Physica Medica-European Journal of Medical Physics最新文献_第4页

Optimising 68Ga-SSTR PET radiomic feature extraction towards improved feature stability and predictive classification models for small neuroendocrine tumours 优化68Ga-SSTR PET放射特征提取，提高小型神经内分泌肿瘤的特征稳定性和预测分类模型。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-16 DOI: 10.1016/j.ejmp.2025.105691

Ann McCann , Mathilde Colombie , Luis León Vintró , Seán Cournane , Hussein Almeamar , Lucian Harris , Anita Dowling , Julie Lucey

Purpose

The application of ⁶⁸Ga PET imaging based radiomic analysis to the classification of neuroendocrine tumours (NETs), predicting the response to peptide receptor radionuclide therapy (PRRT) therapy and investigating the heterogeneity of NETs is an area of active research. However, there is limited information available regarding the stability of ⁶⁸Ga PET based radiomic features for clinically relevant volumes and activities or the optimal pre-processing parameters.

Method

Optimisation of ⁶⁸Ga specific radiomic feature extraction and feature selection methods were performed in this study, using a range of uniform and heterogeneous phantoms. Radiomic feature stability was assessed over a range of activities and volumes, for a selection of reconstruction settings and quantisation methods. The ability of an optimised set of radiomic features to generate a prediction model for NET patient tumour grade using machine learning algorithms was then investigated.

Results

The work presented here confirmed that reducing the radiomic feature set prior to clinical model building was beneficial and led to the generation of more accurate clinical prediction models. Quantitative assessment of volume dependency effectively reduced the feature set while maintaining clinically relevant features. Optimisation of the pre-processing quantisation method improved feature stability for small clinically relevant volumes. Five robust ⁶⁸Ga radiomic features were identified that could accurately predict the patient’s NET grade when the quantisation parameters were optimised using Rice’s rule.

Conclusion

While quantification of small volumes typically seen in NETs remains challenging, optimising the quantisation parameters improves feature stability for volumes > 1.2 cm³.

目的：基于68Ga PET成像的放射组学分析应用于神经内分泌肿瘤（NETs）的分类、预测对肽受体放射性核素治疗（PRRT）的反应以及研究NETs的异质性是一个活跃的研究领域。然而，关于68Ga PET基于临床相关体积和活性的放射学特征的稳定性或最佳预处理参数的信息有限。方法：在本研究中，使用一系列均匀和异质幻影，对68Ga特定放射特征提取和特征选择方法进行了优化。在一系列活动和体积范围内评估放射特征稳定性，以选择重建设置和量化方法。然后研究了一组优化的放射学特征使用机器学习算法生成NET患者肿瘤分级预测模型的能力。结果：本文提出的工作证实，在临床模型建立之前减少放射学特征集是有益的，并导致产生更准确的临床预测模型。体积依赖的定量评估有效地减少了特征集，同时保持了临床相关的特征。预处理定量方法的优化提高了小临床相关体积的特征稳定性。当使用Rice规则优化量化参数时，确定了五个稳健的68Ga放射学特征，可以准确预测患者的NET分级。结论：虽然在NETs中常见的小体积的定量仍然具有挑战性，但优化定量参数可以提高> 1.2 cm3体积的特征稳定性。

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引用次数: 0

Comparative study of inertial measurement unit and optical tracking systems for respiratory motion management in radiotherapy 惯性测量单元与光学跟踪系统在放射治疗中呼吸运动管理中的比较研究。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-16 DOI: 10.1016/j.ejmp.2025.105707

Hyeongmin Jin , Manjin Ha , Jin Jegal , Hyojun Park , Jaeman Son , Seonghee Kang , Jong Min Park , Jung-in Kim , Chang Heon Choi

Purpose

To evaluate the feasibility and accuracy of inertial measurement unit (IMU) for respiratory motion tracking and four-dimensional cone-beam computed tomography (4D CBCT) reconstruction in radiotherapy, particularly in scenarios involving limited line-of-sight such as abdominal compression.

Methods

Respiratory signals were simultaneously acquired using a commercial optical tracking system (Real-time Position Management, RPM) and wireless IMU sensor in twenty healthy volunteers and a dynamic thorax phantom. The phantom was programmed with various motion patterns and amplitudes, and abdominal compression was applied in selected scenarios to simulate clinical obstruction. Signal synchronization and processing were performed using principal component analysis and analyzed by comparing respiratory rate, peak/valley timing, and phase agreement between IMU and RPM signals. The signals were then used for phase-sorted 4D CBCT reconstruction, and images were quantitatively evaluated.

