摘要
目的:为临床准确使用SIEMENS PRIUMS M 5176直线加速器准直器散射因子Sc提供依据。方法:采用PTWundoseFarmer-0.6cc指型电离室及静电计,外加有机玻璃平衡帽,测量SIEMENS PRIUMS M 5176直线加速器产生的6MV-X及10MV-X线辐射源各种情况下的准直器散射因子Sc,并进行数学分析。根据临床上计算矩形野准直器散射因子Sc有效面积周长比公式进行计算,并与实际测量结果响进行比较。结果:准直器散射因子Sc与SCD大小无关;挡铅托架及楔形滤片准直器散射因子Sc的影响可亦忽略不计;SIEMENS PRIUMS M5176直线加速器产生的6MV-X及10MV-X直线加速器准直器散射因子亦可用有效面积周长比公式进行计算,经测量后得出常用矩形野准直互换效应(the collimator effect,CEE)的误差在2%左右。结论:准直器散射因子Sc一般主要由上下独立准直器所形成的照射野确定。但上下独立准直器对其不同程度的影响,反映准直互换效应(the collimator effect,CEE),误差可达3%～4%[1-3],也是影响准直器散射因子Sc主要原因之一,临床上使用窄条野时应注意区分上、下独立准直器的方向;同时准直器散射因子Sc主要加速器的准直器系统结构有关[4]所以须实际测量;在准直器散射因子Sc通过有效面积周长比公式进行计算,可保证剂量计算精度达规定的范围内。
Objective：To the clinical usage of SIEMENS PRIUMS M 5176 linear accelerators provide the basis for colli- mator scatter factor Sc. Methods： PTWundoseFarmer- 0. 6cc type ionization chamber and electrometer, plus organic glass balance cap, collimator scatter factor Sc 6MV - X and 10MV - X - ray radiation source all kinds of measuring SIE- MENS PRIUMS M 5176 under the linear accelerator, and mathematical analysis. According to the clinical calculation of rectangular field collimator scatter factor Sc effective ratio of area and perimeter formula, and compared with the actual measurement results. Results： Of collimator scatter factor Sc and SCD size; effect of block carriage and wedge filter collimator scatter factor Sc can also produce negligible; SIEMENS PRIUMS M 5176 linear accelerator 6MV -X and IOMV - X linear accelerator collimator scatter factor can also be effective area weeks longer than formula, after measuring the common rectangular field alignment swap effect of （the collimator effect, CEE） of the error is about 2%. Conclusions： Determining irradiation field collimator scatter factor Sc is mainly composed of upper and lower independent collimator forms. But independent collimator on the effects of different degree, reflect the collimator exchange effect （the collimator effect, CEE）, error of up to 3% -4%, is also one of the main reasons to impact of collimator scatter factor Sc, narrow strip should be paid attention to when the collimator distinction, ndependent of the direction of clinical use ; at the same time, collimator scatter factor Sc the collimator system structure of accelerator so should be measured; in the collimator scatter factor Sc through the effective ratio of area and perimeter formula, can guarantee the accuracy of dose calculation within the specified range.
出处
《航空航天医学杂志》
2013年第5期527-530,共4页
Journal of Aerospace medicine
