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RADT 465 Image Prod
ARRT registry review covering image production content area
| Question | Answer |
|---|---|
| 1. What does window level adjust? (pg 314) | Brightness |
| 2. What refers to the various body tissue densities and thicknesses? (pg 314) | Subject contrast |
| 3. True or False: mAs has an impact on contrast (pg 315) | False |
| 4. According to what law does exposure rate decrease when SID is increased? (pg 315) | Inverse square law |
| 5. As distance is decreased, intensity of the beam increases, therefore what adjustment should be made? (pg 316) | an increase in mAs |
| 6. Kv affects what 2 things? (pg 317) | quality and quantity (energy/wavelength) |
| 7. According to what rule does mAs need to be cut in half when increasing Kv by 15%? (pg 317) | 15% rule |
| 8. What 3 factors determine scatter radiation production? (pg 318) | field size/beam restriction, kV, thickness/volume and density of tissues |
| 9. What is the most important way to decrease the production of scatter? (pg 321) | collimation |
| 10. What is a device that is used between the patient and IR that functions as absorption of scatter before it reaches the IR? (pg 321) | Grid |
| 11. When should grids be used? (pg 321) | when imaging a body part 10 cm or greater |
| 12. When using a grid, what should you do to your technique? (pg 321) | increase mAs |
| 13. True or False: you should angle against the lead strips when using a grid (pg 323) | False |
| 14. True or False: your tube and grid should be parallel to each other (pg 323) | True |
| 15. What type of grid error has occurred if there is a loss of exposure at the periphery of the IR? (pg 324) | off-focus |
| 16. What type of grid error has occurred if there is uniform loss of exposure across the IR? (pg 324) | off-center |
| 17. True or False: grid cutoff will not occur if you place your grid upside down (pg 324) | False |
| 18. What is the height of the lead strips compared with the distance between them? (pg 325) | Grid ration |
| 19. How much filtration does the primary beam have? (pg 328) | 2.5 mm Al (glass envelope 0.5 mm, collimator 1.0 mm, added 1.0 mm) |
| 20. What is the purpose of filtration? (pg 328) | removes the diagnostically useless xray photons that contribute only to pt dose |
| 21. True or False: filtration has no impact on contrast (pg 328) | True |
| 22. Destructive pathologic conditions include: (pg 331) | osteoporosis, osteomalacia, pneumoperitoneum, emphysema, degenerative arthritis, and atrophic and necrotic conditions |
| 23. Additive pathologic conditions include: (pg 331) | ascites, rheumatoid arthritis, paget's disease, pnuemonia, atelectasis, congestive heart failure, and edematous tissue |
| 24. When using the anode heel affect, which side does the thicker part of the pt go under? (pg 332) | Cathode |
| 25. What is the smallest unit of computer data? (pg 334) | bit |
| 26. What is a two-dimensional element that is measured in the XY direction? (pg 334) | pixel |
| 27. What refers to the # of bits per pixel and identifies the grayscale? (pg 334) | bit depth |
| 28. What is the graphic representation of pixel value distribution? (pg 334) | histogram |
| 29. What is the volume of tissue in each pixel and is measured in the Z direction? (pg 334) | voxel |
| 30. What does window width adjust? (pg 334) | the shades of grey |
| 31. What is defined as how readily the anatomic details can be perceived? (pg 336) | visibility |
| 32. What is defined as how easily we are able to recognize those details? (pg 336) | contrast resolution |
| 33. Where is the ionization chamber located and how does it operate? (pg 338) | under the table, above the IR and as photons emerge from the pt they enter the chamber and ionize the air within |
| 34. Where is the phototimer located and how does it operate? (pg 338) | under the IR and exit radiation from the pt interacts with and exits the IR and emits light and charges the photomultiplier tube |
| 35. What factors affect resolution? (pg 350) | OID, SID, focal spot size, distortion, patient shape/position, and motion |
| 36. Contrast resolution is measured in (handout) | lp/mm |
| 37. What is an adjustment of pixel values to pre-set range of values to produce consistent brightness and grayscale called? (handout) | Rescaling |
| 38. What is a kernel used to average out neighboring pixels and fill it in called? (handout) | Dead pixel correction |
| 39. What is the opposite of smoothing, used to bring out small details, increases contrast, and could make noise more visible? (handout) | Edge enhancement |
| 40. What is the removal of darkest to lightest pixel value from greyscale called? (handout) | equalization |
| 41. What suppresses visible noise and will lose some contrast varying pixels across an image? (handout) | smoothing |
| 42. What is defined as stored histogram values of selected exams? (handout) | LUT |
| 43. What is used to shield viewer eyes from area outside of collimated field should the computer not automatically place black surround? (handout) | masking |
| 44. What is defined as using grid lines from a special wire alignment grid to align multiple images into one? (handout) | stitching |
| 45. Equalization is also known as what? (handout) | dynamic range compression |
| 46. True or False: masking should not be used to collimate anatomy that should not haven been captured | True |
| 47. What is it called when you even out pixel values across an entire image for consistent brightness? (handout) | flat fielding |
| 48. As DQE increases, what happens to patient dose? (handout) | it decreases |
| 49. What is the numeric value that represents the amount of exposure the IR receives? (handout) | EI |
| 50. What is the difference between fixed and variable technique charts? (handout, pg 339) | fixed: specifies a particular Kv for adequate penetrating and requires a change in mAs based upon patient size and condition. variable: mAs is fixed and Kv is increases as part thickness increases. |
Created by:
nlchesser
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