Dental CT Scanners: Common installation missteps and prescribing x-rays

September 1, 2016

Originally published in the August/September 2016 issue of Dispatch

Dental computed tomography (CT) technology has rapidly improved over the past decade. As a result, many dentists are interested in using this imaging modality for the diagnosis and treatment of their patients.

Installation missteps

Certain parameters apply when installing and operating a CT scanner in Ontario. The Ministry of Health and Long-Term Care and the College have outlined steps that a dentist must take to ensure dental CT scanners are being installed and operated properly.

The dentist is ultimately responsible for ensuring they have adhered to the requirements of, and are in compliance with, the College’s Standard of Practice for Dental CT Scanners. Dentists are encouraged not to rely on the information they receive from the manufacturer or the supplier regarding the steps that need to be taken to install and operate a dental CT scanner.

Common missteps that the College has seen, which have resulted in the member not being in compliance with the College’s Standard of Practice for Dental CT Scanners include:

Providing inaccurate or incomplete information to the Ministry of Health and Long-Term Care for approval.
Installing and operating the dental CT scanner prior to obtaining written approval from the Director of X-ray Safety and a letter of designation from the Ministry of Health and Long-Term Care.
Changing the floor plans from those that were originally submitted to the Ministry for approval.
Installing a dental CT scanner that is not new and manufactured within 12 months of installation.
Irradiating patients and/or staff during the required on-site testing/training for the safe operation of the dental CT scanner.

Prescribing x-rays

Dental radiographs should only be prescribed when there is clinical justification to do so. Patients have the right to a high quality x-ray examination with as small amount of risk as possible. Radiology should be performed responsibly, minimizing radiation dosage to the patient, while maximizing the diagnostic benefit.

The As Low As Reasonably Achievable (ALARA) principle applies to dental CT scans as well as to conventional radiography. All radiographs, including dental CT scans which deliver doses of ionizing radiation that are usually significantly higher compared to conventional dental radiographic techniques, should not be taken on a routine basis.

Prior to taking a dental CT scan, the dentist must review the patient’s medical history, perform a clinical examination and interpret any previous radiographs and/or images that have been taken of the patient in the area of interest. There must be documented justification as to why a dental CT scan has been ordered and taken and the benefits must outweigh the potential risks. A dental CT scan should only be ordered and taken when the information that the dentist wishes to receive cannot be obtained with lower dose conventional radiography. The field of view must be collimated to the field of interest.

If a follow-up dental CT scan has to be ordered/taken, it must be justified, and if necessary, reducing the field of exposure should be considered to reduce the radiation dosage to the patient.

For all dental CT scans taken, the entire field of view must be examined and reviewed for disease, regardless of the specific reason it was taken. A written report of this interpretation must be generated and retained in the patient’s file.