精制石膏对钴 - 60、6兆伏、10兆伏和18兆伏X射线的有效衰减系数。
Refined gypsum effective attenuation coefficients for Co-60, 6 MV, 10 MV and 18 MV x-rays.
作者信息
Glasgow Glenn P, Dogan Nesrin, Sethi Anil, Stanton Jerry
机构信息
Department of Radiation Oncology, Loyola University Chicago Stritch School of Medicine, 2160 S 1st Avenue, Maywood, IL 60153, USA.
出版信息
Phys Med Biol. 2003 Jan 7;48(1):63-71. doi: 10.1088/0031-9155/48/1/305.
We report new effective linear attenuation coefficients (mueff) for refined gypsum for Co-60 and 18 MV x-rays. 6 MV and 10 MV mueff agree with published data. For a 100 cm2 field size (FS), tissue defect x = 1.35 cm, target depth d = 1.65 cm beneath the tissue defect x, mueff is 0.123 cm(-1) (Co-60) and 0.0934 cm(-1) (6 MV). For 100 cm2, x = 1.35 cm, and d = 5.65 cm beneath x, mueff is 0.072 cm(-1) (10 MV), and 0.0614 cm(-1) (18 MV). Ford, mueff decreases about 10% from 25 to 400 cm2. For a given FS, mueff decreases with d by 3%-5% for Co-60, and 3% for 6 MV, 10 MV and 18 MV, but depends on (d - x). For d, when x is large (8 cm), depending on energy and FS, mueff is 2%-4% less than when x is small (2 cm). These data were used in a treatment-planning computer to design compensator filters for a step phantom. Compensation was to within 10% in the compensation plane (CP). Above and below CP, computer-calculated ratios of doses with and without filters were 0.75-1.13. Chamber dose ratios with and without filters were 0.75-1.12.
我们报告了经精制的石膏针对钴 - 60 和 18 兆伏 X 射线的新有效线性衰减系数（mueff）。6 兆伏和 10 兆伏的 mueff 与已发表的数据一致。对于 100 平方厘米的射野尺寸（FS），组织缺损 x = 1.35 厘米，在组织缺损 x 下方的靶深度 d = 1.65 厘米，mueff 为 0.123 厘米⁻¹（钴 - 60）和 0.0934 厘米⁻¹（6 兆伏）。对于 100 平方厘米，x = 1.35 厘米，且在 x 下方 d = 5.65 厘米处，mueff 为 0.072 厘米⁻¹（10 兆伏）和 0.0614 厘米⁻¹（18 兆伏）。对于射野尺寸，mueff 从 25 平方厘米到 400 平方厘米大约降低 10%。对于给定的射野尺寸，钴 - 60 的 mueff 随深度 d 降低 3% - 5%，6 兆伏、10 兆伏和 18 兆伏的降低 3%，但取决于（d - x）。对于深度 d，当 x 较大（8 厘米）时，根据能量和射野尺寸，mueff 比 x 较小时（2 厘米）小 2% - 4%。这些数据被用于治疗计划计算机中，以设计用于阶梯模体的补偿滤过器。在补偿平面（CP）内补偿在 10%以内。在 CP 上方和下方，计算机计算的有滤过器和无滤过器时的剂量比为 0.75 - 1.13。有滤过器和无滤过器时电离室剂量比为 0.75 - 1.12。
Zotero 插件