When comparing 100 kV and 70 kV, what effect does using 70 kV have?

Using 70 kV results in less Compton scatter primarily because lower kilovoltages (kV) produce x-rays of lower energy. Compton scatter occurs when x-ray photons collide with matter, particularly with electrons in the tissues. Higher energy x-rays, like those produced at 100 kV, can interact more freely and produce a greater amount of scatter radiation. In contrast, at 70 kV, the x-rays are less energetic, which reduces the likelihood and intensity of Compton interactions, leading to less scatter in the image. This can enhance image quality by improving contrast due to a reduction in scatter noise.

The other options, while relevant aspects of image production, do not align with the specific effects of lowering the kilovoltage to 70 kV. For instance, lowering kV typically decreases exposure latitude, can produce shorter scale contrast (more black and white instead of shades of gray), and may increase patient exposure due to the need for higher mAs to compensate for the lower kV. Understanding these relationships helps to clarify the imaging physics involved in radiographic practice.