Results

IMU-derived respiratory signals demonstrated agreement with RPM data across all motion patterns, with average respiratory rate differences below 0.1 bpm and absolute phase discrepancies under 0.1 %. Peak and valley time differences remained below 0.1 s at standard amplitudes (±10 mm), increasing moderately under smaller motion ranges (up to 0.15 s). In 4D CBCT reconstruction, image quality parameters showed no significant differences between IMU and RPM signals indicating comparable geometric fidelity.

Conclusion

IMU sensors provide a reliable, line-of-sight-independent method for respiratory motion tracking and 4D CBCT reconstruction in radiotherapy. Their robust performance under conditions that hinder optical tracking suggests clinical applicability involving abdominal compression or complex immobilization setups.

目的：评估惯性测量单元（IMU）在放射治疗中用于呼吸运动跟踪和四维锥束计算机断层扫描（4D CBCT）重建的可行性和准确性，特别是在诸如腹部压迫等视线有限的情况下。方法：使用商用光学跟踪系统（实时位置管理，RPM）和无线IMU传感器同时采集20名健康志愿者和动态胸腔假体的呼吸信号。对假体进行编程，使其具有不同的运动模式和幅度，并在选定的场景中应用腹部压迫来模拟临床阻塞。使用主成分分析进行信号同步和处理，并通过比较IMU和RPM信号之间的呼吸频率、峰谷时序和相位一致性进行分析。然后将这些信号用于相位分类的4D CBCT重建，并对图像进行定量评价。结果：imu得出的呼吸信号与所有运动模式下的RPM数据一致，平均呼吸速率差异低于0.1 bpm，绝对相位差异低于0.1%。在标准振幅（±10 mm）下，峰谷时间差保持在0.1 s以下，在较小的运动范围（高达0.15 s）下略有增加。在4D CBCT重建中，IMU和RPM信号的图像质量参数没有显著差异，表明几何保真度相当。结论：IMU传感器为放射治疗中的呼吸运动跟踪和4D CBCT重建提供了可靠的、与视线无关的方法。它们在阻碍光学跟踪的条件下的强大性能表明临床适用于腹部压迫或复杂的固定装置。

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引用次数: 0

Enhancing radiomic feature selection in PET-based heterogeneity analysis through tumor-volume-weighted normalization 通过肿瘤体积加权归一化增强pet异质性分析中的放射学特征选择。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-16 DOI: 10.1016/j.ejmp.2025.105694

Goodluck Okoro , Catherine C. Applegate , Michael B. Nelappana , Elaine A. Nielsen , Iwona T. Dobrucki , Lawrence W. Dobrucki

Purpose

Accurate assessment of intratumoral heterogeneity is critical for tumor characterization and monitoring, but variations in tumor size make it difficult to determine whether radiomic differences reflect true biological heterogeneity or mere volume effects. To address this, we developed Tumor-Volume-Weighted Normalization (TVWN), a framework that minimizes size-related biases while preserving intrinsic image heterogeneity.

Methods

TVWN was evaluated using: (i) computer-simulated tumors (185–800 mm³), (ii) heterogeneous, tumor-mimicking phantoms (10–170 mm³), and (iii) longitudinal PET scans of prostate tumor-bearing mice (35.2–1184 mm³) acquired at four time points. We analyzed 97 radiomic features, including texture metrics from GLRLM and GLSZM, before and after normalization to assess and correct volume dependence.

Results

TVWN consistently reduced the influence of tumor volume across various acquisition and reconstruction conditions, including different noise levels, Gaussian filtering (2 mm), number of iterations and spatial resolutions (0–6.0 mm FWHM). For example, the volume dependence of Glcm_IDN was effectively reduced (Spearman ρ: 0.290 ± 0.097 to 0.007 ± 0.103 at α = 0.01). In phantom experiments, TVWN reduced the CoV of Glrlm_RE from 17.75 % to 3.18 % in filtered data and from 20.14 % to 3.87 % in unfiltered data. It also enhanced heterogeneity discriminability (p = 0.0286). In vivo, TVWN decoupled radiomic features from tumor size progression, ensuring that observed changes reflected biological rather than volumetric effects.

Conclusion

TVWN offers a simple, scalable approach to normalizing radiomic features against tumor volume effects, improving their reproducibility and biological interpretability in longitudinal studies.

