Physics and Imaging in Radiation Oncology最新文献_第7页

Microstructural modelling based on diffusion weighted imaging to guide dose painting in carbon ions for large sacral chordomas 基于弥散加权成像引导碳离子剂量成像的大骶脊索瘤显微结构建模

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100887

Giovanni Parrella , Letizia Morelli , Giuseppe Magro , Lars Glimelius , Jakob Ödén , Mario Ciocca , Sara Imparato , Marco Rotondi , Maria Rosaria Fiore , Ester Orlandi , Guido Baroni , Silvia Molinelli , Chiara Paganelli

Background and purpose

Dose Painting (DP) in radiotherapy is a strategy to account for the tumor microstructural heterogeneity. This study evaluated a DP approach in carbon ion radiotherapy (CIRT), using cell count estimates derived from diffusion-weighted magnetic resonance imaging (DWI).

Materials and methods

Thirty-seven large sacral chordoma (SC) patients were analysed. Voxel-wise cell count was estimated from DWI using a published microstructural model. A Poisson-based tumor control probability (TCP) model, fitted on 27 patients, guided DP optimization in a research version of RayStation 2024A. The approach was tested on 10 patients, comparing uniform-dose plans against two strategies: dose redistribution (DR), which maintained the mean gross tumor volume (GTV) dose, and dose escalation (DE), which allowed a 3 % increase. Plan evaluation on targets and organs at risk (OARs) included dose-volume histogram metrics (D_95%, D_50%, D_1%) and dose-averaged linear energy transfer (LET_d)-volume histogram metrics (L_98%, L_50%, L_1%) to assess clinical acceptability. TCP gain quantified the benefit of biologically targeted strategies. TCP uncertainty was evaluated by propagating the microstructural model’s errors to generate best- and worst-case cell count maps.

Results

DE and DR plans met clinical acceptability criteria. DE increased TCP from 75.5 ± 5.6 % to 83.3 ± 3.9 % (p < 0.001), with −3 to +5 percentage points variation under uncertainty. DR plans showed a TCP gain of 1.8 ± 1.0 percentage points. No significant dose or LET_d increase was observed in OARs, while DE plans showed a lower L_98% in GTV.

Conclusions

Dose painting based on microstructural modelling in CIRT showed potential to improve TCP while sparing OARs.

背景与目的放射治疗中剂量涂绘（DP）是一种考虑肿瘤显微结构异质性的策略。本研究评估了碳离子放疗（CIRT）中的DP方法，使用来自扩散加权磁共振成像（DWI）的细胞计数估计。材料与方法对37例大骶脊索瘤（SC）患者的临床资料进行分析。使用已发表的微观结构模型从DWI估计体素细胞计数。在RayStation 2024A研究版中，基于泊松的肿瘤控制概率（TCP）模型拟合了27例患者，指导了DP优化。该方法在10例患者中进行了测试，将均匀剂量计划与两种策略进行了比较：剂量再分配（DR）和剂量递增（DE），前者维持了平均总肿瘤体积（GTV）剂量，后者允许增加3%。靶和危险器官（OARs）的计划评估包括剂量-体积直方图指标（D95%, D50%, D1%）和剂量平均线性能量转移(LETd)-体积直方图指标（L98%, L50%, l1），以评估临床可接受性。TCP增益量化了生物靶向策略的益处。通过传播微观结构模型的误差来产生最佳和最坏情况的细胞计数图来评估TCP不确定性。结果de和DR方案均符合临床可接受标准。DE将TCP从75.5±5.6%增加到83.3±3.9% (p < 0.001)，在不确定情况下变化幅度为- 3到+5个百分点。DR计划显示TCP增长1.8±1.0个百分点。在OARs中未观察到显著的剂量或LETd增加，而DE计划显示GTV的L98%较低。结论基于CIRT微结构建模的剂量喷涂在保留桨叶的同时改善了TCP。

