Filipow L J, Macey D J, Munro T R
Phys Med Biol. 1979 Mar;24(2):341-52. doi: 10.1088/0031-9155/24/2/010.
The spectrum of the scattered radiation from a 'point' source of 99Tcm located within a slab of tissue-like material has been studied with a 19-phototube gamma camera, a 7.5 cm x 7.5 cm sodium iodide detector and a Ge(Li) counter. Both backscatter and forward scattered radiation contribute to the spectra observed; 'infinite' backscatter is achieved at a thickness of 8 cm. The scattered radiation can be used to estimate the thickness of the overlying material. The scatter from 133Xe and 51Cr was also measured. The depth of a source could usually be determined to within a few millimetres from the proportion of scatter in the spectrum; it was more accurate with the 51Cr (320 keV) than with the lower-energy photopeaks of the other two isotopes. The variation in the spectrum as the source moved across the field of the gamma camera was recorded.
使用一台19光电管γ相机、一个7.5厘米×7.5厘米的碘化钠探测器和一个锗（锂）计数器，研究了位于类组织材料平板内的99锝“点状”源的散射辐射光谱。背散射辐射和前向散射辐射都对观察到的光谱有贡献；在8厘米的厚度时可实现“无限”背散射。散射辐射可用于估计覆盖材料的厚度。还测量了133氙和51铬的散射。通常可以根据光谱中散射的比例将源的深度确定在几毫米以内；对于51铬（320keV）比对于其他两种同位素的较低能量光电峰更准确。记录了源在γ相机视野内移动时光谱的变化。