目的：准确评估肿瘤内异质性对肿瘤的表征和监测至关重要，但肿瘤大小的变化使得难以确定放射学差异是否反映了真正的生物学异质性或仅仅是体积效应。为了解决这个问题，我们开发了肿瘤体积加权归一化（TVWN），这是一个框架，可以最大限度地减少与尺寸相关的偏差，同时保持图像的内在异质性。方法：TVWN通过以下方法进行评估：(i)计算机模拟肿瘤（185-800 mm3），（ii）异质肿瘤模拟幻象（10-170 mm3），以及（iii）在四个时间点对前列腺肿瘤小鼠（362 -1184 mm3）进行纵向PET扫描。我们分析了归一化前后的97个放射学特征，包括GLRLM和GLSZM的纹理指标，以评估和纠正体积依赖性。结果：TVWN在不同的采集和重建条件下，包括不同的噪声水平、高斯滤波（2 mm）、迭代次数和空间分辨率（0-6.0 mm FWHM），都能一致地降低肿瘤体积的影响。例如，glcm_idn的体积依赖性被有效降低（Spearman ρ: 0.290±0.097至0.007±0.103,α = 0.01）。在虚影实验中，TVWN将glrlm_rev在滤波后从17.75%降低到3.18%，在未滤波时从20.14%降低到3.87%。异质性判别性增强（p = 0.0286）。在体内，TVWN将放射学特征与肿瘤大小进展分离开来，确保观察到的变化反映的是生物学效应，而不是体积效应。结论：TVWN提供了一种简单、可扩展的方法来标准化肿瘤体积效应的放射学特征，提高了它们在纵向研究中的可重复性和生物学可解释性。

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引用次数: 0

Enhancing total skin electron therapy: Introducing rotational technique and in-house-built flattening filter 增强全皮肤电子治疗：引入旋转技术和内置压平滤波器。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-16 DOI: 10.1016/j.ejmp.2025.105709

Livia Marrazzo , Gabriele Simontacchi , Danial Seifi , Deborah Chilà , Andrea Lastrucci , Andrea Profili , Silvia Calusi , Marta Casati , Margherita Zani , Chiara Arilli , Antonella Compagnucci , Cinzia Talamonti , Lorenzo Livi , Stefania Pallotta

Purpose

To implement and commission a rotational Total Skin Electron Therapy (TSET) technique using high-dose-rate electron (HDRE) beams on an Elekta VersaHD linac and a custom-made flattening filter (FF), with the aim of improving delivery efficiency and dose uniformity.

Methods

Two HDRE beams (6 and 8 MeV) were characterized at an extended source-to-skin distance (SSD = 490 cm) using EBT3 film dosimetry. A customized FF was designed to optimize field uniformity in both vertical and horizontal directions. Percentage depth dose (PDD) and profile measurements were acquired in static and rotational setups. Monte Carlo simulations with EGSnrc/BEAMnrc and DOSXYZnrc were used to model the linac head and validated against measurements. Output ratios (ORs) were measured on a phantom to estimate the monitor units needed for rotational delivery. End-to-end (E2E) testing with an Alderson-Rando phantom and in vivo dosimetry on the first 50 patients were performed to assess dose uniformity and reproducibility.

Results

The custom FF significantly improved field flatness. Measured surface doses per 1000 MU were 82 cGy (HDRE1) and 106 cGy (HDRE2), with ORs of 0.52 and 0.56, respectively. The rotational technique allowed dose rates of 12.8–17.9 cGy/min and treatment times of 6–8 min. PDDs from Monte Carlo simulations matched measurements. E2E and in vivo dosimetry confirmed high uniformity and <1 % variability. In vivo dosimetry confirmed adequate surface dose coverage and intra-patient consistency.

Conclusions

The rotational TSET technique using HDRE beams on a VersaHD linac with a custom FF is feasible, reproducible, and dosimetrically robust, representing a valid alternative to conventional dual-field approaches.

目的：在Elekta VersaHD直线加速器和定制的压平滤波器（FF）上使用高剂量率电子（HDRE）光束实施和调试旋转全皮肤电子治疗（TSET）技术，旨在提高输送效率和剂量均匀性。方法：采用EBT3膜剂量法在扩展源皮肤距离（SSD = 490 cm）下对2束HDRE （6 MeV和8 MeV）进行了表征。设计了定制的FF，以优化垂直和水平方向的场均匀性。在静态和旋转装置中获得了百分比深度剂量（PDD）和剖面测量。利用EGSnrc/BEAMnrc和DOSXYZnrc进行蒙特卡罗模拟，对直线机头进行了建模，并根据测量结果进行了验证。输出比（ORs）在一个幻影上测量，以估计旋转输送所需的监视器单元。对前50名患者进行了端到端（E2E）测试，使用Alderson-Rando模型和体内剂量测定来评估剂量均匀性和可重复性。结果：自定义FF显著改善了现场平整度。测得的每1000亩表面剂量分别为82 cGy （HDRE1）和106 cGy (HDRE2)， or分别为0.52和0.56。旋转技术允许剂量率为12.8-17.9 cGy/min，治疗时间为6-8 min。蒙特卡罗模拟得到的pdd与测量结果相匹配。结论：在带有定制FF的VersaHD直线加速器上使用HDRE光束的旋转TSET技术是可行的，可重复的，剂量学上稳健，代表了传统双场方法的有效替代方案。

