Exposure and Dismissal

According to law, when a panoramic exposure is made on a patient, the operator must:

1. be positioned to observe the patient throughout the entire exposure and,

2. be either 2 meters (approximately 6 feet) from the patient or if closer than 2 meters, behind a barrier.

Immediately prior to exposure, the patient should be informed that the panoramic unit will move in front of them and take approximately 20 seconds to complete the rotation. The patient should also be reminded to keep their lips together and hold still for the entire exposure. It is helpful to instruct the patient to close their eyes as well so that they do not follow the movement of the receptor. If the patient tracks receptor movement, an error in the midsagittal plane will occur.

Patient exposure is achieved by depressing the exposure button and keeping it depressed throughout the entire rotation of the panoramic unit until it comes to a complete stop. The exposure control is a “Deadman” switch. This means that release of the button will terminate not only the exposure of the patient to x-radiation but the rotational motion. Exposure should be terminated if the patient moves markedly at the beginning of the exposure. This can be due either to the spontaneous patient movement (e.g. cough, sneeze) or to shoulder interference with the rotational motion of the C-arm.

After exposure, most machines will release the temple bars/supports immediately. The clinician should instruct the patient to release the bite block and ask the patient to slowly back away from the head rest. Only after the radiographic image has been determined to be diagnostically acceptable should the patient be dismissed or escorted back to the operatory.