadian rules dont allow you to get a replacement for a damaged passport; youll need to apply for a new one. What If I Find My Lost Passport? If you find your lost passport, report it immediately to the local police and the passport office since you cant hold more than one passport at a time. Contact the passport office for specific exceptions, as they vary on a case-by-case basis. Its worth noting that Canadians who have had multiple passports damaged or reported lost or stolen may face restrictions when applying for a new passport.

Pros and Cons of Having a College Roommate

Pros and Cons of Having a College Roommate You may be a first-year student filling out new-student paperwork, trying to decide if youd like a roommate or not. Or you may be a student who has had a roommate for several years and now is interested in living on your own. So how can you decide if having a college roommate is a good idea for your particular situation? Consider the financial aspects. At the end of the day, at least for most college students, theres only so much money to go around. If living in a single / without a roommate will increase the cost of attending college significantly for you, then sticking it out with a roommate for another year (or two or three) is a good idea. If, however, you think you can swing living on your own financially or you think having your own space is worth the extra cost, than not having a roommate might be in the cards. Just think carefully about what any increased costs will mean for your time in school and beyond, if you are using loans to finance your education. (Also consider whether you should live on or off campus or even in a Greek house when factoring in housing and roommate costs.) Think about having a general roommate, not just one person in particular. You may have lived with the same roommate since your first year on campus, so in your mind, the choice is between that person or no one. But that doesnt have to be the case. While its important to consider if you want to live with an old roommate again, its also important to consider whether you want to live with a roommate in general. Have you enjoyed having someone to talk to? To borrow things from? To share stories and laughs with? To help out when you both needed a little lift? Or are you ready for some space and time on your own? Reflect on what you want your college experience to be like. If youre already in college, think back on the memories and experiences youve come to value the most. Who was involved? What made them meaningful for you? And if youre about to start college, think about what you want your college experience to look like. How does having a roommate fit into all of that? Sure, roommates can be a major pain in the brain, but they can also challenge each other to step outside of comfort zones and try new things. Would you have joined a fraternity, for example, had it not been for your roommate? Or learned about a new culture or food? Or attended an on-campus event that really opened your eyes about an important issue? Think about what set-up would best support your academic experience. True, college life involves a lot of learning outside of the classroom. But your primary reason for being in college is to graduate. If youre the type of person who enjoys, say, hanging out in the quad for a little while but really likes to head back to a quiet room to get a few hours of studying done, than perhaps a roommate isnt the best choice for you. That being said, roommates can also make awesome study buddies, motivators, tutors, and even lifesavers when they let you use their laptop when yours breaks 20 minutes before your paper is due. They can also help keep you focused and ensure the room stays a place where you both can study even when your friends pop over with other plans. Consider all the ways that having a roommate will have an impact on your academics both positively and negatively.

Many topics you can chose from Essay Example | Topics and Well Written Essays - 3000 words

Many topics you can chose from - Essay Example Ground water can also lead to formation of wetlands or oases. There are ways in which ground water can be extracted from the earth’s surface for a score of uses. It can be used for home purposes, industrial usage, in addition to agricultural use for activities like irrigation. This can be possible by construction of extraction wells that draws water underneath the surface of the earth. Ground water has been distributed differently under the surface of the earth. In addition, underground water undergoes movement under the earth’s ground. Study of ground water motions, plus distribution is known as hydrogeology. It is also called ground water hydrology. Ground water can also include soil moisture, immobile water that is found in bedrocks that have very low permeability, and oil formation water that is found very deep in the earth’s surface. Ground water is thought to act as lubricants that cause movement of faults. The points under the surface of the earth where ground water originates are identified as aquifers. An aquifer has layers of porous materials that contain and transmit water. When aquifer is not confined, water can move freely between the earth’s surface and the saturated zone of an aquifer. Since gravity causes water to move downwards, deeper zones of the aquifer are further saturated as compared to the upper parts. Water table refers to the upper zone of the saturated layer of an unconfined aquifer. Below the water table, all spore spaces are saturated with water. This zone is known as phreatic zone. There is a substrate that slight porosity and allows little transmission of ground water. This substrate is called an aquitard. Aquifers have diverse features depending on the geology, and the structure of the substrate as well as the topography in which they happen. Aquifers that contain a high amount of water are situated in sedimentary geologic formations. Crystalline rocks that are weathered and fractured produce a

Research paper on false memory for psychology Essay

Research paper on false memory for psychology - Essay Example This paper aimed at ascertaining whether this is true using a sample of 126 people (36 Females and 90 Males). According to Roediger III, H et al. (2001), visual objects are better remembered than are words which are just memorized. To him, imagery aids are remembered since they are retained in the memory. All recall phenomenon depend on the interaction and retrieval process of the words to be recalled. To Roediger III, H. and McDermott, K.B. (1995), words which are associated with related words presented earlier on are false fully recalled. In a research, Roediger III and McDermott proved that, words which are related in a certain order are easier to false-recall than those that not related. This is so because, the memory tends to recall words in a certain order which may fail if the order is not followed. Human minds often retrieve information due to sheer falsehoods. According to Cathy, L. M. et al. (1999), in day to day life, many people interact, communicate and form and interrelationship between the various words they sue. To Cathy, L. M. et a, the ability to recall this words depends on the preexisting connections between the words and the other associates. The study below is based on the capability of recalling words. Age has also been cited as a factor in memory recall. In this case, this will be tested with the age of the various participants being split into two, those aged between 15-21 and those above 21 years; However, according to many researchers, the ability to recall words not included in any list does not depend on ones age. In this research study, it will be assumed that, the recall capability of all the participants is the same across all ages. Almost all of them are assumed to be able to recall words at the medium level. Some 126 participants were selected for the study with 36 females and 90 males. All of them were required to read the 15 words from the 15 lists and then told to remember

Capstone Course Essay Example | Topics and Well Written Essays - 1000 words

Capstone Course - Essay Example Looking back, much of my time as a student was spent deciphering theories and philosophies with little or no effort in comprehending the practicality and application of these concepts, perspectives, and beliefs. Like many others, I too questioned the relevance of my learning with what I aimed to do in my professional life. Thus, the senior capstone course has acted as a bridge between theory and application, which is an outcome that I value the most. While an integration of subject-specific and cross-disciplinary knowledge and the assimilation of theory and application are the outcomes of my course experience that I greatly value. The learning outcome that I believe will be most helpful in my professional career is that of an enhanced level of self-efficacy, which is one of the characteristics internalized in a student during capstone courses (Dunlap 65). The systematic design of the course included class participation, interdisciplinary project, e-portfolio, research presentation an d a course reflective essay. The effort undertaken for the completion of these tasks allowed me to assume a larger share of the responsibility for my education and also played an integral role in acting as a means of socialization with my classmates and course instructor (Collier 285-299). The fact that the capstone project was planned as an independent endeavor meant that each student had to embark upon the task of using his/her individual learning, distinct perspectives on a range of topics and issues and cross-disciplinary knowledge to produce an independent study. My course project on insurance fraud was reflective of a range of understandings and comprehensions on the subject matter. The most critical factor which shaped the course of my independent study on insurance fraud was being on the ground. I also noted in my reflective essay on insurance fraud, how my interactions with the victims of this menace helped in the establishment of a relationship of trust.

OPERATIONS MANAGEMENT Essay Example | Topics and Well Written Essays - 2500 words - 1

OPERATIONS MANAGEMENT - Essay Example Introduction An organization could only be considered dynamic if it’s operational and it’s performing. The quality of the operation will influence its competitiveness and express its influence in the market to leverage. Part of 1 of this paper is some annotated bibliography on performance management and the second part is a company analysis. Theme 1. Annotated Bibliography Arnason, R., (2009). Fisheries management and operations research, European Journal of Operational Research, Elsevier, vol. 193(3), pages 741-751. Author is a scholar specializing his study on the aquatic reserves and who was challenged to evaluate the fishery industry anent to some deep-rooted problem on economic inefficiency e.g. blaming on inappropriate social institutions which control fishing management and common property development. Author argued the needs to replace the existing institutions that can provide appropriate leadership and management attune to the ideal social objectives of fisher ies. While author recognized the singular objective of fishing industry which is to maximize the present value and benefits from fisheries but empirical realities on the ground showed variegated, conflicting and interests of groups within the industry. Arnason contended that it’s more appropriate to embrace a multi-objective programming system with such management regime that is inclusive of (1) fisheries management system, (2) enforcement and (3) fisheries policies. This system, for him, should be correlated to the cost required in fisheries management and its value of harvest. Author further acknowledged that there ought to be a balance in fisheries management with cost efficiency amid multidisciplinary issues to ensure that managers are able to perform the necessary tasks necessary to have effective produce. Holsapple, C. W. & Lee-Post, A. (2010). Behavior-based analysis of knowledge dissemination channels in operations management, Omega, Elsevier, vol. 38(3-4), pages 167- 178. Authors are scholars taking serious interests on analyzing the behaviors about how knowledge is disseminated in operation management. Both contended that the significance if this discipline is vital for knowledge dissemination through journals, magazines, books, and other online sources for information that are supportive or are exploring more about the significance of operational management, which may include surveys, analyses. Though the study was quite limited by scope and resources utilized to fit the needs of the researcher, however, the examination of behaviors as explicated in the resources used was able to explicate the three metrics for rating publications for operational management studies. Researchers believed that the metric can be utilized by those who are working to determine which OM journals or books uphold substantial relevance. Galindo, G. & Batta, R. (2013). Review of recent developments in OR/MS research in disaster operations management, European Journal of Operational Research, Elsevier, vol. 230(2), pages 201-211. Researchers are scholars who have serious interests in reviewing the developments in OR/MS studies focused on disaster operation management. They affirmed that as disaster impacts to large number of populace and create serious environmental damages, the devastating effects inspire interests on scrutinizing the disaster operations management are undertaken using the studies of Nezih Altay and Walter

