Film dosimetry of megavoltage photon beams: a practical method of isodensity-to-isodose curve conversion.
Film dosimetry of megavoltage photon beams: a practical method of isodensity-to-isodose curve conversion.
复制标题
兆伏光子束的薄膜剂量测定：等密度到等剂量曲线转换的实用方法。
DOI：
10.1118/1.594913
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发表时间：
1981
期刊：
影响因子：
3.8
通讯作者：
Sharma,SC
中科院分区：
文献类型：
--
作者：
Williamson,JF;Khan,FM;Sharma,SC
光子束薄膜剂量测定的中心问题是薄膜响应对光子能量、加工条件和薄膜平面取向的依赖性。我们通过精确地将柯达XV-2胶片（平行于光束轴曝光）的深度相关感光曲线拟合为方程OD（D，d）= OD（1 − exp {−α0[1+β（d-dm）]D}），克服了这些问题，其中OD（D，d）是深度d处剂量D的光密度。OD、α0和β是表征薄膜和束能量的常数，但与场的大小无关。仅需要单个射野的中心轴深度剂量数据来确定其值。根据这个公式编制的计算机程序，成功地从各种射野（包括楔形射野）的胶片数据中生成了单射野等剂量曲线，其精度为± 3%。给出了~（60）Co、4和10 MV X射线的数据。
The central problems of photon beam film dosimetry are the dependence of film response upon photon energy, processing conditions, and film plane orientation. We have overcome these problems by accurately fitting the depth‐dependent sensitometric curve of Kodak XV‐2 film (exposed parallel to beam axis) to the equation OD(D,d) =ODs(1 − exp {−α0[1+β(d−dm)]D}) where OD(D,d) is the optical density for doseDat depthd. ODs, α0, and β are constants characteristic of the film and beam energy but are independent of field size. Only central axis depth dose data for a single field are required to determine their values. A computer program based upon this equation has been written which successfully generates single field isodose curves from film data for a variety of field sizes (including wedged fields) with an accuracy of ±3%. Data are presented for60Co, and 4 and 10 MV x rays.