EPIDs function by capturing images of the treatment field using X-rays. When a patient undergoes radiation therapy, the linear accelerator generates X-rays that pass through the patient's body and are detected by the EPID. The device then converts the X-ray photons into electrical signals, which are processed to form digital images. These images can be used to compare the planned treatment position with the actual position, ensuring that the radiation is delivered precisely to the intended area.
