CT Radiation Safety and Dosimetry Flashcards
6 cards from real Computed Tomography Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CT Radiation Safety and Dosimetry flashcards as text
The DLP (Dose Length Product) in CT is calculated by multiplying CTDI_vol by which parameter?
Answer: Scan length
DLP = CTDIvol × scan length (in cm), providing an estimate of total energy deposited during the entire CT examination.
Which of the following best describes the dose profile of a helical CT scan with a pitch greater than 1?
Answer: Gaps exist between dose profiles from successive rotations
A pitch >1 means the table moves faster than one detector width per rotation, creating gaps in the dose profile and generally reducing patient dose.
In CT, which body region is most sensitive to radiation-induced cancer risk?
Answer: Bone marrow and gonads
Bone marrow and gonads have the highest tissue weighting factors (wT), making them most sensitive to stochastic radiation-induced cancer risk.
What is the recommended lead apron shielding thickness to protect gonads from scattered CT radiation?
Answer: 0.5 mm lead equivalent
A 0.5 mm lead equivalent apron is standard for gonadal shielding, though its effectiveness in CT is debated due to scatter from all directions.
Which population group requires the most careful dose optimization in CT due to higher radiation sensitivity?
Answer: Pediatric patients
Children are more radiosensitive than adults and have more years of life remaining in which radiation-induced cancers could develop, requiring strict dose minimization.
What does the size-specific dose estimate (SSDE) correct for compared to CTDIvol?
Answer: Patient body size and diameter
SSDE adjusts CTDIvol based on the patient's effective diameter to provide a more accurate estimate of actual patient dose.