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RADT 456
ARRT Registry Review Covering Radiation Protection
| Question | Answer |
|---|---|
| As the energy of the beam increases, what happens to wavelength and frequency? | Wavelength decreases and frequency increases. Pg. 225. |
| Is the energy of the beam homogenous or heterogenous? | Heterogeneous (polyenergetic). Pg. 227. |
| In the primary beam, is there more bremsstrahlung or characteristic radiation? | Brems radiation comprises 70-90% of the x-ray beam. Pg. 227. |
| In characteristic radiation, what shell is left vacant? | K shells are left vacant until an e- from a higher energy level moves into it. Pg. 228. |
| What type of interaction between x-ray photons and matter contributes to patient dose? | Photoelectric effect. Pg. 228. |
| What type of interaction between x-ray photons and matter contributes to occupational dose? | Compton scatter. Pg. 228. |
| How fast do x-rays travel? | All electromagnetic radiation travels at 186,000 miles/s. Pg. 229. |
| Are LET and RBE directly/indirectly related? | They are directly related. Pg. 233. |
| Are diagnostic x-rays considered high or low LET? | Low LET. Pg. 233. |
| If a woman is possibly pregnant, when is the safest time to schedule x-rays? | The first 10 days following the onset of menses. Pg. 237. |
| What is the most radiosensitive cell? | Lymphocyte. Pg. 240. |
| What is the overall most efficient beam-restricing device? | Collimator. Pg. 248. |
| Inherent filtration accounts for how many mm Al equivalent? | 0.5 mm Al. Pg. 251. |
| Equipment operating between 50 and 70 kv must have how much Al equivalent? | 1.5 mm Al equivalent. Pg. 252. |
| When should a technologist use gonadal shielding? | When the gonads are within 5 cm of a collimated field. Pg. 253. |
| As film speed increases, what happens to the patient dose? | As film speed increases, patient dose decreases. Pg. 258. |
| What is reproducibility? | Consistency in exposure output during repeated exposures at a particular setting. Pg. 259. |
| The SSD must be how many inches away for mobile fluoroscopic equipment? | 12 inches. Pg. 261. |
| What is the principle function of x-ray beam filtration? | Reduce patient skin dose. Pg. 263. |
| What is the approximate intensity of scattered radiation from the patient? | 1m from the patient is 0.1% of the primary beam. Pg. 268. |
| Leakage radiation from the x-ray tube must not exceed what? | 100 mR/h at 1m from the tube. Pg. 268. |
| Protective lead aprons must be at least what Pb equivalent? | 0.25mm Pb equivalent. Pg. 269. |
| 1Gy equals how many rads? | 100rads. Pg. 279. |
| 1Sv equals how many rem's? | 100rems. Pg. 279. |
| What is the occupational dose limit for exposed individuals per year? | 5rem or 50mSv/y/ Pg. 286. |