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引用次数: 0

Corrigendum to “Proton dose calculation on cone-beam computed tomography using unsupervised 3D deep learning networks”. [Phys Imaging Radiat Oncol 2024;32:100658] “使用无监督3D深度学习网络计算锥束计算机断层扫描的质子剂量”的勘误表。物理成像辐射学报，2024；32:100658]

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100849

Casper Dueholm Vestergaard , Ulrik Vindelev Elstrøm , Ludvig Paul Muren , Jintao Ren , Ole Nørrevang , Kenneth Jensen , Vicki Trier Taasti

引用次数: 0

A phantom study of internal target volume and mid-position accuracy in adaptive and conventional four-dimensional computed tomography across regular and irregular motion 自适应和传统四维计算机断层扫描在规则和不规则运动中的内部靶体积和中间位置精度的模拟研究

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100845

Bart J.J. Kremers , Dave S.C. van Gruijthuijsen , Dominique Reijtenbagh , Jacco L.G. Steenhuijsen , Mariska de Smet , Rob H.N. Tijssen

This technical note evaluates the performance of an adaptive four-dimensional computed tomography (4DCT) acquisition method compared to conventional 4DCT using a motion phantom. Metrics assessed include deviations in volume, CT number, diameter, peak-to-peak amplitude and determination of the internal target volume (ITV) and mid-position. Under regular breathing, most measurements fall within predefined clinical tolerances for all systems. Under irregular motion, the adaptive method showed reduced deviations in ITV and minimal impact on mid-position determination. These findings support the clinical value of adaptive 4DCT in improving motion management and target definition accuracy in radiotherapy planning.

本技术笔记评估了自适应四维计算机断层扫描（4DCT）采集方法的性能，并与使用运动幻象的传统4DCT进行了比较。评估指标包括体积、CT数、直径、峰对峰振幅的偏差，以及内部目标体积（ITV）和中间位置的确定。在正常呼吸的情况下，大多数测量值都在所有系统预定义的临床公差范围内。在不规则运动情况下，自适应方法显示ITV偏差较小，对中间位置确定的影响最小。这些发现支持了适应性4DCT在改善放射治疗计划中的运动管理和靶标定义准确性方面的临床价值。

引用次数: 0

Synthetic computed tomography techniques for adaptive proton therapy in head and neck cancers 头颈癌适应性质子治疗的合成计算机断层扫描技术

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100847

Suryakant Kaushik , Nadine Vatterodt , Jakob Ödén , Albin Fredriksson , Stine S. Korreman , Iuliana Toma-Dasu

Head and neck (HN) radiotherapy often requires corrective interventions. This study evaluated three methods for synthetic computed tomography (CT) generation for adaptive HN planning using cone-beam CT (CBCT) images. CBCT images for 15 patients were paired with same-day repeat CT scans and robustly optimized proton plans were recalculated. The anatomy-preserving virtual CT (APvCT) method utilized organs-at-risk as deformation controlling structures. APvCT and conventional virtual CT methods showed lower mean absolute errors in CT number values compared to corrected CBCT; however, all synthetic CT methods were found suitable for proton dose recalculation with gamma passing rates greater than 96.7% (

2 %, 2 mm

).

头颈部放射治疗通常需要矫正干预。本研究评估了三种使用锥形束CT （CBCT）图像生成自适应HN规划的合成计算机断层扫描（CT）方法。15例患者的CBCT图像与同一天重复CT扫描配对，并重新计算稳健优化的质子计划。保持解剖结构的虚拟CT （APvCT）方法利用危险器官作为变形控制结构。与校正后的CBCT相比，APvCT和传统虚拟CT方法的CT值平均绝对误差更小；然而，所有合成CT方法均适用于质子剂量重新计算，伽玛通过率大于96.7% （2%,2mm）。

引用次数: 0

Clinical target volumes for glioma – Automated delineation to improve neuroanatomic consistency 胶质瘤的临床靶体积-自动划定以提高神经解剖一致性

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100865

Gregory Buti , Marcela Giovenco , Tugba Yilmaz , Ali Ajdari , Christopher P. Bridge , Gregory C. Sharp , Fredrik Löfman , Helen A. Shih , Thomas Bortfeld

Background and purpose

Delineating clinical target volumes (CTVs) for glioma is challenging as consistency with the neuroanatomy needs to be carefully verified. We developed an automated approach that incorporates tumor infiltration pathways and anatomic barriers to improve the neuroanatomical consistency and efficiency of CTV delineation.

