What radiation dose does CBCT impart?
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- First, we need to determine what we mean by radiation dose. We are referring to effective dose which represents the risk of ionizing radiation causing cancer and other genetic damage in those tissues and organs irradiated.
- Effective dose is tissue-weighted for the X-ray dose deposited in specified tissues and organs of the body. Important structures such as the salivary glands now have their own tissue weighting.
- There is no known safe radiation dose; therefore, we need to continue to observe the principle of “as low as reasonably achievable” (ALARA) especially for our most vulnerable patients: children.
- A recent Australian report in the British Medical Journal, published a follow-up on medical CT on individuals in their childhood is relevant to CBCT use. CBCT imparts a significantly greater radiation dose to the patient’s head than conventional radiography and it is more than just one or two panoramic radiographs, more like at least 10. The increased incidence of cancer after CT scan exposure in this cohort was 24%.
- Because the cancer excess was still continuing at the end of follow-up, the eventual lifetime risk from CT scans cannot yet be determined.
- Which CBCT unit is right for my dental office?
- What are the clinical indications for CBCT?
- What will be the likely impact of regulatory and other dental professional bodies on CBCT use?
Dr. David MacDonald
After winning his dental fellowship in Glasgow, In London Dr. MacDonald acquired his MSc in Oral Pathology, his Diploma in Dental Radiology of the Royal College of Radiologists and his law degree. His first specialist appointment was as Head of Radiology in Hong Kong, then Edinburgh, then Bergen and finally UBC in late 2003. His research interests are the radiology of the most frequent & important lesions affecting jaws and the application of systematic review to radiology. In 2008 he successfully defended his doctoral dissertation in Edinburgh and passed his fellowship examination of the Royal College of Dentists of Canada. His Wiley-Blackwell textbook was published in 2011; it has so far received 3 outstanding reviews. This evidence-based textbook also uniquely covered the advanced radiology not only of the face & jaws, but also the neck and the base of the skull. The dentist’s understanding of the last areas is essential in our now cone-beam CT-dominated climate.