PDF(Pubmed)
Abstract：
Ultra-hypofractionated radiotherapy (UHF RT) is revolutionizing the treatment approach for low- and intermediate-risk prostate cancer patients. This study reports the planning process of UHF RT utilizing the cone beam computed tomography (CBCT)-based online adaptive radiotherapy (OART) treatment with the Ethos system, focusing on a comparative analysis between OART and image-guided radiotherapy (IGRT) plans. We also assessed the pre-planning capabilities of the Ethos system against the CyberKnife (CK) (Accuray, Sunnyvale, CA) system. A 66-year-old patient, diagnosed with prostatic acinar adenocarcinoma confirmed via biopsy and presenting with elevated prostate-specific antigen (PSA) levels, underwent UHF OART treatment using the Ethos system. The planning encompassed delineating the gross target volume (GTV) as the prostate, while the clinical target volume (CTV) comprised the prostate and proximal seminal vesicle. The planning target volume (PTV) was derived from the CTV with a 5 mm external margin except for a 3 mm posterior margin. A simultaneous integrated boost (SIB) technique was employed, delivering 40 Gy in five fractions (8 Gy per fraction) to the gross tumor volume (GTV) and 36.25 Gy in five fractions (7.25 Gy per fraction) to the remaining part of the planning target volume (PTV), with treatments scheduled biweekly. We compared OART and IGRT plans and conducted a comparative analysis between Ethos planning and the CK system for pre-planning assessment. When comparing Ethos planning and CK plans, Ethos demonstrated slightly better target coverage and organ-at-risk (OAR) sparing. However, CK plans showed superior containment of low-dose spillage, particularly at 50% and 25% iso-doses, due to non-coplanar beam arrangements. Our results demonstrated that OART plans yielded superior target coverage and improved OAR sparing compared to IGRT plans. Notably, the entire OART process, from planning to delivery, was accomplished within 27 minutes. The Ethos OART system\'s ability to adapt to daily anatomical changes, efficient workflow, and superior OAR-sparing capabilities make it a promising option for prostate cancer treatment using UHF RT.
摘要：
超小分割放疗（UHFRT）正在彻底改变低风险和中风险前列腺癌患者的治疗方法。本研究报告了使用Ethos系统进行基于锥形束计算机断层扫描（CBCT）的在线自适应放射治疗（OART）的UHFRT计划过程，重点是OART和图像引导放射治疗（IGRT）计划之间的比较分析。我们还评估了Ethos系统与Cyberknife（CK）（Accuray，桑尼维尔,CA)系统。一个66岁的病人,诊断为前列腺腺泡腺癌，通过活检证实，并呈现升高的前列腺特异性抗原（PSA）水平，使用Ethos系统进行UHFOART治疗。该计划包括将总目标体积（GTV）描绘为前列腺，而临床目标体积（CTV）包括前列腺和近端精囊。计划目标体积（PTV）来自CTV，其外部边缘为5mm，后部边缘为3mm。采用了同时集成升压(SIB)技术，将五个部分中的40Gy（每个部分8Gy）输送到总肿瘤体积（GTV），将五个部分中的36.25Gy（每个部分7.25Gy）输送到计划目标体积（PTV）的其余部分，每两周安排一次治疗。我们比较了OART和IGRT计划，并对Ethos计划和计划前评估的CK系统进行了比较分析。当比较Ethos计划和CK计划时，Ethos显示出更好的目标覆盖率和风险器官（OAR）保留。然而,CK计划显示对低剂量溢出的良好遏制，特别是在50%和25%的等剂量下，由于非共面梁布置。我们的结果表明，与IGRT计划相比，OART计划具有更高的目标覆盖率，并改善了OAR的节省。值得注意的是,整个OART过程，从计划到交付，在27分钟内完成。EthosOART系统适应日常解剖学变化的能力，高效的工作流程，和卓越的OAR保留能力使其成为使用UHFRT治疗前列腺癌的有希望的选择。
