Srivastava Shraddha, Singh Navin, Kashyap Varun Kumar
PhD, Department of Radiotherapy King George's Medical University Lucknow, Uttar Pradesh, India.
PhD, Department of Community Medicine, HIMSAR, New Delhi, India.
J Biomed Phys Eng. 2022 Aug 1;12(4):339-348. doi: 10.31661/jbpe.v0i0.2104-1306. eCollection 2022 Aug.
Conventional optimization techniques are based on the planning approach in which positions and weights are varied to generate the desired dose distribution. Inverse planning simulated annealing (IPSA) is an advanced optimization method developed to automatically determine a suitable combination of positions to design an acceptable plan.
In this study, three optimization techniques namely IPSA, graphical optimization (GROPT), and geometrical optimization (GOPT) methods are compared in high-dose-rate interstitial brachytherapy of cervical carcinoma.
In this retrospective study, twenty computed tomography (CT) data sets of 10 cervical cancer patients treated with Martinez Universal Perineal Interstitial Template-based interstitial brachytherapy were studied. The treatment plans generated were optimized using the IPSA, and GOPT methods. The prescribed dose was 24 Gy in 4 fractions. Plans produced using IPSA, GrOPT, and GOPT techniques were analyzed for comparison of dosimetric parameters, including target coverage, homogeneity, conformity, and organs at risk (OAR) doses.
V100 values for IPSA, GrOPT and GOPT plans were 95.81±2.33%, 93.12±2.76% and 88.90±4.95%, respectively. The mean D90 values for the IPSA, GrOPT, and GOPT plans were 6.45±0.15 Gy, 6.12±0.21 Gy, and 5.85±0.57 Gy, respectively. Significantly lower doses of OAR were in the IPSA plans that were more homogeneous (HI=0.66). Conformity was comparatively higher in IPSA-based plans (CI=0.75).
IPSA plans were superior and resulted in better target coverage, homogeneity, conformity, and minimal OAR doses.
传统的优化技术基于规划方法，即通过改变位置和权重来生成所需的剂量分布。逆向计划模拟退火（IPSA）是一种先进的优化方法，旨在自动确定合适的位置组合以设计出可接受的计划。
在本研究中，比较了三种优化技术，即IPSA、图形优化（GROPT）和几何优化（GOPT）方法在宫颈癌高剂量率组织间近距离治疗中的应用。
在这项回顾性研究中，研究了10例接受基于马丁内斯通用会阴组织间模板的组织间近距离治疗的宫颈癌患者的20组计算机断层扫描（CT）数据集。使用IPSA和GOPT方法对生成的治疗计划进行优化。处方剂量为24 Gy，分4次给予。分析了使用IPSA、GrOPT和GOPT技术生成的计划，以比较剂量学参数，包括靶区覆盖、均匀性、适形性和危及器官（OAR）剂量。
IPSA、GrOPT和GOPT计划的V100值分别为95.81±2.33%、93.12±2.76%和88.90±4.95%。IPSA、GrOPT和GOPT计划的平均D90值分别为6.45±0.15 Gy、6.12±0.21 Gy和5.85±0.57 Gy。IPSA计划中OAR的剂量显著较低，且更均匀（HI=0.66）。基于IPSA的计划的适形性相对较高（CI=0.75）。
IPSA计划更优，能实现更好的靶区覆盖、均匀性、适形性，并使OAR剂量最小。
