Zeitschrift fur Medizinische Physik最新文献_第5页

Sensitivity and specificity of Monte Carlo based independent secondary dose computation for detecting modulation-related dose errors in intensity modulated radiotherapy 基于蒙特卡罗的独立二次剂量计算在强度调制放疗中检测调制相关剂量误差的灵敏度和特异性。

IF 4.2 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-08-01 DOI: 10.1016/j.zemedi.2023.10.001

Matthias Kowatsch , Philipp Szeverinski , Patrick Clemens , Thomas Künzler , Matthias Söhn , Markus Alber

Background

The recent availability of Monte Carlo based independent secondary dose calculation (ISDC) for patient-specific quality assurance (QA) of modulated radiotherapy requires the definition of appropriate, more sensitive action levels, since contemporary recommendations were defined for less accurate ISDC dose algorithms.

Purpose

The objective is to establish an optimum action level and measure the efficacy of a Monte Carlo ISDC software for pre-treatment QA of intensity modulated radiotherapy treatments.

Methods

The treatment planning system and the ISDC were commissioned by their vendors from independent base data sets, replicating a typical real-world scenario. In order to apply Receiver-Operator-Characteristics (ROC), a set of treatment plans for various case classes was created that consisted of 190 clinical treatment plans and 190 manipulated treatment plans with dose errors in the range of 1.5–2.5%. All 380 treatment plans were evaluated with ISDC in the patient geometry. ROC analysis was performed for a number of Gamma (dose-difference/distance-to-agreement) criteria. QA methods were ranked according to Area under the ROC curve (AUC) and optimum action levels were derived via Youden’s J statistics.

Results

Overall, for original treatment plans, the mean Gamma pass rate (GPR) for Gamma(1%, 1 mm) was close to 90%, although with some variation across case classes. The best QA criterion was Gamma(2%, 1 mm) with GPR > 90% and an AUC of 0.928. Gamma criteria with small distance-to-agreement had consistently higher AUC. GPR of original treatment plans depended on their modulation degree. An action level in terms of Gamma(1%, 1 mm) GPR that decreases with modulation degree was the most efficient criterion with sensitivity = 0.91 and specificity = 0.95, compared with Gamma(3%, 3 mm) GPR > 99%, sensitivity = 0.73 and specificity = 0.91 as a commonly used action level.

Conclusions

ISDC with Monte Carlo proves highly efficient to catch errors in the treatment planning process. For a Monte Carlo based TPS, dose-difference criteria of 2% or less, and distance-to-agreement criteria of 1 mm, achieve the largest AUC in ROC analysis.

背景：基于蒙特卡罗的独立二次剂量计算（ISDC）最近可用于调制放疗的患者特异性质量保证（QA），这需要定义适当的、更敏感的作用水平，因为当代的建议是针对不太准确的ISDC剂量算法定义的。目的：目的是建立一个最佳作用水平，并测量蒙特卡罗ISDC软件对调强放疗治疗前QA的疗效。方法：治疗计划系统和ISDC由其供应商从独立的基础数据集中委托，复制典型的真实世界场景。为了应用受试者-操作员特征（ROC），创建了一套适用于各种病例类别的治疗计划，包括190个临床治疗计划和190个剂量误差在1.5-2.5%范围内的操作治疗计划。所有380个治疗计划都在患者几何结构中用ISDC进行了评估。ROC分析是针对许多Gamma（剂量差异/一致性距离）标准进行的。QA方法根据ROC曲线下面积（AUC）进行排名，最佳作用水平通过Youden的J统计得出。结果：总体而言，对于原始治疗计划，Gamma的平均Gamma通过率（GPR）（1%，1 mm）接近90%。最佳质量保证标准为伽玛（2%，1 mm） > 90%，AUC为0.928。一致性距离较小的Gamma标准的AUC始终较高。原始治疗方案的GPR取决于它们的调节程度。γ的作用水平（1%，1 mm）GPR随调制度的减小是具有灵敏度的最有效的标准 = 0.91和特异性 = 0.95，与Gamma（3%，3 mm）探地雷达 > 99%，灵敏度 = 0.73和特异性 = 0.91作为常用的行动水平。结论：Monte Carlo的ISDC在发现治疗计划过程中的错误方面非常有效。对于基于蒙特卡罗的TPS，剂量差异标准为2%或更低，一致性距离标准为1 mm，在ROC分析中获得最大AUC。

