Which of the following decreases radiation exposure to the patient?

• A. Decreasing the pitch
• B. Increasing kVp
• C. Increasing mAs
• D. Filtering the x-ray beam

Answer: (D)

Filtering the x-ray beam effectively decreases radiation exposure to the patient by removing lower-energy photons from the beam before it reaches the patient. These lower-energy photons contribute to the overall dose but do not contribute significantly to image quality. By filtering out these less useful photons, the overall radiation dose can be reduced without compromising the diagnostic information obtained from the image.

In contrast, decreasing pitch would typically lead to increased radiation exposure because it involves more overlapping scans, thus requiring more radiation to cover the same area. Increasing kVp, while it may improve the penetration ability of the x-ray photons, can also lead to an increase in the radiation dose delivered to the patient. Similarly, increasing mAs directly increases the quantity of radiation used during imaging, leading to higher patient exposure. Thus, filtering the x-ray beam represents a method to minimize radiation exposure while maintaining image quality.