Materials and methods

A deep learning model for brain structure segmentation was developed based on manual delineations of hemispheres, brainstem, cerebellum, optic chiasm, optic nerves, ventricles, and midline on CT images of ninety-nine glioma patients. Brain structures predictions are integrated into a constrained distance transform that defines the CTV as a 15-mm expansion of the gross tumor volume. Connecting structures with white matter tracts allow for expansions across different structure boundaries, e.g., cerebellum and brainstem connecting at the cerebellar peduncles.

Results

Mean (±std) Dice Similarity Coefficient (DSC) for the hemispheres, brainstem, cerebel-lum, chiasm, optic nerves, midline and ventricles were (98.5 ± 0.8)%, (92.5 ± 2.8)%, (96.7 ± 2.2)% (63.9 ± 12.2)%, (83.8 ± 9.0)%, (81.2 ± 7.0) and (91.5 ± 3.9)%. Mean (±std) 95 % Hausdorff distance (HD95) were, in mm, 1.9 ± 2.5, 7.0 ± 5.4, 1.8 ± 1.2, 7.2 ± 3.2, 2.3 ± 1.0, 9.5 ± 10.5, and 3.8 ± 3.1, respectively. Auto-generated CTVs are compared against reference CTVs (15-mm expansion constrained by manually-contoured brain structures). The automatic CTVs showed excellent similarity to the reference CTVs with mean (±std) Surface DSC with 2 mm tolerance and HD95 scores of (95.6 ± 3.4)% and (1.4 ± 1.2) mm, respectively. A physician’s quality assessment reported that the automated method would result in a substantial amount of time saved in 85 % of CTV delineations.

Conclusion

We have successfully incorporated expert knowledge to improve the neuroanatom-ical consistency of automatically-generated CTVs for glioma.

背景和目的描述胶质瘤的临床靶体积（CTVs）具有挑战性，因为需要仔细验证与神经解剖学的一致性。我们开发了一种结合肿瘤浸润路径和解剖屏障的自动化方法，以提高CTV描绘的神经解剖学一致性和效率。材料与方法基于99例胶质瘤患者CT图像的半脑、脑干、小脑、视交叉、视神经、脑室和中线的人工圈定，建立了脑结构分割的深度学习模型。脑结构预测被整合到一个约束距离变换中，该变换将CTV定义为肿瘤总体积扩大15mm。用白质束连接结构允许跨越不同结构边界的扩张，例如，小脑和脑干在小脑梗处连接。结果脑半球、脑干、小脑、交叉、视神经、中线和脑室的平均（±std） Dice Similarity Coefficient （DSC）分别为（98.5±0.8）%、（92.5±2.8）%、（96.7±2.2）%、（63.9±12.2）%、（83.8±9.0）%、（81.2±7.0）%和（91.5±3.9）%。意味着(±std) 95% (HD95)豪斯多夫距离,在毫米,1.9±2.5,7.0±5.4,1.8±1.2,7.2±3.2,2.3±1.0,9.5±10.5,3.8±3.1,分别。将自动生成的ctv与参考ctv进行比较（受手动轮廓脑结构限制的15毫米扩张）。自动CTVs与参考CTVs具有良好的相似性，平均（±std）表面DSC公差为2mm， HD95评分分别为（95.6±3.4）%和（1.4±1.2）mm。一名医生的质量评估报告称，自动化方法将在85%的CTV划定中节省大量时间。结论我们成功地结合了专家知识，提高了神经胶质瘤自动生成cvs的神经解剖学一致性。

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引用次数: 0

Workflow to detect exceeded dose constraints in pancreatic stereotactic body irradiation after intrafraction motion during magnetic resonance-guided adaptive radiotherapy using a deep learning-refined contour propagation tool 使用深度学习-精细轮廓传播工具检测磁共振引导自适应放射治疗中胰腺立体定向照射中超过剂量限制的工作流程

