Factors influencing the effective dose associated with CBCT: a systematic review

Due to potential impact of the effects of ionizing radiation used in medical and dental examinations on public health in recent years, many studies are being conducted to quantify the radiation dose values, evaluate scanners, and indicate factors that could influence or reduce radiation doses.

This study aimed to evaluate, by a systematic review, the factors that influence the effective radiation dose associated with cone beam computed tomography and respective effects, and compared the effective dose of different cone beam computed tomography (CBCT) scanners with similar exposure parameters.

A search was conducted on five databases from 2007 to 2015.

The search identified 741 abstracts, among which 44 eligible articles were retrieved in full text. Twenty-three studies met the inclusion criteria and were included. Additional copper filter was evaluated in one study, patient size in 2 studies, region of interest in 1 study, use of a thyroid shield in 2 studies, scan angle in 3 studies, exposure time in 10 studies, FOV diameter in 17 studies, FOV height in 17 studies, kV in 16 studies, mA in 18 studies, mAs in 13 studies, voxel in 8 studies, and resolution in 3 studies. When similar exposure parameters were evaluated, it was observed that CBCT scanner with lower effective dose was Kodak® 9000C 3D (mean 21.2 μSv) in selected studies.

Thirteen factors were related to changes in the effective dose emitted by different scanners. More studies are needed to identify the image quality requirements in addition to measure the radiation.

Studies that give more information for professionals who request and interpret the exams and for technicians who perform 3D images about effective radiation dose associated with CBCT are necessary.