X-ray diagnostics effective with reduced radiation dose

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Reduced radiation dose in maxillofacial radiology yields comparable diagnostic results, study says

A recent study has found that reducing the patient radiation to 20% of the manufacturer-recommended protocol does not compromise the CBCT image quality. (Image: Massimo Cattaneo/Shutterstock)

MALMÖ, Sweden: Radiographic diagnostics are widely used in healthcare as they provide diagnostically important information that can help improve treatment outcomes. For example, a CBCT scanning protocol is a valuable examination tool in oral and maxillofacial radiology and is readily available in dental offices because of its ease of use. However, a CBCT scan produces a relatively high radiation dose compared with other scanning protocols, and new research has shown that its effectiveness remains unchanged after reducing the radiation dose to one-fifth of the manufacturer-recommended level.

To get a better look at an injury site, a surgeon often refers a patient for CBCT scans. For example, a CBCT scan can be a valuable tool for diagnosis and treatment planning for patients with temporomandibular disorders as it helps clinicians to perform assessments of bone changes with high diagnostic accuracy.

“With the CBCT, we take pictures of the mouth and jaw from three angles—from the front, from below, and from the side; this is in order to be able to answer the question that comes with the referral,” Dr Kristina Hellén-Halme, senior lecturer in the Faculty of Odontology at Malmö University, said in a press release. She went on to add that a radiographic examination is not a risk in itself but that it should not be taken without a valid reason.

Since the use of CBCT scans in dentistry is growing, a recent study sought to evaluate whether the high dose of patient radiation that is often used in CBCT imaging is really necessary to provide acceptable image quality.

Dr Kristina Hellén-Halme (Image: Hanna Svederborn)

“Many different scanning protocols are available, and sometimes the urge from clinicians to have more or less noise-free images can increase the radiation dose to patients without adding more information to the specific aim of the investigation,” the researchers explained.

In the study, 34 adult patients referred for CBCT imaging of the temporomandibular joint underwent two examinations with two scanning protocols: a manufacturer-recommended protocol and a low-dose protocol where the tube current was reduced to 20% of the recommended protocol. The researchers noted that manufacturer-recommended exposure settings for the CBCT scanners vary widely and may result in varying amounts of radiation doses.

After evaluating the visibility of temporomandibular joint anatomic structures and image quality, the radiologists who were tasked to analyse the images concluded that both the low and high dose images yielded diagnostically comparable results. Therefore, the findings suggest that high image quality is not necessary for all clinical situations and that dental professionals should reduce the recommended patient radiation dose provided that it does not affect diagnostic outcomes. They noted that this is especially important when treating younger patients who are at a higher risk from radiographic exposure than adults owing to the radiosensitivity of their developing tissues.

The study, titled “Evaluation of a low-dose protocol for cone beam computed tomography of the temporomandibular joint”, was published in the September 2020 issue of Dentomaxillofacial Radiology.

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