What do Advertisements Tell Young People They Should Value Essay

What do Advertisements Tell Young People They Should Value - Essay Example Advertising has been part of American life for centuries, and has certainly always had some kind of effect on the behaviour of Americans in a wide variety of ways. Throughout the past ten to twenty years, however, the amount of advertising exposure and kind of advertising has changed significantly, and may have an increased effect on American youths. It is incredibly difficult to construct a causal relationship between advertising and behaviour, something that advertisers have used to their advantage to fight regulation throughout history, from the cigarette era to today. The problems of determining causal relationships are myriad, but most simply rest on the well known idea that correlation is not causation: wearing your favorite team’s jersey and them winning does not indicate any causal relationship between your jersey choice and your team’s success. Furthering the complexity of this problem is the fact that advertising in fact mirrors many of the issues inherent to many forms of media, such as film and television, in, for instance, constructing unrealistic ideas of beauty. Advertisers, for instance, are often blamed on helping to cause eating disorders, while there may be many different societal and media factors at work in those issues. To construct a causal relationship, one must therefore go much further than simply analyzing correlation (though correlation certainly plays some part in the analysis). Through analyzing the behaviour advertisers, the explosion of new media, the psychological makeup of young adults, and the correlation between youth behaviour and advertising, it is possible to construct a causal relationship between advertiser’s construction of the ideals of beauty and negative behaviour among young adults, such as the development of eating disorders. The first thing that must be unequivocally establishes is the fact that advertising does, in fact, affect behaviour. This is its whole point of the entire industry, to lea d people to buy products. There are various interpretations of the role of advertising. The most generous would say that advertising merely influences behaviour through demonstrations of a product’s usefulness to its client; advertising affects behaviour merely through informing (). The least generous would say that advertising twists people’s emotions, world view, and so on, in order to manipulate them into buying a given product (). The truth is probably somewhere in between, that advertising does rely on a product’s abilities, but that advertising also manipulates viewers to a significant extent. That advertising affects people’s behaviour can be seen merely by the size of the industry: it is a multi-hundred billion dollar industry worldwide (Shaman, 2012), and a single thirty second spot in the Super Bowl can sell for â€Å"upwards of $5 million† (Shaman, 2012). There is no way corporations would spend this kind of money on advertising if they were not confident in its

OPERATIONS MANAGEMENT Essay Example | Topics and Well Written Essays - 2500 words - 1

OPERATIONS MANAGEMENT - Essay Example Introduction An organization could only be considered dynamic if it’s operational and it’s performing. The quality of the operation will influence its competitiveness and express its influence in the market to leverage. Part of 1 of this paper is some annotated bibliography on performance management and the second part is a company analysis. Theme 1. Annotated Bibliography Arnason, R., (2009). Fisheries management and operations research, European Journal of Operational Research, Elsevier, vol. 193(3), pages 741-751. Author is a scholar specializing his study on the aquatic reserves and who was challenged to evaluate the fishery industry anent to some deep-rooted problem on economic inefficiency e.g. blaming on inappropriate social institutions which control fishing management and common property development. Author argued the needs to replace the existing institutions that can provide appropriate leadership and management attune to the ideal social objectives of fisher ies. While author recognized the singular objective of fishing industry which is to maximize the present value and benefits from fisheries but empirical realities on the ground showed variegated, conflicting and interests of groups within the industry. Arnason contended that it’s more appropriate to embrace a multi-objective programming system with such management regime that is inclusive of (1) fisheries management system, (2) enforcement and (3) fisheries policies. This system, for him, should be correlated to the cost required in fisheries management and its value of harvest. Author further acknowledged that there ought to be a balance in fisheries management with cost efficiency amid multidisciplinary issues to ensure that managers are able to perform the necessary tasks necessary to have effective produce. Holsapple, C. W. & Lee-Post, A. (2010). Behavior-based analysis of knowledge dissemination channels in operations management, Omega, Elsevier, vol. 38(3-4), pages 167- 178. Authors are scholars taking serious interests on analyzing the behaviors about how knowledge is disseminated in operation management. Both contended that the significance if this discipline is vital for knowledge dissemination through journals, magazines, books, and other online sources for information that are supportive or are exploring more about the significance of operational management, which may include surveys, analyses. Though the study was quite limited by scope and resources utilized to fit the needs of the researcher, however, the examination of behaviors as explicated in the resources used was able to explicate the three metrics for rating publications for operational management studies. Researchers believed that the metric can be utilized by those who are working to determine which OM journals or books uphold substantial relevance. Galindo, G. & Batta, R. (2013). Review of recent developments in OR/MS research in disaster operations management, European Journal of Operational Research, Elsevier, vol. 230(2), pages 201-211. Researchers are scholars who have serious interests in reviewing the developments in OR/MS studies focused on disaster operation management. They affirmed that as disaster impacts to large number of populace and create serious environmental damages, the devastating effects inspire interests on scrutinizing the disaster operations management are undertaken using the studies of Nezih Altay and Walter

EHarmony Case Study Essay Example | Topics and Well Written Essays - 750 words

EHarmony Case Study - Essay Example The advent of new technologies has facilitated this change in social media and has made it a common activity. By 2005, the number of subscribers and user of social media and internet personals websites had increased with eHarmony recording over 15 million subscribers. This growth was attributed to a change in online dating perception. Currently, the social media industry has become extremely competitive and lucrative with companies employing different strategies to capture the market and increase customer base. Organizations have realized that apprehending the competitive forces and their fundamental roots discloses the causes of the industry’s present productivity (Porter, 2008). By the time online dating was gaining popularity, there had been few internet personals websites. For this reason, there was less competition in the industry. In the contemporary, competitive business environment, publicity is a significant facet of any organization. This therefore poses a great thre at to the existing business as more and more new entries are aiming the market in order to gain a share of the profits. This is therefore threatening the dominance of companies such as eHarmony an aspect that might affect even the overall returns of the company. The marketing strategy in the social media industry determines the profit potentiality of the company. For instance, Piskorski et al (2008) asserts that eHarmony centered on creating publicity through the owners who appeared in TV and radio programs including home news programs. The company focused on selling its unique features which yielded increased number of subscribers. According to Walker et al (2005), this is a competitive advantage that the company used to acquire a greater market share. In addition, eHarmony heightened its advertising campaigns in the radios and TV to capture wide audience. The contemporary social media have been characterized by fraudsters who have made people lose hope in finding serious mates in the internet personals websites. Arguably, social media sites have tried to employ a personality profile based on many questions, which discourage the not serious users from joining the site (Alex, 2010). For instance, eHarmony personality profile contains 258 questions, which portray seriousness of the subscriber. One of the major threats that online dating poses is erosion of culture. Initially, people had the chance to select his/her mate physically. This gave the person a chance to analyze the mate’s behavior and attitudes. With the current technology, this aspect has eroded. In addition young people will be exposed to early relationships an aspect that could expose them to early sex and marriages. This market therefore will lead to increased divorces and abusive marriages due to poor decision making before choosing the partner (Alex, 2010).. Increase of companies such as eHarmony would therefore reduce the time that was previously used to know your partner which is a thr eat to the new families. The company faces a great threat from ghost companies which retrieve money from the customers only to for the client to realize that the site has very few members. This mistrust by people creates a great threat to expansion of the company an aspect that hinders it to reach global standards. Another major threat that if facing companies such as eHarmony is lack of adequate resources to keep up with the increasing technological competition which makes communication easier. This

