A radiographer is using a c-arm and the radiographer stands six feet behind the image intensifier to limit exposure. Which position is this?

A radiographer is using a c-arm and the radiographer stands six feet behind the image intensifier to limit exposure. Which position is this?

• A. Immediately behind the tube side.
• B. Six feet behind the tube side.
• C. Six feet behind the image intensifier.
• D. Immediately behind the image intensifier.

Answer: (C)

The main idea here is using distance and shielding to reduce radiation exposure during fluoroscopy. Most scatter comes from the patient, so moving farther away from the source and standing behind a barrier greatly lowers dose. The image intensifier acts as a protective barrier on the radiographer’s side, attenuating scatter that would otherwise reach you. Standing six feet behind the image intensifier places you both behind that shielding and at a greater distance from the scatter source, which, by the inverse-square relationship, reduces exposure significantly. Choosing positions closer to the tube side or directly behind the image intensifier without adding distance would expose you to more scatter or bring you nearer the source, so they’re not as protective.

The main idea here is using distance and shielding to reduce radiation exposure during fluoroscopy. Most scatter comes from the patient, so moving farther away from the source and standing behind a barrier greatly lowers dose. The image intensifier acts as a protective barrier on the radiographer’s side, attenuating scatter that would otherwise reach you. Standing six feet behind the image intensifier places you both behind that shielding and at a greater distance from the scatter source, which, by the inverse-square relationship, reduces exposure significantly. Choosing positions closer to the tube side or directly behind the image intensifier without adding distance would expose you to more scatter or bring you nearer the source, so they’re not as protective.