Physics and Imaging in Radiation Oncology最新文献_第10页

Definition of a framework for volumetric modulated arc therapy plan quality assessment with integration of dose-, complexity-, and robustness metrics 定义体积调制弧线治疗计划质量评估框架，整合剂量、复杂性和稳健性指标。

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-10-01 DOI: 10.1016/j.phro.2024.100685

Tina Orovwighose , Bernhard Rhein , Oliver Schramm , Oliver Jäkel , Vania Batista

Background and purpose

Conventionally, the quality of radiotherapy treatment plans is assessed through visual inspection of dose distributions and dose-volume histograms. This study developed a framework to evaluate plan quality using dose, complexity, and robustness metrics. Additionally, a method for predicting plan robustness metrics using dose and complexity metrics was introduced for cases where plan robustness evaluation is unavailable or impractical.

Materials and methods

The framework and prediction models were developed and validated using 103-bronchial Volumetric Modulated Arc Therapy (VMAT)-plans. The application of the framework was demonstrated using 25-VMAT-plans. To identify significant metrics for plan evaluation, 122-metrics were analysed and narrowed down using multivariate Spearman correlation. Metric limits were set with Statistical process control (SPC). Robustness metrics were predicted using multivariable or single linear regression models based on dose-and complexity-metrics.

Results

Twenty-five-metrics were selected based on the amount and strength of correlations. R₉₅(dose coverage) and HI_95/5(homogeneity index) stood out among the dose-metrics, while the complexity-metrics showed similar correlations. Average scenarios dose at 95 % Clinical Target Volume D95_mean(CTV) and Errorbar-based Volume-Histograms (EVH) were notable for robustness metrics. Approximately 99 % of evaluated metrics fell within established SPC limits. The prediction model for D95_mean(CTV) showed good performance (adjusted R² = 0.88, mean squared error (MSE) = 3.84 × 10⁻⁶), while the model for EVH demonstrated moderate reliability (adjusted R² = 0.52, MSE = 0.2). No statistically significant differences were found between the predicted (using dose-and complexity-metrics) and calculated robustness metrics (EVH (p-value = 0.9) and D95_mean(CTV) (p-value = 1)).

Conclusions

The developed framework enables early detection of sub-optimal, complex and non-robust treatment plans. The predictive model can be used when robustness evaluations are impractical.

背景和目的：传统上，通过目测剂量分布和剂量-体积直方图来评估放射治疗计划的质量。本研究开发了一个使用剂量、复杂性和稳健性指标评估计划质量的框架。此外，在计划稳健性评估不可用或不切实际的情况下，介绍了一种使用剂量和复杂性指标预测计划稳健性指标的方法。材料和方法：采用103支气管体积调节弧线治疗（VMAT）计划建立框架和预测模型并进行验证。使用25- vmat -plan演示了该框架的应用。为了确定计划评估的重要指标，分析了122个指标，并使用多变量Spearman相关性缩小了范围。用统计过程控制（SPC）设定计量限度。鲁棒性指标使用基于剂量和复杂性指标的多变量或单线性回归模型进行预测。结果：根据相关性的数量和强度选择了25个指标。R95（剂量覆盖）和HI95/5（均匀性指数）在剂量指标中表现突出，而复杂性指标也表现出类似的相关性。在95%临床目标体积d95平均值（CTV）和基于误差条的体积直方图（EVH）的平均方案剂量在稳健性指标方面是显著的。大约99%的评估指标落在既定的SPC限制之内。d95均值（CTV）预测模型具有较好的可靠性（调整后R2 = 0.88，均方误差(MSE) = 3.84 × 10-6）， EVH预测模型具有中等的可靠性（调整后R2 = 0.52, MSE = 0.2）。预测（使用剂量和复杂性指标）和计算的稳健性指标（EVH （p值= 0.9）和d95平均值（CTV）（p值= 1））之间没有统计学差异。结论：开发的框架能够早期发现次优，复杂和非稳健的治疗计划。当鲁棒性评估不切实际时，可以使用预测模型。

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引用次数: 0

A commissioning protocol for portal imaging-based radiotherapy in vivo dosimetry systems 基于门户成像的放射治疗体内剂量测定系统调试协议

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-10-01 DOI: 10.1016/j.phro.2024.100666

Marco Esposito , Riccardo Baldoni , Evy Bossuyt , Sara Bresciani , Catharine H Clark , Matthew Jones , Stephen Kry , Joseph Perry , Jeroen van de Kamer , Dirk Verellen , Nuria Jornet

Background and Purpose

With the availability of commercial electronic portal imaging detector-based in vivo dosimetry (EPID-based IVD) solutions, many radiotherapy departments are adopting this technology. However, comprehensive commissioning guidance is lacking. This study aims to provide a protocol for testing the accuracy and sensitivity of EPID-based IVD systems.