Step By Wicked Step by Anne Fine Essay Example for Free

Step By Wicked Step by Anne Fine Essay The setting for the story Step by Wicked Step is one dark stormy night when five schoolchildren on a school trip stayed in a towering mansion. They found secret tower room that was hidden behind a wall. The lights in the mansion were not working and they has to depend on the streaks of lightning and the moonlight for light. The tower room, covered in a coat of dust, had not been used for a long time. There were heavy drapes, plain dark coverlet and frame old maps. A dusty green album revealed the story of Richard Clayton Harwick’s journal entitiled† My story, Read and Weep. Following this each one of them related their own sad story of their broken homes and relationship with their family members. Time : 1)Evening- party meals organized by Stella for Claudia father thirty- seventh birthday. 2) Night- Claudia decides to make something for her stepmother when she fells sorry for her. Location 1) Her granny’s house- her father stays in her granny’s after argue with her mother 2) Stella’s house – the party meal for her fathers’ birthday and the things she does for Stella. Richard related the story of his life with his stepfather and he ran away to escape his problems. All the five children symphatised with Richard’s situation and they each has their own sad tale to tell. The setting enhances the plot of the story by providing the atmosphere for the story. The tower was dark except for flashes of lightning and later the moonlight. It gave the children the mood and courage to tell their story. The dust in the room symbolized their past which should be wiped away so they could look forward to a brighter future. Write about difficult decision made by one of the characters The novel Step by Wicked Step is about five schoolchildren who found and read Richard Clayton Harwick’s journal of his life with his stepfather and his running away from home. The five children were inspired to tell their own sad family stories of broken homes. In the story, Richard Clayton Harwick made the difficult decision of running away. Richard Clayton Harwick felt sidetracked by his father who made him promise to look after his mother and sister after his death. His father made no reference to him. He was disappointed and to make matters worse, his mother remarried. His stepfather Mr. Coldstone or the ‘black, black bat’ as Richard referred to him imposed very strict rules on Richard, to the extend that he felt his home was more of a prison. He was sent to Mordanger School where he spent ‘four long years’ and it was a place of bad memories. He was extremely unhappy in his own home, a place where he had such a good memories of his father. He was disappointed that his mother did not seem to want to make any effort to protect him from his stepfather. Richard decided to run away from home. He felt that the three of them, his stepfather, mother and Charlotte would be happier without him around. His mother would find life more pleasant, Mr Coldstone would be pleased and Charlotte would not miss him. I think this was wrong decision as his decision changed three lives for the worst. His mother died of heartbreak, his stepfather of fury while Charlotte probably of childbirth. I feel he should have stayed on and tried to get along with his stepfather for his mothers’ sake. He should have let the past go and kept the happy memories of his father instead of feeling and showing unhappiness all the time. As Charlotte told him just because life had dealt them one hard blow, there was no reason fro them to be unhappy forever. His decision to run away was not right decision as it caused too much sorrow. Write about the social issue in the story In the novel step by wicked steps, five schoolchildren read the journal of Richard Clayton Harwick which detailed his sad story of family life with a stepfather. The five schoolchildren who come from broken homes were prompted to relate their own family life story. The reader is reminded of the issue of family relationships. Richard came from a happy family unit until his father passed away and his mother married to Mr. Coldstone, somebody Richard could not get along well with. He felt that he did not belong to his family, his mother and his sister anymore. While Cahrlotte got along well with their stepfather, Richard could not and did not want to. So, he decided to run away, thus breaking off family relationship with them rather than bear the unhappiness of bad family relationship. The five schoolchildren coming from broken homes had to deal with stepparents, stepsiblings, and half siblings. Some accepted these relationships well other could not. Most of the time they pretended to be amiable for their parents’ sake. When matter came to head, some like Claudia and Pixie sorted to out their feeling with their stepmothers. They were thus able to rebuild their family relationships. Others like Callie, Robbo’s sister, preferred to run away from their problems. The common thing about them was they felt their opinions and feelings did not count with their parents. Family relationships should be built on understanding and parents should take into account children’s opinion, especially on the issue of family relationship.

