What is the main purpose of collimation in radiography?

What is the main purpose of collimation in radiography?

• A. Reduce exposure time
• B. Increase the intensity or penetrating power of the X-ray beam
• C. Increase the quantity or number of photons in an X-ray beam
• D. Limits field size reducing patient dose

Answer: (D)

Limiting the X-ray field to the area of interest is the main purpose of collimation. By narrowing the beam, fewer tissues are irradiated, which directly lowers the patient’s radiation dose. A smaller field also produces less scatter inside the body, and the reduction in scatter improves image contrast and overall diagnostic quality. Collimation doesn’t change exposure time or the total number of photons the tube emits; those are set by other exposure factors. So, the key idea is to limit field size to reduce patient dose.

Limiting the X-ray field to the area of interest is the main purpose of collimation. By narrowing the beam, fewer tissues are irradiated, which directly lowers the patient’s radiation dose. A smaller field also produces less scatter inside the body, and the reduction in scatter improves image contrast and overall diagnostic quality. Collimation doesn’t change exposure time or the total number of photons the tube emits; those are set by other exposure factors. So, the key idea is to limit field size to reduce patient dose.