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引用次数: 0

Quantum physics at a historic milestone: How has it shaped medical physics? 历史里程碑上的量子物理学：它是如何影响医学物理学的？

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/j.zemedi.2025.02.002

Michael Bock , Jürgen R. Reichenbach

引用次数: 0

Impact of log file source and data frequency on accuracy of log file-based patient specific quality assurance 日志文件来源和数据频率对基于日志文件的患者特异性质量保证准确性的影响

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/j.zemedi.2023.05.006

Akbar Azzi , Gerd Heilemann , Dietmar Georg , Supriyanto Ardjo Pawiro , Terry Mart , Wolfgang Lechner

Performing phantom measurements for patient-specific quality assurance (PSQA) adds a significant amount of time to the adaptive radiotherapy procedure. Log file based PSQA can be used to increase the efficiency of this process. This study compared the dosimetric accuracy of high-frequency linear accelerator (Linac) log files and low-frequency log data stored in the oncology information system (OIS). Thirty patients were included, that were recently treated in the head and neck (HN), brain, and prostate region with volumetric modulated arc therapy (VMAT) and an additional ten patients treated using stereotactic body radiation therapy (SBRT) with 3D-conformal radiotherapy (3D-CRT) technique. Log data containing a single fraction were used to calculate the dose distributions. The dosimetric differences between Linac log files and OIS logs were evaluated with a gamma analysis with 2%/2 mm criterion and dose threshold of 30%. The original treatment plan was used as a reference. Moreover, DVH parameters of D_98%, D_50%, and D_2% of the planning-target volume (PTV) and dose to several organs at risk (OARs) were reported. Significant differences in dose distributions between the two log types and the original dose were observed for PTV D_98% and D_2% (r < 0.001) for HN cases, PTV D_98% (r = 0.005) for brain cases, and PTV D_50% (r = 0.015) for prostate cases. No significant differences were found between the two log types with respect to D_50%. The root mean square (RMS) error of the leaf positions of the OIS log was approximately twice the RMS error of the Linac log file for VMAT plans, but identical for 3D-CRT plans. The relationship between the gamma pass rate and the RMS error showed a moderate correlation for the Linac log files (r = −0.58, p < 0.001) and strong correlation for OIS logs (r = −0.71, p < 0.001). Furthermore, all doses calculated using Linac log files and OIS log data had a GPR >90% for an RMS error < 3.3 mm. Based on these findings, a tolerance limit of RMS error of 3.3 mm for considering OIS log based PSQA was established. Nevertheless, the OIS log data quality should be improved to achieve adequate PSQA.

为患者特异性质量保证（PSQA）进行幻像测量增加了适应性放疗程序的大量时间。可以使用基于日志文件的PSQA来提高此过程的效率。本研究比较了存储在肿瘤信息系统（OIS）中的高频直线加速器（Linac）日志文件和低频日志数据的剂量学准确性。30例患者最近在头颈部（HN），脑和前列腺区域接受了体积调制电弧治疗（VMAT），另外10例患者接受了立体定向体放射治疗（SBRT）和3d适形放疗（3D-CRT）技术。使用含有单一组分的测井数据来计算剂量分布。采用2%/2 mm标准和30%剂量阈值的伽马分析来评估Linac日志文件和OIS日志之间的剂量学差异。参照原治疗方案。此外，还报道了计划靶体积（PTV）的D98%、D50%和D2%的DVH参数，以及对几个危险器官（OARs）的剂量。两种log类型的剂量分布与原始剂量有显著差异：HN病例的PTV D98%和D2% (r <； 0.001)，脑病例的PTV D98% (r = 0.005)，前列腺病例的PTV D50% （r = 0.015）。两种原木类型在D50%方面无显著差异。OIS日志的叶片位置的均方根误差（RMS）大约是VMAT计划的Linac日志文件的均方根误差的两倍，但与3D-CRT计划相同。gamma通过率与RMS误差之间的关系显示，对于Linac日志文件（r = −0.58,p <； 0.001）具有中等相关性，对于OIS日志文件（r = −0.71,p <； 0.001）具有强相关性。此外，使用Linac日志文件和OIS日志数据计算的所有剂量的GPR为90%，均方根误差为 <； 3.3 mm。基于这些发现，建立了考虑OIS测井的PSQA的RMS误差容限为3.3 mm。尽管如此，OIS测井数据质量仍有待提高，以达到足够的PSQA。