Development of CT Scans for Cancer Studies

Development of CT Scans for Cancer Studies According to the statistics presented by the World Health Organization (WHO), with around 7.4 million deaths (around 13% of the total death) in 2004, cancer is the leading cause of death throughout the world (WHO, 2009). These levels are expected to rise further in future, with an estimated 12 million death in 2030 (WHO, 2009). There are more than 100 different types of cancer (Crosta, n.d.), among them the Lung cancer, stomach cancer, colorectal cancer, liver cancer and the breast cancer are the most common types. Tobacco is the most important risk factor for cancer, with nearly 1.3 million deaths per year just due to lung cancer alone (WHO, 2009). Cancer At the primary level, human body consists of large number building blocks, called the cells. Under normal circumstances, new cells are formed by the body depending on the body requirement, in order to replace the dead cells. But sometimes, under abnormal conditions, there is an exponential (uncontrolled) increase in the formation and growth of new cells. The accumulation of these extra cells forms mass or lumps of tissues, called the tumor (National Cancer Institute, 2010). Most of the cancers, in general form tumors, but there are certain exceptions, like leukemia, that do not form tumors (in leukemia or blood cancer, the cancer cells hinder the normal blood functions due to abnormal cell disintegration in the blood stream (Crosta, n.d.)). The tumors can be of two types; benign tumor and malignant tumor. The benign tumors do not propagate to other sections of the body and have restrained growth (Crosta, n.d.), whereas the malignant tumor cells have the ability to invade into the sur rounding tissues. Also the malignant tumor cells can escape from their initial location and spread to other sections of the body through blood or lymph. Only the malignant tumors are cancerous in nature. Therefore, the cancer has three distinctive properties that distinguish malignant tumors from benign tumors: Uncontrolled growth Invasive nature Metastasis (ability to spread to other sections of the body) These disorders in cells are the result of the interaction between the genetic factors and external agents (which are called carcinogens) (WHO, 2009). The carcinogens can be categorized as (WHO, 2009): Biological carcinogens, like certain bacteria, viruses or parasites. Physical carcinogens, which includes the high energy radiations (ionizing radiations). Chemical carcinogens, these include substances like tobacco smoke, arsenic (water contaminant), aflatoxin (food contaminant), asbestos etc. Another factor essential in the development of cancer is the age. According to the studies conducted by the Cancer Research UK, the risk increase predominantly with increasing age, with nearly 74% of the cases of cancer diagnosed in people aged 60 and above (Cancer Research UK, 2009). Cancer Treatment Principle In case of normal cells there is specific pattern of growth, division and death (orderly destruction of cells is called apoptosis) (Crosta, n.d.). It is known that the cancer is the result of the uncontrolled growth of cells which do not die (Crosta, n.d.), that is, the apoptosis process fails in the cancer cells. The cancer cells thus do not die and rather continue to grow, resulting in the formation of tumors. As the problem in the cancer cells lies in the DNA, therefore a possible treatment of cancer is the destruction of the DNA in cancer cells, leading to a self initiated destruction of the cells. There are various methods used for the treatment of cancer depending upon the type of cancer. The most common types of treatment are (Fayed, 2009): Surgery Chemotherapy Radiation therapy or Radiotherapy Biologic or Targeted Therapy Radiotherapy Radiotherapy, also referred to as radiation therapy, is one of the most common types of treatments used for cancer. It is the utilization of higher energy radiations like x-rays, gamma rays in order to kill cancer cells, treatment of thyroid disorder and even some blood disorders, in a particular section (effected part) of the body (Nordqvist, 2009). The high energy ionizing radiations can be produced using a number of radioactive substrates like Cobalt (60Co), Radium (228Ra), Iodine (131I), Radon (221Rn), Cesium (137Cs), Phosphorus (32P), Gold (198Au), Iridium (192Ir), and Yttrium (90Y) (Howington, 2006). The cancer cells have the ability to multiply faster than other body cells. The high energy ionizing radiations are more destructive towards the faster growing cells, and thus they damage the cancer cell more than the other body cells (Mason, 2008). These high energy radiations like gamma rays and x-rays; especially damage the DNA inside these cancer cells (or tumor cells) thereby annihilating the ability of the cells to reproduce or grow. Apart from treatment of cancer, radiation therapy is also used to shrink a tumor before being surgically removed (Mason, 2008). Depending upon the method of irradiation, the process of radiation therapy is categorized into two forms (Mason, 2008): External Radiotherapy In this method (more common), the infected part of the body (tumor) is irradiated by high energy x-rays from outside the body. Internal Radiotherapy For this method, a radioactive substance are injected (or taken orally) into the body (close to the tumor) in the form of fluids. These substances, taken up by the cancer cells, radiate the tumor through internal beam radiation (or interstitial radiation) (Mason, 2008). Radiotherapy Planning A careful planning is essentially required for radiation therapy, as over exposure can be critically dangerous to healthy tissues in the body. The ionizing radiations have side effects, therefore once the full dose of radiations is decided; the patient is given these radiations in the form of small doses in a series of therapy sessions (Cancer Research UK, 2009). Each small dose of radiation is called a fraction. The gap between sessions provides the recovery time for the body, which may depend on the type of cancer and patients health condition. The area of the body that is radiated during the treatment is called the radiotherapy field and the section inside the body that experiences the maximum exposure dose is called the target volume (Cancer Research UK, 2009). The doctors decide the marginal area around the tumor that should be radiated to encapsulate any movement of the cancer cells. In order to accurately determine the position of tumor (or target volume), body scans are done. Computed Tomography (CT) scans are done as a planning procedure, this provides vital information regarding the location of the tumor as well as the kind of treatment required by the patient (Cancer Research UK, 2009). The radiotherapy treatment planning process can be divided into 6 major steps . Computer Tomography (CT) Scan The invention of Computer Tomography (CT) scanned is credited to Sir Godfrey Hounsfield in early 1970s, for which he along with Allen Cormack, was awarded the Nobel Prize in 1979 (Smith, n.d.). A CT scanner, also known as the Computed Axial Tomography (CAT) scanner uses X-rays to produce cross sectional images (or slices) of the body like a slice in a loaf of bread (FDA, 2010). The word tomography suggests the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram) (Nordqvist, 2009). These cross-sectional slides render an accurate picture of the size and location of the tumor along with the position of major organs in the body (Cancer Research UK, 2009). This would be essentially useful during the radiotherapy process, where these can be used to lower the dose of radiations on the organs. It is known that in case of radiation therapy treatment, the doses are given in fractions over a certain period of time (to prevent major side effects), which may vary from few weeks to months. Thus, before each fraction of radiation dose, computed tomography (CT) scan of the patients is done to determine the exact location of the tumor or cancer cells. So in case the full dose has been divided into 30 fractions, then the patient has to undergo 30 CT scans, each before a fractional therapy. The machine used for the radiation therapy planning is known as the simulator (Cancer Research UK, 2009). The simulator identifies the position of the tumor and marks the position of radiation on the body with the help of light rays. The radiographer uses ink markers on the body before the actual radiotherapy is begun. These linear ink marks are used by the radiographer for positioning the machine for radiotherapy (Cancer Research UK, 2009). Simulators take the pictures (CT scans) in the form of X-rays, which locates the accurate tumor position for the radiographer to carry out the treatment. During a CT scan, it is essential that the person remains completely still so that the measurements are accurate. In order to insure the correct position supports like neck rest, chest board or arm pole are used (Cancer Research UK, 2009). In case of children it is ensured by giving proper sedatives. Sometimes, under critical condition, extra measures are taken in order to prevent essential organs from being radiated during the therapy. These measures include injecting fluids or dyes which mark the position of vital human organs in the CT scan (Cancer Research UK, 2009). These markers may be given orally, through injections or rectally depending upon the requirement. Using this vital information from the CT scans, a treatment plan for radiation therapy is prepared. This plan indicates the position and direction of the radiations during the therapy, so as to minimize the exposure of healthy cells and organs. The scans generated by a CT scanner are in the form of 2 dimensional (2-D) slides, but by the used of digital geometry processing they can be used to generate a 3 dimensional (3-D) images of the body (Nordqvist, 2009). This can be achieved by integrating all the slides (along the same axis) together using a computer system. The CT scan can be understood as a technically advanced format of X-rays machines. The x-rays images are produced by the projection of a broad beam of x-rays on a film after passing through the body (Medindia, 2010). It provides a 2-dimentional projection of the body, where much of the information is lost. In case of CT scan, a thin beam of x-rays is absorbed by the detector after passing though the patients body (Medindia, 2010). Like the x-ray process, the CT scanning is a painless process for the patients but has been known to be accompanied with some side effects. These side effects may vary from the patient to patient depending upon the amount of radiation dose and health of the patient. The detailed discussion on the health effects of CT scanning has been discussed in the later sections of the project. Theory In order to understand the working of a computed tomography (CT) scanner it is essential to understand the properties of ionizing radiations (X-rays) used in the scanning process. The electromagnetic radiations are the arrangement of electric-field and magnetic-field vectors perpendicular to each other and also perpendicular to the propagation direction of the wave (Resnick et al., 2009). These Electromagnetic radiations have penetrating powers, which are directly dependent on the energy (or frequency) of these radiations. So that radiations with higher frequency have higher penetration powers. Therefore, on the basic the energy, the electromagnetic radiations are categorized as Non-ionizing radiations and Ionizing radiations. Non-Ionizing radiations refer to the electromagnetic radiations which have energy lower than that required for an atomic ionization (MIT, 2001). The non-ionizing radiations include radio waves, micro waves, visible light etc. These radiations have lower penetration powers. Alternatively the Ionizing radiations are the high frequency radiations which have enough energy to knockout an electron from an atom and thus causing ionization (MIT, 2001). The Gamma rays and X-rays are the common type of ionizing radiations. Even the alpha particles and beta particles emitted in a nuclear reaction are ionizing radiations (MIT, 2001). Due to the higher energy they have higher penetration power than the non-ionizing radiations. Principle of CT Scanning The most important section of a Computed Tomography (CT) scanning is the interaction of the ionizing X-ray radiations with the living tissues in the body. When the ionizing radiations (X-rays) interact with the living tissues in the body, they break up atoms and molecules from the living tissues