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100866

Christina Sarosiek, Asma Amjad, Renae Conlin, Beth Erickson, William A. Hall, Eric S. Paulson

Introduction

The adapt-to-shape (ATS) process on the MR-Linac involves manual contour edits followed by treatment plan re-optimization on daily pre-beam MRIs. A verification image is acquired after plan optimization to assess the dose distribution with respect to intrafraction motion using the pre-beam contours. We introduce here a workflow to automatically detect organ motion of gastrointestinal structures that results in exceeded planned dose constraints.

Materials and methods

The workflow first transferred the contours and dose distribution created on the daily pre-beam MRI to the verification MRI. A deep learning-refined contour propagation (DL-RCP) tool, trained on 79 images, improved the transferred contours and the dose to 0.03 cm³ (D_{0.03 cm³}) is updated. The workflow notified the physician if D_{0.03 cm³} exceeds the constraint. We tested the workflow on 48 daily ATS fractions of 11 patients treated for pancreatic cancer (33–40 Gy in 5 fractions). We added manually drawn contours to the verification images for reference.

Results

The Dice similarity coefficient and mean distance to agreement for the clinical/DL-refined contours were 0.56/0.71 and 9.08/5.08 mm, respectively. The workflow detected exceeded constraints with specificity 0.90, sensitivity 0.75, and accuracy 0.85. In one case, the duodenal D_{0.03 cm³} was 29.9 Gy for the clinical contour, and 36.0 Gy and 35.6 Gy with the reference and DL-refined contours.

Conclusion

The proposed method detected exceeded dose constraints in gastrointestinal structures due to intrafraction motion during ATS planning for pancreatic treatments and can aid in the clinical decision to re-optimize the plan on the verification MR.

MR-Linac上的形状适应（ATS）过程包括手动轮廓编辑，然后对每日预束mri进行治疗计划重新优化。在计划优化后获得验证图像，以利用预束轮廓评估相对于屈光度运动的剂量分布。我们在这里介绍一个工作流程来自动检测胃肠道结构的器官运动，导致超过计划的剂量限制。材料和方法该工作流程首先将每日预束MRI上生成的轮廓和剂量分布转移到验证MRI上。使用深度学习-精细轮廓传播（DL-RCP）工具对79张图像进行训练，改进了转移轮廓，并更新了剂量至0.03 cm3 （D0.03 cm3）。如果D0.03 cm3超过限制，工作流通知医生。我们对11例胰腺癌患者的48个每日ATS分数（5个分数33-40 Gy）进行了工作流程测试。我们将手工绘制的轮廓添加到验证图像中以供参考。结果临床轮廓与dl轮廓的Dice相似系数和平均吻合距离分别为0.56/0.71和9.08/5.08 mm。检测到的工作流程超出约束，特异性0.90，灵敏度0.75，准确性0.85。1例十二指肠D0.03 cm3临床轮廓为29.9 Gy，参考轮廓和dl -精轮廓分别为36.0 Gy和35.6 Gy。结论本方法在胰腺治疗ATS计划过程中可检测到胃肠道结构中由于牵引力运动导致的剂量超出限制，可在验证MR上帮助临床决策重新优化计划。

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引用次数: 0

Risk of genitourinary late effects after radiotherapy for prostate cancer associated with early changes in bladder shape 前列腺癌放疗后泌尿生殖系统晚期效应与早期膀胱形状改变的风险

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100855

Oscar Casares-Magaz , Renata G. Raidou , Katarina Furmanová , Niclas Pettersson , Vitali Moiseenko , John Einck , Austin Hopper , Rick Knopp , Ludvig P. Muren

Background and purpose

The risk of genitourinary late effects is a major dose-limiting factor in radiotherapy for prostate cancer. By using shape analysis and machine learning, the aim of this study was to evaluate whether bladder shape descriptors from the first week of treatment could identify patients experiencing genitourinary late effects.

