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Radiology
9-Jolene
Question | Answer |
---|---|
1. What is meant by latent period? | period of time after exposure to x-rays and first clinical symptoms of exposure |
2. What phrase is represented by the acronym ALARA? | As Low As Reasonably Achievable |
3. Why do x-rays pose a health hazard to humans? | some of the x-ray energy is transferred to the tissues as it passes through |
4. Which parts of the body are listed as especially sensitive to damage from x-radiation? | small lymphocyte, bone marrow, reproductive cells, intestinal mucosa, skin, lens of eye, oral mucosa |
5. Which two tissue types are especially sensitive to x-rays but should not be damaged by dental x-radiation? | reproductive and fetus |
6. What is the recommendation for filtering a 90 k V x-ray machine? | 2.5 mm of aluminum equivalent |
7. What is the recommendation for filtering a 65 k V x-ray machine? | 1.5 mm of aluminum equivalent |
8. What is the safety implication of using a longer PID? | less radiation to the patient*s skin |
9. Does the use of a film holding device contribute to patient safety? | yes, especially if it has a beam alignment device - helps minimize retakes |
10. What is the best position for the operator during exposures? | behind a suitable barrier, such as lead or slump block |
11. If barriers are inadequate, what is the best position for the operator during exposure? | at least 6 feet away, 90 to 135 degrees from the source of the beam |
12. When should the operator hold the film in the patient's mouth? | never |
13. When should the lead apron and thyroid collar be used? | every patient and every exposure AND when another person is holding a child during an exposure |
14. What is the MPD formula? | MPD = 50 mSv x N (N = age in years and 50 mSv is max dose/yr for radiation workers) |
15. What is the maximum permissible dose of radiation per year? | 50 mSv; aka 5 rems; aka .05 Sv |
16. What is the purpose for a film badge? | record the amount and type of radiation received within a specific period of time |
17. Who has custodial rights to the radiographs? | the dentist only |
18. What is meant by property rights? | the dentist and the patient |
19. What is meant by informed consent? | the pt. is fully conscious & alert & understands & consents after procedure has been explained, the necessity, what the risks are & what effect the lack of high-quality diagnostic films may have on treatment & prognosis |
20. What is implied consent? | patient gives blanket consent to have any and all treatment and diagnosis performed without necessarily knowing the specifics of each individual procedure |
21. What unit of measurement is for absorbed doses? | rad or gray |
22. What unit of measurement is for exposure? | R (Roentgen unit) |
23. What unit of measurement is for dose equivalent? | rem or sievert |
24. What is meant by cumulative effects of radiation? | each exposure to radiation never fully repairs, damage from radiation continues to accumulate |
25. What is the term given to cells that are easily damaged by x-rays? | radiosensitive |
26. What is the term given to cells that are resistant to the damaging effects of x-rays? | radioresistant |
27. What is an ion? | atom or chemical bearing an electrical charge, either negative or positive |
28. What is a free radical? | a compound produced when an x-ray photon interacts with water and oxygen causing radiolysis |
29. What are the effects of chronic exposure to x-rays? | cataracts, leukemia, cancer to thyroid, salivary gland and skin, genetic abnormalities |
30. What is the skin dose delivered during a single periapical exposure? | 1.75 - 3.75 mGy, depending upon kVp and cone length (SFD) |
31. What effect does changing the PID length have on the radiation delivered to the patient? | longer PID length reduces the amount of exposure to the patient*s skin |