BP06 Presentation Time: 4:45 PM

IF 1.7 4区医学 Q4 ONCOLOGY

Brachytherapy Pub Date : 2024-10-25 DOI:10.1016/j.brachy.2024.08.030

Usha Abraham MS, DABR, Ranjini Tolakanahalli Ph.D., Fiona Perk RTT, Marc Morcos Ph.D., Maria A. Rodrigues MD, Alonso Gutierrez Ph.D., Vibha Chaswal Ph.D.

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引用次数: 0

Abstract

Purpose

To present dosimetric outcomes of Strut Adjusted Volumetric Implant (SAVI) brachytherapy treatment plans delivered over 4 years using Tri-fraction Radiation Therapy Used to Minimize Patient Hospital Trips (TRIUMPH-T) Trial at our institution; and investigation into a plan-coverage-complexity indicator.

Method and Materials

Retrospective analysis on dosimetric parameters derived from clinically delivered treatment plans using different size SAVI (Cianna Medicals, Aliso Viejo CA) applicators during 2019 and 2023 were performed. Treatment plans were prepared using Ir-192 source modeled in BrachyVision (Varian Medical Systems, Inc.) and Oncentra (Elekta Brachy, Veenendaal, The Netherlands) treatment planning systems. Triumph-T trial dose regimen (22.5 Gy in 3 fractions, Bi-daily, 6 hours apart) and dosimetric criterion were employed for APBI delivery. Target [PTV_Eval] and organs at risk (OAR) [chestwall and ribs] were delineated in accordance with NSABP-B39/RTOG-0413 and Triumph-T trials. A 3 mm skin rind was contoured, as institutional preference, for skin-sparing. V_90% ≥ 90% was desired for PTV_Eval with V_150% < 40cc and V_200% < 17 cc for high dose metrics and D_0.03cc < 100% and D_0.03cc < 110% for skin and chestwall/ribs, respectively. A PTV-ratio was defined in this study as the ratio of PTV_Eval to PTV_1cm (volume encompassing 1 cm expansion around lumpectomy cavity) and was analyzed for linear correlation with the PTV_Eval coverage (V_90%) metric to determine feasibility of serving as a plan-coverage-complexity indicator. Pearson correlation coefficient (with a two-tailed t-test of significance; p<0.05) was used.

Results

Our center treated 147 patients with median PTV_Eval volume of 67.1 cc [35.9 cc-116.1 cc] using SAVI brachytherapy, following the Triumph-T trial planning technique. Amongst these, twenty (n=20) cavities were treated with 6-1-mini SAVI, fifty-two (n=52) cavities with 6-1 SAVI, fifty (n=50) with 8-1 SAVI, and twenty-five (n=25) with 10-1 SAVI, and these cavity groups had a median volume of 9.7 cc [7.7 cc - 15.4 cc], 18.1 cc [14.9 cc - 22.8 cc], 33.3 cc [15.3 cc - 41.3 cc] and 53.1cc [21.9 cc - 65.4 cc], respectively. Excellent coverage was achieved for PTV_Eval with mean V_90% at 97.0% ± 2.3%. Mean V_150% and V_200% were at 28.2cc ± 3.5cc and 12.7cc ± 2.4cc, respectively. From 6-1-mini to 10-1 SAVI, V_150% and V_200% values increase from 20.4cc to 35.7cc and 10.8cc to 14.1cc, respectively. For OARs, the mean D_0.03cc to skin, chestwall, and ribs were 86.9% ± 15.5%, 88.7% ± 30.6% and 59.5% ± 23.4%, respectively, and were within tolerance. Average PTV-ratio values were 0.92 ± 0.08 for all plans evaluated. Starting from 6-1mini to the 10-1 SAVI, the Pearson correlation coefficients between PTV-ratio and V_90% were 0.86, 0.90, 0.77, and 0.72, (p<0.05) indicating a high correlation.

Conclusion

Retrospective analysis from 147 patients treated at our institution show that SAVI- brachytherapy using a 3-fraction Triumph-T trial regimen is an efficient alternative for APBI. Treatment plans delivered met dosimetric constraints outlined in the trial with excellent target coverage, minimal hot-spots, and OAR sparing. A novel metric, PTV-ratio, serving as a plan-coverage-complexity indicator showed a positive correlation to V_90% for all SAVI applicators.