and disrupt chemical reactions within the body (Zamanian Hardiman, 2005). The intensity of absorption of the x-ray radiations by the body varies depending upon the tissue coming in interaction. Different body tissues have different absorption power, where some are permeable to x-rays others are impermeable (Medindia, 2010). It is due to this difference in the absorption ability of different sections of the body, which results in the generation of a graded pattern in the scans. High density tissues like the bones appear white in the scan while the soft tissues (like brain and kidneys) appear dark. The cavities (like the lungs) are seen as black sections in the scan (Medindia, 2010). Therefore, this gradation in the pattern can be used as method to distinguish different body organs depending upon their absorption capacity. This forms the basic principle behind the working of an X-ray scanning. Radon (1917) was the first to develop the principles of computed tomography (CT) mathematically (Bushberg et al., 2002). According to Radon, with the help of infinite number of projections through an object, it could be possible to produce an image of an unknown object. In case of film imaging (as in conventional X-rays), a two-dimensional (2-D) projection of the body is generated on the film. Due to this, details in the dimension of the body along the direction parallel to the x-ray beam are lost. In order to overcome this drawback (only up to a certain level) projections can be taken along two directions; posteroanterior (PA) projection and lateral projection (Bushberg et al., 2002) (as shown in Figure 4). Increasing the number of scans improves the amount of information but in critical and complex cases where much more details are required. For these critical cases, CT scan is done. The CT scan provides the tomographical image, which is the picture of patients body in the sections or slabs. The thickness of these uniform slabs may vary from 1 millimeter to 10 millimeter (Bushberg et al., 2002), according to the program, depending upon the requirement. Each CT image consists of an array of large number of pixels forming a two dimensional (2-D) image, which corresponds to the same number of three dimensional thin rectangular slabs called the voxel. The voxels are the volume element whereas the pixels are the picture element (Bushberg et al., 2002). Every ray from the X-ray source passes (transmits) through the patient before the transmission measurement is done by the detector. Intensity of the un-attenuated x-ray radiation emitted by the source is Io whereas the intensity of the attenuated radiation after transmitting through the patient is given as It. The intensities Io and It are related by the equation (Bushberg et al., 2002):   Ã‚  Ã‚  Ã‚  Ã‚  It=Ioe-ÃŽ ¼t   Ã‚  Where;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚ µ is the total linear attenuation coefficient of the tissue (Smith, n.d.).   Ã‚  Ã‚  Ã‚  Ã‚  t is the distance travelled by the radiation in the tissue i.e. the tissue thickness. The coefficient  µ is dependent on the atomic number and electron density of the tissues (Smith, n.d.). Higher the atomic number and electron density of the tissues, higher would be the attenuation coefficient (Smith, n.d.). This form the basic principle of CT scanning, that different tissues have different level of attenuation properties depending upon their atomic number and electron density. For every measurement, the overall attenuation coefficient is calculated using the above equation. During a complete 360o ­ scan, various transmission measurements for the intensity of X-ray photon are done. Using these intensity measurements specific attenuation values are allotted to every voxel (volume element). These attenuation numbers are directly proportional to the linear attenuation coefficient. The average of these attenuation values is called the CT number (Smith, n.d.). These values can be arranged on a linear scale, the units of which are called the Hounsfield units (HU). The scale for modern CT scanners varies from approximately -1,000 to 3,000 HU. The attenuation scale is based on binary system and therefore the exact values range from -1,024 to +3,071, with a total of 4,096 (or 212) attenuation numbers. Here, the lower represent the black section while the higher values represent the white section of the CT image. On this scale the attenuation value of water is zero HU and that of air is -1,000 HU (Smith, n.d.). Both of these values act as the reference points. Construction of a CT scanner CT scanner is a complex machine, but the basic structure is simple. A common CT scanner has been shown in Figure 2. Two most important parts of a CT scanner are the X-ray source and detector. The source and detector are placed in a circular structure, which has a shape similar to a doughnut. This doughnut shaped circular opening is called the gantry (RadiologyInfo, 2009), with an inner (opening) diameter varying from 60 cms to 70 cms. The X-ray source and detector are placed exactly (diagonally) opposite each other, so that the radiations emitted by the source pass through the body and the transmitted radiations are measured by the detector. The x-ray source and detector system in the gantry is motorized to rotate around the patient for measurements in different projection angles. The rational speed of the system is adjusted according to the detectors ability to measure and convert the x-ray beam into electronic signal. Cobalt (60Co) is generally used as the source of x-rays in the CT scanners. The detector used in CT scanner consists of an array of detectors in a slightly curved shape (like a banana). This curved shape is especially useful in fan-shaped beam projects. Two types of detectors are generally utilized in the CT scans; solid state or scintillation detector and Xenon gas detector (Reddinger, 1997). But the solid state detectors with scintillators like Cadmium Tungstate (CdWO4), yttrium, gadolinium ceramics etc are commonly used (Bushberg et al., 2002). The principle of the scintillation detector is that, when it is struck by a x-ray photon, it produces light. This light signal is then transformed to electrical signal with the help of photodiode. The Depending upon their structure, the detectors are categorized into two categories; single detector array and multiple detector array. Another essential part of a CT scanner is the motorized examination table. The table is controlled to move in and out of the gantry during the scanning process. As the position of the x-ray source and detector is fixed therefore the section being scanned is controlled by the movement of the examination table. For a better scan it is necessary that the patient remains completely still. To insure this table is equipped with neck rest, chest board and arm pole (Cancer Research UK, 2009). The detector measures the intensity of the radiation and converts them into electrical signals. These raw signals are analyzed and manipulated by the computer to convert them into images which can be understood by the radiologists and the technicians. Multiple computers are required in a CT scanner. The main computer that controls the operation of the entire system is called the host computer (Imaginis, n.d.). The computers and controls are located in a room adjoining the scanning room. This prevents the technicians and the radiographer from exposure to x-rays. Scanning Procedure in a CT scanner Initially the patient is positioned on the examination (or scanning) table in a flat upright posture (face towards the roof). In order to insure the correct and stationary position, straps and pillows may be used along the body. Once the patient is correctly positioned on the scanning table, the motorized table moves the patient into the circular opening of the CT scanner (FDA, 2010), which the x-ray radiations are projected on the patient from the scanning. For a particular position of the x-ray source and detector, the rays from the source pass through a region called the projection or view. There are two different types of projection geometries that are used in CT scanning; parallel beam geometry and fan beam geometry. In the parallel beam geometry, the rays projected on the patient are parallel to each other whereas in fan beam geometry, the rays diverge from the source in the shape of a fan (Bushberg et al., 2002) as shown in Figure 7. The fan beam projections are the most commonly in used x-ray projections in the CT scanners. The X-ray tube is attached with a collimator which controls the thickness of the fan beam. This thickness (of the fan beam projection) determines the width of the tissue slide in the scanning process. It is through the collimator that the slice thickness is varied between 1mm to 10mm (Smith, n.d.). The x-ray source and detector rotate around the patient (for imaging) in a circular motion such that they always remain exactly (diametrically) opposite to each other (as shown in Figure 7). During the rotation the source keeps emitting x-rays which are attenuated after passing through the patient. For a single projection (or slice), the x-ray source and detector make a complete 360o rotation around the patient. During the rotation the detector takes a large number of snapshots of the absorbed X-ray beam at different projection angles. A single image may involve approximately 800 rays and there can be up to 1,000 different projection angles (Bushberg et al., 2002). Therefore for a single projection (one slice), the detector does nearly 800,000 transmission measurements (Bushberg et al., 2002). The scanning of a single projection generally takes around 1 sec (for axial CT scanners) (FDA, 2010). Once all the transmission measurements (complete 360o) for a projection (or slice) are completed, the motorized table moves along the axis of the gantry so that the next slice of tissues forms the projection view. The process is continued till the complete required section of the body has been scanned. In the traditional CT scanners, the table moved on to the next projection (slice) only when the scanning of the previous was completed. Such conventional type of scanning is called the axial scanning. But in modern CT scanners, called the helical or spiral CT scanners, the rotation of the x-ray source and detector is accompanied with the uniform movement of the examination table, thus producing a helical projection. The helical CT scanning has been shown in Figure 9. These modern helical CT scanners are much faster than the traditional scanners due to continuous scanning process. They have been reported to take nearly half the time for scanning as compared to the traditional CT scanner s. In order to analyze and study the cardiac structure which is under constant motion, even helical CT is ineffective. For such applications a special CT scanner with an exposure time of 50ms and a maximum exposure rate of 17 images per second are used (Smith, n.d.). These scanners, called the cine CT, freeze the cardiac motion due to extremely low exposure time resulting in a sharp image (Smith, n.d.). These scanners use electron beam to generate x-rays, thus are also known as Electron Beam Computed Tomography (EBCT). In the CT scanning process large volume of data and operations are required to be processed, which is achieved with the help of multiple computers. The detector converts the intensity measurements of the attenuated x-rays in to electrical signals. The main computer, called the hub computer processes these signals and converts them into an image. These images can then be analyzed for radiotherapy planning. Result Computed Tomography (CT) has become an invaluable medical tool. It provides detailed 3-D images of various sections of the body like pelvis, soft tissues, lungs brain, blood vessels and bones (Nordqvist, 2009). Generally, CT scanning is the preferred method of diagnosing different types of cancers like liver, lungs and pancreatic cancers (Nordqvist, 2009). The tomographic images produced by the CT scan provide specific location and size of the tumor along with the details of affected tissues in the proximity of the tumor. This is especially advantageous in planning, guiding, and monitoring therapies like radiotherapy (FDA, 2010). CT scanning has various benefits over other traditional diagnostic techniques; some of the benefits are (RadiologyInfo, 2009): It is non-invasive, painless and extremely accurate. A major advantage is the ability to identify and distinguish bones, soft tissues and blood vessels in the same image. It also provides real time images which cannot be done in