Comparison of online adaptive and non-adaptive magnetic resonance image-guided radiation therapy in prostate cancer using dose accumulation

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology Pub Date : 2024-10-01 DOI:10.1016/j.phro.2024.100662

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引用次数: 0

Abstract

Background and purpose

Conventional image-guided radiotherapy (conv-IGRT) is standard in prostate cancer (PC) but does not account for inter-fraction anatomical changes. Online-adaptive magnetic resonance-guided RT (OA-MRgRT) may improve organ-at-risk (OARs) sparing and clinical target volume (CTV) coverage. The aim of this study was to analyze accumulated OAR and target doses in PC after OA-MRgRT and conv-IGRT in comparison to pre-treatment reference planning (refPlan).

Material and methods

Ten patients with PC, previously treated with OA-MRgRT at the 1.5 T MR-Linac (20x3Gy), were included. Accumulated OA-MRgRT doses were determined by deformably registering all fraction’s MR-images. Conv-IGRT was simulated through rigid registration of the planning computed tomography with each fraction’s MR-image for dose mapping/accumulation. Dose-volume parameters (DVPs), including CTV D50% and D98%, rectum, bladder, urethra, Dmax and V56Gy for OA-MRgRT, conv-IGRT and refPlan were compared using the Wilcoxon signed-rank test. Clinical relevance of accumulated dose differences was analyzed using a normal-tissue complication-probability model.

Results

CTV-DVPs were comparable, whereas OA-MRgRT yielded decreased median OAR-DVPs compared to conv-IGRT, except for bladder V56Gy. OA-MRgRT demonstrated significantly lower median rectum Dmax over conv-IGRT (59.1/59.9 Gy, p = 0.006) and refPlan (60.1 Gy, p = 0.012). Similarly, OA-MRgRT yielded reduced median bladder Dmax compared to conv-IGRT (60.0/60.4 Gy, p = 0.006), and refPlan (61.2 Gy, p = 0.002). Overall, accumulated dose differences were small and did not translate into clinically relevant effects.

Conclusion

Deformably accumulated OA-MRgRT using 20x3Gy in PC showed significant but small dosimetric differences comparted to conv-IGRT. Feasibility of a dose accumulation methodology was demonstrated, which may be relevant for evaluating future hypo-fractionated OA-MRgRT approaches.

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利用剂量累积对前列腺癌进行在线自适应和非自适应磁共振图像引导放射治疗的比较

背景和目的传统图像引导放疗（conv-IGRT）是前列腺癌（PC）的标准治疗方法，但不能考虑分段间的解剖变化。在线自适应磁共振引导放疗（OA-MRgRT）可改善风险器官（OARs）疏通和临床靶体积（CTV）覆盖。本研究旨在分析 PC 患者在接受 OA-MRgRT 和 conv-IGRT 治疗后的累积 OAR 和靶剂量，并与治疗前参考规划（refPlan）进行比较。OA-MRgRT的累积剂量是通过对所有部分的磁共振图像进行变形注册确定的。Conv-IGRT是通过将规划计算机断层扫描与各部分的磁共振图像进行刚性配准来模拟剂量映射/累积的。使用 Wilcoxon 符号秩检验比较了 OA-MRgRT、conv-IGRT 和 refPlan 的剂量体积参数（DVPs），包括 CTV D50% 和 D98%、直肠、膀胱、尿道、Dmax 和 V56Gy。使用正常组织并发症概率模型分析了累积剂量差异的临床相关性。结果 CTV-DVPs 相当，而与 conv-IGRT 相比，OA-MRgRT 产生的中位 OAR-DVPs 减少，但膀胱 V56Gy 除外。OA-MRgRT 与 conv-IGRT（59.1/59.9 Gy，p = 0.006）和 refPlan（60.1 Gy，p = 0.012）相比，直肠中位 Dmax 明显较低。同样，OA-MRgRT 与 conv-IGRT（60.0/60.4 Gy，p = 0.006）和 refPlan（61.2 Gy，p = 0.002）相比，膀胱中位 Dmax 也有所降低。结论在 PC 中使用 20x3Gy 的变形累积 OA-MRgRT 与 conv-IGRT 相比，显示出显著但微小的剂量学差异。该研究证明了剂量累积方法的可行性，这可能与评估未来的低分次 OA-MRgRT 方法有关。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Physics and Imaging in Radiation Oncology Physics and Astronomy-Radiation

CiteScore

5.30

自引率

18.90%

发文量

审稿时长

6 weeks