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引用次数: 0

Radiomics-based brain aging prediction with multi-modal magnetic resonance imaging: detecting regional biomarkers in adults 基于放射组学的多模态磁共振成像脑老化预测：检测成人的区域生物标志物。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-16 DOI: 10.1016/j.ejmp.2025.105695

Heesoon Sheen , Han-Back Shin , Hyun Ju Kim , Jang-Hoon Oh

Introduction

We developed a radiomics-based model to classify brain MRI scans into two age groups: younger (<30 years) and older (>65 years) adults using multi-modal magnetic resonance imaging (MRI; T1 and T2 sequences), identify regional biomarkers that distinguish younger and older adults, and identify radiomic signatures across brain regions and MRI modalities.

Methods

In this cross-sectional study, brain MRI data were obtained from the Information eXtraction from Images dataset and segmented using Freesurfer. Radiomic features were extracted from seven key brain regions using PyRadiomics software, adhering to the Image Biomarker Standardisation Initiative guidelines. A multi-step feature selection process was employed to identify significant radiomic signatures, which were used to develop logistic regression models for brain age prediction. Significant radiomic features were identified as indicative of brain aging across various regions.

Results

The cohort included 122 participants. The T1 + T2 Rad-Score demonstrated high predictive accuracy, particularly for the hippocampus (area under the curve [AUC] = 0.96). Regional variability in model performance was observed, with the thalamus, caudate, and hippocampus showing the highest AUCs (0.95, 1.00, and 0.96, respectively). Radiomic signature importance varied across brain regions and MRI modalities: the thalamus, caudate, and hippocampus/amygdala were the most important in T1, T2, and T1 + T2 model images, respectively. The robustness and reproducibility of our findings were assured.

Conclusion

Radiomic signatures from T1 and T2 MRI data provided robust brain aging predictors, with models demonstrating high discriminative performance. We demonstrated the efficacy of a radiomics-based approach using multi-modal MRI for predicting brain aging and identifying regional biomarkers.

我们开发了一个基于放射组学的模型，将脑MRI扫描分为两个年龄组：使用多模态磁共振成像（MRI； T1和T2序列）的年轻（65岁）成年人，识别区分年轻人和老年人的区域生物标志物，并识别跨脑区域和MRI模式的放射学特征。方法：在横断面研究中，从图像信息提取数据集中获得脑MRI数据，并使用Freesurfer进行分割。遵循图像生物标志物标准化倡议指南，使用PyRadiomics软件从七个关键脑区域提取放射组学特征。采用多步骤特征选择过程来识别重要的放射性特征，这些特征用于开发用于脑年龄预测的逻辑回归模型。重要的放射学特征被确定为表明大脑在各个区域衰老。结果：该队列包括122名参与者。T1 + T2 Rad-Score显示出较高的预测准确性，特别是对海马（曲线下面积[AUC] = 0.96）。观察到模型表现的区域差异，丘脑、尾状体和海马的auc最高（分别为0.95、1.00和0.96）。不同脑区和MRI模式的放射学特征重要性不同：丘脑、尾状核和海马/杏仁核分别在T1、T2和T1 + T2模型图像中最重要。我们的发现的稳健性和可重复性得到了保证。结论：T1和T2 MRI数据的放射学特征提供了可靠的脑衰老预测指标，模型具有高判别性能。我们证明了使用多模态MRI预测脑老化和识别区域生物标志物的基于放射组学的方法的有效性。

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引用次数: 0

Validation of a TOPAS cone beam computed tomography (CBCT) Monte Carlo model towards personalised CBCT dosimetry in interventional radiology (IR) TOPAS锥形束计算机断层扫描（CBCT）蒙特卡罗模型在介入放射学（IR）个体化CBCT剂量测定中的验证。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-15 DOI: 10.1016/j.ejmp.2025.105690

Nina McWilliams , Jackie McCavana , Seán Cournane , Luis León Vintró

Purpose

Accurately estimating patient-specific radiation dose from cone beam CT (CBCT) in interventional radiology (IR) is essential for assessing exposure to radiosensitive organs. This study aimed to evaluate the accuracy of Monte Carlo (MC) dosimetry models for two CBCT IR systems, the Philips Azurion and the Siemens Artis Q, using a realistic anthropomorphic phantom and its CT images.

