MacDonald-Jankowski D S, Lawinski C P
Department of Dental Radiology, King's College School of Medicine and Dentistry, Denmark Hill, London, UK.
Br J Radiol. 1991 Jun;64(762):524-8. doi: 10.1259/0007-1285-64-762-524.
The aim of this investigation was to reduce the radiation dose to patients undergoing intra-oral dental radiography by using thin K-edge filters in addition to the existing aluminum filter. The subject was a head phantom (a human skull embedded in tissue-equivalent material), which was exposed to X rays over a range of tube voltages (50-90 kVp) for each of the four filter systems. These were 2.7 mm aluminium alone (the existing total filtration) or with added 0.1 mm erbium, 0.1 mm yttrium or 0.05 mm niobium. The radiation dose was measured at four selected sites along the primary beam. These were the entrance skin dose, the exit skin dose and intra-orally both in front and behind the dental film packet. The exposure times and radiation doses required to produce an equivalent density (degree of blackening) on a radiograph of an upper molar tooth were determined. Within the usual diagnostic range of 60-80 kV the use of the thin K-edge filter resulted in a doubling of the exposure time (owing to the additional attenuation of the added filters). However, the skin dose and the total dose imparted to the patient were significantly reduced.
本研究的目的是，除现有的铝滤过板外，通过使用薄K边滤过板来降低口腔内牙科X线摄影患者所接受的辐射剂量。研究对象是一个头部模体（嵌入组织等效材料中的人类头骨），对于四种滤过系统中的每一种，该模体在一系列管电压（50 - 90 kVp）下接受X射线照射。这四种滤过系统分别是：仅2.7 mm铝（现有的总滤过），或添加0.1 mm铒、0.1 mm钇或0.05 mm铌。在沿原射线束的四个选定部位测量辐射剂量。这四个部位分别是：皮肤入射剂量、皮肤出射剂量以及牙片包前方和后方的口腔内剂量。确定了在上颌磨牙X线片上产生等效密度（黑化程度）所需的曝光时间和辐射剂量。在60 - 80 kV的常规诊断范围内，使用薄K边滤过板会使曝光时间加倍（由于添加滤过板的额外衰减）。然而，皮肤剂量和给予患者的总剂量显著降低。
