Arcovito G, Piermattei A, D'Abramo G, Bassi F A
Br J Radiol. 1984 Dec;57(684):1119-30. doi: 10.1259/0007-1285-57-684-1119.
Dosimetric experiments have been carried out in order to obtain the dose distribution in water around a Fletcher applicator loaded by a Buchler system containing two 137Cs 148 GBq (4 Ci) sources and one 192Ir 740 GBq (20 Ci) source. The mechanical system which controls the movement of the 192Ir source and the resulting motion of the source are described. The dose distribution around the sources was measured photographically and by a PWT Normal 0.22 cm3 ionisation chamber. The absolute dose rate was measured along the lateral axes of the sources. The measurements of exposure in water near the sources were corrected for the effect due to the finite volume of the chamber. The "quantisation method" described by Cassell (1983) was utilised to calculate the variation of the dose rate along the lateral axes of the sources. The dose distribution around both 192Ir and 137Cs sources was found to be spherical for angles greater than 40 degrees from the longitudinal axes of the sources. A simple algorithm fitting the data for the moving 192Ir source is proposed. A program written in FORTRAN IV and run on a Univac 1100/80 computer has been used to plot dose distributions on anatomical data obtained from CT images. The uncertainties of the measurements and calculations have been examined and the greatest error has been found to be 5.5%. The clinical significance of the treatment method is discussed.
为了获得在装有由一个包含两个137Cs 148 GBq（4居里）源和一个192Ir 740 GBq（20居里）源的布赫勒系统加载的弗莱彻施源器周围水中的剂量分布，已开展了剂量学实验。描述了控制192Ir源移动的机械系统以及源的相应运动。通过摄影和使用一个PWT Normal 0.22 cm³电离室测量了源周围的剂量分布。沿着源的横向轴测量了绝对剂量率。针对由于电离室有限体积所产生的效应，对源附近水中的照射测量值进行了校正。利用卡塞尔（1983年）描述的“量化方法”来计算沿源横向轴的剂量率变化。发现对于与源的纵轴夹角大于40度的情况，192Ir和137Cs源周围的剂量分布均为球形。提出了一种拟合移动192Ir源数据的简单算法。已使用用FORTRAN IV编写并在Univac 1100/80计算机上运行的程序，在从CT图像获得的解剖数据上绘制剂量分布。已检查了测量和计算的不确定性，发现最大误差为5.5%。讨论了该治疗方法的临床意义。
