Dosimetric evaluation of field width variation in helical Tomotherapy for sinonasal tumours: Implications for organ-at-risk sparing, treatment efficiency, and setup error sensitivity

IF 2.8 3区物理与天体物理 Q3 CHEMISTRY, PHYSICAL

Radiation Physics and Chemistry Pub Date : 2025-09-26 DOI:10.1016/j.radphyschem.2025.113338

Supratik Sen , Sandeep Singh , Abhay Kumar Singh , Dipesh , Manindra Bhushan , Mahipal , Sarthak Tandon , Munish Gairola

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引用次数: 0

Abstract

Aim

To evaluate the dosimetric impact of varying field widths (1 cm, 2.5 cm, and 5 cm) in Helical Tomotherapy (HT) for sinonasal tumours, focusing on target coverage, organ-at-risk (OAR) sparing, treatment efficiency, and robustness against setup errors.

Materials and methods

This retrospective study included 497 patients with sinonasal malignancies treated using HT. Three plans per patient were generated using field widths of 1 cm, 2.5 cm, and 5 cm. Dosimetric parameters including D95 %, D98 %, D2 %, homogeneity index (HI), Paddick's conformity index (PCI), low-dose spillage (V10–V90), and Beam-on time (BOT) were evaluated. OARs assessed included optic nerves, chiasm, brainstem, lenses, and cochlea. Statistical analysis was performed using paired t-tests (p < 0.05). Setup robustness was evaluated using an anthropomorphic phantom and optically stimulated luminescent dosimeters (OSLDs) under controlled displacements (0–5 mm).

Results

The 1 cm field width demonstrated superior PTV conformity (PCI: 0.82), better homogeneity, and reduced OAR doses, especially to the optic structures and brainstem. BOT was significantly higher with 1 cm (286 s) but remained clinically acceptable. Wider fields (5 cm) reduced BOT but increased dose spillage and OAR exposure. Phantom analysis showed higher dose sensitivity to setup shifts in 1 cm fields but within tolerable limits.

Conclusion

The 1 cm field width in HT provides optimal dosimetric benefits for sinonasal tumours, improving conformity and sparing critical structures despite a modest increase in treatment time. Personalized field width selection remains essential to balance treatment quality with efficiency.

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鼻窦肿瘤螺旋断层治疗中场宽变化的剂量学评价：对高危器官保留、治疗效率和设置误差敏感性的影响

目的评估不同视场宽度（1cm、2.5 cm和5cm）对鼻窦肿瘤螺旋断层治疗（HT）的剂量学影响，重点关注靶标覆盖率、器官风险（OAR）保留、治疗效率和对设置误差的稳健性。材料与方法回顾性研究497例鼻窦恶性肿瘤患者。每位患者使用1厘米、2.5厘米和5厘米的视野宽度生成三个平面图。评估剂量学参数包括d95%、d98%、D2 %、均匀性指数（HI）、帕迪克符合性指数（PCI）、低剂量溢出（V10-V90）和照射时间（BOT）。评估的桨包括视神经、交叉、脑干、晶状体和耳蜗。采用配对t检验进行统计学分析（p < 0.05）。在控制位移（0-5 mm）下，使用拟人化幻影和光刺激发光剂量计（osld）评估设置的鲁棒性。结果1 cm视场宽度具有较好的PTV一致性（PCI: 0.82），较好的均匀性，减少了OAR剂量，特别是对视神经结构和脑干的影响。BOT明显高于1 cm (286 s)，但临床仍可接受。更宽的区域（5厘米）减少了BOT，但增加了剂量溢出和桨暴露。幻影分析显示，在1厘米范围内，对设置位移的剂量敏感性较高，但在可容忍的范围内。结论1 cm的视场宽度为鼻窦肿瘤提供了最佳的剂量学益处，尽管治疗时间略有增加，但可改善一致性并保留关键结构。个性化的场宽选择对于平衡处理质量和效率至关重要。

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来源期刊

Radiation Physics and Chemistry 化学-核科学技术

CiteScore

5.60

自引率

17.20%

发文量

574

审稿时长

12 weeks

期刊介绍： Radiation Physics and Chemistry is a multidisciplinary journal that provides a medium for publication of substantial and original papers, reviews, and short communications which focus on research and developments involving ionizing radiation in radiation physics, radiation chemistry and radiation processing. The journal aims to publish papers with significance to an international audience, containing substantial novelty and scientific impact. The Editors reserve the rights to reject, with or without external review, papers that do not meet these criteria. This could include papers that are very similar to previous publications, only with changed target substrates, employed materials, analyzed sites and experimental methods, report results without presenting new insights and/or hypothesis testing, or do not focus on the radiation effects.