Wang Tonghe, Press Robert H, Giles Matt, Jani Ashesh B, Rossi Peter, Lei Yang, Curran Walter J, Patel Pretesh, Liu Tian, Yang Xiaofeng
1 Department of Radiation Oncology and Winship Cancer Institute, Emory University , Atlanta, GA , USA.
Br J Radiol. 2019 May;92(1097):20190089. doi: 10.1259/bjr.20190089. Epub 2019 Apr 9.
The purpose of this study is to investigate the dosimetric feasibility of delivering focal dose to multiparametric (mp) MRI-defined DILs in CT-based high-dose-rate (HDR) prostate brachytherapy with MR/CT registration and estimate its clinical benefit.
We retrospectively investigated a total of 17 patients with mp-MRI and CT images acquired pre-treatment and treated by HDR prostate brachytherapy. 21 dominant intraprostatic lesions (DILs) were contoured on mp-MRI and propagated to CT images using a deformable image registration method. A boost plan was created for each patient and optimized on the original needle pattern. In addition, separate plans were generated using a virtually implanted needle around the DIL to mimic mp-MRI guided needle placement. DIL dose coverage and organ-at-rick (OAR) sparing were compared with original plan results. Tumor control probability (TCP) was estimated to further evaluate the clinical impact on the boost plans.
Overall, optimized boost plans significantly escalated dose to DILs while meeting OAR constraints. The addition of mp-MRI guided virtual needles facilitate increased coverage of DIL volumes, achieving a V150 > 90% in 85 % of DILs compared with 57 % of boost plan without an additional needle. Compared with original plan, TCP models estimated improvement in DIL control by 28 % for patients with external-beam treatment and by 8 % for monotherapy patients.
With MR/CT registration, the proposed mp-MRI guided DIL boost in CT-based HDR brachytherapy is feasible without violating OAR constraints, and indicates significant clinical benefit in improving TCP of DIL. It may represent a strategy to personalize treatment delivery and improve tumor control.
This study investigated the feasibility of mp-MRI guided DIL boost in HDR prostate brachytherapy with CT-based treatment planning, and estimated its clinical impact by TCP and NTCP estimation.
本研究旨在探讨在基于CT的高剂量率（HDR）前列腺近距离放射治疗中，通过MR/CT配准向多参数（mp）MRI定义的弥漫性前列腺内病变（DIL）给予局部剂量的剂量学可行性，并评估其临床获益。
我们回顾性研究了17例接受HDR前列腺近距离放射治疗的患者，这些患者在治疗前均获取了mp-MRI和CT图像。在mp-MRI上勾勒出21个主要的前列腺内病变（DIL），并使用可变形图像配准方法将其映射到CT图像上。为每位患者制定了一个追加剂量计划，并在原始针阵模式上进行优化。此外，围绕DIL使用虚拟植入针生成单独的计划，以模拟mp-MRI引导下的针放置。将DIL剂量覆盖情况和危及器官（OAR）的保护情况与原始计划结果进行比较。估计肿瘤控制概率（TCP）以进一步评估追加剂量计划的临床影响。
总体而言，优化后的追加剂量计划在满足OAR限制的同时，显著提高了DIL的剂量。添加mp-MRI引导的虚拟针有助于增加DIL体积的覆盖范围，85%的DIL实现了V150>90%，而在没有额外针的追加剂量计划中这一比例为57%。与原始计划相比，TCP模型估计，对于接受外照射治疗的患者，DIL控制改善了28%，对于单一疗法患者改善了8%。
通过MR/CT配准，在基于CT的HDR近距离放射治疗中，所提出的mp-MRI引导的DIL追加剂量是可行的，且不违反OAR限制，并在改善DIL的TCP方面显示出显著的临床获益。它可能代表了一种个性化治疗方案并改善肿瘤控制的策略。
本研究探讨了在基于CT治疗计划的HDR前列腺近距离放射治疗中mp-MRI引导的DIL追加剂量的可行性，并通过TCP和正常组织并发症概率（NTCP）估计评估了其临床影响。
