What part of the x-ray beam has different signal intensities that correspond to the anatomy represented on the image receptor?

The remnant beam is the portion of the x-ray beam that passes through the patient and interacts with the image receptor. As the x-rays traverse various tissues, they are attenuated to different degrees based on the atomic density and thickness of the anatomy they encounter. Dense structures, such as bones, absorb more x-rays, resulting in lower signal intensity in those areas on the image receptor. Conversely, less dense structures allow more x-rays to pass through, leading to higher signal intensities.

Therefore, the remnant beam is critical in creating contrast in the final image because it is responsible for the varying signal intensities that allow visualization of the different anatomical features within the patient. This results in a diagnostic image that reflects the underlying anatomy based on the varying degrees of radiation exposure captured by the image receptor.

While the primary beam refers to the initial x-ray beam emitted from the tube, and scatter radiation pertains to x-rays that have interacted with matter and changed direction, it is the remnant beam that ultimately provides the essential information needed for image evaluation and quality control. Receptor exposure may refer to the overall exposure of the film or detector, but it does not specifically indicate the varying signal intensities that map to anatomical details.