conventional X-rays. This technique is fast and simple; and is extensively used to locate internal injuries after accidents. It is less sensitive towards patient movement as compared to MRI. CT scanning can be used on patients with medical implants unlike the MRI. For an effective radiation therapy treatment, it is necessary that only the tumor is irradiated while minimum damage occurs to the surrounding health (normal) body tissues (Badcock, 1982). This is achieved with the help of CT imaging technique. In a study by Badcock (1982), 186 patients with various malignancies were studied and it was found that in nearly 39% of the treatment cases CT scanning was valuable in the assessment of the radiationdose calculation (Badcock, 1982). According to his study, CT scanner resulted in an alternation in target dose by more than 5%, (as compared to the traditional methods) in 27% of the patients (Badcock, 1982). The result has been shown in the table below. The mean alternation was 6.5% of the target dose and usually resulted in reduction of dose per fraction by factors upto 35% (Badcock, 1982). Even with these advantages, the adverse affect of the ionizing x-ray radiations cannot be neglected. Various experiments and researches have consolidated the fact that ionizing radiations like x-rays, gamma rays etc have adverse effect on living tissues. Zamanian Hardiman (2005) have explained that when high energy ionizing radiations interact with living tissues they strip-off atoms and molecules from them. This disrupts the chemical reaction within the body and failure in organ functioning (Zamanian Hardiman, 2005). The adverse effects of ionizing radiations were seen shortly after its discovery in 1890s, with a scientist involved in the study of radioactivity were reported with skin cancer in 1902. But is was not until 1944, that the role of radiations in causing leukemia in human was first documented, mainly in radiologists and physicists (Zamanian Hardiman, 2005). In recent years the use of x-rays has extensviely increased in medical field for diagonostic and treatment application. According to the U.S. Environmental Protection Agency, X-ray deveices are the largest source of man-made radiation exposure (US_EPA, 2007). According to NCRP Report No. 160 (2006), the average annual effective dose per individual in the US population, from all sources has increase from 1.7mSv in 1980s to 6.2mSv in 2006. This increase is mainly attributed to the striking growth of high dose medical imaging procedures that utilize x-rays and radionuclides (NCRP, 2008). Such man-made devices include X-ray machines, CT scans etc. CT scans, especially result in high dose x-ray exposure, with nealy 100 times the exposure dose as compared to standard x-ray equipments (Coach, 2008). Some of the major risks associated with CT scanning are: It is well documented that ionizing radiaitons like x-rays have the ability to cause cancer on exposure. Therefore, the CT dose in radiotherapy increase the probabilty of cancer in the future. Even though only 4% of the total x-ray examinations are CT scans, they account for more than 20% of the radiation dose to the population by medical x-rays (King Saud University, 2004). In general, the effective dose in a CT scan procedure ranges from 2 mSv to 10mSv, which is nearly equivalent to the amount of radiation that a person receive from the background exposures in three to five years (RadiologyInfo, 2009). A CT scan during preganacy make cause serious illness or even birth defects in the unborn baby (FDA, 2010). Children are more sensitive and vulnerable to x-ray exposures than the adults, therefore their CT scanning should be done only under extremely essential and necessary conditions. Women have higher risk of developing cancer in the lifetime, as compared to men under same levels of exposure (FDA, 2009). In some rare situation of high-dose prolonged radiation exposure, the x-rays can cause adverse effects like skin reddening (erythema), skin tissue injury, hair loss, cataracts etc (FDA, 2010). In a study, Sawyer et al (2009) estimated the effective dose resulting from a cone beam CT scanning for planning of radiation therapy using thermoluminescent dosemeters (TLDs) for organ dose and using International Commission on Radiological Protection (ICRP) 60 tissue weighing factor (Sawyer et al., 2009). The results obtained for effective dose from TLD measurements and ICRP 60 weighting factor, for breast, pelvis and head simulation have been shown in the table below. The scanning process results in the exposure of the normal tissues outside the treatment volume (Waddington McKenzie, 2004). It is thus important to analyze the effect that the irradiation caused by the CT scanning process has on the patients body. In a study, Waddington McKenzie (2004) analyzed the propability of developing cancer from the irradiations caused by the extended field portal imaging techniques, the results of which are given in the table below (Waddington McKenzie, 2004). In order to illustrate a real life situation, the calulations in the study were done for an average man with a height of 170 cms and weight of 70 kgs (Waddington McKenzie, 2004). Therefore, these values may change depending upon the height, weight and tumor size of the patient. Discussion Various studies have been done to statistically evaluate the effect of the ionizing radiations on the human health. These risks have severely amplified due to the rapid increase in the number of CT scans for diagnostic applications. CT scans form nearly 5% of all procedures used in diagnostic radiology in the developed countries (Wrixon et al., 2004). In U.S., nearly 70 million CT scans were done in 2007 as compared to just 3 million done in 1980 (Steenhuysen, 2009), this includes more than 4 million children in 2006 (Brenner Hall, 2007). Thus, according to the NCRP Report no. 160, the average radiation dose per person has increased from 3.6 mSv in early 1980s to 6.2 mSv in 2006 (NCRP, 2008). Steenhuysen (2009) has reported that the radiations from CT scans done in 2007 will cause 29,000 cancers and kill nearly 15,000 people in America (Steenhuysen, 2009). These stats explain the level of exposure caused by the CT scans. According to estimates by Amy Berrington de Gonzalez of the National Cancer Institute, Development of CT Scans for Cancer Studies Development of CT Scans for Cancer Studies According to the statistics presented by the World Health Organization (WHO), with around 7.4 million deaths (around 13% of the total death) in 2004, cancer is the leading cause of death throughout the world (WHO, 2009). These levels are expected to rise further in future, with an estimated 12 million death in 2030 (WHO, 2009). There are more than 100 different types of cancer (Crosta, n.d.), among them the Lung cancer, stomach cancer, colorectal cancer, liver cancer and the breast cancer are the most common types. Tobacco is the most important risk factor for cancer, with nearly 1.3 million deaths per year just due to lung cancer alone (WHO, 2009). Cancer At the primary level, human body consists of large number building blocks, called the cells. Under normal circumstances, new cells are formed by the body depending on the body requirement, in order to replace the dead cells. But sometimes, under abnormal conditions, there is an exponential (uncontrolled) increase in the formation and growth of new cells. The accumulation of these extra cells forms mass or lumps of tissues, called the tumor (National Cancer Institute, 2010). Most of the cancers, in general form tumors, but there are certain exceptions, like leukemia, that do not form tumors (in leukemia or blood cancer, the cancer cells hinder the normal blood functions due to abnormal cell disintegration in the blood stream (Crosta, n.d.)). The tumors can be of two types; benign tumor and malignant tumor. The benign tumors do not propagate to other sections of the body and have restrained growth (Crosta, n.d.), whereas the malignant tumor cells have the ability to invade into the sur rounding tissues. Also the malignant tumor cells can escape from their initial location and spread to other sections of the body through blood or lymph. Only the malignant tumors are cancerous in nature. Therefore, the cancer has three distinctive properties that distinguish malignant tumors from benign tumors: Uncontrolled growth Invasive nature Metastasis (ability to spread to other sections of the body) These disorders in cells are the result of the interaction between the genetic factors and external agents (which are called carcinogens) (WHO, 2009). The carcinogens can be categorized as (WHO, 2009): Biological carcinogens, like certain bacteria, viruses or parasites. Physical carcinogens, which includes the high energy radiations (ionizing radiations). Chemical carcinogens, these include substances like tobacco smoke, arsenic (water contaminant), aflatoxin (food contaminant), asbestos etc. Another factor essential in the development of cancer is the age. According to the studies conducted by the Cancer Research UK, the risk increase predominantly with increasing age, with nearly 74% of the cases of cancer diagnosed in people aged 60 and above (Cancer Research UK, 2009). Cancer Treatment Principle In case of normal cells there is specific pattern of growth, division and death (orderly destruction of cells is called apoptosis) (Crosta, n.d.). It is known that the cancer is the result of the uncontrolled growth of cells which do not die (Crosta, n.d.), that is, the apoptosis process fails in the cancer cells. The cancer cells thus do not die and rather continue to grow, resulting in the formation of tumors. As the problem in the cancer cells lies in the DNA, therefore a possible treatment of cancer is the destruction of the DNA in cancer cells, leading to a self initiated destruction of the cells. There are various methods used for the treatment of cancer depending upon the type of cancer. The most common types of treatment are (Fayed, 2009): Surgery Chemotherapy Radiation therapy or Radiotherapy Biologic or Targeted Therapy Radiotherapy Radiotherapy, also referred to as radiation therapy, is one of the most common types of treatments used for cancer. It is the utilization of higher energy radiations like x-rays, gamma rays in order to kill cancer cells, treatment of thyroid disorder and even some blood disorders, in a particular section (effected part) of the body (Nordqvist, 2009). The high energy ionizing radiations can be produced using a number of radioactive substrates like Cobalt (60Co), Radium (228Ra), Iodine (131I), Radon (221Rn), Cesium (137Cs), Phosphorus (32P), Gold (198Au), Iridium (192Ir), and Yttrium (90Y) (Howington, 2006). The cancer cells have the ability to multiply faster than other body cells. The high energy ionizing radiations are more destructive towards the faster growing cells, and thus they damage the cancer cell more than the other body cells (Mason, 2008). These high energy radiations like gamma rays and x-rays; especially damage the DNA inside these cancer cells (or tumor cells) thereby annihilating the ability of the cells to reproduce or grow. Apart from treatment of cancer, radiation therapy is also used to shrink a tumor before being surgically removed (Mason, 2008). Depending upon the method of irradiation, the process of radiation therapy is categorized into two forms (Mason, 2008): External Radiotherapy In this method (more common), the infected part of the body (tumor) is irradiated by high energy x-rays from outside the body. Internal Radiotherapy For this method, a radioactive substance are injected (or taken orally) into the body (close to the tumor) in the form of fluids. These substances, taken up by the cancer cells, radiate the tumor through internal beam radiation (or interstitial radiation) (Mason, 2008). Radiotherapy Planning A careful planning is essentially required for radiation therapy, as over exposure can be critically dangerous to healthy tissues in the body. The ionizing radiations have side effects, therefore once the full dose of radiations is decided; the patient is given these radiations in the form of small doses in a series of therapy sessions (Cancer Research UK, 2009). Each small dose of radiation is called a fraction. The gap between sessions provides the recovery time for the body, which may depend on the type of cancer and patients health condition. The area of the body that is radiated during the treatment is called the radiotherapy field and the section inside the body that experiences the maximum exposure dose is called the target