Material and methods

The protocol was tested across four institutions using two different systems. Accuracy was evaluated with homogeneous slab phantoms using different square regular fields, and clinical plans in a CIRS lung phantom. Multiple forward and back-projected algorithm implementations were assessed for different energies. Sensitivity analysis in the lung phantom examined responses to setup errors, anatomical variations, and delivery errors.

Results

In homogeneous phantoms, over 85 % of pixels passed the 5 %/2mm gamma criteria, except for the 2x2 cm² field. In the lung phantom, all systems and implementations achieved over 95 %-pixel pass rates at the 2 %/2mm criterion for volumetric modulated arc therapy (VMAT) plans. For conformal radiation therapy (3DCRT) plans, one system implementation showed poor accuracy, with over 90 % agreement only at the 5 %/2mm criterion. Considering all systems and implementations, average sensitivity and specificity for CRT plans ranged from 0.92 and 0.42 (at 2 %/2mm) to 0.71 and 0.52 (at 5 %/2mm), while for VMAT plans ranged from 0.41 and 0.81 (at 2 %2mm) to 0.37 and 0.81 (at 5 %/2mm).

Conclusion

We successfully developed a protocol to commission EPID IDV systems. It was found that not all systems and implementations achieved satisfactory accuracy and sensitivity, emphasising the need for thorough commissioning and benchmarking.

背景和目的随着基于电子门户成像探测器的体内剂量测定（EPID-based IVD）商用解决方案的推出，许多放射治疗部门正在采用这种技术。然而，目前还缺乏全面的调试指导。本研究旨在为测试基于 EPID 的 IVD 系统的准确性和灵敏度提供一个方案。使用不同方形规则场的均质平板模型和 CIRS 肺部模型中的临床计划对准确性进行了评估。针对不同的能量评估了多种正向和反向投影算法的实施情况。在肺部模型中进行的灵敏度分析检查了对设置误差、解剖变化和传输误差的反应。结果在均质模型中，除 2x2 平方厘米场外，超过 85% 的像素通过了 5%/2mm 伽马标准。在肺部模型中，对于容积调制弧治疗（VMAT）计划，所有系统和实施方案在 2%/2mm 标准下的像素通过率均超过 95%。对于适形放射治疗（3DCRT）计划，一种系统的实施显示出较低的准确性，仅在 5%/2mm 标准下的一致性超过 90%。考虑到所有系统和实施情况，CRT计划的平均灵敏度和特异度分别为0.92和0.42（2%/2mm时）至0.71和0.52（5%/2mm时），而VMAT计划的平均灵敏度和特异度分别为0.41和0.81（2%/2mm时）至0.37和0.81（5%/2mm时）。我们发现，并非所有的系统和实施方案都能达到令人满意的准确度和灵敏度，这就强调了进行全面调试和基准测试的必要性。

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引用次数: 0

Proof-of-concept of real-time electromagnetic guidance for gynecologic interstitial catheters in high dose rate brachytherapy 高剂量率近距离治疗中妇科间质导管的实时电磁引导概念验证

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-10-01 DOI: 10.1016/j.phro.2024.100661

Audrey Cantin , Marie-Claude Lavallée , Eric Poulin , Gilion Hautvast , William Foster , Luc Beaulieu

Background and Purpose

The addition of interstitial needles to intracavitary gynecologic (GYN) high dose rate (HDR) brachytherapy has been shown to improve target coverage and organs-at-risk (OAR) sparing. However, no commercial solution allows real-time guidance of interstitial catheter placement. This phantom study aimed to evaluate the feasibility of an electromagnetic (EM) tracking system guidance workflow for GYN HDR brachytherapy treatment in a magnetic resonance imaging (MRI) and real-time transrectal ultrasound (TRUS) fusion scenario.

Materials and Methods

A clinical investigational system combining a treatment planning system and the EM tracking technology was used. The 3D T2 weighted magnetic resonance (MR) image set of a patient treated with intracavitary and interstitial HDR brachytherapy was retrospectively chosen. The MR image set was used to delineate the target and the OARs. A preplan was generated to determine needles positions in advance. The implant was reproduced in a water phantom. A 3D TRUS scan was acquired, and a rigid registration between the MR and the TRUS images was performed.

Results

The accuracy of the EM tracking system was < 1 mm for both the sagittal and the transverse modes of the TRUS probe. Contours that were delineated on the MRI were propagated on the TRUS images after the rigid registration. Needle insertion was successfully guided in real time with the EM tracking system on the TRUS live image using the MRI contours for guidance.

Conclusion

Based on this proof-of-concept, real-time EM-guidance of interstitial needle for GYN HDR brachytherapy appears to be feasible.

