COMPARISON OF OPERATOR EXPOSURE DOSE IN PORTABLE INTRAORAL X-RAY DEVICES AND DOSE MANAGEMENT

Y. Otaka, Y. Harata, M. Izawa, N. Shiba, A. Iwawaki, T. Ishii, A. Ochiai, N. Takahashi, H. Saka, S. Kito

Abstract: Objectives. Portable intraoral X-ray devices were widely used for personal identification following the Great East Japan Earthquake. Although various models have been developed and are commercially available, few studies have compared their characteristics. As portable intraoral X-ray devices are often hand-held during use, it is important to understand the dose to the operator and to undertake dose management.
Methods. Fourteen types of portable intraoral X-ray device were compared. Semiconductor detectors were used to measure the output characteristics, using a cylindrical head phantom for computed tomography dose measurement as the object. An ionization chamber dosimeter was used to measure the dose distribution in air, with measurement points placed at radii of 0.5 m and 1.0 m from the center of the phantom. Measurements were taken over 360° at intervals of 15° with the primary X-ray beam at 0°.
Results. For all 14 devices, the average dose ± standard deviation was 0.243 ± 0.175 μSv per 1 mGy of cone-tip air kerma at 120° to 240° at a radius of 0.5 m. This value equates to approximately 200 intraoral radiographs per day at 2 mGy per radiograph, which exceeds the annual occupational exposure limit for operators.
Conclusions. Whenever there is risk of exceeding the dose limit, a plan for the task of identification must be formulated considering radiation protection.
Keywords: portable intraoral X-ray device, personal identification, operator exposure dose, dose management