Methods

MC simulations of abdominal CBCT protocols were performed using the CIRS® ATOM phantom. For the Philips system, manufacturer-supplied exposure parameters were used. For the Siemens system, a previously developed AECScorer module was implemented to account for automatic exposure control (AEC), modulating simulated projections based on phantom attenuation. Experimental organ doses were measured using thermoluminescent dosimeters (TLDs) and compared against MC results.

Results

The Philips MC model showed good agreement with TLD data, with an average difference of 14 % for organs in the central field of view (FOV). Simulated organ doses were consistent with published literature, but underestimated empirical values in some cases. The Siemens model, while reasonably accurate, overestimated organ doses by an average of 11 %. For both systems, the largest discrepancies were observed in the peripheral FOV. On average, Siemens experimental doses were 3.45 times higher than those from the Philips system.

Conclusion

Results of this study suggest that MC models, informed by manufacturer-provided CBCT acquisition parameters or appropriate AEC MC simulation, can reliably replicate experimental dosimetry in the irradiated volume with good accuracy. This supports the feasibility of scanner-, region-, and exam-specific dose estimations using the proposed MC methodologies.

目的：在介入放射学（IR）中，准确估计来自锥形束CT （CBCT）的患者特异性辐射剂量对评估放射敏感器官的暴露至关重要。本研究旨在评估两种CBCT红外系统（飞利浦Azurion和西门子Artis Q）的蒙特卡罗（MC）剂量学模型的准确性，使用逼真的拟人化幻影及其CT图像。方法：使用CIRS®ATOM幻影进行腹部CBCT方案的MC模拟。对于飞利浦系统，使用制造商提供的曝光参数。对于西门子系统，采用了先前开发的AECScorer模块来实现自动曝光控制（AEC），根据幻像衰减调制模拟投影。用热释光剂量计（TLDs）测量实验器官剂量，并与MC结果进行比较。结果：Philips MC模型与TLD数据吻合较好，中心视场（FOV）器官的平均差异为14%。模拟器官剂量与已发表的文献一致，但在某些情况下低估了经验值。西门子模型虽然相当准确，但平均高估了11%的器官剂量。对于这两个系统，最大的差异是观察到的周边视场。平均而言，西门子的实验剂量是飞利浦系统的3.45倍。结论：本研究结果表明，MC模型，根据制造商提供的CBCT采集参数或适当的AEC MC模拟，可以可靠地复制实验剂量学在辐照体积中具有良好的准确性。这支持了使用提议的MC方法进行扫描仪、区域和检查特异性剂量估计的可行性。

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引用次数: 0

Performance tests of the B-RAD survey meter and portable γ-spectrometer in a clinical environment B-RAD测量仪和便携式γ谱仪在临床环境下的性能测试。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-13 DOI: 10.1016/j.ejmp.2025.105701

Marco Silari , Marco Brambilla , Alessandro Carriero , Pierfrancesco Franco , Gianfranco Loi , Michele Lorenzoli , Roberta Matheoud

Introduction

This note describes performance test of B-RAD, a commercial γ-survey meter/portable γ-spectrometer designed to operate in strong magnetic field. The instrument consists of an active probe housing a cylindrical LaBr₃ crystal, and a central unit connected by a cable.

Methods

The measurements were performed at an MR-Linac Elekta Unity (1.5 T) and a Philips Ingenia (3 T) MRI system, by measuring the H*(10) rate and the gamma energy distributions using two certified radioactive sources of ⁵⁷Co and ¹³⁷Cs providing a reference irradiation while the detector was exposed to increasing values of the magnetic field. Measurements were performed in various configurations, with probe and central unit either kept close together or separate, and either aligned or orthogonal to the magnetic field.

Results

The results outline stable H*(10) rates and gamma spectrometry performances in the entire magnetic field range. The device’s performance is unaffected when only the probe is exposed to the static magnetic field while the central unit is in a lower field zone. When the latter is exposed to a strong field, the loss in dose rate remains within 10% for all configurations tested.

Conclusion

The results demonstrate the potential application of the instrument for operational and decommissioning measurements at MRI-Linac and PET-MRI systems.

