Establishment of diagnostic reference levels for dentomaxillofacial radiography in Japan

这项研究的目的是建立日本牙颌面放射摄影的诊断参考水平(DRL)，以促进为患者提供最佳的放射防护，并在常规X射线检查中管理患者的剂量。为了评估这些DRL，我们研究了辐射测量的辐射量和方法，然后调查了大学口腔医院和口腔诊所的辐射量和患者剂量，区域调查使用便携式剂量计结合X射线胶片，局部地区调查使用电离室，由日本质量保证组织校准。根据调查结果，确定了标准成人剂量分布的三分之一：(1)口腔内摄影：患者入院剂量，PED=2.1mGy2，剂量面积乘积DAP=59mGycm2；DAP=59mGycm2；D速片的DAP是PED的两倍，DAP应按矩形野面积的PED乘积计算；(2)全景摄影：剂量宽度乘积，DWP=65mGymm，DAP=113mGycm2；(3)头影测量：入射面空气比释动能，ESAK=0.4 mGY，但由于使用了楔形滤光片和楔形辐射场，DAP未被提出；(4)用于双颌牙种植手术计划的CT：加权CT剂量指数，CTDI_w=35 mGY，剂量-长度乘积，DLP=360 mGycm，但每个颌骨的DLP是DLP的一半。日本应实现这些与欧洲建议的DRL几乎相同的DRL，以保持足够的管电位、束流过滤和高灵敏度的图像接收系统用于牙科放射检查。

The objectives of this research were to establish diagnostic reference levels (DRLs) for dentomaxillofacial radiography in Japan in order to promote optimization of radiological protection for patients and to manage patient doses in routine X-ray examinations. For evaluation of these DRLs we studied the radiation quantities and methods of radiation measurement, and then surveyed the quantities and patient doses in university dental hospitals and in dental clinics.Transportable dosimeters coupled with X-ray films were used for the regional area survey and ionization chambers were used for the local area survey, which were calibrated by the Japanese Quality Assurance Organization. The ionization chambers were compared with the transportable dosimeters which were composed by an optically stimulate luminescence dosimeter for intraoral radiography and a thermoluminescent dosimeter array for panoramic radiography.From the results of the survey the DRLs were determined as a third quartile of the dose distributions for standard adults as follows : (1)intraoral radiography : patient entrance dose, PED=2.1 mGy and dose-area product, DAP=59 mGy cm^2 ; but a double of PED or DAP for D-speed films and the DAP should be calculated from the product of PED by the area of a rectangular field ; (2)panoramic radiography : dose-width product, DWP=65 mGy mm and DAP=113 mGy cm^2 ; (3)cephalometric radiography : entrance surface air kerma, ESAK=0.4 mGy, but DAP was not proposed because of the usage of wedge filters and radiation fields of wedge shapes ; (4)computed tomography (CT) for planning of dental implantation surgery of both jaws : weighted CT dose index, CTDI_w=35 mGy and dose-length product, DLP=360 mGy cm, but a half of DLP for each jaw.These DRLs, which are almost the same as those proposed in Europe, should be achieved in Japan to maintain adequate tube potentials, beam filtrations, and high sensitivity image receptor systems in dental radiographic examinations.