Kaur Guneet, Lehmann Joerg, Greer Peter B, Martin Jarad, Simpson John
Department of Radiation Oncology, The Mater Hospital, Rocklands Road, Crows Nest, Sydney, NSW, 2065, Australia.
Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, NSW, Australia.
Phys Eng Sci Med. 2023 Mar;46(1):131-140. doi: 10.1007/s13246-022-01204-5. Epub 2022 Dec 6.
This study quantified the performance of Intra-fraction Motion Review (IMR) during prostate Stereotactic Body Radiotherapy (SBRT) treatments. IMR was evaluated using prostate motion data from patients treated in an SBRT clinical trial (PROMETHEUS, NCT00587990).IMR measured prostate displacements were compared to those of two 3D motion management methods: Kilovoltage Intra-fraction Motion management (KIM) and MV/kV triangulation. A planning study assessing the impact of a defined prostate motion (2-5 mm) on the PTV coverage with and without IMR was performed. A clinically relevant IMR search region for prostate cancer SBRT treatments was determined using a customised anthropomorphic pelvis phantom with implanted gold seeds and a motion platform. IMR showed submillimeter agreement with corresponding 2D projections from both KIM and MV/kV triangulation. However, IMR detected actual displacements consistently in considerably fewer frames than KIM (3D), with the actual numbers depending on the settings. The Default Search Region (DSR) method employing a circular search region proved superior to user-contoured structures in detecting clinically relevant prostate motion. Reducing the DSR search region radius can reduce the impact of the 2D nature of IMR and improve the detectability of actual motion (by 10% per 0.5 mm reduction) but must be balanced against increased beam interruptions from minor, clinically irrelevant motion. The use of IMR for SBRT prostate treatments has the potential to improve target dose coverage (minimum dose to 98% of the PTV, D98%) by > 20% compared to treatment without IMR. Calculated D98% of IMR monitored treatments with motion was within 1.5% of plans without motion.
本研究对前列腺立体定向体部放疗（SBRT）治疗期间的分次内运动复查（IMR）性能进行了量化。使用在一项SBRT临床试验（PROMETHEUS，NCT00587990）中接受治疗的患者的前列腺运动数据对IMR进行了评估。将IMR测量的前列腺位移与两种三维运动管理方法的位移进行了比较：千伏分次内运动管理（KIM）和MV/kV三角测量法。进行了一项计划研究，评估在有和没有IMR的情况下，定义的前列腺运动（2-5毫米）对计划靶体积（PTV）覆盖范围的影响。使用植入了金籽源的定制拟人化骨盆体模和运动平台，确定了前列腺癌SBRT治疗的临床相关IMR搜索区域。IMR与KIM和MV/kV三角测量法的相应二维投影显示出亚毫米级的一致性。然而，与KIM（三维）相比，IMR在明显更少的帧数中持续检测到实际位移，实际数量取决于设置。采用圆形搜索区域的默认搜索区域（DSR）方法在检测临床相关前列腺运动方面优于用户勾勒的结构。减小DSR搜索区域半径可减少IMR二维特性的影响并提高实际运动的可检测性（每减小0.5毫米提高10%），但必须与因微小的、临床无关运动导致的射束中断增加相平衡。与不使用IMR的治疗相比，在SBRT前列腺治疗中使用IMR有可能将靶区剂量覆盖范围（PTV的98%的最小剂量，D98%）提高>20%。计算得出的有运动的IMR监测治疗的D98%在无运动计划的1.5%以内。
