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RADT 456 rad prot.
ARRT reg review
Question | Answer |
---|---|
What type of dose response curve used to predict stochastic effects is the | linear nonthreshold |
A dose of 0.25 Gy or 25 rad to the fetus during the 3rd/4th week of pregnancy is more likely to cause _____ _____ | skeletal anomalies |
What is the effect on relative biologic effectiveness(RBE) as LET decreases | RBE decreases |
How does filtration affect primary beam | filtration increases average energy of primary beam |
The principal function of -ray beam filtration is to | reduce patient skin dose |
Patient dose can be decreased by using | high-speed film and screen combination |
Each time an x-ray photon scatters, its intensity at 1 meter from the scattering object is what fraction of its original intensity | 1/1000 |
Guidelines used to reduce personnel and/or patient dose in fluoroscopy; 1)..... 2)..... | 1)maximum tabletop intensity 10R/min 2)minimum filtration 2.5 mm Al equivalent |
Primary radiation barriers must be at least how high | 7 feet |
The operation of personal radiation monitoring devices can depend upon 1.....2..... | 1)ionization 2)thermoluminescence |
What type of crystals are used in an optically luminescent dosimetry system | aluminum oxide |
The unit of measurement used to express occupational exposure is the | Rem/Sievert |
Exposure rate to individual standing 4 m from a source of radiation 10mR/h, what will be the dose received after 20 min at a distance of 6 m from the source | 1.48 mR |
The interaction between ionization radiation and the target molecule that is most likely to occur is the | indirect effect |
What is the established annual occupational dose-equivalent limit for the lens of the eye | 150 mSv |
Occupational radiation monitoring is required when it is possible that the individual might receive more than | 1/10 annual dose limit |
Source of natural background radiation contributing to whole-body radiation dose include 1 & 2 | 1)terrestrial radionuclides 2)internal radionuclides |
What are used to account for the differences in tissue characteristics when determining effective dose to biologic material | tissue weighting factors |
The exposure rate to the body 4 ft from the source of radiation is 16 R/h. What distance from source would be necessary to decrease the exposure to 6 R/h | 7 ft |
A thermoluminescent dosimetry system would use what crystal | lithium fluoride |
The photoelectric effect is more likely to occur with; 1..... 2..... | 1)absorbers having high Z number 2)positive contrast media |
What anomalies are possible if an exposure dose of 40 rad(400mGy) were delivered to a pregnant uterus in the 3rd week of pregnancy | organ anomaly |
Medical and dental radiation accounts for what percentage of the general public's exposure to human-made radiation | 90% |
Patient dose increases as fluoroscopic | FOV decreases |
What unit of measure is used to express ionizing radiation dose to biologic material | Rem(Sv) |
For exposure to 1 rad of ionizaing radiations, what would result in the greatest dose to the individual | internal source alpha particles |
Biologic material is least sensitive to irradiation under what condition | anoxia |
The reduction in the intensity of an x-ray beam as it passes through material is termed | attenuation |
According to NCRP regulations, leakage radiation from the x-ray tube must not exceed | 100 mR/h |
What most effectively can minimize radiation exposure to the patient | high-speed intensifying screens |
Primary radiation barriers usually require ___ thickness of shielding | 1/16 in lead |
According to the NCRP, the annual occupational dose-equivalent limit(50 rem) to the thyroid, skin, and extremities is | 500 mSv |
What is the intensity of scatter radiation perpendicular to and 1 m from the patient compared with the useful beam at the patient's surface | 0.1% |
The amount of time that x-rays are being produced and directed toward a particular wall is referred to as the | use factor |
What typeof personnel radiation monitor can provide an immediate reading | ionization chamber |
The law of Bergonie and Tribondeau states that cells are more radiosensitive if they are 1..... 2..... | 1)highly proliferative 2)immature |
The most radiosensitive portion of GI tract is the | small bowel |
What body parts are included in whole-body dose 1.....2..... | 1)gonads 2)blood-forming organs |
What personnel monitoring devices used in diagnostic radiography is considered to be the most sensitive and accurate | OSL dosimeter |
Examples of late effects of ionizing radiation on humans include | 1)leukemia 2)local tissue damage 3)malignant disease |
What cells are most radiosensitive | erythroblasts |
What contributes most to patient dose | photoelectric effect |
Biologic material irradiated under hypoxic conditions is | less sensitive than under oxygenated conditions |
Which interaction between ionizing radiation and the target molecule involves formation of a free radical | indirect effect |
Student radiographer under 18 years old must not receive an annual occupational dose of greater than | 0.1 rem (1 mSv) |
3 types of secondary radiation barriers include | 1)control booth 2)lead aprons 3)x-ray tube housing |
Somatic effects of radiation refer to effects that are manifested | during life of exposed individual |
The dose of radiation that will cause a noticeable skin reaction is referred to as the | SED |
Somatic effects resulting from radiation exposure can; 1..... 2..... | 1)have possible consequences on exposed individual 2)cause temporary infertility |
Protective devices such as lead aprons function to protect the user from | scattered radiation |
The tabletop exposure rate during fluoroscopy shall not exceed | 10 R/min |
3 things that are considered radiosensitive tissues | 1)bone marrow 2)intestinal crypt cells 3)erythroblast |
The correct way to check for cracks in lead aprons is to | fluoroscope them once a year |
The target theory applies to | DNA molecules |
Where have sources of radon exposure been identified | 1)indoors, in houses 2)smoking cigarettes |