Simeoni R J, Thiele D L
Department of Physical Sciences, Royal Brisbane Hospital, Herston, Australia.
Australas Phys Eng Sci Med. 1993 Mar;16(1):33-6.
Current information pertinent to scatter radiation for mammographic x-ray spectra is limited. Data presented by the National Council on Radiation Protection and Measurements (NCRP), the current shielding authority, are restricted to 50 kVp tungsten target spectra and contain several incompatibilities with the modern mammographic situation. The ratio of scattered to incident exposure was measured for two molybdenum target spectra (36 kVp, 30 microns molybdenum filtration and 49 kVp, 50 microns aluminium filtration). The maximum scatter ratio occurred at 150 degrees to the primary beam direction for both spectra; the values were (1.73 +/- 0.09) x 10(3) and (2.6 +/- 0.1) x 10(3) respectively for a field area of 400 cm2, a scattering distance of 1 m and a primary beam exposure distance of 1 m from the x-ray source. The results obtained differ significantly from NCRP based data presently used for mammographic shielding calculations. The consequences of these differences are discussed.
目前与乳腺钼靶X射线光谱散射辐射相关的信息有限。当前的屏蔽权威机构——美国国家辐射防护与测量委员会（NCRP）所提供的数据仅限于50 kVp钨靶光谱，并且与现代乳腺钼靶检查的情况存在一些不匹配之处。针对两种钼靶光谱（36 kVp、30微米钼滤过和49 kVp、50微米铝滤过）测量了散射与入射曝光的比率。两种光谱的最大散射比率均出现在与原射线束方向成150度的位置；对于400 cm2的照射野面积、1 m的散射距离以及距X射线源1 m的原射线束曝光距离，其值分别为(1.73±0.09)×10(3)和(2.6±0.1)×10(3)。所获得的结果与目前用于乳腺钼靶屏蔽计算的基于NCRP的数据有显著差异。讨论了这些差异的后果。