Material and methods

From a cohort of 258 prostate cancer patients treated with daily cone-beam computed tomography (CBCT)-guided radiotherapy (prescription doses of 77.4–81.0 Gy), 7 pre-treatment asymptomatic cases experiencing RTOG genitourinary late effects ≥Grade 2 and 21 matched controls were selected. The bladder was manually contoured on each CBCT, and a 17-D vector comprising shape descriptors was used for patient clustering, focusing on bladder contours from the first week of treatment. ANOVA was used to test statistical significance of descriptors across and within clusters.

Results

Of the contours from the first week of treatment, 84 % could be classified in two main clusters with distinct bladder shape characteristics. This cluster stratification remained identical when bladder contours from the entire course of treatment were used. Convexity, elliptic variance and compactness were significantly different between patients with vs. without genitourinary late effects ≥Grade 2 (p < 0.05). Dice Coefficients between predictive models using descriptors of the first week and the voxels’ probability of belonging to the bladder were above 93 ± 6 % (median ± interquartile range).

Conclusion

Bladder shape descriptors in the first week of treatment showed potential to predict the risk of developing genitourinary late effects after radiotherapy for prostate cancer.

背景与目的泌尿生殖系统晚期效应的风险是前列腺癌放疗的一个主要剂量限制因素。通过使用形状分析和机器学习，本研究的目的是评估从治疗第一周开始的膀胱形状描述符是否可以识别患有泌尿生殖系统晚期效应的患者。材料与方法258例接受每日锥束计算机断层扫描（CBCT）引导放射治疗（处方剂量77.4-81.0 Gy）的前列腺癌患者中，选择7例治疗前出现RTOG晚期效应≥2级的无症状患者和21例匹配对照。在每个CBCT上手动绘制膀胱轮廓，并使用包含形状描述符的17-D向量进行患者聚类，重点关注治疗第一周的膀胱轮廓。方差分析用于检验描述符在集群间和集群内的统计显著性。结果治疗后第一周的膀胱外形特征中，有84%的患者可分为两类。当使用整个治疗过程的膀胱轮廓时，这种簇状分层保持相同。泌尿生殖系统晚期效应≥2级患者与非泌尿生殖系统晚期效应患者的凸度、椭圆方差和致密度差异有统计学意义（p < 0.05）。使用第一周描述符的预测模型与属于膀胱的体素概率之间的骰子系数大于93±6%（中位数±四分位数范围）。结论前列腺癌放疗后第一周膀胱形态描述符可预测患者发生泌尿生殖系统晚期反应的风险。

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引用次数: 0

Time-saving potential of daily online adaptive proton therapy for head and neck cancers by reducing number of beams 通过减少光束数量，每日在线自适应质子治疗头颈癌节省时间的潜力

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100853

Evangelia Choulilitsa , Katarzyna Czerska , Barbara Bachtiary , Damien Charles Weber , Antony John Lomax , Francesca Albertini

Background and purpose

Standard care for head and neck cancer (HNC) treatment with proton therapy typically involves a 4–6 field Intensity Modulated Proton Therapy plan to enhance robustness towards anatomical changes and patient misalignments. This study aimed to evaluate whether a more efficient plan with fewer beams, designed for faster delivery, can be combined with online daily adaptation (DAPT) to provide treatment of comparable quality, and improve treatment outcomes.

Materials and methods

We retrospectively analyzed five HNC patients with available daily 3D imaging treated at our institution. To simulate DAPT, synthetic Computed Tomography (CT) images were generated by deforming planning CT to each daily Cone-Beam CT with targets and organs-at-risk (OARs) propagated to daily images. Three plans were created per-patient: Offline_SBC and DAPT_SBC with standard, and DAPT_RBC with reduced, beam configuration. DAPT_SBC and DAPT_RBC were reoptimized on daily synCTs, while Offline_SBC followed clinical workflow, with offline replanning as needed.

