Experts advocate using low-dose CBCT imaging protocols
Dr Michael Bornstein is Clinical Professor in Oral and Maxillofacial Radiology and Associate Dean for Research and Innovation at the University of Hong Kong in China. He has followed the ongoing evolution of low-dose CBCT imaging closely, encourages all clinicians to increase their use of dose limitation measures, and has said that the radiation dose to the patient will continue to become lower.
Dr Bornstein is also one of the leading CBCT imaging experts in the dental community. He was one of the speakers at Planmeca’s stand at the 2019 International Dental Show in Cologne in Germany and gave a presentation titled “Low-dose CBCT protocols in dental medicine and their impact on daily clinical practice”. It covered the changes and paradigm shifts that have taken place in the field of dental 3D imaging, with a particular emphasis on low-dose protocols. Highlights of this presentation are given in this short article.
Cone beam computed tomography (CBCT) is an imaging technique that has been a game-changer in dentistry over the last decades. It has allowed clinicians to easily acquire 3D images that have a significantly higher diagnostic value than traditional 2D images do. However, this improvement is not one completely without downsides, as the additional dimension comes at the cost of higher effective radiation doses to patients. Their exact biological effects have been difficult and sometimes even impossible to measure, but potential harm from high radiation dose levels should not be ignored.
Although the risks of CBCT imaging are very small to individuals, they are still significant when examined in the context of large population bases. Dr Bornstein states that six to eight patients per million are at risk of developing cancer related to dental imaging in their lifetime. This is why ways to reduce patient doses without losing diagnostic image quality are considered so valuable.
Over the past five years, there has been an ongoing shift in the minds of radiologists from ALARA to ALADA—from capturing images that are as low as reasonably achievable to as low as diagnostically acceptable. One could even say that finding an optimal balance between image quality and dose is at the core of modern dental imaging. Dr Bornstein’s own research has indicated that images can be used for diagnosis as intended also when using ultra-low-dose imaging protocols.
From low to ultra-low
The Planmeca Ultra Low Dose imaging protocol has been leading the way in patient dose minimisation over the last five years. According to research done by John Barrett Ludlow and Juha Koivisto several years ago, a mean dose reduction of 77% can be achieved using it as part of CBCT imaging.  This figure is set to improve further with Planmeca’s research and development team steadily working towards new technological breakthroughs.
Dr Bornstein views low-dose imaging not only as a mere technological question but also as one intricately related to usability. “We all talk about digital workflows, but they are not always that easy to implement. That is why they need to be straightforward and intuitive. I think it is safe to say that our smartphones, for example, would never have become so popular if they were very difficult to use.”
It was always possible to manually adjust the dose levels of various radiographic units, but it was not that easy. Various manufacturers have also struggled to maintain a diagnostically acceptable image quality at lower doses. Activating Planmeca Ultra Low Dose, however, is as easy as pressing a button. Furthermore, it can be used with any resolution or volume size, as the protocol does not rely on taking fewer frames or using a smaller rotational angle to lower the patient dose.
“Planmeca was one of the first to come up with a preset modality that makes it very easy to apply dose limitation measures. By doing this, they were also leading the way for many others.”
The broad field of radiology
Dr Bornstein went to dental school at the University of Basel in his native country of Switzerland and went on to become an oral surgeon. Working as a dentist further expanded his interests and led him to the world of oral and maxillofacial radiology and diagnostic imaging. He soon discovered that radiology is quite an extensive discipline that encompasses not only 2D and 3D radiographic imaging but also ultrasound and magnetic resonance imaging in some countries.
“Radiology is a broad and challenging field. Because it is so technically driven, it is also very innovative. I think these factors together have kept me so interested and enthusiastic about it,” Dr Bornstein elaborated.
Although he now resides in Asia, for Dr Bornstein, IDS still holds a special significance—as is the case for countless dental professionals worldwide. In fact, he has witnessed the international atmosphere significantly strengthen at the exhibition over the years. “Being from Switzerland, IDS has always been on my agenda, although I don’t go every time. In contrast to many other fairs and exhibitions, it seems to still be growing, and has become more and more international,” Dr Bornstein commented. “Twenty years ago, IDS was still very European- and German-centric. Now, I think it has become much more of a global village for dentistry.”
No limit to how low doses can go
Although significant strides have already been made in lowering patient doses to levels unimaginable in previous decades, Dr Bornstein still sees much room for improvement. “I would say there is no limit really to how much lower doses can go. Ten years ago, nobody would have even said that ultra-low-dose imaging would provide reasonable image quality, so I hope this shift will continue,” he said.
“Maybe in ten or 20 years, the term ‘low dose’ will not even be applied anymore, because all 3D imaging will be low dose. Maybe the low doses we talk about today will be the regular doses of the future.”
About Dr Bornstein
Originally from Basel, Dr Michael Bornstein is an oral surgeon turned radiology expert. He headed the section of dental radiology and stomatology at the University of Bern in Switzerland from 2007 to 2014. Currently, Dr Bornstein holds the position of Clinical Professor in Oral and Maxillofacial Radiology and is Associate Dean for Research and Innovation at the University of Hong Kong’s Faculty of Dentistry. His key fields of research include dental CBCT imaging, stomatology, guided bone regeneration procedures and dental implants. During his academic career thus far, he has published over 140 original articles and authored numerous case reports, review articles and book chapters.
1. Ludlow JB, Koivisto J. Dosimetry of orthodontic diagnostic FOVs using low dose CBCT protocol. Poster session presented at: 93rd General Session & Exhibition of the International Association for Dental Research; 2015 Mar 11–14; Boston, MA.
Editorial note: This article was originally published in the international magazine, CAD/CAM No. 02/2019.