What effect does decreasing the primary beam field size have on scatter radiation?

Decreasing the primary beam field size reduces the volume of tissue irradiated and, consequently, the amount of scatter radiation generated. A smaller field size limits the area being exposed, which results in fewer photons interacting with the anatomical structures that can produce scatter. As a result, less scatter radiation reaches the image receptor (IR). This reduction in scatter helps to enhance image quality by decreasing noise and improving contrast on the radiographic images.

In contrast, a larger field size can lead to increased scatter because more tissues are irradiated, which generates more scatter photons that might reach the image receptor, thereby complicating image interpretation. Thus, by carefully controlling the primary beam field size, radiographers can effectively manage scatter radiation, leading to better diagnostic images.