Which three factors define beam geometry in radiographic imaging?

Beam geometry in radiographic imaging is fundamentally influenced by the relationships between the source of radiation, the object being imaged, and the image receptor. The correct answer highlights the factors that define how the X-ray beam is directed and how it interacts with these elements.

Source-to-image distance (SID) is crucial because it affects the intensity and sharpness of the radiographic image. A larger SID reduces the geometric unsharpness and enhances image quality. It is the distance between the X-ray tube (source) and the film or image receptor, making it a critical factor in determining the beam geometry.

The object-to-image distance (OID) plays a similar role in that it involves the distance from the object to the image receptor. An increased OID magnifies the object but also increases the potential for distortion and reduces image sharpness due to increased scatter radiation. This relationship helps in understanding how positioning affects image quality.

Tube angulation, while not mentioned in the accepted answer, is another significant factor affecting beam geometry. The angle at which the X-ray tube is positioned relative to the object and image receptor can influence the projection and the geometry of the shadow cast on the image receptor, especially in angled structures.

Film sensitivity, while important in determining the film's