Radiologic Technologist Practice Exam

Decreasing the kVp will ________ receptor exposure and ________ contrast.

1. Decrease; decrease

2. Decrease; increase

3. Increase; decrease

4. Increase; increase

The correct answer is: Decrease; increase

Decreasing the kilovoltage peak (kVp) has a significant impact on both receptor exposure and contrast in radiographic imaging. When kVp is reduced, the energy of the x-ray photons produced is also lower, which results in a decrease in the overall receptor exposure. This occurs because lower energy photons are less likely to penetrate through the body or the subject being imaged, thereby reducing the number of photons that reach the imaging receptor. On the other hand, a reduction in kVp increases the contrast of the image. Contrast refers to the difference in density between various areas of the image, which makes it easier to distinguish between different tissues or structures. Lowering the kVp leads to a greater differential attenuation of x-ray photons by various tissues, as different tissues absorb x-rays to varying extents. This enhanced differentiation makes the structures more discernible on the radiograph, effectively increasing the image contrast. Thus, the correct answer is that decreasing the kVp will decrease receptor exposure and increase contrast.