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RADT 456 Protection
ARRT Registry Review
Question | Answer |
---|---|
What type of wavelength and frequency does energetic radiation have? | Shorter wavelength and higher frequency |
What percentage does medical radiation contribute to the populations' exposure? | 31% |
A high speed electron is deflected from its path and the loss of kinetic energy is emitted in the form of an xray photon during which type of radiation interaction? | Bremsstrahlung |
A high speed electron encounters a tungsen atom and ejects a K shell electron leaving a vacancy in the K shell in which a higher energy level shell electron fills the vacancy and gives off what type of radiation? | Characteristic |
Characteristic and Bremsstrahlung radiation take place where? | At the tungsten target |
This type of xray interaction with matter interacts with an absorber having high atomic number and low energy photons. It contributes significantly to patient dose because all its energy is used up? | Photoelectric effect |
During__________, a fairly high energy xray photon interacts with matter and ejects an outer shell electron. It retains most of its original energy and exits the body as scatter. Contributes to image fog and dose to personnel. | Compton scatter |
These types of effects appear a short time after exposure as a result of high dose in short time and is not usually seen in diagnostic radiology. | Early effects |
These types of effects appear years after exposure and include examples such as carcinogenesis, cataractogenesis, embryologic effect, and lifespan shortening. | Late effects |
Response is proportional to dose. | Linear |
Response is not proportional to dose. | Nonlinear |
A dose must be recieved before a response can occur. | Threshold |
No safe dose, even one photon can cause a response. | Nonthreshold |
This type of risk includes threshold, non linear, early effects, and some later effects? | Deterministic |
This type of risk includes no threshold, linear, genetic effects, cancer, and most late effects. | Stochastic |
This law states that very young cells, undifferentiated cells, and cells having the most reproductive activity are highly radiosensitive. | Law of Bergonie and Tribondeau |
The law of Bergonie and Tribondeau states that which three types of cells are radiosensitive? | Stem cells, Young/immature tissues, and highly mitotic cells |
List some examples of highly radiosensitive tissues. | epithelial cells and cells of the rapidly developing embryo and fetus |
Occurs when the ionizing particle interacts directly with the key molecule or another critical enzyme or protein. | Direct effect |
Occurs most frequently when ionization takes place away from the DNA molecule in cellular water. | Indirect effect |
What are the three Acute Radiation Syndromes? | Hematopoietic, Gastrointestinal, and Cental Nervous System |
What are the stages of Acute Radiation Syndrome? | Prodromal, Latent, Manifest illness, and Recovery or death |
What is the single most important factor in keeping patient dose to a minimum? | Beam restriction |
What are some examples of inherent filtration? | Perminant parts of the xray tube such as anode, window, thin layer of oil coolant/insulation |
What is added filtration? | Thin sheets of aluminum that are added |
NCRP guidelines state that equipment operating above 70kVp must have a minimum total filration of how much? | 2.5mm AL equivalent |
When should gonadal shielding be used? | If the gonads lie within 5 cm of the collimated field, the patent has reasonable reproductive potential, or diagnostic objectives permit. |
Consists of a radiolucent chamber just beneath the tabletop above the IR and grid. | Ionization chamber |
A small fluorescent screen is positioned beneath the IR. | Phototimer |
What are the cardinal radiation protection rules? | Time, Distance, Shielding |
Protect from the useful beam. | Primary barriers |
Protect from scattered and leakage radiation. | secondary barriers |
Lead walls and doors of the radiographic room or any surface that could be struck by the useful beam are examples of which type of barriers? | Primary |
Portions of the walls above 7 ft, lead aprons/gloves, and the control booth are which type of barrier? | Secondary |
Contains a thin layer of aluminum oxide which absorbs and stores the energy associated with exposure to ionizing radiation. It is stimulated with green light and the blue light emitted is proportional to the amount. | Optically Stimulated Luminescence |
Consists of special radiation dosimetry film packaged like dental film and enclosed in special plastic holder and are used for 1 month. | Film Badge |
Contains crystalline chips of lithium fluoride that are heated which causes a release of visible light from the chips in proportion to the amount of ionizing radiation absorbed. Very sensitive. | Thermoluminescent dosimeter |
Used with high exposures or large qantities of radiation for short periords of time. Immediate reading is available. | Pocket Dosimeter |