Radiography: Radiation Protection Flashcards
Measurement of radiation exposure from X-rays, gamma rays, or other types of radiation used in the treatment or detection of diseases, including cancer, is called _____________________ .
dosimetry
Increasing the kVp of an X-ray beam will result in the photons having shorter or longer wavelengths?
Shorter
An optically stimulated luminescence dosimetry measuring device uses what substance as a detector?
Aluminum oxide (Al2O3)
What are the 3 classic acute radiation syndromes?
Hematopoietic syndrome (also called bone marrow syndrome), gastrointestinal syndrome, and cerebrovascular syndrome
What are the 4 stages of acute radiation syndromes?
The prodromal stage (N-V-D stage), the latent stage, the manifest illness stage, and the recovery or death stage
What term denotes the shedding of the outer-most layer of skin due to high radiation exposure?
Desquamation
During which gestational trimester of development is a fetus most radiosensitive?
The first trimester
_________________ is the restriction of the useful X-ray beam to the anatomy being imaged, thereby sparing adjacent tissue from unnecessary radiation exposure.
Collimation
What does ALARA stand for?
As Low As Reasonably Achievable
The effective dose to biologic material is expressed using what unit of measure?
Sievert (Sv)
The absorbed dose is expressed using what unit of measure?
Gray (Gy)
Does bone, muscle, or fat have the highest effective atomic number?
Bone
What are the 3 cardinal principles of radiation protection?
Time, distance, and shielding
Federal law requires at least __________________ total filtration for general-purpose X-ray tubes that operate above 70 kVp.
2.5 mm of aluminum equivalent
The percentage of time when an X-ray beam is on and directed toward a protective barrier is called the _________________.
use factor
Thermoluminescence dosimeters use what substance for radiation detection?
Lithium fluoride
What type of secondary radiation protection is not always included as part of a typical lead apron and can decrease the amount of effective dose by 2.5-fold, with almost a 50% reduction in total exposure?
The thyroid shield
_____________________ measures radiation exposure from natural background radiation sources during the monitoring period and any incidental exposure that may occur during shipment or storage.
A control dosimeter
In fluoroscopy, what feature is used to maintain a consistent overall appearance of the image by automatically adjusting the kVp and/or mAs?
Automatic brightness control
What are the main goals for using magnification mode in fluoroscopy?
To provide better spatial resolution and contrast resolution
What components of a fluoroscopic imaging system serve as the primary protective barrier?
The image receptor assembly
What type of radiation detectors are gas-filled?
Ion chambers and Geiger-Muller counters
Substances or anatomy with higher atomic numbers have higher or lower attenuation values?
Higher
Structures or anatomy with a low attenuation value that appear dark or black on a radiograph are considered to be _________________________ .
Radiolucent
What is the equivalent dose of most diagnostic radiographic procedures?
Less than 0.01 Sv
For occupational radiation dose exposure, equivalent annual dose limits for the lens of the eye are ______________ .
150 mSv
What is the annual occupational effective dose limit?
50 mSv
What is typically used to line the X-ray image intensifier/tube housing that protects RTs and patients from radiation leakage?
Lead
Why must RTs using mobile radiographic equipment wear protective aprons?
Because there is no protective barrier included in the construction of mobile radiography equipment
In situations where an RT must hold a patient upright for mobile radiography, the RT should stand in what position?
At right angles or 90° to the scattering object
Fluoroscopic mAs must not exceed ___________________
5 mAs
What is the dose limit for RTs who have formally declared their pregnancy to their employer?
0.5 mSv per month
Protective lead aprons, gloves, and other protective equipment should be inspected how frequently for cracks and other defects?
Yearly
Where is a dose area product meter generally located in imaging equipment?
In the collimator assembly
Which type of shielding is suspended in the area of the collimator positioning light?
The shadow shield
The disease with the shortest latent period as a result of radiation exposure is ____________
leukemia
What are the 2 time periods associated with acute radiation lethality?
The prodromal period and the latent period
What dose-reduction feature allows fluoroscopic imaging to be paused or stopped in order to retain a snapshot of the image displayed on the monitor?
The last image hold/save grab feature
What type of radiation barriers are the imaging control booth walls and windows considered to be?
Secondary barriers
The minimum source-to-skin distance for a stationary fluoroscopy unit is ____________ .
38 cm or 15 inches
What thicknesses of lead barriers must be used for primary and secondary radiation barriers?
Primary barriers must have 1/16th inch of lead protection and secondary barriers must have 1/32nd inch of lead protection
A fluoroscopic Bucky slot cover/shielding device protects what general area of the body?
The gonad level/area