volume (Cancer Research UK, 2009). The doctors decide the marginal area around the tumor that should be radiated to encapsulate any movement of the cancer cells. In order to accurately determine the position of tumor (or target volume), body scans are done. Computed Tomography (CT) scans are done as a planning procedure, this provides vital information regarding the location of the tumor as well as the kind of treatment required by the patient (Cancer Research UK, 2009). The radiotherapy treatment planning process can be divided into 6 major steps . Computer Tomography (CT) Scan The invention of Computer Tomography (CT) scanned is credited to Sir Godfrey Hounsfield in early 1970s, for which he along with Allen Cormack, was awarded the Nobel Prize in 1979 (Smith, n.d.). A CT scanner, also known as the Computed Axial Tomography (CAT) scanner uses X-rays to produce cross sectional images (or slices) of the body like a slice in a loaf of bread (FDA, 2010). The word tomography suggests the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram) (Nordqvist, 2009). These cross-sectional slides render an accurate picture of the size and location of the tumor along with the position of major organs in the body (Cancer Research UK, 2009). This would be essentially useful during the radiotherapy process, where these can be used to lower the dose of radiations on the organs. It is known that in case of radiation therapy treatment, the doses are given in fractions over a certain period of time (to prevent major side effects), which may vary from few weeks to months. Thus, before each fraction of radiation dose, computed tomography (CT) scan of the patients is done to determine the exact location of the tumor or cancer cells. So in case the full dose has been divided into 30 fractions, then the patient has to undergo 30 CT scans, each before a fractional therapy. The machine used for the radiation therapy planning is known as the simulator (Cancer Research UK, 2009). The simulator identifies the position of the tumor and marks the position of radiation on the body with the help of light rays. The radiographer uses ink markers on the body before the actual radiotherapy is begun. These linear ink marks are used by the radiographer for positioning the machine for radiotherapy (Cancer Research UK, 2009). Simulators take the pictures (CT scans) in the form of X-rays, which locates the accurate tumor position for the radiographer to carry out the treatment. During a CT scan, it is essential that the person remains completely still so that the measurements are accurate. In order to insure the correct position supports like neck rest, chest board or arm pole are used (Cancer Research UK, 2009). In case of children it is ensured by giving proper sedatives. Sometimes, under critical condition, extra measures are taken in order to prevent essential organs from being radiated during the therapy. These measures include injecting fluids or dyes which mark the position of vital human organs in the CT scan (Cancer Research UK, 2009). These markers may be given orally, through injections or rectally depending upon the requirement. Using this vital information from the CT scans, a treatment plan for radiation therapy is prepared. This plan indicates the position and direction of the radiations during the therapy, so as to minimize the exposure of healthy cells and organs. The scans generated by a CT scanner are in the form of 2 dimensional (2-D) slides, but by the used of digital geometry processing they can be used to generate a 3 dimensional (3-D) images of the body (Nordqvist, 2009). This can be achieved by integrating all the slides (along the same axis) together using a computer system. The CT scan can be understood as a technically advanced format of X-rays machines. The x-rays images are produced by the projection of a broad beam of x-rays on a film after passing through the body (Medindia, 2010). It provides a 2-dimentional projection of the body, where much of the information is lost. In case of CT scan, a thin beam of x-rays is absorbed by the detector after passing though the patients body (Medindia, 2010). Like the x-ray process, the CT scanning is a painless process for the patients but has been known to be accompanied with some side effects. These side effects may vary from the patient to patient depending upon the amount of radiation dose and health of the patient. The detailed discussion on the health effects of CT scanning has been discussed in the later sections of the project. Theory In order to understand the working of a computed tomography (CT) scanner it is essential to understand the properties of ionizing radiations (X-rays) used in the scanning process. The electromagnetic radiations are the arrangement of electric-field and magnetic-field vectors perpendicular to each other and also perpendicular to the propagation direction of the wave (Resnick et al., 2009). These Electromagnetic radiations have penetrating powers, which are directly dependent on the energy (or frequency) of these radiations. So that radiations with higher frequency have higher penetration powers. Therefore, on the basic the energy, the electromagnetic radiations are categorized as Non-ionizing radiations and Ionizing radiations. Non-Ionizing radiations refer to the electromagnetic radiations which have energy lower than that required for an atomic ionization (MIT, 2001). The non-ionizing radiations include radio waves, micro waves, visible light etc. These radiations have lower penetration powers. Alternatively the Ionizing radiations are the high frequency radiations which have enough energy to knockout an electron from an atom and thus causing ionization (MIT, 2001). The Gamma rays and X-rays are the common type of ionizing radiations. Even the alpha particles and beta particles emitted in a nuclear reaction are ionizing radiations (MIT, 2001). Due to the higher energy they have higher penetration power than the non-ionizing radiations. Principle of CT Scanning The most important section of a Computed Tomography (CT) scanning is the interaction of the ionizing X-ray radiations with the living tissues in the body. When the ionizing radiations (X-rays) interact with the living tissues in the body, they break up atoms and molecules from the living tissues and disrupt chemical reactions within the body (Zamanian Hardiman, 2005). The intensity of absorption of the x-ray radiations by the body varies depending upon the tissue coming in interaction. Different body tissues have different absorption power, where some are permeable to x-rays others are impermeable (Medindia, 2010). It is due to this difference in the absorption ability of different sections of the body, which results in the generation of a graded pattern in the scans. High density tissues like the bones appear white in the scan while the soft tissues (like brain and kidneys) appear dark. The cavities (like the lungs) are seen as black sections in the scan (Medindia, 2010). Therefore, this gradation in the pattern can be used as method to distinguish different body organs depending upon their absorption capacity. This forms the basic principle behind the working of an X-ray scanning. Radon (1917) was the first to develop the principles of computed tomography (CT) mathematically (Bushberg et al., 2002). According to Radon, with the help of infinite number of projections through an object, it could be possible to produce an image of an unknown object. In case of film imaging (as in conventional X-rays), a two-dimensional (2-D) projection of the body is generated on the film. Due to this, details in the dimension of the body along the direction parallel to the x-ray beam are lost. In order to overcome this drawback (only up to a certain level) projections can be taken along two directions; posteroanterior (PA) projection and lateral projection (Bushberg et al., 2002) (as shown in Figure 4). Increasing the number of scans improves the amount of information but in critical and complex cases where much more details are required. For these critical cases, CT scan is done. The CT scan provides the tomographical image, which is the picture of patients body in the sections or slabs. The thickness of these uniform slabs may vary from 1 millimeter to 10 millimeter (Bushberg et al., 2002), according to the program, depending upon the requirement. Each CT image consists of an array of large number of pixels forming a two dimensional (2-D) image, which corresponds to the same number of three dimensional thin rectangular slabs called the voxel. The voxels are the volume element whereas the pixels are the picture element (Bushberg et al., 2002). Every ray from the X-ray source passes (transmits) through the patient before the transmission measurement is done by the detector. Intensity of the un-attenuated x-ray radiation emitted by the source is Io whereas the intensity of the attenuated radiation after transmitting through the patient is given as It. The intensities Io and It are related by the equation (Bushberg et al., 2002):   Ã‚  Ã‚  Ã‚  Ã‚  It=Ioe-ÃŽ ¼t   Ã‚  Where;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚ µ is the total linear attenuation coefficient of the tissue (Smith, n.d.).   Ã‚  Ã‚  Ã‚  Ã‚  t is the distance travelled by the radiation in the tissue i.e. the tissue thickness. The coefficient  µ is dependent on the atomic number and electron density of the tissues (Smith, n.d.). Higher the atomic number and electron density of the tissues, higher would be the attenuation coefficient (Smith, n.d.). This form the basic principle of CT scanning, that different tissues have different level of attenuation properties depending upon their atomic number and electron density. For every measurement, the overall attenuation coefficient is calculated using the above equation. During a complete 360o ­ scan, various transmission measurements for the intensity of X-ray photon are done. Using these intensity measurements specific attenuation values are allotted to every voxel (volume element). These attenuation numbers are directly proportional to the linear attenuation coefficient. The average of these attenuation values is called the CT number (Smith, n.d.). These values can be arranged on a linear scale, the units of which are called the Hounsfield units (HU). The scale for modern CT scanners varies from approximately -1,000 to 3,000 HU. The attenuation scale is based on binary system and therefore the exact values range from -1,024 to +3,071, with a total of 4,096 (or 212) attenuation numbers. Here, the lower represent the black section while the higher values represent the white section of the CT image. On this scale the attenuation value of water is zero HU and that of air is -1,000 HU (Smith, n.d.). Both of these values act as the reference points. Construction of a CT scanner CT scanner is a complex machine, but the basic structure is simple. A common CT scanner has been shown in Figure 2. Two most important parts of a CT scanner are the X-ray source and detector. The source and detector are placed in a circular structure, which has a shape similar to a doughnut. This doughnut shaped circular opening is called the gantry (RadiologyInfo, 2009), with an inner (opening) diameter varying from 60 cms to 70 cms. The X-ray source and detector are placed exactly (diagonally) opposite each other, so that the radiations emitted by the source pass through the body and the transmitted radiations are measured by the detector. The x-ray source and detector system in the gantry is motorized to rotate around the patient for measurements in different projection angles. The rational speed of the system is adjusted according to the detectors ability to measure and convert the x-ray beam into electronic signal. Cobalt (60Co) is generally used as the source of x-rays in the CT scanners. The detector used in CT scanner consists of an array of detectors in a slightly curved shape (like a banana). This curved shape is especially useful in fan-shaped beam projects. Two types of detectors are generally utilized in the CT scans; solid state or scintillation detector and Xenon gas detector (Reddinger, 1997). But the solid state detectors with scintillators like Cadmium Tungstate (CdWO4), yttrium, gadolinium ceramics etc are commonly used (Bushberg et al., 2002). The principle of the scintillation detector is that, when it is struck by a x-ray photon, it produces light. This light signal is then transformed to electrical signal with the help of photodiode. The Depending upon their structure, the detectors are categorized into two categories; single