Where does the primary radiation originate from?

The primary radiation originates from the tube, which is the source of X-rays or other radiation in imaging modalities like radiography and fluoroscopy. This tube comprises a cathode and an anode, where electrons are accelerated and collide with the anode target, producing X-rays. The radiation produced in the tube is specifically aimed at the patient or object being imaged, thereby serving as the primary source for diagnostic imaging procedures.

The control panel, while crucial for operating the equipment, does not produce primary radiation; it merely controls the settings of the tube and other functions. The image receptor is designed to capture the radiation after it has passed through the patient, making it a secondary element in the process. The surrounding environment may contain ambient radiation or scatter but is not a source of the primary radiation used in imaging. Understanding these distinctions is essential for grasping the principles of radiation safety and protection.