ICRP Publication 129: Radiological Protection in Cone Beam Computed Tomography (CBCT)

Abstract

The objective of this publication is to provide guidance on radiological protection in the new technology of cone beam computed tomography (CBCT). Publications 87 and 102 dealt with patient dose management in computed tomography (CT) and multi-detector CT. The new applications of CBCT and the associated radiological protection issues are substantially different from those of conventional CT. The perception that CBCT involves lower doses was only true in initial applications. CBCT is now used widely by specialists who have little or no training in radiological protection. This publication provides recommendations on radiation dose management directed at different stakeholders, and covers principles of radiological protection, training, and quality assurance aspects. Advice on appropriate use of CBCT needs to be made widely available. Advice on optimisation of protection when using CBCT equipment needs to be strengthened, particularly with respect to the use of newer features of the equipment. Manufacturers should standardise radiation dose displays on CBCT equipment to assist users in optimisation of protection and comparisons of performance. Additional challenges to radiological protection are introduced when CBCT-capable equipment is used for both fluoroscopy and tomography during the same procedure. Standardised methods need to be established for tracking and reporting of patient radiation doses from these procedures. The recommendations provided in this publication may evolve in the future as CBCT equipment and applications evolve. As with previous ICRP publications, the Commission hopes that imaging professionals, medical physicists, and manufacturers will use the guidelines and recommendations provided in this publication for implementation of the Commission's principle of optimisation of protection of patients and medical workers, with the objective of keeping exposures as low as reasonably achievable, taking into account economic and societal factors, and consistent with achieving the necessary medical outcomes.

Uses of cone-beam computed tomography in San José, Costa Rica

“…Tube current and voltage are operator-dependent factors and should be kept as low as possible to reduce the radiation dose, while maintaining the diagnostic quality of the image. 6 …”

“…It is suggested that these centers should evaluate their protocols and establish different protocols for adults, adolescents, and children. The doses were measured in CTDIw, which combines the measurements of the center and the periphery of a phantom to generate a weighted dose index, 6 11 so the dose measurements were not a direct evaluation of the effective dose received by each patient. As the CTDIw describes an average dose, it can be inferred that children receive a higher dose than is recorded by the equipment.…”

“…This has been shown in several investigations, in which the use of the same exposure parameters for both children and adults produced a greater effective radiation dose in children. 6 20 This higher dose can be explained because a small FOV covers a greater area in children than in adults, and the thyroid gland is therefore located closer to the primary beam. In addition, the other organs are closer to the surface, so they receive a larger dose.…”

“…The probability of these effects occurring, but not their severity, is proportional to the radiation dose. 4 6 …”

Designing and Fabricating Nano-Structured and Micro-Structured Radiation Shields for Protection against CBCT Exposure

“…As a result of this, CBCT is now widely used by practitioners who have not received the traditional radiation safety training of specialists in radiology. Therefore, more emphasis on radiation protection equipment, guidelines, and standardization for CBCT procedures seems reasonable [ 13 ].…”