背景和目的在腔内妇科（GYN）高剂量率近距离放射治疗（HDR）中加入间质针已被证明可提高靶点覆盖率和危险器官（OAR）疏通率。然而，目前还没有一种商业解决方案可以实时引导间质导管的放置。这项模型研究旨在评估在磁共振成像（MRI）和实时经直肠超声（TRUS）融合的情况下，电磁（EM）跟踪系统引导妇科 HDR 近距离治疗工作流程的可行性。回顾性地选择了一名接受腔内和间质 HDR 近距离放射治疗的患者的三维 T2 加权磁共振（MR）图像集。核磁共振图像集用于划定靶点和OAR。生成预案以提前确定针头位置。在水模型中再现植入物。结果电磁跟踪系统对 TRUS 探头的矢状模式和横向模式的精确度均为 1 毫米。刚性配准后，MRI 上划定的轮廓在 TRUS 图像上得以传播。结论根据这一概念验证，妇科 HDR 近距离放射治疗间质针的实时电磁引导似乎是可行的。

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引用次数: 0

Reduced-distortion diffusion weighted imaging for head and neck radiotherapy 用于头颈部放射治疗的降低失真扩散加权成像技术

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-09-23 DOI: 10.1016/j.phro.2024.100653

Eric Aliotta , Ramesh Paudyal , Alex Dresner , Amita Shukla-Dave , Nancy Lee , Laura Cerviño , Ricardo Otazo , Victoria Y. Yu

Background and purpose

Quantitative Diffusion Weighted Imaging (DWI) has potential value in guiding head and neck (HN) cancer radiotherapy. However, clinical translation has been hindered by severe distortions in standard single-shot Echo-Planar-Imaging (ssEPI) and prolonged scan time and low SNR in Turbo-Spin-Echo (ssTSE) sequences. In this study, we evaluate “multi-shot” (ms) msEPI and msTSE acquisitions in the context of HN radiotherapy.

Materials and methods

ssEPI, ssTSE, msEPI with 2 and 3 shots (2sEPI, 3sEPI), and msTSE DWI were acquired in a phantom, healthy volunteers (N=10), and patients with HN cancer (N=5) on a 3-Tesla wide-bore MRI in radiotherapy simulation RF coil setup, with matched spatial resolution (2x2x5mm) and b = 0, 200, 800 s/mm².

Geometric distortions measured with deformable vector field (DVF) and contour analysis, apparent diffusion coefficient (ADC) values, and signal-to-noise-ratio efficiency (SNR_eff) were quantified for all scans.

Results

All techniques significantly (P<1x10^-3) reduced distortions compared with ssEPI (DVF_mean = 3.1 ± 1.3 mm). Distortions were marginally lower for msTSE (DVF_mean = 1.5 ± 0.6 mm) than ssTSE (1.8 ± 0.9 mm), but were slightly higher with 2sEPI and 3sEPI (2.6 ± 1.0 mm, 2.2 ± 1.0 mm). SNR_eff reduced with decreasing distortion with ssEPI=21.9 ± 7.9, 2sEPI=15.1 ± 5.0, 3sEPI=12.1 ± 4.5, ssTSE=6.0 ± 1.6, and msTSE=5.7 ± 1.9 for b = 0 images. Phantom ADC values were consistent across all protocols (errors ≤ 0.03x10^-3mm²/s), but in vivo ADC values were ∼ 4 % lower with msEPI and ∼ 12 % lower with ssTSE/msTSE compared with ssEPI.

Conclusions

msEPI and TSE acquisitions exhibited improved geometric distortion at the cost of SNR_eff and scan time. While msTSE exhibited the least distortion, 3sEPI may offer an appealing middle-ground with improved geometric fidelity but superior efficiency and in vivo ADC quantification.

背景和目的定量弥散加权成像（DWI）在指导头颈部癌症放疗方面具有潜在价值。然而，标准单次回波-平面成像（ssEPI）的严重失真以及涡轮螺旋回波（ssTSE）序列的扫描时间长和信噪比低阻碍了临床应用。在本研究中，我们评估了在 HN 放射治疗中的 "多拍"（ms）msEPI 和 msTSE 采集。材料和方法：在放疗模拟射频线圈设置的 3-Tesla 宽孔径 MRI 上，以匹配的空间分辨率（2x2x5mm）和 b = 0、200、800 s/mm2 对模型、健康志愿者（10 人）和 HN 癌症患者（5 人）进行了 mssEPI、ssTSE、2 次和 3 次 msEPI（2sEPI、3sEPI）以及 msTSE DWI 采集。用可变形矢量场（DVF）和轮廓分析测量的几何失真、表观扩散系数（ADC）值和信噪比效率（SNReff）对所有扫描进行了量化。结果与 ssEPI 相比，所有技术都能显著（P<1x10-3）减少失真（DVF 平均值 = 3.1 ± 1.3 mm）。msTSE 的失真（DVFmean = 1.5 ± 0.6 mm）略低于 ssTSE（1.8 ± 0.9 mm），但略高于 2sEPI 和 3sEPI（2.6 ± 1.0 mm、2.2 ± 1.0 mm）。对于 b = 0 的图像，SNReff 随畸变的减小而降低，ssEPI=21.9 ± 7.9，2sEPI=15.1 ± 5.0，3sEPI=12.1 ± 4.5，ssTSE=6.0 ± 1.6，msTSE=5.7 ± 1.9。所有方案的模拟 ADC 值都一致（误差≤ 0.03x10-3mm2/s），但与 ssEPI 相比，msEPI 的体内 ADC 值低 4%，ssTSE/msTSE 的体内 ADC 值低 12%。msTSE的失真最小，而3sEPI可能是一种有吸引力的中间方案，其几何保真度更高，但效率和体内ADC定量更优。

