Final answer:
The three items that must be precisely aligned for a quality radiograph are the patient, the X-ray tube, and the image receptor, ensuring accurate imaging and minimized radiation exposure.
Step-by-step explanation:
The three items that must be precisely aligned to obtain a quality radiograph are the patient, the X-ray tube, and the image receptor. This alignment ensures that the X-rays are directed correctly through the patient's body to the image receptor, creating a clear and detailed image. Proper alignment also minimizes exposure to unnecessary radiation and ensures that the area of interest is accurately captured.
For example, in dental radiography, an X-ray machine is used to produce low-energy radiation that is directed at the patient's teeth, and a fast film or digital image receptor captures the resulting image. Shielding and protective measures, such as lead aprons, are employed to reduce radiation exposure to other parts of the body.