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引用次数: 0

Physical wedge as a tool for radiochromic film calibration 物理楔子作为放射色膜校准的工具

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/j.zemedi.2023.05.008

Stevan Pecić , Miloš Vićić , Ivan Belča , Strahinja Stojadinović , Borko Nidžović , Ljubomir Kurij , Slobodan Dević

Reliable calibration is one of the major challenges in using radiochromic films (RCF) for radiation dosimetry. In this study the feasibility of using dose gradients produced by a physical wedge (PW) for RCF calibration was investigated. The aim was to establish an efficient and reproducible method for calibrating RCF using a PW. Film strips were used to capture the wedge dose profile for five different exposures and the acquired scans were processed to generate corresponding net optical density wedge profiles. The proposed method was compared to the benchmark calibration, following the guidelines for precise calibration using uniform dose fields. The results of the benchmark comparison presented in this paper showed that using a single film strip for measuring wedge dose profile is sufficient for estimating a reliable calibration curve within the recorded dose range. Furthermore, the PW calibration can be extrapolated or extended by using multiple gradients for the optimal coverage of the desired calibration dose range. The method outlined in this paper can be readily replicated using the equipment and expertise commonly found in a radiotherapy center. Once the dose profile and central axis attenuation coefficient of the PW are determined, they can serve as a reference for a variety of calibrations using different types and batches of film. This investigation demonstrated that the calibration curves obtained with the presented PW calibration method are within the bounds of the measurement uncertainty evaluated for the conventional uniform dose field calibration method.

可靠的校准是使用放射性致色膜（RCF）进行辐射剂量测定的主要挑战之一。本研究探讨了利用物理楔（PW）产生的剂量梯度进行RCF校准的可行性。目的是建立一种使用PW校准RCF的有效和可重复的方法。使用薄膜条捕获五种不同曝光的楔形剂量分布图，并对获得的扫描进行处理以生成相应的净光密度楔形分布图。按照均匀剂量场精确校准的指导方针，将所提出的方法与基准校准进行了比较。本文给出的基准对比结果表明，在记录的剂量范围内，用单个薄膜条测量楔形剂量分布足以估计出可靠的校准曲线。此外，PW校准可以通过使用多个梯度来外推或扩展，以获得所需校准剂量范围的最佳覆盖范围。本文概述的方法可以使用放射治疗中心常见的设备和专业知识很容易地复制。一旦确定了PW的剂量分布和中轴衰减系数，就可以作为使用不同类型和批次的薄膜进行各种校准的参考。研究表明，所提出的PW校准方法得到的校准曲线在常规均匀剂量场校准方法的测量不确定度范围内。

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引用次数: 0

Comparison of different neurite density metrics with brain asymmetry evaluation 不同神经突密度指标与脑不对称评价的比较

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/j.zemedi.2023.07.003

Ivan I. Maximov , Lars T. Westlye

The standard diffusion MRI model with intra- and extra-axonal water pools offers a set of microstructural parameters describing brain white matter architecture. However, non-linearities in the standard model and diffusion data contamination by noise and imaging artefacts make estimation of diffusion metrics challenging. In order to develop reliable diffusion approaches and to avoid computational model degeneracy, additional theoretical assumptions allowing stable numerical implementations are required. Advanced diffusion approaches allow for estimation of intra-axonal water fraction (AWF), describing a key structural characteristic of brain tissue. AWF can be interpreted as an indirect measure or proxy of neurite density and has a potential as useful clinical biomarker. Established diffusion approaches such as white matter tract integrity, neurite orientation dispersion and density imaging (NODDI), and spherical mean technique provide estimates of AWF within their respective theoretical frameworks. In the present study, we estimated AWF metrics using different diffusion approaches and compared measures of brain asymmetry between the different metrics in a sub-sample of 182 subjects from the UK Biobank. Multivariate decomposition by mean of linked independent component analysis revealed that the various AWF proxies derived from the different diffusion approaches reflect partly non-overlapping variance of independent components, with distinct anatomical distributions and sensitivity to age. Further, voxel-wise analysis revealed age-related differences in AWF-based brain asymmetry, indicating less apparent left-right hemisphere difference with higher age. Finally, we demonstrated that NODDI metrics suffer from a quite strong dependence on used numerical algorithms and post-processing pipeline. The analysis based on AWF metrics strongly depends on the used diffusion approach and leads to poorly reproducible results.

