DANB Radiation Health and Safety (RHS) Practice Exam

What is the primary purpose of the filter in an x-ray machine?

1. To enhance image resolution

2. To reduce patient exposure

3. To increase tube life

4. To concentrate x-ray production

The correct answer is: To reduce patient exposure

The primary purpose of the filter in an x-ray machine is to reduce patient exposure to unnecessary radiation. Filters are designed to allow only the higher-energy x-rays to pass through while absorbing the lower-energy x-rays that contribute minimally to diagnostic information but increase the patient's dose of ionizing radiation. By eliminating these lower-energy rays, the filter not only helps minimize patient exposure but also improves the quality of the x-ray image since the remaining beams are more effective at penetrating tissues and producing clearer images. While enhancing image resolution, increasing tube life, and concentrating x-ray production might be potential considerations in the operation of an x-ray machine, they do not describe the primary role of the filter. The filter's main focus is on patient safety and maintaining quality imaging, making the reduction of patient exposure its most critical function.