Quality Assurance of Superficial Radiotherapy X-Ray Machine

Quality Assurance of Superficial Radiotherapy X-Ray Machine Study the Quality Assurance of Superficial Radiotherapy  X-ray Machine using some Techniques Abstract The aim of the present paper is to investigate some factors affecting on quality assurance of superficial radiotherapy x-ray such as reproducibility of dose out put, linearity, reference, entrance and some skin cancer doses were measured for hand, face and nose. Examinations of these factors are studied using Farmer dose master connected with 0.6 cc ionization chamber which was placed on the couch inside the selected field and contacted with an applicator to avoid any air gap inside a field size and 10 exposures were made. The measurements were carried out using an operating condition such as 50kV, 90mAs, 15mA 0.10 min, 6 sec. The tolerance limit for the reproducibility is equal to 0.2% , which is lower than the tolerance limit as mentioned. in American Association of physics in Medicine, AAPM . The relative Error for entrance skin dose equals 3%. The quality assurance tests of superficial radiotherapy x-ray machine are measured and compared with the international tolerance. Key words: Quality Assurance, Farmer dosemaster. .0.6 cc ionization chamber Introduction The principle goal of quality assurance of superficial x-ray machine is obtained accurately and timely assessment. The secondary goal is to maximize of radiation exposure and obtain high radiation quality. This can be assess by performance the x-ray machine by optimum operating parameters such as reproducibility of dose out put, linearity, Reference , Entrance and Exit dose measurements according to code safe of practice for use x-ray in medical diagnosis (NRL, 1994). [1]. Many associations reported work concerning quality assurance of superficial x-ray machine like , AAPM, [2,3] that describes quality assurance protocol for superficial radiotherapy x-ray equipment at the therapeutic technologist level. American Association of Medical Physicists in Medicine ~AAPM, [4] presents a new protocol, developed by the Radiation Therapy Committee Task Group 61, for reference dosimetry of low- and medium energy x rays for radiotherapy and radiobiology (40 kV(4) . Austerlitz C, et.al, 2008 mentioned that the beam outputs presented percent differences ranging from -13 to +25%.[5]. Mehran Goharian et.al , 2010 mentioned that The measured output showed an increase of up to 7.3% relative to the neutral position (0 ° in-plane and 0 ° cross-plane) over the possible range of angles of in-plane rotation for 75 kVp (half-value layer, HVL = 1.84 mm Al)[6]. Modern research indicated that the continued successful use of kilovoltage X-ray units for superficial therapy and their different design compared with linear accelerators indicates that specific advice for this type of equipment is required. Useful guidance on quality control of kilo-voltage units is also given in Klevenhagen.et.al [7] and Williams.et.al [8]. Paevans .et.al [9] mentioned that the applicator, system interlocks and dose monitor performance that used in check of Gulmay D3300 kilovoltage X-ray therapy unit were satisfactory and the tube leakage was below the UK recommended maximum (air kerma rate 300 mGy/ h at 5 cm from the tube head). The quality assurances of therapeutic x-ray are based on the Basic Safety Standard –BSS[10] and International Commission of Radiological Protection where they mentioned that there is no limit for medical exposure but they ensure that medical exposure have to decide by consultation between medical authorities and professional bodies . The aim of the present paper is to investigate some factors affecting on quality assurance of superficial radiotherapy x-ray such as reproducibility of dose out put, linearity, Reference, Entrance and Exit dose measurements. Material and Method The X-strahl superficial x-ray machine was investigated for some factors of quality assurance such as reproducibility and linearity . Reproducibility is one component of the precision of a test and reported as a standard deviation. Reproducibility of dose out put of X-strahl machine was measured with Farmer Dose master connected with 0.6 cc ionization chamber, which was placed on the couch inside the selected field and contacted with an applicator to avoid any air gap inside a field size and 10 exposures were made. The measurements were carried out using same operating condition such as 50kV, 90mAs, 15mA , 6 sec. The reproducibility Pz was calculated based on NEWZELAND Radiation Laboratory, NRL protocol (J.L.Plotti , 1995).