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Rad Procedures
RADT 465
Question | Answer |
---|---|
average u.s. doses | annual background dose=approx 3 mSv, average chest x-ray= approx .1 mSv, average whole body CT= approx 10 mSv (Radiology Prep, p.230). |
linear | response is proportional to dose (Radiology Prep, p.231). |
nonlinear | response is not proportional to dose (Radiology Prep, p.231). |
threshold | a dose must be received before a response can occur (Radiology Prep, p.231). |
nonthreshold | no safe dose- even one photon can cause a response (Radiology Prep, p.231). |
early effects | appear a short time after exposure, usually as a result of high dose in short period of time, should not be seen in diagnostic radiology (Radiology Prep, p.231). |
late effects | can appear years after exposure: carcinogenesis, cataractogenesis, embryologic effect, lifespan shortening (Radiology Prep, p.231). |
types of risks | deterministic: threshold, nonlinear, includes all early effects, includes some later effects; stochastic: nonthreshold, linear, genetic effects, cancer, includes most late effects (Radiology Prep p.232). |
types of DNA damage | main chain, double-side rail break; main chain, single-side rail break; main chain breakage, cross-linking; base damage, point mutations (Radiology Prep, p.235). |
ways to reduce risk to recently fertilized ovum | elective scheduling/10 day rule, patient questionnaire, posting (Radiology Prep, p.237). |
acute radiation syndromes | hematopoietic, gastrointestinal, CNS (Radiology Prep, p.241). |
stages of acute radiation syndrome | prodromal, latent, manifest illness, recovery or death (Radiology Prep, p.241). |
beam restriction | reduces patient dose, reduces production of scattered radiation, improves image quality (Radiology Prep, p.250). |
beam restrictor types | aperture diaphragm, cone/cylinder, collimator (Radiology Prep, p.250). |
gonadal shielding should be used if | the gonads lie in, or within 5 cm of, collimated field; the patient has reasonable reproductive potential; diagnostic objectives permit (Radiology Prep, p.255). |
ways to decrease patient fluoro dose | decrease length of fluoro exposure, employ use of last image hold, keep patient as close to the II as possible, use ABC setting with highest kV/lowest mA combination, minimize boost usage, collimation, small FOV, pulse rate (Radiology Prep, p.262). |
rules for selecting someone to assist the patient in the radiographic department | a male older than 18, provide them lead, as far from protective useful beam, individual must not be afraid to stand in the path of useful beam. |
radiation protection rules | time, distance, shielding (Radiology Prep, 272) |
primary barriers | protect from the useful beam (Radiology Prep, 272) |
secondary barriers | protect from scattered and leakage radiation (Radiology Prep, 272) |
roentgen | measures ionization in air, measures x- or gamma radiation only, is valid up to 3, in air (Radiology Prep, 281) |
rad | Gray (Radiology Prep, 281) |
rem | Sievert (Radiology Prep, 281) |
personal radiation monitors | optically stimulated luminescence, film badge, pocket dosimeter, thermoluminescent dosimeter (Radiology Prep, 283) |
t/f: when used correctly, digital imaging can significantly reduce patient dose | true (Radiology Prep, 263) |
t/f: grids reduce the radiographic image by reducing the amount of scattered radiation fog. | false; grids improves the radiographic image by reducing the amount of scattered radiation fog (Radiology Prep, 263) |
reproducablity | a given group of exposure factors, output intensity must be consistent from one exposure to the next (Radiology Prep, 262) |
linearity | output intensity must be constant when adjacent when mA stations are used, with exposure times adjusted to maintain the same mAs; any variation in output intensity must not exceed 10% (Radiology Prep, 262) |