{"title":"Reduced-distortion diffusion weighted imaging for head and neck radiotherapy","authors":"Eric Aliotta , Ramesh Paudyal , Alex Dresner , Amita Shukla-Dave , Nancy Lee , Laura Cerviño , Ricardo Otazo , Victoria Y. Yu","doi":"10.1016/j.phro.2024.100653","DOIUrl":"10.1016/j.phro.2024.100653","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Quantitative Diffusion Weighted Imaging (DWI) has potential value in guiding head and neck (HN) cancer radiotherapy. However, clinical translation has been hindered by severe distortions in standard single-shot Echo-Planar-Imaging (ssEPI) and prolonged scan time and low SNR in Turbo-Spin-Echo (ssTSE) sequences. In this study, we evaluate “multi-shot” (ms) msEPI and msTSE acquisitions in the context of HN radiotherapy.</div></div><div><h3>Materials and methods</h3><div>ssEPI, ssTSE, msEPI with 2 and 3 shots (2sEPI, 3sEPI), and msTSE DWI were acquired in a phantom, healthy volunteers (N=10), and patients with HN cancer (N=5) on a 3-Tesla wide-bore MRI in radiotherapy simulation RF coil setup, with matched spatial resolution (2x2x5mm) and b = 0, 200, 800 s/mm<sup>2</sup>.</div><div>Geometric distortions measured with deformable vector field (DVF) and contour analysis, apparent diffusion coefficient (ADC) values, and signal-to-noise-ratio efficiency (SNR<sub>eff</sub>) were quantified for all scans.</div></div><div><h3>Results</h3><div>All techniques significantly (P<1x10<sup>-3</sup>) reduced distortions compared with ssEPI (DVF<sub>mean</sub> = 3.1 ± 1.3 mm). Distortions were marginally lower for msTSE (DVF<sub>mean</sub> = 1.5 ± 0.6 mm) than ssTSE (1.8 ± 0.9 mm), but were slightly higher with 2sEPI and 3sEPI (2.6 ± 1.0 mm, 2.2 ± 1.0 mm). SNR<sub>eff</sub> reduced with decreasing distortion with ssEPI=21.9 ± 7.9, 2sEPI=15.1 ± 5.0, 3sEPI=12.1 ± 4.5, ssTSE=6.0 ± 1.6, and msTSE=5.7 ± 1.9 for b = 0 images. Phantom ADC values were consistent across all protocols (errors ≤ 0.03x10<sup>-3</sup>mm<sup>2</sup>/s), but <em>in vivo</em> ADC values were ∼ 4 % lower with msEPI and ∼ 12 % lower with ssTSE/msTSE compared with ssEPI.</div></div><div><h3>Conclusions</h3><div>msEPI and TSE acquisitions exhibited improved geometric distortion at the cost of SNR<sub>eff</sub> and scan time. While msTSE exhibited the least distortion, 3sEPI may offer an appealing middle-ground with improved geometric fidelity but superior efficiency and <em>in vivo</em> ADC quantification.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100653"},"PeriodicalIF":3.4,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A review of whole gland prostate brachytherapy with focal dose escalation to intra-prostatic lesions: Clinical efficacy and technical aspects 对前列腺内病灶进行病灶剂量升级的全腺前列腺近距离放射治疗的综述：临床疗效和技术方面

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-09-16 DOI: 10.1016/j.phro.2024.100645

Joel Poder , Peter Hoskin , Hayley Reynolds , Tsz Him Chan , Annette Haworth

Focal boost to intra-prostatic lesions (IPLs) in radiotherapy could enhance treatment efficacy. Brachytherapy (BT), delivering highly conformal dose with sharp dose gradients emerges as a potentially optimal approach for precise dose escalation to IPLs. This study aims to consolidate clinical and planning studies that implemented whole gland prostate BT and focal dose escalation to IPLs, with the view to synthesize evidence on the strategy’s effectiveness and variability. In this review, we identified nine clinical studies and ten planning/simulation studies focusing on whole gland prostate BT with IPL dose escalation. From the clinical studies, the use of whole gland prostate BT with focal dose escalation in combination with external beam radiotherapy (EBRT) appears to be a safe and effective 21 form of treatment for men with T1b – T2c prostate cancer with average five-year biochemical failure22 free survival (BFFS) of 94 % (range 81.1 %−100 %) and minimal grade three toxicities reported. Both clinical and planning studies exemplified the high level of focal dose escalation achievable using BT with a mean IPL D90 % of 132 % and 146 %, respectively (expressed as a % of the whole gland prescription dose). There was considerable variation in the reporting of clinical and technical data in the identified studies. To facilitate a more widespread and uniform adoption of the technique, recommendations on essential and desirable items to be included in future studies incorporating whole gland prostate BT with focal boost to IPLs are provided.

