RADT_153_Unit_13_Exam

RADT_153_Unit_13_Exam - RADT 153 Image Analysis Unit 13...

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Unformatted text preview: RADT 153 Image Analysis Unit 13 Exam The Effects of Intensifying Screens on Radiographic Quality 2 13.0 The Effects of Intensifying Screens on Radiographic Quality Directions: 1. Write your name and the date on your Scantron form. Identify the subject as the course number (for example, RADT 150) along with the test number (for example, Unit 1). 2. For each of the questions below, select the best answer to the question. 3. Using a No. 2 pencil, fill in the appropriate answer on the answer sheet. 4. Erase unwanted answers completely. Questions with two or more filled in answer spaces are graded as incorrect. 5. Answer all questions. 6. You have a maximum 15 minutes to complete the following 25 questions. (Note this time factor approximates the amount of time you would be allowed to answer the same number of questions on the Registry examination in radiography) -----------------------------------------------------------------------------------------1. What is the major difference between intensifying screens? A. B. C. D. E. The The The The The number of layers it has. number of phosphor layers it has. different types of phosphor crystals. different colors that the crystals emit. type of cassettes that hold them. 3 2. What are the five layers of intensifying screens? I. II. III. IV. V. VI. VII. A. B. C. D. E. 3. Support layer/base Strong layer Curl-control backing Undercoat or reflective layer Phosphor layer Protective coating Light layer I, II, III, IV and V I, III, IV, V and VI II, III, IV, V and VI II, III, IV, V and VII I, III, IV, V and VII What three types of materials might make up the support / base layer? I. II. III. IV. V. A. B. C. D. E. 4. Phosphor crystals Paper Plastic Cardboard Steel I, II, and III I, III, and IV I, II, and IV II, III, and IV I, II, and V What layer in intensifying screens helps hold down the screen so it does not warp? A. B. C. D. E. Back support layer Reflective Layer Base Layer Support Layer Curl-backing layer 4 5. What layer may not be included in every intensifying screen? A. B. C. D. E. 6. What gives screens their varying speeds? A. B. C. D. E. 7. layers of which they are composed. number of crystals on the screen. different sizes, types and thicknesses. amount of crystals that actually fluoresce. amounts of photons they absorb. Phosphor layer Curl-backing layer Reflective layer Support/base layer Protective coating layer What absorbs photons, converts the x-ray energy to light and emits light photons? A. B. C. D. E. 9. The The The The The Which layer enables the screen to be cleaned with either a special cleaner or soap and water? A. B. C. D. E. 8. Reflective layer Curl-backing layer Support Layer Base layer Strong layer The The The The The reflective layer. phosphor crystals intensifying screens cassette protective coating layer Which one of the following statements is not one of the four things phosphor crystals must have in order to be useful in radiology? A. B. C. D. E. They can not be placed in direct sunlight. They must respond to a wide range of kV. They can not deteriorate with age. They must have minimal after-glow (screen lag). They must be in the visible light emission spectrum that is most sensitive to the film being used. 5 10. What are the three most common phosphor crystals? I. II. III. IV. V. VI. A. B. C. D. E. 11. Calcium tungstate Phosphor calcium Phosphor-containing barium Phosphors from lathanide or rare-earth Calcium bromide Potassium bromide II, IV and V I, III, and IV I, II, and III II, III, and IV I, III and V How are intensifying screens rated? A. B. C. D. E. 12. What is the definition of intensifying screen speed? A. B. C. D. E. 13. By the amount of phosphor crystals they contain. The number of screen inside a cassette. By their image visibility. By the amount of time it takes to produce a quality image. According to speed The speed at which screens produce images. The sensitivity of the film to exposure by x-rays or light. The a screen that has a higher speed. An intensification of a screen’s speed A way to get photons to absorb. Which statement is not a factor that affects the speed of intensifying screens? A. B. C. D. E. The inherent film speed. The absorption efficiency of the screen. The screen spectral emission match with film spectral sensitivity. The ability of the photons to absorb. Screen efficiency in converting absorbed x-ray to light. 6 14. What is inherent film speed? A. B. C. D. E. 15. What are two factors that influence the phosphor’s absorption efficiency? A. B. C. D. E. 16. The thickness of the phosphor layer and the type of phosphor being used. The color that is emitted and the time it takes to be emitted. The time and the amount of available light. The color which is produced and the amount of x-rays produced. The number of phosphor crystals and amount of xrays. What is screen spectral emission? A. B. C. D. E. 17. The natural speed that film has. The time it takes for film to absorb x-rays or light. It is the built-in characteristics of diagnostic x-ray film. The speed that intensifying screens have. A chart which rates all the inherent speeds of film. The color a screen gets after many years of use. The amount of spectral emission a screen gives off. The placement of screens on the visible light spectrum. The film must be compatible with whatever color that the screen emits. The spectrum emitter by screens. What does screen efficiency indicate? A. B. C. D. E. It indicates how efficient the intensifying screens are in producing images. The time it takes to absorb x-rays. The efficiency of the phosphor crystals to The efficiency of the absorbed x-rays to light. The amount of radiation absorbed by the patient. 7 18. What are the four classifications of intensifying screen speeds? I. II. III. IV. V. VI. A. B. C. D. E. 19. Par Rare Earth High Fine Detail Slow Fine Par I, II, III, and V I, II, III, and IV II, III, IV, and V II, III, V, and VI I, III, IV, and V What is the greatest advantage to using intensifying screens? A. B. C. D. E. 20. What is the greatest disadvantage to using intensifying screens? A. B. C. D. E. 21. It is more cost efficient because it reduces the number of retakes. Quantum mottle. It takes up less of the x-rays. It reduces the amount of radiation a patient receives. It is much quicker then without a screen. Quantum mottle. It reduces patient dose. It is too quick, thus making a very bad image. It is so costly. All your cassettes must be modified to incorporate them, thus costing a good deal of money. How is density created on the film? A. B. C. D. E. It is created by many waves of radiation. By the x-rays being absorbed. By the light hitting the crystals and fluorescing. By photon absorption on the intensifying screen which causes the phosphor crystal to emit more light. It is created when the exposure is made. 8 22. Film contrast changes with photographic density. A. B. 23. What type of relationship is there between intensifying screen speed and contrast? A. B. C. 24. Direct Indirect None The larger the penumbra the less ______________________. A. B. C. D. E. 25. True False image contrast recorded detail magnification the size of phosphor crystals size distortion Why do intensifying screens have no effect on size distortion? A. B. C. D. E. Intensifying screens do have an effect of size distortion. Size distortion can only be effected by the size of the penumbra. Because size distortion/magnification are only affected by geometric changes. Size distortion is never effected in radiographic images. Because it is only affected by the thickness of the phosphor crystals. ...
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