Center for Research in Medical Physics and Biomedical Engineering, Shiraz University of Medical Sciences, Shiraz, Iran.
J Appl Clin Med Phys. 2012 Mar 8;13(2):3687. doi: 10.1120/jacmp.v13i2.3687.
Accuracy of treatment planning systems may significantly influence the efficacy of brachytherapy. The purpose of this work is a detailed, varied and independent evaluation of an in-house brachytherapy treatment planning software called STPS. Operational accuracy of STPS was investigated. Geometric tests were performed to validate entry and reconstruction of positional information from scanned orthogonal films. MCNP4C Monte Carlo code and TLDs were used for simulation and experimental measurement, respectively. STPS data were also compared with those from a commercial planning system (Nucletron PLATO). Discrepancy values between MCNP and STPS data and also those of PLATO and STPS at Manchester system dose prescription points (AL and AR) of tandem and ovoid configurations were 2.5% ± 0.5% and 5.4% ± 0.4%, respectively. Similar results were achieved for other investigated configurations. Observed discrepancies between MCNP and STPS at the dose prescription point and at 1 cm from the tip of the vaginal applicator were 4.5% and 25.6% respectively, while the discrepancy between the STPS and PLATO data at those points was 2.3%. The software showed submillimeter accuracy in its geometrical reconstructions. In terms of calculation accuracy, similar to PLATO, as attenuation of the sources and applicator body is not considered, dose was overestimated at the tip of the applicator, but based on the available criteria, dose accuracy at most points were acceptable. Our results confirm STPS's geometrical and operational reliability, and show that its dose computation accuracy is comparable to an established commercial TPS using the same algorithm.
治疗计划系统的准确性可能会显著影响近距离放射治疗的疗效。本工作的目的是对一种名为 STPS 的内部近距离放射治疗计划软件进行详细、多样和独立的评估。研究了 STPS 的运行准确性。进行了几何测试，以验证从扫描正交胶片输入和重建位置信息的能力。使用 MCNP4C 蒙特卡罗代码和 TLD 分别进行模拟和实验测量。还将 STPS 数据与商业计划系统（Nucletron PLATO）的数据进行了比较。在曼彻斯特系统剂量规定点（AL 和 AR）的串联和卵形配置下，MCNP 与 STPS 数据之间以及 PLATO 与 STPS 数据之间的差异值分别为 2.5%±0.5%和 5.4%±0.4%。对于其他研究的配置，也得到了类似的结果。在剂量规定点和阴道施源器尖端 1cm 处，MCNP 与 STPS 之间的观察到的差异分别为 4.5%和 25.6%，而 STPS 与 PLATO 数据之间的差异为 2.3%。该软件在几何重建方面具有亚毫米级的精度。在计算精度方面，与 PLATO 相似，由于未考虑源和施源器体的衰减，施源器尖端的剂量被高估，但根据现有标准，大多数点的剂量准确性是可以接受的。我们的结果证实了 STPS 的几何和运行可靠性，并表明其剂量计算精度可与使用相同算法的既定商业 TPS 相媲美。
