Which action is considered one of the most important in avoiding unnecessary radiation exposure to the patient?

• A. Collimation
• B. Filtration
• C. Gonad shielding
• D. Grid usage

Answer: (A)

Limiting the irradiated tissue by shaping the beam to the exact area of interest is the most effective way to prevent unnecessary exposure. When the beam is tightly collimated, only the tissues that need to be imaged receive radiation, so the overall dose to the patient drops and less scatter is produced. Since dose is largely tied to the volume of tissue exposed, reducing the field size has the biggest impact on patient dose compared with other dose-control measures, and it also helps improve image quality by reducing scatter.

Filtration removes low-energy photons from the beam and thus lowers skin and superficial tissue dose, but the direct, large-scale reduction you get from tightening the field is greater. Gonad shielding provides targeted protection for reproductive organs, but it’s not universally applicable or the primary way to minimize dose across all exams. Grid usage improves image quality by reducing scatter, yet it often requires higher exposure to maintain receptor exposure, which can increase patient dose if not compensated.