具有轴突内和轴突外水池的标准弥散MRI模型提供了一组描述脑白质结构的微结构参数。然而，标准模型中的非线性和受噪声和成像伪影污染的扩散数据使得扩散度量的估计具有挑战性。为了开发可靠的扩散方法并避免计算模型退化，需要允许稳定数值实现的附加理论假设。先进的扩散方法允许估计轴突内水分数（AWF），描述脑组织的关键结构特征。AWF可以被解释为神经突密度的间接测量或代理，具有潜在的有用的临床生物标志物。已建立的扩散方法，如白质束完整性、神经突取向弥散和密度成像（NODDI）和球面平均技术，在各自的理论框架内提供了AWF的估计。在本研究中，我们使用不同的扩散方法估计了AWF指标，并比较了来自英国生物银行的182名受试者的不同指标之间的大脑不对称测量。通过关联独立分量分析进行多元分解，发现不同扩散方法得到的AWF指标部分反映了独立分量的非重叠方差，具有不同的解剖分布和对年龄的敏感性。此外，体素分析揭示了基于awf的大脑不对称性的年龄相关差异，表明年龄越大，左右半球差异越不明显。最后，我们证明了NODDI指标非常依赖于所使用的数值算法和后处理管道。基于AWF指标的分析强烈依赖于所使用的扩散方法，导致结果的可重复性很差。

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引用次数: 0

Gamma radiation detector selection for CT scanner CT扫描仪伽玛辐射探测器的选择

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/j.zemedi.2023.07.006

Kajal Kumari, Mayank Goswami

Three types of gamma radiation detectors associated with distributed electronics namely, NaI (Tl), HPGe and

{LaBr}_{3} (C e)

are compared primarily focusing on electronic noise and scattering noise. Additionally, detectors of same make, material, size and electronics are also compared. A methodology is proposed to select the most suitable detector for computed tomography (CT) among the available options. Standard deviation parameter is employed to estimate electronic noise without performing CT experiment. Kanpur theorem-1(KT-1) is used to estimate the scattering noise quantitatively after verifying its sensitivity to scattering noise. The impact of scattering noise on CT profiles is evaluated using dice similarity dice coefficient. A good resemblance between KT-1 and dice coefficient is observed. A maximum difference of 56% in scattering noise is observed when five detectors used simultaneously instead of single detector whereas a discrepancy of 85% is observed between different types of radiation detectors. As far as ease of handling, operational and capital cost is concern one has to compromise minimum 12% of accuracy in CT reconstruction if NaI (Tl) detector is used with respect to best alternative available.

The proposed methodology can be applied to measurement that require minimal scattering interference data other than CT experiments. The manufacturer can add noise level of detector as a characteristic parameter in the data sheet.

比较了三种与分布式电子学相关的伽马辐射探测器，即NaI （Tl）、HPGe和LaBr3(Ce)，主要关注电子噪声和散射噪声。此外，还对相同制造、材料、尺寸和电子器件的探测器进行了比较。提出了一种方法，以选择最合适的检测器的计算机断层扫描（CT）中可用的选项。在不进行CT实验的情况下，采用标准差参数估计电子噪声。在验证了Kanpur定理1（KT-1）对散射噪声的敏感性后，利用Kanpur定理1对散射噪声进行了定量估计。利用骰子相似系数评价了散射噪声对CT轮廓的影响。观察到KT-1和骰子系数之间有很好的相似性。同时使用5个探测器而不是单个探测器时，散射噪声的最大差异为56%，而不同类型的辐射探测器之间的差异为85%。考虑到操作、操作和资金成本，如果使用NaI （Tl）检测器作为最佳替代方案，则必须在CT重建中牺牲至少12%的准确性。该方法可应用于CT实验以外的散射干扰最小的测量。制造商可以在数据表中添加探测器的噪声级作为特征参数。

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引用次数: 0

Editorial Board + Consulting Editorial Board 编辑委员会+咨询编辑委员会

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/S0939-3889(25)00044-3

引用次数: 0

Quality assurance and temporal stability of a 1.5 T MRI scanner for MR-guided Photon and Particle Therapy 用于核磁共振引导光子和粒子治疗的1.5 T MRI扫描仪的质量保证和时间稳定性

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/j.zemedi.2023.04.004

Stefan Dorsch , Katharina Paul , Cedric Beyer , Christian P Karger , Oliver Jäkel , Jürgen Debus , Sebastian Klüter

Purpose

To describe performance measurements, adaptations and time stability over 20 months of a diagnostic MR scanner for integration into MR-guided photon and particle radiotherapy.