在放射治疗中对前列腺内病变（IPL）进行局部增强可提高治疗效果。近距离放射治疗（BT）可提供高度适形的剂量和尖锐的剂量梯度，是对IPL进行精确剂量升级的最佳方法。本研究旨在整合实施全腺前列腺 BT 和 IPL 局灶剂量升级的临床和规划研究，以综合有关该策略有效性和可变性的证据。在这篇综述中，我们确定了九项临床研究和十项规划/模拟研究，重点关注 IPL 剂量升级的全腺前列腺 BT。从临床研究来看，对 T1b - T2c 前列腺癌男性患者而言，使用全腺体前列腺 BT 配合病灶剂量递增疗法与体外射束放疗 (EBRT) 联合治疗似乎是一种安全有效的治疗方式，平均五年无生化失败22 存活率 (BFFS) 为 94 %（范围为 81.1 %-100%），且报告的三级毒性极低。临床研究和计划研究都表明，使用 BT 可以实现高水平的病灶剂量升级，IPL D90 的平均值分别为 132% 和 146%（以占整个腺体处方剂量的百分比表示）。在已确定的研究中，临床和技术数据的报告存在很大差异。为了促进该技术更广泛、更统一的应用，本文就未来将全腺前列腺 BT 与 IPL 聚焦增强相结合的研究中应包含的基本项目和理想项目提出了建议。

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引用次数: 0

Incorporating patient-specific information for the development of rectal tumor auto-segmentation models for online adaptive magnetic resonance Image-guided radiotherapy 为在线自适应磁共振图像引导放射治疗开发直肠肿瘤自动分割模型时纳入患者特异性信息

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-09-16 DOI: 10.1016/j.phro.2024.100648

Chavelli M. Kensen , Rita Simões , Anja Betgen , Lisa Wiersema , Doenja M.J. Lambregts , Femke P. Peters , Corrie A.M. Marijnen , Uulke A. van der Heide , Tomas M. Janssen

Background and purpose

In online adaptive magnetic resonance image (MRI)-guided radiotherapy (MRIgRT), manual contouring of rectal tumors on daily images is labor-intensive and time-consuming. Automation of this task is complex due to substantial variation in tumor shape and location between patients. The aim of this work was to investigate different approaches of propagating patient-specific prior information to the online adaptive treatment fractions to improve deep-learning based auto-segmentation of rectal tumors.

Materials and methods

243 T2-weighted MRI scans of 49 rectal cancer patients treated on the 1.5T MR-Linear accelerator (MR-Linac) were utilized to train models to segment rectal tumors. As benchmark, an MRI_only auto-segmentation model was trained. Three approaches of including a patient-specific prior were studied: 1. include the segmentations of fraction 1 as extra input channel for the auto-segmentation of subsequent fractions, 2. fine-tuning of the MRI_only model to fraction 1 (PSF_1) and 3. fine-tuning of the MRI_only model on all earlier fractions (PSF_cumulative). Auto-segmentations were compared to the manual segmentation using geometric similarity metrics. Clinical impact was assessed by evaluating post-treatment target coverage.

Results

All patient-specific methods outperformed the MRI_only segmentation approach. Median 95th percentile Hausdorff (95HD) were 22.0 (range: 6.1–76.6) mm for MRI_only segmentation, 9.9 (range: 2.5–38.2) mm for MRI+prior segmentation, 6.4 (range: 2.4–17.8) mm for PSF_1 and 4.8 (range: 1.7–26.9) mm for PSF_cumulative. PSF_cumulative was found to be superior to PSF_1 from fraction 4 onward (p = 0.014).

Conclusion

Patient-specific fine-tuning of automatically segmented rectal tumors, using images and segmentations from all previous fractions, yields superior quality compared to other auto-segmentation approaches.

