Purdy J A, Choi M C, Feldman A
Med Phys. 1980 May-Jun;7(3):251-3. doi: 10.1118/1.594680.
The relative dose reduction by Lipowitz metal of 6 to 20 MeV electrons from a Varian Associates Clinac-20 linear accelerator has been measured using a parallel plate thin wall ionization chamber. Metal thickness required for a 5% attenuation level for a 10 X 10 cm2 field are as follows: 6 MeV-2.3 mm, 9 MeV-4.4 mm, 12 MeV-8.5 mm, 16 MeV--18.0 mm, 20 MeV-25.0 mm.
使用平行板薄壁电离室测量了利波维茨合金对瓦里安公司Clinac - 20直线加速器产生的6至20兆电子伏电子的相对剂量减少情况。对于10×10平方厘米的射野,达到5%衰减水平所需的合金厚度如下:6兆电子伏 - 2.3毫米,9兆电子伏 - 4.4毫米,12兆电子伏 - 8.5毫米,16兆电子伏 - 18.0毫米,20兆电子伏 - 25.0毫米。