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
Which CT technique reduces dose by acquiring fewer projections and reconstructing with iterative algorithms?
Answer: Low-dose CT with iterative reconstruction
Low-dose CT combined with iterative reconstruction algorithms can reduce dose by up to 80% compared to traditional filtered back projection while maintaining diagnostic quality.
The term 'Z-axis dose profile' in CT refers to dose distribution along which direction?
Answer: Patient cranio-caudal (head-to-foot) axis
The Z-axis is the cranio-caudal axis along which the patient moves through the gantry, and the dose profile describes radiation distribution along this direction.
What effect does increasing CT tube voltage (kVp) have on patient dose?
Answer: Increases dose due to higher photon energy and greater beam penetration
Higher kVp increases photon energy and quantity (via space charge effect), generally increasing patient dose, though it may allow mAs reduction in large patients.
In CT fluoroscopy-guided procedures, which group is at highest risk for radiation injury?
Answer: The interventionalist's hands if placed in the beam
CT fluoroscopy uses continuous X-ray exposure, and the interventionalist's hands can receive very high doses if placed near or in the primary beam.
Which regulatory body in the United States sets occupational radiation dose limits for CT technologists?
Answer: Nuclear Regulatory Commission (NRC)
The NRC sets the annual occupational whole-body dose limit of 50 mSv (5 rem) for radiation workers in the US, including CT technologists.
What is the primary shielding material used in CT scanning room walls?
Answer: Lead or lead-equivalent concrete
CT room walls are constructed with lead or high-density concrete to attenuate primary and scatter radiation to acceptable levels for adjacent areas.