本文介绍了B-RAD的性能测试，B-RAD是一种商用γ测量仪/便携式γ光谱仪，设计用于在强磁场中工作。该仪器由一个带有圆柱形LaBr3晶体的主动探头和一个由电缆连接的中心单元组成。方法：在MR-Linac Elekta Unity （1.5 T）和Philips Ingenia (3 T) MRI系统上进行测量，通过使用57Co和137Cs两种认证放射源作为参考照射，测量H*(10)率和γ能量分布，同时探测器暴露在增加的磁场值中。测量是在不同的配置下进行的，探针和中心单元要么紧密相连，要么分开，要么与磁场对齐，要么与磁场正交。结果：该结果勾勒出在整个磁场范围内稳定的H*(10)速率和伽马能谱性能。当只有探针暴露在静态磁场中，而中心单元处于较低的磁场区时，设备的性能不受影响。当后者暴露于强场时，所有测试配置的剂量率损失保持在10%以内。结论：结果证明了该仪器在MRI-Linac和PET-MRI系统的运行和退役测量中的潜在应用。

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引用次数: 0

An innovative approach for the segmentation of lung consolidative adherent to chest wall in CT scans CT扫描中肺实变附著胸壁分割的创新方法

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-13 DOI: 10.1016/j.ejmp.2025.105697

Alessio Gnerucci , Maurizio Bartolucci , Guglielmo Baccani , Margherita Betti , Roberto Carpi , Evaristo Cisbani , Ilaria Cupparo , Sandra Doria , Luca Fedeli , Cesare Gori , Lorenzo Lasagni , Lorenzo Nicola Mazzoni , Alessandro Marconi , Vittorio Miele , Guido Risaliti , Marco Rossetti , Adriana Taddeucci , Federico Valeri , Diletta Cozzi

Objectives

Lung segmentation in CT images represents a fundamental process for quantitative evaluations of changes in lung parenchyma density and volume as well as for radiomics investigations, in order to assess the frame, extent, and severity of diffuse lung pathologies. A relevant limitation of commonly used segmentation software is the difficulty or inability to properly detect the lung/chest-wall interface in the case of pathologically increased parenchymal density (e.g. ARDS or COVID-19) adherent to the chest-wall. In order to overcome such limitation and, at the same time, to avoid time-consuming manual segmentation we developed an innovative semi-automatic algorithm.

Materials & methods

The actual lung parenchyma volume is identified by modelling lung edges with appropriate spline functions calculated by considering shape and position of lung neighboring anatomical districts and local density patterns (pixel-based radiomics). Thereafter the internal high-density pathological regions are segmented with proper thresholds.

Results

The algorithm segmentation accuracy was compared to the one of experienced radiologists showing performances at least not inferior to that of their manual segmentation.

Conclusions

A new algorithm, (international patent pending) was developed using an innovative approach to accurately segment lung parenchyma and, in particular, consolidative tissues, even in cases where commercial algorithms tipically fail, such as when these tissues adhereto the lung wall.

目的CT图像中的肺分割是定量评估肺实质密度和体积变化以及放射组学调查的基本过程，以评估弥漫性肺病变的框架、程度和严重程度。常用分割软件的一个相关限制是，在病理性实质密度增加（例如ARDS或COVID-19）粘附在胸壁的情况下，难以或无法正确检测肺/胸壁界面。为了克服这种局限性，同时避免耗时的人工分割，我们开发了一种创新的半自动算法。材料&方法通过考虑肺邻近解剖区域的形状和位置以及局部密度模式（基于像素的放射组学）计算适当的样条函数，通过建模肺边缘来识别实际肺实质体积。然后用合适的阈值对内部高密度病理区域进行分割。结果该算法的分割精度与经验丰富的放射科医生的分割精度相比，至少不逊于他们的人工分割。我们开发了一种新的算法（正在申请国际专利），该算法使用一种创新的方法来准确分割肺实质，特别是实变组织，即使在商业算法通常失败的情况下，例如当这些组织粘附在肺壁上时。

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引用次数: 0

Determining optimal spot delivery pattern using log file Derived dose discrepancy factor in pencil beam scanning reference dosimetry 铅笔束扫描参考剂量法中使用日志文件导出剂量差异因子确定最佳点递送模式。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-13 DOI: 10.1016/j.ejmp.2025.105698

Kah Seng Lew , Calvin Wei Yang Koh , Kang Hao Lee , Clifford Ghee Ann Chua , Andrew Wibawa , Zubin Master , Wen Siang Lew , James Cheow Lei Lee , Sung Yong Park , Hong Qi Tan

Introduction

Spatial uncertainties in spot position during reference dosimetry measurements of pencil beam scanning system were found to cause fluctuations in the reference dosimetry curve. This study aims to develop a method to determine the optimal delivery pattern for reference dosimetry measurement using information obtained from log file and quantifying the expected dose discrepancy.