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BP06 演讲时间：下午 4:45

方法和材料对2019年和2023年期间使用不同尺寸的SAVI（Cianna Medicals, Aliso Viejo CA）涂抹器实施的临床治疗计划的剂量参数进行了回顾性分析。治疗计划是使用 BrachyVision（瓦里安医疗系统公司）和 Oncentra（荷兰维南达尔的 Elekta Brachy）治疗计划系统中的 Ir-192 源建模编制的。APBI 给药采用 Triumph-T 试验剂量方案（22.5 Gy，分 3 次给药，每天两次，每次间隔 6 小时）和剂量学标准。靶区[PTV_Eval]和危险器官（OAR）[胸壁和肋骨]是根据NSABP-B39/RTOG-0413和Triumph-T试验划定的。根据机构偏好，对 3 毫米的皮肤边缘进行轮廓处理，以保留皮肤。PTV_Eval希望V90%≥90%，高剂量指标为V150% < 40cc和V200% < 17cc，皮肤和胸壁/肋骨分别为D0.03cc < 100%和D0.03cc < 110%。本研究将 PTV 比率定义为 PTV_Eval 与 PTV1cm（肿瘤切除腔周围扩展 1 厘米的容积）之比，并分析了 PTV_Eval 覆盖率（V90%）指标与 PTV_Eval 的线性相关性，以确定作为计划覆盖复杂性指标的可行性。结果我们中心采用 Triumph-T 试验计划技术，使用 SAVI 近距离放射治疗了 147 名患者，中位 PTV_Eval 容量为 67.1 毫升 [35.9 毫升-116.1 毫升]。其中，二十（n=20）个空腔采用 6-1-mini SAVI 治疗，五十二（n=52）个空腔采用 6-1 SAVI 治疗，五十（n=50）个空腔采用 8-1 SAVI 治疗，二十五（n=25）个空腔采用 10-1 SAVI 治疗，这些空腔组的中位体积为 9.7毫升[7.7毫升 - 15.4毫升]、18.1毫升[14.9毫升 - 22.8毫升]、33.3毫升[15.3毫升 - 41.3毫升]和53.1毫升[21.9毫升 - 65.4毫升]。PTV_Eval 的覆盖率非常高，平均 V90% 为 97.0% ± 2.3%。平均 V150% 和 V200% 分别为 28.2cc ± 3.5cc 和 12.7cc ± 2.4cc。从 6-1-mini 到 10-1 SAVI，V150%和 V200% 值分别从 20.4cc 增加到 35.7cc 和 10.8cc 增加到 14.1cc。对于 OAR，皮肤、胸壁和肋骨的平均 D0.03cc 值分别为 86.9% ± 15.5%、88.7% ± 30.6% 和 59.5% ± 23.4%，均在容许范围内。所有评估计划的平均 PTV 比率值为 0.92 ± 0.08。从 6-1mini 到 10-1 SAVI，PTV-ratio 与 V90% 之间的皮尔逊相关系数分别为 0.86、0.90、0.77 和 0.72，（p<0.05）表明两者之间具有高度相关性。所提供的治疗方案符合试验中列出的剂量限制，具有极佳的靶点覆盖率、最小的热点和OAR间隔。作为计划覆盖复杂性指标的新指标 PTV 比率显示，所有 SAVI 施用器的 V90% 均与之呈正相关。

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

Brachytherapy 医学-核医学

CiteScore

3.40

自引率

21.10%

发文量

119

审稿时长

9.1 weeks

期刊介绍： Brachytherapy is an international and multidisciplinary journal that publishes original peer-reviewed articles and selected reviews on the techniques and clinical applications of interstitial and intracavitary radiation in the management of cancers. Laboratory and experimental research relevant to clinical practice is also included. Related disciplines include medical physics, medical oncology, and radiation oncology and radiology. Brachytherapy publishes technical advances, original articles, reviews, and point/counterpoint on controversial issues. Original articles that address any aspect of brachytherapy are invited. Letters to the Editor-in-Chief are encouraged.