PDF(Pubmed)
Abstract：
Introduction: In this study, we sought to develop a thermoplastic patient-specific helmet bolus that could deliver a uniform therapeutic dose to the target and minimize the dose to the normal brain during whole-scalp treatment with a humanoid head phantom. Methods: The bolus material was a commercial thermoplastic used for patient immobilization, and the holes in the netting were filled with melted paraffin. We compared volumetric-modulated arc therapy treatment plans with and without the bolus for quantitative dose distribution analysis. We analyzed the dose distribution in the region of interest to compare dose differences between target and normal organs. For quantitative analysis of treatment dose, OSLD chips were attached at the vertex (VX), posterior occipital (PO), right (RT), and left temporal (LT) locations. Results: The average dose in the clinical target volume was 6553.8 cGy (99.3%) with bolus and 5874 cGy (89%) without bolus, differing by more than 10% from the prescribed dose (6600 cGy) to the scalp target. For the normal brain, it was 3747.8 cGy (56.8%) with bolus and 5484.6 cGy (83.1%) without bolus. These results show that while the dose to the treatment target decreased, the average dose to the normal brain, which is mostly inside the treatment target, increased by more than 25%. With the bolus, the OSLD measured dose was 102.5 ± 1.2% for VX and 101.5 ± 1.9%, 95.9 ± 1.9%, and 81.8 ± 2.1% for PO, RT, and LT, respectively. In addition, the average dose in the treatment plan was 102%, 101%, 93.6%, and 80.7% for VX, PO, RT, and LT. When no bolus was administered, 59.6 ± 2.4%, 112.6 ± 1.8%, 47.1 ± 1.6%, and 53.1 ± 2.3% were assessed as OSLD doses for VX, PO, RT, and LT, respectively. Conclusion: This study proposed a method to fabricate patient-specific boluses that are highly reproducible, accessible, and easy to fabricate for radiotherapy to the entire scalp and can effectively spare normal tissue while delivering sufficient surface dose.
摘要：
引言：在这项研究中，我们试图开发一种针对患者的热塑性头盔推注,在使用人形头模进行全头皮治疗期间,可以向目标提供均匀的治疗剂量,并将对正常大脑的剂量降至最低.方法：丸剂材料是用于患者固定的商业热塑性塑料，网上的洞里充满了融化的石蜡。我们比较了使用和不使用推注的体积调节电弧疗法治疗计划，以进行定量剂量分布分析。我们分析了感兴趣区域的剂量分布，以比较目标器官和正常器官之间的剂量差异。为了定量分析治疗剂量，OSLD芯片连接在顶点(VX)，枕后(PO),右(RT),和左时间(LT)位置。结果：推注的临床目标体积平均剂量为6553.8cGy（99.3％），不推注的cGy为5874cGy（89％），与头皮目标的规定剂量(6600cGy)相差10%以上。对于正常的大脑来说,有推注的cGy为3747.8cGy(56.8%)，无推注的cGy为5484.6cGy(83.1%)。这些结果表明，虽然治疗目标的剂量下降，正常大脑的平均剂量，主要在治疗目标内部，增加了25%以上。随着推注，VX的OSLD测量剂量为102.5±1.2%，101.5±1.9%，95.9±1.9%，PO为81.8±2.1%，RT,LT,分别。此外,治疗计划中的平均剂量为102%，101%,93.6%,VX为80.7%，PO,RT,LT。当没有注射时，59.6±2.4%,112.6±1.8%，47.1±1.6%,53.1±2.3%被评估为VX的OSLD剂量，PO,RT,LT,分别。结论：这项研究提出了一种方法来制造具有高度可重复性的患者特异性推注，可访问,并且易于制造以对整个头皮进行放射治疗，并且可以有效地节省正常组织，同时提供足够的表面剂量。