[11]. Where: SD is the estimator of standard deviation of a series of measurements dose [mGy], Zap is the means value of the measured [dose [mGy]. Extensive measurements were made to assess of changes in mAs on reproducibility and linearity of radiation output. It formed over a range of clinical settings. Calibrated ionization chamber used to measure output expressed as ÃŽ ¼Gy per mAs, at a set distance, without backscatter. Linearity The linearity of superficial x-ray machine was studied using farmer dose master that connected with 0.6 cc ionization chamber above Perspex phantom. The linearity was checked using the next equation that stated by NEWZELAND Radiation Laboratory, NRL protocol (J.L.Plotti , 1995) .[11]. à ¯Ã†â€™Ã‚ §X1-X2à ¯Ã†â€™Ã‚ ª/X1+X2 à ¯Ã¢â€š ¬Ã‚ ¼0.1 Where X1 and X2 are two successive readings. Applications of superficial x-ray machine Measurement the Surface Radiotherapy Dose for Hands, Face and Nose were conducted using suitable applicator for each case. The applicator for hand treatment was 5 cm diameter, 15 FSD , the applicator for face treatment was 3 cm diameter , 15 FSD and the applicator for nose treatment was 1.5 cm diameter, 15 FSD. Results and Discussions Reproducibility Dose reproducibility for repeated doses of superficial x-ray machine was measured using farmer dosemaster connected with 0.6cc ionization chamber on the surface of Perspex phantom as shown in table 1. In the present work the maximum value was 4.404 , the minimum value was 4.374 and mean doses and standard deviation of the measurements was 4.391  ± 0.008 . The machine reproducibility was found to be 0.2% which is lower than the tolerance limit as mentioned. in NEWZELAND Radiation Laboratory, NRL protocol (J.L.Plotti , 1995) .[11]. Table 1 the Dose reproducibility for superficial radiotherapy machine using an operating condition of 50kV, 90mAs, 15mA , 6 sec. For 0.6 cc Ionization chamber. Dose, cGy 0.6 cc Run No. 4.374 1 4.386 2 4.388 3 4.394 4 4.394 5 4.386 6 4.390 7 4.391 8 4.404 9 4.401 10 4.391  ± 0.008 Mean  ± Standard Deviation Linearity of X-ray Machine The dose output was measured as a function in miliamper second. These measurements were recorded at 25 cm source to detector distance using special applicator of diameter 25 x 25 cm2 as shown in table.2. The linearity of the superficial x-ray machine was given a result lower than 0.1 that means it lower than the tolerance level of the American Association of physics in Medicine AAPM[3] and NEWZELAND Radiation Laboratory, NRL protocol (J.L.Plotti , 1995) .[11]. Linearity was accepted that means the x-ray tube of a machine is calibrated. Table 2. Linearity of superficial X-ray Machine Dose, , cGy mAs Time, sec Setting 23 30 6 50 kV, 5 Ma 30 60 12 45 150 30 72 240 48 90 300 60 . Measurement the Surface Radiotherapy Dose for Hands, Face and Nose The X-ray tube of the X-strahl machine was located in middle of the room surrounded by one meter from each side. The focus to skin distance, FSD for each applicator under use was adjusted for surface radiotherapy treatment such as hand, face and nose of tissue equivalent phantom. The Ionization chamber was adjusted for operating conditions of the X-ray machine as filter 1, 50kV, 5 mA, 0.2 min, and 0.2 mmAl for different applicators. The Surface dose for skin, nose and hand were recorded as shown in table 4. X-strahl -100 x-ray system low energy X-ray for treatment a wide range of superficial dermatological condition including: basal cell carcinoma, Squamous cell carcinoma and dermatological conditions including psoriasis. Orthovoltage units continue to be used today to treat superficial lesions; in fact, they were practically the only machines treating skin lesions before the recent emergence of electron therapy. The maximum dose from any of these low-energy units is found on the sur face of patients; thus, skin becomes the dose-limiting structure when treating patients at these energies. The depth at which the dose is 50% of the maximum is about 7 cm. Therefore the physician can be calculate the treatment dose for superficial x-ray therapy for each case. Since the total dose is equal to dose rate times the time , so, the time of treatment can calculate easily . Table 4. Entrance patient dose measurements for face, nose and hand.. ESD, (cGy) Case Applicator dimensions 56.68  ± 0.307 Face cancer 3 cm diameter , 15 FSD 241.2  ± 2.15 Nose cancer 1.5 cm diameter, 15 FSD 58.8  ± 0.669 Hand cancer 5 cm diameter, 15 FSD Conclusion This work concluded that The machine reproducibility dose out put was found to be 0.2% so patient risk will decrease. Linearity was lower than 0.1 which is lower than the tolerance limit of the international publications. The maximum dose from any of these low-energy units is found on the surface of patients; thus, skin.X-strahl machine treating skin lesions, hand, face and nose. The treatment time for hand, face, and nose cancer calculated via the surface patient dose measurement.

