Cone beam computed tomography (CBCT) and breast tomosynthesis
Statement by the German Commission on Radiological Protection
Adopted at the 277th meeting of the SSK on 02/03 July 2015
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Abstract
Cone beam computed tomography (CBCT) or digital volume tomography (DVT) is a process which produces three-dimensional image data using a combination of X-ray tube and flat-panel detector or image intensifier which rotates around the patient. Breast tomosynthesis is an additional feature of modern digital mammography equipment, which generates two-dimensional images of the glandular tissue in different depths that are largely free of overlapping. In recent years, CBCT has become an integral part of medical imaging in dentistry, oral and maxillofacial surgery and otolaryngology. It is primarily suitable for displaying high-contrast objects and enables a significantly lower radiation exposure compared with conventional computed tomography (CT). Due to the increasing availability of CBCT systems these are often also used for imaging soft tissues, in which case doses are reached that are comparable to a conventional CT. In its recommendation, the German Commission on Radiological Protection therefore stresses that for the application of CBCT the fundamental principles of radiation protection must be observed especially with respect to both the justifying indication and the protection of patients and staff, and that potentially lower-dose procedures should be preferred. To enable dose optimisation, the German Commission on Radiological Protection recommends that manufacturers are asked to provide standardised information on patient exposure. The indication for digital breast tomosynthesis should only be confirmed in cases of mammographically unclear findings in dense glandular tissue when other methods such as ultrasound or targeted compression views provide no clarification.