Operator exposure from CT exams is generally very low because: 1) CT beam is well collimated, 2) scattered radiation is confined to the exam room, 3) operators control the fluoroscopic beam.

• A. 1 and 2
• B. 1 and 3
• C. 2 and 3
• D. 1, 2, and 3

Answer: (A)

The main idea is that operator exposure in CT is kept very low because the system uses a tightly collimated X-ray beam and protective room design to limit scatter. When the beam is well collimated to the anatomy of interest, less tissue is irradiated outside the target area, which means less secondary radiation is produced. In addition, CT rooms are designed with shielding and barriers that contain scatter within the room, and the operator sits away from the primary beam in a controlled area. The statement about operators controlling the fluoroscopic beam doesn’t apply to CT, since CT imaging is automated and does not rely on real-time fluoroscopy controlled by the operator. So the best explanation involves the combination of precise beam collimation and room/shielding containment, which is why exposure from CT is generally very low.