detector array and multiple detector array. Another essential part of a CT scanner is the motorized examination table. The table is controlled to move in and out of the gantry during the scanning process. As the position of the x-ray source and detector is fixed therefore the section being scanned is controlled by the movement of the examination table. For a better scan it is necessary that the patient remains completely still. To insure this table is equipped with neck rest, chest board and arm pole (Cancer Research UK, 2009). The detector measures the intensity of the radiation and converts them into electrical signals. These raw signals are analyzed and manipulated by the computer to convert them into images which can be understood by the radiologists and the technicians. Multiple computers are required in a CT scanner. The main computer that controls the operation of the entire system is called the host computer (Imaginis, n.d.). The computers and controls are located in a room adjoining the scanning room. This prevents the technicians and the radiographer from exposure to x-rays. Scanning Procedure in a CT scanner Initially the patient is positioned on the examination (or scanning) table in a flat upright posture (face towards the roof). In order to insure the correct and stationary position, straps and pillows may be used along the body. Once the patient is correctly positioned on the scanning table, the motorized table moves the patient into the circular opening of the CT scanner (FDA, 2010), which the x-ray radiations are projected on the patient from the scanning. For a particular position of the x-ray source and detector, the rays from the source pass through a region called the projection or view. There are two different types of projection geometries that are used in CT scanning; parallel beam geometry and fan beam geometry. In the parallel beam geometry, the rays projected on the patient are parallel to each other whereas in fan beam geometry, the rays diverge from the source in the shape of a fan (Bushberg et al., 2002) as shown in Figure 7. The fan beam projections are the most commonly in used x-ray projections in the CT scanners. The X-ray tube is attached with a collimator which controls the thickness of the fan beam. This thickness (of the fan beam projection) determines the width of the tissue slide in the scanning process. It is through the collimator that the slice thickness is varied between 1mm to 10mm (Smith, n.d.). The x-ray source and detector rotate around the patient (for imaging) in a circular motion such that they always remain exactly (diametrically) opposite to each other (as shown in Figure 7). During the rotation the source keeps emitting x-rays which are attenuated after passing through the patient. For a single projection (or slice), the x-ray source and detector make a complete 360o rotation around the patient. During the rotation the detector takes a large number of snapshots of the absorbed X-ray beam at different projection angles. A single image may involve approximately 800 rays and there can be up to 1,000 different projection angles (Bushberg et al., 2002). Therefore for a single projection (one slice), the detector does nearly 800,000 transmission measurements (Bushberg et al., 2002). The scanning of a single projection generally takes around 1 sec (for axial CT scanners) (FDA, 2010). Once all the transmission measurements (complete 360o) for a projection (or slice) are completed, the motorized table moves along the axis of the gantry so that the next slice of tissues forms the projection view. The process is continued till the complete required section of the body has been scanned. In the traditional CT scanners, the table moved on to the next projection (slice) only when the scanning of the previous was completed. Such conventional type of scanning is called the axial scanning. But in modern CT scanners, called the helical or spiral CT scanners, the rotation of the x-ray source and detector is accompanied with the uniform movement of the examination table, thus producing a helical projection. The helical CT scanning has been shown in Figure 9. These modern helical CT scanners are much faster than the traditional scanners due to continuous scanning process. They have been reported to take nearly half the time for scanning as compared to the traditional CT scanner s. In order to analyze and study the cardiac structure which is under constant motion, even helical CT is ineffective. For such applications a special CT scanner with an exposure time of 50ms and a maximum exposure rate of 17 images per second are used (Smith, n.d.). These scanners, called the cine CT, freeze the cardiac motion due to extremely low exposure time resulting in a sharp image (Smith, n.d.). These scanners use electron beam to generate x-rays, thus are also known as Electron Beam Computed Tomography (EBCT). In the CT scanning process large volume of data and operations are required to be processed, which is achieved with the help of multiple computers. The detector converts the intensity measurements of the attenuated x-rays in to electrical signals. The main computer, called the hub computer processes these signals and converts them into an image. These images can then be analyzed for radiotherapy planning. Result Computed Tomography (CT) has become an invaluable medical tool. It provides detailed 3-D images of various sections of the body like pelvis, soft tissues, lungs brain, blood vessels and bones (Nordqvist, 2009). Generally, CT scanning is the preferred method of diagnosing different types of cancers like liver, lungs and pancreatic cancers (Nordqvist, 2009). The tomographic images produced by the CT scan provide specific location and size of the tumor along with the details of affected tissues in the proximity of the tumor. This is especially advantageous in planning, guiding, and monitoring therapies like radiotherapy (FDA, 2010). CT scanning has various benefits over other traditional diagnostic techniques; some of the benefits are (RadiologyInfo, 2009): It is non-invasive, painless and extremely accurate. A major advantage is the ability to identify and distinguish bones, soft tissues and blood vessels in the same image. It also provides real time images which cannot be done in conventional X-rays. This technique is fast and simple; and is extensively used to locate internal injuries after accidents. It is less sensitive towards patient movement as compared to MRI. CT scanning can be used on patients with medical implants unlike the MRI. For an effective radiation therapy treatment, it is necessary that only the tumor is irradiated while minimum damage occurs to the surrounding health (normal) body tissues (Badcock, 1982). This is achieved with the help of CT imaging technique. In a study by Badcock (1982), 186 patients with various malignancies were studied and it was found that in nearly 39% of the treatment cases CT scanning was valuable in the assessment of the radiationdose calculation (Badcock, 1982). According to his study, CT scanner resulted in an alternation in target dose by more than 5%, (as compared to the traditional methods) in 27% of the patients (Badcock, 1982). The result has been shown in the table below. The mean alternation was 6.5% of the target dose and usually resulted in reduction of dose per fraction by factors upto 35% (Badcock, 1982). Even with these advantages, the adverse affect of the ionizing x-ray radiations cannot be neglected. Various experiments and researches have consolidated the fact that ionizing radiations like x-rays, gamma rays etc have adverse effect on living tissues. Zamanian Hardiman (2005) have explained that when high energy ionizing radiations interact with living tissues they strip-off atoms and molecules from them. This disrupts the chemical reaction within the body and failure in organ functioning (Zamanian Hardiman, 2005). The adverse effects of ionizing radiations were seen shortly after its discovery in 1890s, with a scientist involved in the study of radioactivity were reported with skin cancer in 1902. But is was not until 1944, that the role of radiations in causing leukemia in human was first documented, mainly in radiologists and physicists (Zamanian Hardiman, 2005). In recent years the use of x-rays has extensviely increased in medical field for diagonostic and treatment application. According to the U.S. Environmental Protection Agency, X-ray deveices are the largest source of man-made radiation exposure (US_EPA, 2007). According to NCRP Report No. 160 (2006), the average annual effective dose per individual in the US population, from all sources has increase from 1.7mSv in 1980s to 6.2mSv in 2006. This increase is mainly attributed to the striking growth of high dose medical imaging procedures that utilize x-rays and radionuclides (NCRP, 2008). Such man-made devices include X-ray machines, CT scans etc. CT scans, especially result in high dose x-ray exposure, with nealy 100 times the exposure dose as compared to standard x-ray equipments (Coach, 2008). Some of the major risks associated with CT scanning are: It is well documented that ionizing radiaitons like x-rays have the ability to cause cancer on exposure. Therefore, the CT dose in radiotherapy increase the probabilty of cancer in the future. Even though only 4% of the total x-ray examinations are CT scans, they account for more than 20% of the radiation dose to the population by medical x-rays (King Saud University, 2004). In general, the effective dose in a CT scan procedure ranges from 2 mSv to 10mSv, which is nearly equivalent to the amount of radiation that a person receive from the background exposures in three to five years (RadiologyInfo, 2009). A CT scan during preganacy make cause serious illness or even birth defects in the unborn baby (FDA, 2010). Children are more sensitive and vulnerable to x-ray exposures than the adults, therefore their CT scanning should be done only under extremely essential and necessary conditions. Women have higher risk of developing cancer in the lifetime, as compared to men under same levels of exposure (FDA, 2009). In some rare situation of high-dose prolonged radiation exposure, the x-rays can cause adverse effects like skin reddening (erythema), skin tissue injury, hair loss, cataracts etc (FDA, 2010). In a study, Sawyer et al (2009) estimated the effective dose resulting from a cone beam CT scanning for planning of radiation therapy using thermoluminescent dosemeters (TLDs) for organ dose and using International Commission on Radiological Protection (ICRP) 60 tissue weighing factor (Sawyer et al., 2009). The results obtained for effective dose from TLD measurements and ICRP 60 weighting factor, for breast, pelvis and head simulation have been shown in the table below. The scanning process results in the exposure of the normal tissues outside the treatment volume (Waddington McKenzie, 2004). It is thus important to analyze the effect that the irradiation caused by the CT scanning process has on the patients body. In a study, Waddington McKenzie (2004) analyzed the propability of developing cancer from the irradiations caused by the extended field portal imaging techniques, the results of which are given in the table below (Waddington McKenzie, 2004). In order to illustrate a real life situation, the calulations in the study were done for an average man with a height of 170 cms and weight of 70 kgs (Waddington McKenzie, 2004). Therefore, these values may change depending upon the height, weight and tumor size of the patient. Discussion Various studies have been done to statistically evaluate the effect of the ionizing radiations on the human health. These risks have severely amplified due to the rapid increase in the number of CT scans for diagnostic applications. CT scans form nearly 5% of all procedures used in diagnostic radiology in the developed countries (Wrixon et al., 2004). In U.S., nearly 70 million CT scans were done in 2007 as compared to just 3 million done in 1980 (Steenhuysen, 2009), this includes more than 4 million children in 2006 (Brenner Hall, 2007). Thus, according to the NCRP Report no. 160, the average radiation dose per person has increased from 3.6 mSv in early 1980s to 6.2 mSv in 2006 (NCRP, 2008). Steenhuysen (2009) has reported that the radiations from CT scans done in 2007 will cause 29,000 cancers and kill nearly 15,000 people in America (Steenhuysen, 2009). These stats explain the level of exposure caused by the CT scans. According to estimates by Amy Berrington de Gonzalez of the National Cancer Institute,