Results

Offline_SBC showed >5% target underdosage in 15% of fractions, with both adaptive approaches significantly improving coverage. Although DAPT_RBC outperformed Offline_SBC for target coverage, its advantage in OARs sparing was less definitive. DAPT_SBC reduced pooled average normal tissue dose across patients and fractions by 13% and pooled average normal tissue complication probability for xerostomia by 7%. Delivery of DAPT_RBC with fewer beams was 24% faster than plans with conventional arrangement.

Conclusions

Our delivery efficiency study shows that DAPT can allow fewer beams to achieve faster delivery, as shown in case of DAPT_RBC workflow, and a reduction in the dose to normal tissue.

背景和目的质子治疗头颈癌（HNC）的标准护理通常包括4-6场强度调制质子治疗计划，以增强对解剖改变和患者错位的稳健性。本研究旨在评估一种更有效的方案，采用更少的光束，设计更快的交付，是否可以与在线每日适应（DAPT）相结合，提供同等质量的治疗，并改善治疗结果。材料和方法我们回顾性分析了5例在我院接受每日3D成像治疗的HNC患者。为了模拟DAPT，通过将规划CT变形为每个日常锥束CT生成合成计算机断层扫描（CT）图像，并将目标和危险器官（OARs）传播到日常图像中。为每位患者创建了三种方案：标准的OfflineSBC和DAPTSBC，以及减少光束配置的DAPTRBC。在每日同步ct上重新优化DAPTSBC和DAPTRBC，而OfflineSBC则遵循临床工作流程，并根据需要进行离线重新规划。结果sofflinesbc在15%的分数中显示5%的目标剂量不足，两种适应性方法均显著提高了覆盖率。尽管DAPTRBC在目标覆盖方面优于OfflineSBC，但其在桨叶保护方面的优势并不确定。DAPTSBC将患者和部分患者的正常组织总平均剂量降低了13%，口干症的正常组织并发症总平均发生率降低了7%。采用较少光束的DAPTRBC比采用常规布置的方案快24%。结论DAPT的递送效率研究表明，在DAPTRBC的工作流程中，DAPT可以使更少的光束实现更快的递送，并且可以减少对正常组织的剂量。

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引用次数: 0

Using three-dimensional equieffective dose mapping to audit a methodology for calculating permitted doses for head and neck reirradiation 使用三维等有效剂量图审核头颈部再照射允许剂量的计算方法

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100867

David Nash , Sarah Muscat , Chelmis M. Thiong’o , Eliana Vasquez Osorio , Antony L. Palmer

Background and purpose

Reirradiation is increasingly common, but accounting for prior dose to the spinal cord and brainstem is challenging. This study compares a simple isodose-based method of previous dose compensation with voxel-wise equivalent dose in 2 Gy fractions (EQD_2/2) dose mapping to assess accuracy and safety.

Materials and methods

Ten head and neck reirradiation cases were retrospectively reviewed. During planning, original dose distributions were mapped onto the reirradiation computed tomography scan. Isodoses within the cord and brainstem were used to segment dose-level substructures, with cumulative doses kept within defined tolerances. Following 3D EQD_2/2 mapping, the same cases were audited by recalculating cumulative maximum doses. Cumulative doses from both methods were compared.

Results

Retrospective EQD_2/2 analysis confirmed all cumulative doses were within tolerance, with up to 9.7 Gy difference between the two methods. In two cases, cord and brainstem doses approached tolerance.

Conclusions

A simple, isodose-based approach to spinal cord and brainstem reirradiation tolerance calculation has been shown to be safe when retrospectively compared with voxel-wise EQD_2/2 mapping. This method can be implemented in any planning system capable of generating contours from isodose lines, offering a practical alternative where advanced EQD_2/2 dose accumulation software is unavailable.

