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RADT 456
ARRT Reg Review Rad Proct
Question | Answer |
---|---|
What is used to account for the differences in tissue sensitivity to ionizing radiation when determining effective dose E? | Tissue weighting factors |
List a cell type that has the greatest radiosensitivity in the human adult? | lymphocytes |
Guidelines for the use of protective shielding state that gonadal shielding should be used when___? | the patient has reasonable reproductive potential and when the gonads are within 5 cm of the collimated field |
The ineraction between ionizing radiation and the target molecule that is most likely to occur is what? | indirect effect |
List two devices that help reduce patient dose. | collimator and gonad shield |
How will x-ray photon intensity be affected if the source-to-image distance (SID) is doubled? | its intensity decreases four times |
List two sources of natural background radiation contributing to whole-body radiation dose. | terrestrial radionuclides and internal radionuclides |
Irradiation of water molecules within the body and their resulting breakdown is termed what? | radiolysis |
What contributes most to occupational exposure? | Compton scatter |
The x-ray interaction with mater that is responsible for the majority of scattered radiation reaching the image receptor is what? | compton scatter |
A thermoluminescent dosimetry system would use which kind of crystals? | lithium fluoride |
List three things that has an effect on patient dose. | kilovoltage, milliampere-seconds, inherent filtration |
The photoelectric effect is more likely to occur with what? | absorbers having a high Z number (atomic #) and positive contrast media |
List three radiation-exposure responses that exhibit nonlinear threshold dose-response relationship. | skin erythema, hematologic depression, radiation lethality |
What is recommended for the pregnant radiographer? | wear a second dosimeter under the lead apron |
The annual dose limit for medical imaging personnel includes radiation from what? | occupational exposure |
Medical and dental radiation accounts for what percentage of the general public's exposure to human-made radiation? | 90% |
Which cells are nondividing cells? | neurons and neuroglia |
How does filtration affect the primary beam? | it increases the average energy of the primary beam |
Immature cells are refferred to as what? | stem cells and undifferentiated cells |
Patient dose increases as fluoroscopic _________ decreases. | FOV |
LET is defined as what? | a method of expressing radiation quality and a measure of the rate at which radiation energy is transferred to soft tissue |
The skin response to radiation exposure that appears as hair loss is known as what? | epilation |
The reduction in the intensity of an x-ray beam as it passes through material is called what? | attenuation |
What method is used to reduce radiation exposure to a recently fertilized ovum? | elective booking, patient questionnaire, and the 10-day rule |
What most effectively minimizes radiation exposure to the patient? | high-speed intensifying screens |
For radiographic examinations of the skull, it is preferred that the skull be examined in what projection? | PA projection |