1. The primary reason that fast screen/film combinations reduce the patient dose because they permit a reduction of the

(A) kVp

(B) mAs

(C) grid ratio

(D focal spot size

(E) added filtration

2. When compared with calcium tungstate,  rare earth screens generally result in a decrease of

(A) number of light photons per absorbed X-ray

(B) screen mottle

(C) speed

(D) patient dose

(E) all of the above

3. The number of scattered photons reaching a screen/film receptor decreases with increasing

(A) field size

(B) patient thickness

(C) kVp

(D) filtration

(E) grid ratio

4. The height of lead strips divided by the gap between these strips is called the grid

(A) focus

(B) range

(C) frequency

(D) ratio

(E)  none of the above

5. High ratio grids generally result in an increase in the

(A) required mAs

(B)  image contrast

(C) patient dose

(D)  removal of scatter

(E)  all of the above

6. Grids primarily attenuate which of the following types of photon arising from the patient?

(A) Compton scatter

(B) Coherent scatter

(C) Backscatter

(D) Characteristic x-rays

(E) All of the above

7.  What effect will an air gap have on image contrast

(A) Increase

(B) Reduce

(C) Eliminate

(D) None

(E)  Unpredictable

8. Match the following grids with the application or characteristic.

(A) No grid

(B) 12:1,  30 lines/cm

(C) 6:1,  40 lines/cm

(D) 4:1, 60 lines/cm

(i) Portable examinations

(ii) Extremity radiography

(iii) Mammography grid

(iv) Common Bucky grid

9. The reason 12:1 grids are seldom used with portable radiography is because

(A) output of portable x-ray units is too low

(B) low kVp used is unable to penetrate grids

(C) accurate grid alignment is to difficult

(D) scatter is not important in portable x rays

(E) air gaps are preferred to eliminate scatter

10. The modulation transfer function (MTF) does NOT generally

(A) describe the system resolution

(B) compare image to object contrast

(C) approach 1 at low spatial frequencies

(D) equal unity for perfect spatial resolution

(E) increase with increasing spatial frequency

11. Which of the following factors affect image sharpness?

(A) Focal spot Size

(B) Motion

(C) Screen thickness

(B) Screen/film contact

(E) All of the above

12. True (T) or False (F). Geometric magnification

(A) requires more radiation at screen/film

(B) can improve system spatial resolution

(C) needs larger focal spot sizes

(D) increases the amount of scatter in the image

13. Increasing magnification WITHOUT changing focal spot size affects image detail (resolution) in a screen/film radiograph by

(A) reducing image blur

(B) not affecting image blur

(C) increasing image blur

(D) eliminating image blur

(E) not enough information provided

14. Poor screen/film contact will result in a significant loss of

(A) contrast

(B) magnification

(C)  image detail

(D) x-ray absorption efficiency

(F) none of the above

15. Which of the following would most likely increase the spatial resolution of a screen/film combination?

(A) High grid ratio

(B) Slower film

(C) Thicker screen

(D) Thinner screen

(E) Faster film

16. Match the following radiographic imaging systems and limiting spatial resolution.

(A) General radiography screen/film

(B) No screen extremity radiography

(C) Photospot film

(D) Mammography

(i) 4 to 5 line pairs/mm

(ii) 5 to 10 line pairs/mm

(iii) 15 to 20 line pairs/mm

(iv) > 25 line pairs/mm

17. When a rare earth screen with three times the conversion efficiency and twice the absorption efficiency is substituted for a CaWO4 screen, the patient dose would be expected to

(A) increase slightly

(B) stay the same

(C) be reduced by a factor of 2

(D) be reduced by a factor of 5

(E) be reduced by a factor of 6

18. A screen with a higher conversion efficiency, but the same x-ray absorption efficiency and screen thickness, will likely result in

(A) increased patient dose

(B) constant image noise

(C) reduced image noise

(D) loss of image detail

(E) none of the above

19. True (T) or False (F). The speed of an imaging system can be increased WITHOUT increasing the noise by using

(A) faster films

(B) phosphors with a higher conversion efficiency

(C) higher developer temperatures

(D) phosphor with higher absorption efficiency

(E) thicker phosphors

20. Quantum mottle is primarily determined by which one of the following factors?

(A) X-ray beam filtration

(B) Number of x-ray photons absorbed in screen

(C) X-ray photon energy

(D) Screen conversion efficiency

(E) Screen thickness

21. Reducing the temperature of a film processor from 95F to 90F, and keeping film density constant, will increase

(A) contrast

(B) fog

(C) quantum mottle

(D) screen blur

(E) patient dose

22. Film contrast, as opposed subject contrast, is primarily affected by the

(A) kVp

(B) beam filtration

(C) presence of contrast agents (iodine, barium)

(D) tissue density differences

(E)  film optical density level

23. Compared to a regular screen, a detail screen, of the same phosphor and same examination, will have a higher

(A) spatial resolution

(B) speed

(C) noise level

(D) grid ratio

(E) none of the above

24. The most likely reason a phototimed chest unit would produce dark PA radiographs is

(A) incorrect kVp selection

(B) incorrect mA selection

(C) automatic exposure control (AEC) is faulty

(D) grid has been left out

(E) reduced developer temperature

25. Raising kVp in screen/film radiography, while maintaining a constant film density, will generally increase the

(A) need for a high mA

(B) entrance skin dose

(C) scatter

(D) exposure time

(E)   film processing time

26. Gastrointestinal (GI) tract contrast on film radiographs is NOT normally improved by

(A) infusion of barium

(B) reducing kV

(C) increasing mA

(D) tighter x-ray beam collimation

(E) increasing the grid ratio

27. Match the following problems and image quality defects.

(A) Poor screen/film contact

(B) Broken automatic exposure control (AEC)

(C) Bad rollers in processor

(D)  High kVp

(i) Dark films

(ii) Reduced image contrast

(iii) Local area of decreased resolution

(iv) Line artifacts

28. Increasing x-ray beam filtration alone, while keeping film density constant, results in decreased

(A) subject contrast

(B) exposure times

(C) tube heat loading

(D) motion blur

(E) heel effect

29. Decreasing x-ray beam filtration alone, while keeping film. density constant, results in increased

(A) maximum photon energy

(B) average photon energy

(C) entrance skin exposure

(D) importance of the Compton effect

(E) patient penetration

30. Match the "malfunction" with the phototimed x-ray result.

(A) Blown x-ray tube

(B) kVp set too low

(C) kVp set too high

(D) mA set too high

(E) Broken phototimer

(i) Film normal

(ii) Film too dark

(iii) Increased image contrast

(iv) Film uniformly clear

(v)  Reduced image contrast