背景和目的在在线自适应磁共振成像（MRI）引导放疗（MRIgRT）中，在日常图像上手动绘制直肠肿瘤轮廓是一项劳动密集型且耗时的工作。由于不同患者的肿瘤形状和位置存在很大差异，这项任务的自动化非常复杂。这项工作的目的是研究向在线自适应治疗分数传播患者特定先验信息的不同方法，以改进基于深度学习的直肠肿瘤自动分割。作为基准，训练了一个仅使用 MRI 的自动分割模型。研究了包含患者特异性先验的三种方法：1.将第 1 部分的分割作为后续部分自动分割的额外输入通道；2.对第 1 部分的纯 MRI 模型进行微调（PSF_1）；3.对所有早期部分的纯 MRI 模型进行微调（PSF_cumulative）。使用几何相似度指标将自动分割与手动分割进行比较。通过评估治疗后的目标覆盖范围来评估临床效果。仅核磁共振成像分割的第 95 百分位数 Hausdorff (95HD) 中值为 22.0（范围：6.1-76.6）毫米，核磁共振成像+先前分割为 9.9（范围：2.5-38.2）毫米，PSF_1 为 6.4（范围：2.4-17.8）毫米，PSF_cumulative 为 4.8（范围：1.7-26.9）毫米。PSF_cumulative从第4分段开始就优于PSF_1（p = 0.014）。结论与其他自动分段方法相比，使用之前所有分段的图像和分段对患者特定的直肠肿瘤自动分段进行微调可获得更高的质量。

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引用次数: 0

Impact of motion management strategies on abdominal organ at risk delineation for magnetic resonance-guided radiotherapy 运动管理策略对磁共振引导放疗中腹部危险器官划定的影响

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-09-16 DOI: 10.1016/j.phro.2024.100650

Mairead Daly , Lisa McDaid , Carmel Anandadas , Andrew Brocklehurst , Ananya Choudhury , Alan McWilliam , Ganesh Radhakrishna , Cynthia L. Eccles

Background and purpose

The impact of respiratory motion management strategies for abdominal radiotherapy, such as abdominal compression (AC) and breath hold (BH), on abdominal organ at risk (OAR) delineation on magnetic resonance imaging (MRI) is unknown. This feasibility study compared the inter- and intra- observer delineation variation on MRI acquired with AC, BH for three critical abdominal OAR.

Materials and methods

T2-weighted (W) 3D MRI in free-breathing (FB) and with AC, and T1W 3D mDixon exhale BH were acquired. Four observers blinded to motion management strategy used, delineated stomach, liver, and duodenum on all MRI. One case per strategy was repeated over 6 weeks later to quantify intra-observer variation. Simultaneous truth and performance level estimation (STAPLE) contours for each OAR were generated, median and IQR mean distance to agreement (mDTA) and maximum Hausdorff distance (HD) between observer and STAPLE contours were calculated. Observers scored organ visibility on each MRI using a four-point Likert scale.

Results

A total of 27 scans including repeats were delineated. Pooled mDTA for all OARs was 1.3 mm (0.5 mm) with AC, 1.4 mm (1.0 mm) with BH, and 1.3 mm (0.5 mm) in FB. Intra-observer mDTA was highest for all organs in FB with 10.8 mm for duodenum, 1.8 mm for liver, and 2.7 mm for stomach. The pooled mean perceptual quality score value was highest for AC across organs.

Conclusions

No motion management strategy demonstrated superior similarity across OAR, emphasizing the need for personalised approaches based on individual clinical and patient factors.

背景和目的腹部放疗中的呼吸运动管理策略，如腹部加压（AC）和屏气（BH），对磁共振成像（MRI）上腹部危险器官（OAR）划分的影响尚不清楚。这项可行性研究比较了用 AC 和 BH 对三个关键腹部 OAR 进行 MRI 采集时观察者之间和观察者内部的划线差异。材料和方法采集了自由呼吸 (FB) 和 AC 时的二维加权（W）三维 MRI 以及 T1W 三维 mDixon 呼气 BH。四名观察者对所使用的运动管理策略保密，在所有 MRI 上划定胃、肝和十二指肠。6周后，每种策略重复一个病例，以量化观察者内部的差异。为每个 OAR 生成同步真相和性能水平估计 (STAPLE) 等值线，计算观察者与 STAPLE 等值线之间的中位数和 IQR 平均一致距离 (mDTA) 以及最大豪斯多夫距离 (HD)。观察者使用李克特四点量表对每个 MRI 上的器官可见度进行评分。在 AC、BH 和 FB 中，所有 OAR 的汇总 mDTA 分别为 1.3 毫米（0.5 毫米）、1.4 毫米（1.0 毫米）和 1.3 毫米（0.5 毫米）。在所有器官中，FB 的观察者内部 mDTA 最高，十二指肠为 10.8 毫米，肝脏为 1.8 毫米，胃为 2.7 毫米。结论：没有一种运动管理策略在 OAR 中显示出卓越的相似性，这强调了根据个人临床和患者因素采取个性化方法的必要性。

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引用次数: 0

Machine learning automated treatment planning for online magnetic resonance guided adaptive radiotherapy of prostate cancer 前列腺癌在线磁共振引导自适应放疗的机器学习自动治疗计划

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-09-14 DOI: 10.1016/j.phro.2024.100649

Aly Khalifa , Jeff D. Winter , Tony Tadic , Thomas G. Purdie , Chris McIntosh

Background and purpose

No best practices currently exist for achieving high quality radiation therapy (RT) treatment plan adaptation during magnetic resonance (MR) guided RT of prostate cancer. This study validates the use of machine learning (ML) automated RT treatment plan adaptation and benchmarks it against current clinical RT plan adaptation methods.