Material and methods

For realization of MR-guided photon and particle therapy (MRgRT/MRgPT), a 1.5 T MR scanner was installed at the Heidelberg Ion Beam Therapy Center. To integrate MRI into the treatment process, a flat tabletop and dedicated coil holders for flex coils were used, which prevent deformation of the patient external contour and allow for the use of immobilization tools for reproducible positioning. The signal-to-noise ratio (SNR) was compared for the diagnostic and therapy-specific setup using the flat couch top and flexible coils for the a) head & neck and b) abdominal region as well as for different bandwidths and clinical pulse sequences. Additionally, a quality assurance (QA) protocol with monthly measurements of the ACR phantom and measurement of geometric distortions for a large field-of-view (FOV) was implemented to assess the imaging quality parameters of the device over the course of 20 months.

Results

The SNR measurements showed a decreased SNR for the RT-specific as compared to the diagnostic setup of (a) 26% to 34% and (b) 11% to 33%. No significant bandwidth dependency for this ratio was found. The longitudinal assessment of the image quality parameters with the ACR and distortion phantom confirmed the long-term stability of the MRI device.

Conclusion

A diagnostic MRI was commissioned for use in MR-guided particle therapy. Using a radiotherapy specific setup, a high geometric accuracy and signal homogeneity was obtained after some adaptions and the measured parameters were shown to be stable over a period of 20 months.

目的描述诊断性磁共振扫描仪集成到磁共振引导光子和粒子放射治疗中的性能测量，适应性和时间稳定性超过20个月。材料和方法为了实现核磁共振引导光子和粒子治疗（MRgRT/MRgPT），在海德堡离子束治疗中心安装了一台1.5 T核磁共振扫描仪。为了将MRI整合到治疗过程中，使用了一个扁平的桌面和专用的弯曲线圈支架，以防止患者外部轮廓变形，并允许使用固定工具进行可重复定位。比较诊断和治疗特定设置的信噪比（SNR），使用平沙发顶和柔性线圈作为a)头；颈部和腹部区域以及不同的带宽和临床脉冲序列。此外，实施了质量保证（QA）方案，每月测量ACR模体和测量大视场（FOV）的几何畸变，以评估设备在20个月内的成像质量参数。结果信噪比测量显示，与诊断设置(a) 26%至34%和(b) 11%至33%相比，rt特异性的信噪比降低。该比率没有发现明显的带宽依赖关系。利用ACR和畸变模体对图像质量参数进行纵向评估，证实了该MRI装置的长期稳定性。结论磁共振诊断技术可用于磁共振引导粒子治疗。使用放射治疗专用装置，经过一些调整后获得了高几何精度和信号均匀性，并且测量参数在20个月的时间内显示稳定。

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引用次数: 0

Silicone phantoms fabricated with multi-material extrusion 3D printing technology mimicking imaging properties of soft tissues in CT 采用多材料挤压3D打印技术制作模拟软组织CT成像特性的硅胶模型

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/j.zemedi.2023.05.007

Sepideh Hatamikia , Laszlo Jaksa , Gernot Kronreif , Wolfgang Birkfellner , Joachim Kettenbach , Martin Buschmann , Andrea Lorenz

Recently, 3D printing has been widely used to fabricate medical imaging phantoms. So far, various rigid 3D printable materials have been investigated for their radiological properties and efficiency in imaging phantom fabrication. However, flexible, soft tissue materials are also needed for imaging phantoms for simulating several clinical scenarios where anatomical deformations is important. Recently, various additive manufacturing technologies have been used to produce anatomical models based on extrusion techniques that allow the fabrication of soft tissue materials. To date, there is no systematic study in the literature investigating the radiological properties of silicone rubber materials/fluids for imaging phantoms fabricated directly by extrusion using 3D printing techniques. The aim of this study was to investigate the radiological properties of 3D printed phantoms made of silicone in CT imaging. To achieve this goal, the radiodensity as described as Hounsfield Units (HUs) of several samples composed of three different silicone printing materials were evaluated by changing the infill density to adjust their radiological properties. A comparison of HU values with a Gammex Tissue Characterization Phantom was performed. In addition, a reproducibility analysis was performed by creating several replicas for specific infill densities. A scaled down anatomical model derived from an abdominal CT was also fabricated and the resulting HU values were evaluated. For the three different silicone materials, a spectrum ranging from −639 to +780 HU was obtained on CT at a scan setting of 120 kVp. In addition, using different infill densities, the printed materials were able to achieve a similar radiodensity range as obtained in different tissue-equivalent inserts in the Gammex phantom (238 HU to −673 HU). The reproducibility results showed good agreement between the HU values of the replicas compared to the original samples, confirming the reproducibility of the printed materials. A good agreement was observed between the HU target values in abdominal CT and the HU values of the 3D-printed anatomical phantom in all tissues.

