CAMRT Radiography Practice Exam

How can off-focus radiation be controlled in x-ray tubes?

1. Using a higher kVp

2. Employing fixed diaphragms

3. Reducing the focal spot size

4. Implementing a rotating anode

The correct answer is: Employing fixed diaphragms

Controlling off-focus radiation is crucial in ensuring image clarity and reducing patient exposure in radiographic procedures. Employing fixed diaphragms effectively minimizes off-focus radiation by limiting the x-ray beam to the desired area of interest. Fixed diaphragms essentially function as a barrier that restricts the scattering of x-rays, ensuring that only the primary beam reaches the patient and the receptor. This targeted approach enhances image quality by reducing unwanted radiation and improving contrast. Maintaining control over off-focus radiation is also influenced by factors like the focal spot size, the anode design, and the kVp settings. While reducing the focal spot size can improve spatial resolution, it does not directly address off-focus radiation. Similarly, a rotating anode may enhance tube cooling and increase efficiency but does not inherently mitigate off-focus radiation. Using a higher kVp can increase penetration but does not specifically control the scatter that contributes to off-focus radiation. Thus, employing fixed diaphragms remains the most direct method for controlling off-focus radiation in x-ray applications.