Materials and methods

We trained an atlas-based ML automated treatment planning model using reference MR RT treatment plans (42.7 Gy in 7 fractions) from 46 patients with prostate cancer previously treated at our institution. For a held-out test set of 38 patients, retrospectively generated ML RT plans were compared to clinical human-generated adaptive RT plans for all 266 fractions. Differences in dose-volume metrics and clinical objective pass rates were evaluated using Wilcoxon tests (p < 0.05) and Exact McNemar tests (p < 0.05), respectively.

Results

Compared to clinical RT plans, ML RT plans significantly increased sparing and objective pass rates of the rectum, bladder, and left femur. The mean ± standard deviation of rectum D20 and D50 in ML RT plans were 2.5 ± 2.2 Gy and 1.6 ± 1.3 Gy lower than clinical RT plans, respectively, with 14 % higher pass rates; bladder D40 was 4.6 ± 2.9 Gy lower with a 20 % higher pass rate; and the left femur D5 was 0.8 ± 1.8 Gy lower with a 7 % higher pass rate.

Conclusions

ML automated RT treatment plan adaptation increases robustness to interfractional anatomical changes compared to current clinical adaptive RT practices by increasing compliance to treatment objectives.

背景和目的在磁共振（MR）引导的前列腺癌 RT 治疗过程中，目前尚无实现高质量放射治疗（RT）治疗计划适应性的最佳实践。本研究验证了机器学习（ML）自动 RT 治疗计划适应性的使用，并将其与当前的临床 RT 计划适应性方法进行了比较。材料和方法我们使用先前在本机构接受治疗的 46 名前列腺癌患者的参考 MR RT 治疗计划（42.7 Gy，分 7 次）训练了基于图集的 ML 自动治疗计划模型。在保留的 38 例患者测试集中，我们将回顾性生成的 ML RT 计划与临床人工生成的自适应 RT 计划进行了比较，结果显示所有 266 个分段都是如此。结果与临床 RT 计划相比，ML RT 计划显著提高了直肠、膀胱和左股骨的疏通率和客观通过率。与临床 RT 计划相比，ML RT 计划中直肠 D20 和 D50 的平均值（± 标准差）分别为 2.5 ± 2.2 Gy 和 1.6 ± 1.3 Gy，通过率提高了 14%；膀胱 D40 的平均值（± 标准差）为 4.6 ± 2.9 Gy，通过率提高了 20%；左股骨 D5 的平均值（± 标准差）为 0.结论与目前的临床适应性 RT 相比，自动 RT 治疗计划适应性可提高对治疗目标的依从性，从而增强对点阵间解剖变化的稳健性。

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引用次数: 0

Autodelineation methods in a simulated fully automated proton therapy workflow for esophageal cancer 食管癌全自动质子治疗模拟工作流程中的自动划线方法

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-09-14 DOI: 10.1016/j.phro.2024.100646

Pieter Populaire , Beatrice Marini , Kenneth Poels , Stina Svensson , Edmond Sterpin , Albin Fredriksson , Karin Haustermans

Background and purpose

Proton Online Adaptive RadioTherapy (ProtOnART) harnesses the dosimetric advantage of protons and immediately acts upon anatomical changes. Here, we simulate the clinical application of delineation and planning within a ProtOnART-workflow for esophageal cancer. We aim to identify the most appropriate technique for autodelineation and evaluate full automation by replanning on autodelineated contours.

Materials and methods

We evaluated 15 patients who started treatment between 11-2022 and 01-2024, undergoing baseline and three repeat computed tomography (CT) scans in treatment position. Quantitative and qualitative evaluations compared different autodelineation methods. For Organs-at-risk (OAR) deep learning segmentation (DLS), rigid and deformable propagation from baseline to repeat CT-scans were considered. For the clinical target volume (CTV), rigid and three deformable propagation methods (default, heart as controlling structure and with focus region) were evaluated. Adaptive treatment plans with 7 mm (ATP_7mm) and 3 mm (ATP_3mm) setup robustness were generated using best-performing autodelineated contours. Clinical acceptance of ATPs was evaluated using goals encompassing ground-truth CTV-coverage and OAR-dose.

Results

Deformation was preferred for autodelineation of heart, lungs and spinal cord. DLS was preferred for all other OARs. For CTV, deformation with focus region was the preferred method although the difference with other deformation methods was small. Nominal ATPs passed evaluation goals for 87 % of ATP_7mm and 67 % of ATP_3mm. This dropped to respectively 2 % and 29 % after robust evaluation. Insufficient CTV-coverage was the main reason for ATP-rejection.

