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Methods of improving the accuracy of high-energy X-ray absorbed dose calculated using a convolution approach

提高卷积法高能X射线吸收剂量计算精度的方法

基本信息

批准号：
13670907
负责人：
IWASAKI Akira
金额：
$ 2.3万
依托单位：
Hirosaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

Using a linear accelerator producing triplet-energy beams of 4-, 10-, and 15-MV X-rays. the following experimental and theoretical studies were performed.1.On the basis of X-ray intensity transmission data, we developed a method to estimate X-ray spectra and then constructed its calculation program. Under this situation, the primary X-ray spectrum variation caused by using wedges and compensators can be easily evaluated with accuracy and the primary X-ray spectrum variation within an irradiated body can also be easily evaluated with accuracy : Therefore, more accurate dose calculations can now be performed.2.On the basis of the X-ray spectrum, the in-water attenuation coefficient was expressed as a function of depth, and then the zero-area tissue-maximum ratio (TIR) was formulated. Some of the constants in the zero-area TMR formulation were utilized for constructing primary and scatter dose spread functions.3.Sets of tissue-phantom ratios (TPRs) were measured using water and 3-layed co … More rk phantoms for several irradiation fields. Sets of dose OCRs (off-center ratios) were also measured using water and 3-layed cork phantoms for several irradiation fields. These sets of data were utilized to reconfirm such fundamental functions, for dose calculation using a convolution method, as primary-dose spread functions, scatter-dose spread functions, contaminant electron intensity functions, and collimator OCR functions.4.The concept of "collimator OCR" was introduced for evaluation of the shielding effect due to a pair of lower and upper jaws. The concept of "source OCR" was also introduced for evaluation of the incident X-ray intensity at an infinite field. It was proposed that the incident X-ray intensity at a point for a finite field was expressed as the product of the collimator OCR and source OCR functions.5.A dose calculation approach was proposed to regard the multi-leaf collimator (MLC), the wedge, the shielding blocks, and the couch as parts of an irradiated body.6.Speeding Up of the 3D dose calculation soft was attempted by utilizing the fact that both primary and scatter dose spread functional expressions could be integrated analytically. Less

使用直线加速器产生 4-MV、10-MV 和 15-MV X 射线三线态能量束。进行了以下实验和理论研究： 1.基于X射线强度透射数据，提出了一种X射线能谱估计方法，并构建了其计算程序。在这种情况下，可以轻松准确地评估使用楔块和补偿器引起的初级X射线能谱变化，也可以轻松准确地评估受照射体内的初级X射线能谱变化：因此，现在可以进行更准确的剂量计算。2.在X射线能谱的基础上，将水中衰减系数表示为深度的函数，然后将零面积组织最大值表示为水中衰减系数。制定了比率（TIR）。零面积 TMR 公式中的一些常数用于构建初级和散射剂量扩散函数。3.使用水和 3 层复合 rk 体模测量多个照射场的组织-体模比 (TPR) 组。还使用水和 3 层软木模型对多个照射场测量了多组剂量 OCR（偏心比）。这些数据集被用来重新确认这些基本函数，用于使用卷积方法进行剂量计算，如初级剂量扩散函数、散射剂量扩散函数、污染物电子强度函数和准直器OCR函数。4.引入“准直器OCR”的概念来评估一对下钳口和上钳口产生的屏蔽效果。还引入了“源 OCR”的概念，用于评估无限视野下的入射 X 射线强度。提出有限视场内一点的入射X射线强度表示为准直器OCR和源OCR函数的乘积。5.提出了一种剂量计算方法，将多叶准直器(MLC)、楔块、屏蔽块和沙发视为被照射体的一部分。6.利用初级和散射的事实尝试加速3D剂量计算软件。剂量扩散函数表达式可以通过分析进行积分。较少的

项目成果

期刊论文数量（34）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

奈良鉄造: "矩形照射野コリメータ散乱係数に対する等価正方形評価法の検討"日本放射線技術学会誌. 58・6. 848-857 (2002)

奈良哲三：“矩形场准直器散射系数的等效平方评估方法的研究”日本放射线技术学会杂志58・6（2002）。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

岩崎晃: "10 MV x-ray central-axis dose calculation in thorax-like phantoms (water/cork) using the differential primary and scatter method"Radiation Physics and Chemistry. (印刷中). (2002)

Akira Iwasaki：“使用微分初级和散射方法计算胸腔模型（水/软木塞）中的 10 MV X 射线中轴剂量”辐射物理与化学（2002 年出版）。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

A method for 10 MV X-ray scatter dose-spread kernel construction based on the Bjarngard scatter factor formulation

基于 Bjarngard 散射因子公式的 10 MV X 射线散射剂量扩散核构建方法

DOI：
发表时间：
2002
期刊：
Radiation Physics and Chemistry 61
影响因子：
0
作者：
A.Iwasaki;H.Matsutani;M.Kubota;A.Fujimori;K.Suzaki;Y.Abe;A.Iwasaki;奈良鉄造;A.Iwasaki
通讯作者：
A.Iwasaki

A method for 10 MV X-ray scatter dose-spread kernel construction based on the Bjarngarcl scatter factor formulation.

一种基于 Bjarngarcl 散射因子公式的 10 MV X 射线散射剂量扩散核构建方法。