背景和目的放射治疗越来越普遍，但对脊髓和脑干的先前剂量的解释是具有挑战性的。本研究比较了一种简单的基于异剂量的先前剂量补偿方法与2 Gy分数（EQD2/2）剂量测绘的体素等效剂量，以评估准确性和安全性。材料与方法对10例头颈部再照射病例进行回顾性分析。在计划期间，将原始剂量分布映射到再照射计算机断层扫描上。脊髓和脑干内的等剂量用于分割剂量水平的亚结构，累积剂量保持在规定的耐受范围内。在3D EQD2/2制图后，通过重新计算累积最大剂量对相同病例进行审计。比较了两种方法的累积剂量。结果回顾性EQD2/2分析证实所有累积剂量均在耐受范围内，两种方法之间的差异高达9.7 Gy。在两个病例中，脊髓和脑干剂量接近耐受。结论与EQD2/2体素制图相比，一种简单的、基于异剂量的脊髓和脑干再照射耐受计算方法是安全的。该方法可以在任何能够从等剂量线生成等高线的规划系统中实施，在没有先进的EQD2/2剂量累积软件的情况下提供实用的替代方案。

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引用次数: 0

Improving reirradiation of recurrent non-small cell lung cancer through non-coplanar beam arrangements 通过非共面光束排列改善复发性非小细胞肺癌的再照射

IF 3.3 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-10-01 DOI: 10.1016/j.phro.2025.100874

Nathan Torelli , Jonas Willmann , Katja Dähler , Madalyne Day , Nicolaus Andratschke , Jan Unkelbach

Background and purpose

Reirradiation for non-small cell lung cancer (NSCLC) is commonly delivered using coplanar techniques. In this study, we investigated whether the selection of favorable non-coplanar beam orientations may limit cumulative doses to critical organs-at-risk (OARs) and thus improve the therapeutic window.

Materials and methods

Fifteen cases of challenging high-dose reirradiation for locoregionally recurrent NSCLC were included in this in-silico study. For each patient, the dose distribution from the previous treatment was first mapped to the new patient anatomy using rigid dose registration, and subsequently converted to equivalent dose in 2 Gy fractions (EQD2). A two-arc non-coplanar reirradiation plan was then generated using an EQD2-based direct aperture optimization algorithm, which allows for the simultaneous optimization of dynamic gantry-couch paths and the cumulative EQD2 distribution. Non-coplanar reirradiation plans were benchmarked against two-arc coplanar plans.

Results

Considerable reductions of at least 5 Gy in the maximum cumulative EQD2 to critical organs were achieved in 6 out of 15 patients using non-coplanar versus coplanar arcs. In particular, the maximum cumulative EQD2 was reduced by up to −9.0 Gy for the bronchial tree, −5.8 Gy for the esophagus, −5.3 Gy for the trachea and −5.6 Gy for the great vessel. At the same time, target coverage and lung EQD2 metrics were comparable for both methods.

Conclusions

The automated selection of favorable non-coplanar beam orientations may reduce the maximum cumulative EQD2 to critical OARs in challenging thoracic reirradiation cases. This allows to explore either better OAR sparing or dose-escalation in future clinical studies.

背景与目的非小细胞肺癌（NSCLC）的放射治疗通常采用共面技术。在这项研究中，我们研究了选择有利的非共面光束方向是否可以限制关键危险器官（OARs）的累积剂量，从而改善治疗窗口。材料和方法本计算机研究纳入了15例局部复发性非小细胞肺癌的高剂量再照射治疗。对于每个患者，先前治疗的剂量分布首先使用严格的剂量登记映射到新的患者解剖结构，随后转换为2 Gy分数的等效剂量（EQD2）。采用基于EQD2的直接孔径优化算法生成两弧非共面再照射方案，同时优化动态龙台路径和累积EQD2分布。非共面再照射计划以两弧共面计划为基准。结果15例患者中有6例采用非共面弧线与共面弧线相比，对关键器官的最大累积EQD2减少了至少5 Gy。特别是，支气管树的最大累积EQD2减少了- 9.0 Gy，食道减少了- 5.8 Gy，气管减少了- 5.3 Gy，大血管减少了- 5.6 Gy。同时，两种方法的靶覆盖率和肺EQD2指标具有可比性。结论在具有挑战性的胸部再照射病例中，自动选择有利的非共面光束方向可将最大累积EQD2降低到临界OARs。这允许在未来的临床研究中探索更好的OAR保留或剂量递增。

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引用次数: 0