Conclusion

Autodelineation aids a ProtOnART-workflow for esophageal cancer. Currently available tools regularly require manual annotations to generate clinically acceptable ATPs.

背景和目的质子在线自适应放射治疗（ProtOnART）利用质子的剂量学优势，并根据解剖结构的变化立即采取行动。在此，我们模拟了食道癌在 ProtOnART 工作流程中的划线和规划的临床应用。我们的目标是找出最合适的自动划线技术，并通过在自动划线的轮廓上重新扫描来评估全自动化。材料和方法我们评估了在 2022 年 11 月至 2024 年 1 月期间开始治疗的 15 名患者，他们在治疗位置接受了基线和三次重复计算机断层扫描（CT）。定量和定性评估比较了不同的自动划线方法。对于风险器官（OAR）的深度学习分割（DLS），考虑了从基线到重复 CT 扫描的刚性和可变形传播。对于临床靶体积（CTV），评估了刚性和三种可变形传播方法（默认、心脏作为控制结构和有病灶区域）。使用表现最佳的自动划线轮廓生成了具有 7 毫米（ATP7 毫米）和 3 毫米（ATP3 毫米）设置稳健性的自适应治疗计划。使用包含地面真实 CTV 覆盖率和 OAR 剂量的目标对 ATP 的临床接受度进行了评估。对于所有其他 OAR，DLS 更受青睐。对 CTV 而言，虽然与其他变形方法的差异很小，但首选方法是焦点区域变形法。87% 的 ATP7mm 和 67% 的 ATP3mm 标称 ATP 通过了评估目标。经过稳健评估后，这一比例分别降至 2% 和 29%。CTV覆盖率不足是ATP被拒绝的主要原因。目前可用的工具通常需要手动注释才能生成临床上可接受的 ATP。

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引用次数: 0

Tools and recommendations for commissioning and quality assurance of deformable image registration in radiotherapy 放射治疗中可变形图像配准的调试和质量保证工具与建议

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2024-09-14 DOI: 10.1016/j.phro.2024.100647

Lando S. Bosma , Mohammad Hussein , Michael G. Jameson , Soban Asghar , Kristy K. Brock , Jamie R. McClelland , Sara Poeta , Johnson Yuen , Cornel Zachiu , Adam U. Yeo , the 2021 ESTRO Physics Workshop on Commissioning and Quality Assurance for Deformable Image Registration in Radiotherapy

Multiple tools are available for commissioning and quality assurance of deformable image registration (DIR), each with their own advantages and disadvantages in the context of radiotherapy. The selection of appropriate tools should depend on the DIR application with its corresponding available input, desired output, and time requirement. Discussions were hosted by the ESTRO Physics Workshop 2021 on Commissioning and Quality Assurance for DIR in Radiotherapy. A consensus was reached on what requirements are needed for commissioning and quality assurance for different applications, and what combination of tools is associated with this.

For commissioning, we recommend the target registration error of manually annotated anatomical landmarks or the distance-to-agreement of manually delineated contours to evaluate alignment. These should be supplemented by the distance to discordance and/or biomechanical criteria to evaluate consistency and plausibility. Digital phantoms can be useful to evaluate DIR for dose accumulation but are currently only available for a limited range of anatomies, image modalities and types of deformations.

For quality assurance of DIR for contour propagation, we recommend at least a visual inspection of the registered image and contour. For quality assurance of DIR for warping quantitative information such as dose, Hounsfield units or positron emission tomography-data, we recommend visual inspection of the registered image together with image similarity to evaluate alignment, supplemented by an inspection of the Jacobian determinant or bending energy to evaluate plausibility, and by the dose (gradient) to evaluate relevance. We acknowledge that some of these metrics are still missing in currently available commercial solutions.

有多种工具可用于可变形图像配准（DIR）的调试和质量保证，在放射治疗方面各有利弊。选择合适的工具应取决于 DIR 应用及其相应的可用输入、所需输出和时间要求。ESTRO 2021 物理研讨会就放疗中 DIR 的调试和质量保证进行了讨论。在调试方面，我们建议使用人工标注解剖标志的目标注册误差或人工划定轮廓的距离-吻合度来评估对准情况。此外，还应辅之以不一致距离和/或生物力学标准，以评估一致性和可信度。数字模型可用于评估剂量累积的 DIR，但目前仅适用于有限范围的解剖、图像模式和变形类型。为了保证对剂量、Hounsfield 单位或正电子发射断层扫描数据等定量信息进行翘曲处理的 DIR 的质量，我们建议对注册图像进行目视检查，并结合图像相似性来评估对齐情况，同时辅以雅各布行列式或弯曲能量检查来评估可信度，并通过剂量（梯度）来评估相关性。我们承认，目前可用的商业解决方案中仍缺少其中一些指标。

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引用次数: 0