Ozaki Daisuke, Miyazawa Makoto, Habano Youji, Kawashima Motohiro, Hoshino Yoshihiko, Sutou Takayuki
Department of Radiology, Gunma University Hospital.
Gunma University Heavy Ion Medical Center.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2018;74(4):354-361. doi: 10.6009/jjrt.2018_JSRT_74.4.354.
Hybrid inverse treatment planning optimization (HIPO) is a new optimization tool for brachytherapy. We verified its utility using treatment plans for combined intracavitary and interstitial brachytherapy in cervical cancer.
MATERIALS & METHODS: We compared the manually optimized plan and the plan optimized using HIPO. The plan using HIPO was optimized with three different methods: needle only, tandem and needle, and all applicators. The dose volume histogram (DVH) parameters such as D of high risk clinical target volume (HR-CTV) and D of OAR (rectum, sigmoid colon and bladder) were used to evaluate each treatment plan.
The D of HR-CTV in most plans was received more than 600 cGy. In addition, the D of OAR also was less than the tolerance dose on the average of all plans. However, the D of the rectum and bladder treatment plans optimized only with needles was significantly higher than other plans.
The treatment plans used in clinical practice and obtained by HIPO have similar dose distributions and DVH parameters. Moreover, the time needed to create treatment plan was reducing by HIPO. We suggest that HIPO will be an effective tool in treatment planning.
混合逆向治疗计划优化（HIPO）是一种用于近距离放射治疗的新型优化工具。我们使用宫颈癌腔内和组织间联合近距离放射治疗的治疗计划来验证其效用。
我们比较了手动优化计划和使用HIPO优化的计划。使用HIPO的计划通过三种不同方法进行优化：仅针、串联和针以及所有施源器。使用高风险临床靶区（HR-CTV）的D和危及器官（直肠、乙状结肠和膀胱）的D等剂量体积直方图（DVH）参数来评估每个治疗计划。
大多数计划中HR-CTV的D超过600 cGy。此外，所有计划的平均而言，危及器官的D也低于耐受剂量。然而，仅用针优化的直肠和膀胱治疗计划的D显著高于其他计划。
临床实践中使用的以及通过HIPO获得的治疗计划具有相似的剂量分布和DVH参数。此外，HIPO减少了创建治疗计划所需的时间。我们认为HIPO将成为治疗计划中的一种有效工具。