The Human Genome Project :: Exploratory Essays Research Papers

The Human Genome Project    With technology increasing daily in our modern society, we have to wonder what will come of all of the recent studies and large-scale research projects that have involved genetics. After recently reading two articles, I have been able to formulate some of my own predictions of what’s to come. In Lisa Sowle Cahill’s article, â€Å"The genome project: more than a medical milestone† she tells us in a concise manner, the history of the Human Genome Project. â€Å"The Human Genome (H.G. P.) began in 1990 as an international consortium of scientific terms. It planned to map systematically the entire human genome by the year 2005 on a budget of $3 billion. The major supporters of the H.G. P. are the Wellcome Trust, a large medical charity in the United Kingdom, and the U.S. federal government’s National Institute of Health. The H.G.P.’s leaders are the N.I.H.’s James D. Watson, his successor Francis S. Collins, and John. E Sulston, director of the Sanger Center in Cambridge, England. They have made it a point of seeking out international collaborators. These include experts in Germany, France, Japan, and China, all of whom have made important contributions to the recent success of the project.† A quick history it may be, but it is an extremely important one. As you can tell by the date of its beginning, the Human Genome Project is not very old by scientific standards, yet even though it may seem to be very young, the developments that have been made since its creation have been quite impressive. Personalized medicine is not very far away. This will mean that there will be drugs tailored to the individual genetic makeup of the patient, thus enhancing the effectiveness of treatments for ailments like cancer, heart disease and some forms of mental illness (Cahill). Someday, we will most likely be able to intervene in germ cell or embryos to remove or change a gene (Cahill). â€Å"Issues of confidentiality and social control take these questions a step further, into economic and political realms,† referring to whether or not genetic information will be completely private or available to others such as family members, insurance agencies, and even employers (Cahill) This last issue brings me to the next article that I read. In Jeffrey Kluger’s, â€Å"Who owns our genes?

Whole Foods Market Case Questions

1. What are the chief elements of the strategy that Whole Foods Market is pursuing? Is Whole Foods' strategy well matched to market conditions in the food retailing industry? The chief element of the strategy that whole food is pursuing is providing the finest quality of products in the market that is free from preservative and other genetically engineered products that reduce the quality of being organic. They promote the vision of the whole food, whole people, and the whole planet. Whole food market is focus to extend their market to get dominant position in both the local and the international market through increase the amount of stores itself and acquisition. For high demand from customer and higher profit margin than normal food, Whole food's expansion and quality control market strategy was well matched to recent developments and conditions in natural and organic goods segment of food retailing industry. 2. Do Whole Foods Market's core values as presented in case Exhibit 3 really matter? Are they â€Å"real † or just cosmetic window dressing? Have Whole Foods' core values contributed to the company's success? Explain/support. The 7 core values are very important. It guides the company on how to achieve the company mission â€Å"bringing the highest quality products to satisfy the consumer†. The core values are also real. Through these 7 core values, the company link their own profit and growth to customer benefit, bind their suppliers with win-win partnerships and try to create an interests community involving all their stakeholders. For example, to implement the first core value â€Å"selling the highest quality natural and organic products available†, the company set â€Å"nutrition, freshness, appearance, and taste † quality standard and abundant principal categories to supply thousands of organic food and gourmet products in their store. All these value can directly deliver to customer, better satisfy their needs and lead to success in product quality and variety. 3. Based on the financial statement data in case Exhibits 9, 10, and 11, how well is Whole Foods Market performing? From E9 statement of operations, sales eventually increased 1 billion every year from 4.7 billion 2005 to 8.03 billion 2009. However, the net incomes were kept in the scale between 114 million to 203 million these years due to the increasing input of store contribution. This situation matches the expansion activities of their business operations. Then, combine with the data from E10 Return on stockholders' equity 9.02% 7.60% Working capital(in thousand) 371356 -43571 Long term debt-to-equity ratio 0.65 0.80 Long term debt-to-capital ratio 0.28 0.36 The long-term debt largely decreased from 08 to 09 which is the main difference between the 2 years. In E11, the cash provided by operation activities in 09 is more than 08 and 07. And outside the business Whole Food also have investment activities. The company was trying to earn extra profits from exchanging securities. In 07, it earned 198343 thousands; in 08 it didn't earn anything, then in 09 the company didn't have any investment activities on exchange securities. 4. How well is Whole Foods Market performing from a strategic perspective? Does Whole Foods enjoy a competitive advantage over its 3 chief rivals â€Å"Wild Oats, Fresh Market and Trader Joe's? Whole Foods Market is performing exceptionally well from strategic perspective. Whole Foods Market is performing well by increasing their locations and markets. The company has made strategies for its stores, their location, and Whole Food's product line, the design of the stores, the product quality, and marketing and for providing their customer most satisfactory service. It follows the strategy of team based management for store operations. It also offers compensation and rewards to its employees. It has also made strategies that are feasible for the purchasing and distribution of items. All these strategies are in accordance with the company's requirement and thus the company maintains a competitive advantage over its rivals due to its sustainable implementation of strategies for achieving its goals and managing the company. It acquired one of its biggest rivals Wild Oats in 2007. The company's strategy has helped it in gaining the d position in the market. 5. What recommendations would you make to John Mackey regarding the actions that Whole Foods' management needs to take to sustain the company's growth and financial performance? Whole Food was very successes on decreasing their long-term debt level while keeping their profitability and increasing sales. However, through it kept expansion through opening new stores and acquisition, the net income is not enough for big change like enter into a new area. So, I suggest Whole Food may extend their service, such as adding a fast food to go window or even a dining area in their store to better utilize their urban metropolitan store location and cooking ability. The costs of food service just need to develop the new recipe and change the store wouldn't too much but can attractive more customers.

The Knowledge Of God s Existence And Fundamental...

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