Methods

A total of 7 different delivery pattern were delivered five times each and log files for each delivery were collected. We introduced a new metric known as dose discrepancy factor (DDF) to quantify the expected dose discrepancy in the measurement arising from spot positioning error. DDF is calculated using a simple pencil beam algorithm and actual spot positions from the log file. Type A and B uncertainties of DDF are quantified to draw statistically rigorous conclusion on the most optimal delivery pattern.

Results

Relative dose difference of up to 2 % can be observed in some of the delivery pattern when reference dosimetry curve was plotted. Linear fit of DDF calculated from log file against measured dose ratio yields an R² of 0.56 which suggest moderate correlation. Delivery patterns with repainting and X fast scan (50MU) have the lowest average uncertainty. Friedman test and post-hoc test shows that different delivery patterns were proven to be statistical different with the exception of Y fast scan (50MU) versus both X fast scan (50MU) and random scan (50MU). Y fast scan (50MU) with the highest average DDF value of 0.979 ± 0.005 was found to be the most optimal delivery pattern as it has the least discrepancy from an ideal delivery.

Conclusion

Delivery patterns used during reference dosimetry had a non-negligible impact on measurement. We had detailed a log file-based approach to determine the optimal delivery pattern such that dose measurement would be least affected by spot positioning error.

在铅笔束扫描系统的参考剂量测量中，发现点位置的空间不确定性会引起参考剂量曲线的波动。本研究旨在建立一种方法，利用从日志文件中获得的信息和量化预期剂量差异来确定参考剂量测量的最佳递送模式。方法：共7种不同的分娩方式，每种分娩5次，并收集每次分娩的日志文件。我们引入了一个被称为剂量差异因子（DDF）的新度量来量化由点定位误差引起的测量中的预期剂量差异。使用简单的铅笔束算法和日志文件中的实际点位置计算DDF。对DDF的A型和B型不确定性进行量化，得出最优交付模式的统计严谨结论。结果：绘制参考剂量学曲线时，在某些给药方式中可观察到相对剂量差达2%。从日志文件计算的DDF与测量剂量比的线性拟合R2为0.56，表明相关性中等。重涂和X快速扫描（50MU）的交付模式具有最低的平均不确定性。Friedman检验和事后检验表明，除了Y快速扫描（50MU）与X快速扫描（50MU）和随机扫描（50MU）外，不同的传递模式被证明具有统计学差异。Y快速扫描（50MU）的平均DDF值最高，为0.979±0.005，与理想分娩相差最小，是最理想的分娩方式。结论：参考剂量测定中使用的给药方式对测量结果有不可忽略的影响。我们详细介绍了一种基于日志文件的方法，以确定最佳的给药模式，使剂量测量受点定位误差的影响最小。

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引用次数: 0

Spectral performance of dual source flash mode on the emerging photon counting CT: Comparison with dual energy CT for body imaging 双源闪光模式在新兴光子计数CT上的光谱性能：与双能CT身体成像的比较。

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

Physica Medica-European Journal of Medical Physics

Pub Date : 2025-12-13 DOI: 10.1016/j.ejmp.2025.105703

Wendy Siman , Nolan Dang , Donglai Huo , Lorna P. Browne , Jason P. Weinman , Wei Zhou

Purpose

To evaluate the spectral performance of dual-source (DS) compared to single-source (SS) mode on the photon counting CT (PCCT), and conventional dual-energy CT (DECT).

Methods

Multi-Energy CT phantoms (20, 40 cm) were configured with solid-iodine (2–15mgI/cc) and solid-water rods to simulate pediatric and adult-sized abdomens. PCCT scans were acquired with SS (pitch-1.5) and DS (pitch-3.0). DECT scans were performed using 80/Sn140 and 100/Sn140kV with a maximum-pitch 1.2. At the clinical dose setting, CTDI values were 0.63 mGy (20-cm) and 4.30 mGy (40-cm). Dose and reconstruction parameters were matched across all scan modes. Virtual monoenergetic images (VMI) between 40 and 80 keV and iodine maps (IM) were generated. Noise, noise power spectra and section sensitive profiles of VMIs were then calculated. HU accuracy was evaluated using absolute percent error (APE) between measured and reference attenuation values, while iodine quantification accuracy was assessed by linear regression and root-mean-square-error (RMSE) comparing measured and reference concentrations.

