The Source-to-Object Distance (SOD) is the distance measured between the focal spot on the target of an x-ray tube and the center mass of the patients anatomical organ. The SOD distance changes as every patient is made up differently in both size and weight. For example, the SOD distance is longer for a female with smaller tissue breasts and shorter in distance for a female with larger breast tissue. Another example, is a male with a smaller mid section the SOD is longer in distance to cover versus a larger male with a large abdominal distension (e.g. gas, bloating, fat) to cover a shorter SOD distance.