Final answer:
The patient lying on her back with X-rays entering the right side and the image receptor on the left side is in the Right lateral decubitus position for radiographic imaging.
Step-by-step explanation:
The radiographic position described where the patient is lying on her back with the X-ray tube directed horizontally and the central ray (CR) entering the right side of the body, while the image receptor is on the left side of the body is known as the Right lateral decubitus position. This positioning is used in radiology to obtain images of the patient from their side while they are lying down. The decubitus position refers to the patient lying down and lateral indicates the side of the body closest to the image receptor. In this case, since the X-ray enters the right side, it is the right lateral decubitus position.