Homogeneous Gamma Knife boost following Linac-RT: A feasibility study for nasopharyngeal carcinoma

IF 2.7 3区医学 Q1 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Physica Medica-European Journal of Medical Physics Pub Date : 2025-06-04 DOI:10.1016/j.ejmp.2025.105022

Manon Spaniol , Yasser Abo-Madyan , Arne M. Ruder , Beate Schweizer , Jens Fleckenstein , Frank A. Giordano , Florian Stieler

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引用次数: 0

Abstract

Purpose

Radiotherapy plays a critical role in the treatment of nasopharyngeal carcinoma (NPC). However, the number and close proximity of organs at risk (OAR) hampers dose escalation using classical techniques. The Leksell Gamma Knife® (LGK, Elekta AB) achieves a steep dose gradient, which might be beneficial to apply sequential/upfront boosts to these tumors. This study explores the feasibility of fractionated, homogeneous LGK Icon boost compared to a linear accelerator (LINAC) boost.

Methods

Eight NPC patients treated with LINAC-based therapy at our institution were retrospectively analyzed. Each patient received a base plan (60/2Gy) to the primary tumor and nodes, followed by a boost (10/2Gy) targeting the primary tumor. LGK boost plans were generated using a research prototype version of LGK Lightning® (Elekta AB) for enhanced homogeneity in order to reduce hot spots within critical regions. Gradient index (GI), Paddick conformity index (PCI), and institutional OAR constraints were evaluated.

Results

Over all patients, the LGK boost plans had improved GI compared to the LINAC boost plans (3.11vs.5.46) and decreased PCI (0.79vs.0.81). The sum of base and LGK boost plans showed overall lower OAR doses [0.5–1.3 Gy] compared to the sum of base and LINAC boost. With the LGK boost plans, hot spots inside the PTV were in mean 1.6 Gy higher compared to the LINAC boost.

Conclusion

This study demonstrated the feasibility and dosimetric benefits of using fractionated LGK boost following LINAC base treatment for NPC. The prototype version effectively reduced doses to OAR and controlled hot spots within the target.

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Linac-RT后均匀伽玛刀增强：鼻咽癌的可行性研究

目的放射治疗在鼻咽癌的治疗中起着至关重要的作用。然而，危险器官（OAR）的数量和接近程度阻碍了使用传统技术增加剂量。Leksell伽玛刀®（LGK, Elekta AB）实现陡峭的剂量梯度，这可能有利于对这些肿瘤进行顺序/预先增强。本研究探讨了分馏、均匀的LGK图标增压与线性加速器（LINAC）增压的可行性。方法回顾性分析我院接受linac为基础治疗的8例鼻咽癌患者。每位患者接受原发肿瘤和淋巴结的基础计划（60/2Gy），然后针对原发肿瘤进行强化（10/2Gy）。LGK升压计划是使用LGK Lightning®（Elekta AB）的研究原型版本生成的，用于增强均匀性，以减少关键区域内的热点。评估梯度指数（GI）、帕迪克一致性指数（PCI）和机构OAR约束。结果在所有患者中，与LINAC提升计划相比，LGK提升计划改善了GI (3.11vs.5.46)，降低了PCI （0.79vs.0.81）。与基础和LINAC增压计划的总和相比，基础和LGK增压计划的总和显示出总体上较低的桨叶剂量[0.5-1.3 Gy]。在LGK增压方案中，PTV内部的热点比LINAC增压方案平均高1.6 Gy。结论本研究证明了在LINAC基础治疗鼻咽癌后使用分级LGK增强治疗的可行性和剂量学上的益处。原型版本有效地减少了对桨部的剂量，并控制了目标内的热点。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Physica Medica-European Journal of Medical Physics 生物-生物物理

CiteScore

6.80

自引率

14.70%

发文量

493

审稿时长

78 days

期刊介绍： Physica Medica, European Journal of Medical Physics, publishing with Elsevier from 2007, provides an international forum for research and reviews on the following main topics: Medical Imaging Radiation Therapy Radiation Protection Measuring Systems and Signal Processing Education and training in Medical Physics Professional issues in Medical Physics.