To ensure consistent high quality panoramic images, a quality assurance program should be in place and carried out by qualified dental personnel. Radiographic quality assurance procedures include regular testing, planned monitoring and scheduled maintenance of x-ray equipment, darkroom conditions, film processing and image receptors.
X-ray machines should be inspected periodically for x-ray output, kilovoltage calibration, half value layer, timer accuracy, milliamperage reproducibility, and collimation as required by state law. Operators must be qualified and credentialed according to state regulations.
The darkroom should be evaluated on a monthly basis to eliminate any white light leaks and to ensure proper safelight conditions. The coin test is an effective method for determining whether or not darkroom conditions are optimal. These procedures will prevent film fog which darkens and degrades the radiographic image.
Film processing solutions should be evaluated on a daily basis prior to processing patient films to correct problems or any chemical deficiencies. Commercial test tools and metal stepwedge devices are available to produce test films for this purpose. Solution replenishment, proper time-temperature regimens and regular processor cleaning and solution change are important factors in the production of quality radiographic images.
Panoramic film must be stored properly in a cool, dry environment away from chemical fumes and an x-ray source. After the film box has been opened, it is best to place the open end of the film envelope into the box away from the lid. This practice will help avoid film fog and unwanted darkening of one end of the film. Cassettes should be inspected for damage and the intensifying screens cleaned on a regular basis. Commercial screen cleaning products with an anti-static agent are available to complete this task.
It is recommended that a retake log be maintained to help monitor the number of retakes and the errors committed. Identification of recurring errors indicates a need for continuing education and in-service staff training.
The American Academy of Oral and Maxillofacial Radiology has published several articles7,8 that provide guidance in the assessment of and compliance with recommended quality assurance procedures and radiation safety measures.