Swanick Cameron W, Shang Michael H, Erhart Kevin, Cabrera Jonathan, Burkavage James, Dvorak Tomas, Ramakrishna Naren, Li Zhiqiu, Shah Amish, Meeks Sanford L, Zeidan Omar A, Kelly Patrick
Center for Advanced Radiation Therapy, Orlando Health Cancer Institute, Orlando, FL, USA.
.decimal, LLC, Sanford, FL, USA.
Int J Part Ther. 2023 Nov 8;10(2):85-93. doi: 10.14338/IJPT-23-00005.1. eCollection 2023 Fall.
Many patients with metastatic cancer live years beyond diagnosis, and there remains a need to improve the therapeutic ratio of metastasis-directed radiation for these patients. This study aimed to assess a process for delivering cost-effective palliative proton therapy to the spine using diagnostic scan-based planning (DSBP) and prefabricated treatment delivery devices.
We designed and characterized a reusable proton aperture system that adjusts to multiple lengths for spine treatment. Next, we retrospectively identified 10 patients scan treated with thoracic proton therapy who also had a diagnostic computed tomography within 4 months of simulation. We contoured a T6-T9 target volume on both the diagnostic scans (DS) and simulation scans (SS). Using the aperture system, we generated proton plans on the DS using a posterior-anterior beam with no custom range compensator to treat T6-T9 to 8 Gy × 1. Plans were transferred to the SS to compare coverage and normal tissue doses, followed by robustness analysis. Finally, we compared normal tissue doses and costs between proton and photon plans. Results were compared using the Wilcoxon signed-rank test.
Median D on the DS plans was 101% (range, 100%-102%) of the prescription dose. Median D was 107% (range, 105%-108%). When transferred to SS, coverage and hot spots remained acceptable for all cases. Heart and esophagus doses did not vary between the DS and SS proton plans ( >.2). Robustness analysis with 5 mm X/Y/Z shifts showed acceptable coverage (D > 98%) for all cases. Compared with the proton plans, the mean heart dose was higher for both anterior-posterior/posterior-anterior and volumetric modulated arc therapy plans ( < .01). Cost for proton DSBP was comparable to more commonly used photon regimens.
Proton DSBP is technically feasible and robust, with superior sparing of the heart compared with photons. Eliminating simulation and custom devices increases the value of this approach in carefully selected patients.
许多转移性癌症患者在确诊后能存活数年，因此仍有必要提高针对这些患者的转移灶定向放疗的治疗比。本研究旨在评估一种使用基于诊断扫描的计划（DSBP）和预制治疗输送装置为脊柱提供具有成本效益的姑息性质子治疗的方法。
我们设计并表征了一种可重复使用的质子孔径系统，该系统可根据脊柱治疗的多种长度进行调整。接下来，我们回顾性地确定了10例接受胸椎质子治疗的患者，他们在模拟治疗的4个月内也进行了诊断性计算机断层扫描。我们在诊断扫描（DS）和模拟扫描（SS）上勾勒出T6 - T9靶区体积。使用孔径系统，我们在DS上使用前后向射束生成质子计划，不使用定制的射程补偿器，将T6 - T9治疗至8 Gy×1。计划被转移到SS上以比较靶区覆盖情况和正常组织剂量，随后进行鲁棒性分析。最后，我们比较了质子计划和光子计划之间的正常组织剂量和成本。使用Wilcoxon符号秩检验比较结果。
DS计划的中位剂量是处方剂量的101%（范围为100% - 102%）。中位剂量为107%（范围为105% - 108%）。当转移到SS时，所有病例的靶区覆盖和热点情况仍然可以接受。DS和SS质子计划之间心脏和食管剂量没有差异（>.2）。进行5 mm X/Y/Z移位的鲁棒性分析表明，所有病例的靶区覆盖均可接受（剂量>98%）。与质子计划相比，前后向/后前向和容积调强弧形放疗计划的平均心脏剂量更高（<.01）。质子DSBP的成本与更常用的光子治疗方案相当。
质子DSBP在技术上是可行且稳健的，与光子治疗相比，对心脏的保护效果更好。消除模拟和定制装置增加了这种方法在精心挑选患者中的价值。