Results

PCCT DS and SS modes showed comparable noise levels across keV. Both PCCT modes had lower noise than DECT across all conditions, although discrepancies diminished in larger phantoms and higher VMI keV. At the 20-cm phantom, median APEs for iodine CT numbers were lower for PCCT SS (0.53%) and DS (0.55%) than for DECT (0.98%, 1.06%). RMSE values of iodine quantification are 0.50mgI/cc for PCCT DS and 0.53mgI/cc for PCCT SS.

Conclusion

Ultra-fast PCCT dual-source mode yields spectral image quality comparable to PCCT single-source and DECT, supporting its use when fast scanning is critical for pediatric and cardiac applications.

目的：比较双源（DS）模式与单源（SS）模式在光子计数CT （PCCT）和传统双能CT （DECT）上的光谱性能。方法：使用固体碘（2-15mgI/cc）和固体水棒模拟儿童和成人大小的腹部。使用SS （pitch-1.5）和DS （pitch-3.0）获得PCCT扫描。使用80/Sn140和100/Sn140kV进行DECT扫描，最大节距为1.2。在临床剂量设置下，CTDI值分别为0.63 mGy （20 cm）和4.30 mGy （40 cm）。剂量和重建参数匹配所有扫描模式。生成40 ~ 80 keV的虚拟单能图像（VMI）和碘图（IM）。然后计算VMIs的噪声、噪声功率谱和截面敏感曲线。HU准确度采用测量值与参考衰减值之间的绝对百分比误差（APE）进行评估，而碘定量准确度采用线性回归和测量浓度与参考浓度的均方根误差（RMSE）进行评估。结果：PCCT的DS和SS模式显示出相当的噪声水平。两种PCCT模式在所有条件下都比DECT具有更低的噪声，尽管在较大的幻影和较高的VMI keV下差异减小。在20 cm影区，PCCT SS（0.53%）和DS（0.55%）碘CT值的中位数ape低于DECT（0.98%, 1.06%）。结论：超快速PCCT双源模式可获得与PCCT单源和DECT相当的光谱图像质量，支持其在儿科和心脏应用中快速扫描的应用。

{"title":"Spectral performance of dual source flash mode on the emerging photon counting CT: Comparison with dual energy CT for body imaging","authors":"Wendy Siman , Nolan Dang , Donglai Huo , Lorna P. Browne , Jason P. Weinman , Wei Zhou","doi":"10.1016/j.ejmp.2025.105703","DOIUrl":"10.1016/j.ejmp.2025.105703","url":null,"abstract":"<div><h3>Purpose</h3><div>To evaluate the spectral performance of dual-source (DS) compared to single-source (SS) mode on the photon counting CT (PCCT), and conventional dual-energy CT (DECT).</div></div><div><h3>Methods</h3><div>Multi-Energy CT phantoms (20, 40 cm) were configured with solid-iodine (2–15mgI/cc) and solid-water rods to simulate pediatric and adult-sized abdomens. PCCT scans were acquired with SS (pitch-1.5) and DS (pitch-3.0). DECT scans were performed using 80/Sn140 and 100/Sn140kV with a maximum-pitch 1.2. At the clinical dose setting, CTDI values were 0.63 mGy (20-cm) and 4.30 mGy (40-cm). Dose and reconstruction parameters were matched across all scan modes. Virtual monoenergetic images (VMI) between 40 and 80 keV and iodine maps (IM) were generated. Noise, noise power spectra and section sensitive profiles of VMIs were then calculated. HU accuracy was evaluated using absolute percent error (APE) between measured and reference attenuation values, while iodine quantification accuracy was assessed by linear regression and root-mean-square-error (RMSE) comparing measured and reference concentrations.</div></div><div><h3>Results</h3><div>PCCT DS and SS modes showed comparable noise levels across keV. Both PCCT modes had lower noise than DECT across all conditions, although discrepancies diminished in larger phantoms and higher VMI keV. At the 20-cm phantom, median APEs for iodine CT numbers were lower for PCCT SS (0.53%) and DS (0.55%) than for DECT (0.98%, 1.06%). RMSE values of iodine quantification are 0.50mgI/cc for PCCT DS and 0.53mgI/cc for PCCT SS.</div></div><div><h3>Conclusion</h3><div>Ultra-fast PCCT dual-source mode yields spectral image quality comparable to PCCT single-source and DECT, supporting its use when fast scanning is critical for pediatric and cardiac applications.</div></div>","PeriodicalId":56092,"journal":{"name":"Physica Medica-European Journal of Medical Physics","volume":"141 ","pages":"Article 105703"},"PeriodicalIF":2.7,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145758401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0