Which combination reduces patient radiation dose?

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

Answer: (B)

The key idea is cutting the dose while preserving diagnostic image quality by controlling how much radiation reaches the patient. The two strategies represented by the second and third items work together to achieve that best reduction: restricting the X-ray beam to the area of interest and shielding radiosensitive tissues. Collimation minimizes the irradiated volume and reduces scatter, so less tissue is exposed and image quality is maintained with lower dose. Shielding provides a protective barrier for organs not needed for the exam, directly lowering the dose to those tissues. When these two are used together, you address both where the beam goes and what it hits, giving the greatest overall dose reduction. The first item, by itself or in combination with the others, does not contribute to dose reduction as effectively, so the combination of the second and third strategies yields the best outcome.