近年来，3D打印技术被广泛应用于医学成像幻影的制造。到目前为止，人们已经研究了各种刚性3D打印材料的放射学性能和成像幻影制造的效率。然而，灵活的软组织材料也需要成像的幻影，以模拟几种临床场景，其中解剖变形是重要的。最近，各种增材制造技术已被用于生产基于挤压技术的解剖模型，从而可以制造软组织材料。迄今为止，文献中还没有系统的研究硅橡胶材料/流体的放射学特性，用于使用3D打印技术直接挤压制造的成像幻影。本研究的目的是探讨三维打印的硅胶模型在CT成像中的放射学特性。为了实现这一目标，通过改变填充密度来调整其放射学性能，评估了由三种不同硅酮印刷材料组成的几个样品的放射密度，即霍斯菲尔德单位（HUs）。将HU值与Gammex组织表征幻影进行比较。此外，通过创建特定填充密度的多个副本进行再现性分析。我们还制作了一个由腹部CT得出的按比例缩小的解剖模型，并对所得的HU值进行了评估。对于三种不同的有机硅材料，在扫描设置为120 kVp的CT上获得了−639至+780 HU的光谱。此外，使用不同的填充密度，打印材料能够获得与Gammex模型中不同组织等效插入物相似的辐射密度范围（238 HU至- 673 HU）。再现性结果表明，与原始样品相比，复制品的HU值吻合良好，证实了印刷材料的再现性。腹部CT HU目标值与3d打印解剖模体各组织HU值吻合良好。

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引用次数: 0

A modular system of flexible receive-only coil arrays for 3 T Magnetic Resonance Imaging 用于3t磁共振成像的柔性仅接收线圈阵列的模块化系统

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik

Pub Date : 2025-05-01 DOI: 10.1016/j.zemedi.2023.05.002

Lena Nohava, Michael Obermann, Roberta Frass-Kriegl, Onisim Soanca, Elmar Laistler

Flexible form-fitting radiofrequency coils provide high signal-to-noise ratio (SNR) for magnetic resonance imaging (MRI), and in array configuration large anatomical areas of interest can be covered. We propose a modular system - “ModFlex”- of flexible lightweight 4-channel coaxial coil arrays for 3 T MRI. We investigated the performance difference between commercial reference coils and 8- and 16-channel ModFlex receive-only array systems. In vivo, six anatomical targets in four regions of interest – the neck, the ankle, the spine and the hip – were imaged with the novel coil array system. The versatility of ModFlex and the robustness of the coil characteristics for different use cases is demonstrated. We measured an SNR gain for 4 out of 6 and similar SNR for 2 out of 6 anatomical target regions as compared to commercial reference coils. Parallel imaging capabilities are comparable to standard coils in hip and neck imaging, but ModFlex outperforms standard coils in ankle and spine imaging. High SNR combined with high acceleration possibilities enables faster imaging workflows and/or high-resolution MR acquisitions. The coil’s versatility is beneficial for use cases with varying subject sizes and could improve patient comfort.

柔性贴合射频线圈为磁共振成像（MRI）提供高信噪比（SNR），并且在阵列配置中可以覆盖感兴趣的大解剖区域。我们提出了一种模块化系统-“ModFlex”-用于3t MRI的柔性轻质4通道同轴线圈阵列。我们研究了商用参考线圈与8通道和16通道ModFlex仅接收阵列系统之间的性能差异。在体内，使用新型线圈阵列系统对颈部、脚踝、脊柱和髋关节四个感兴趣区域的六个解剖目标进行成像。演示了ModFlex的多功能性和线圈特性在不同用例中的鲁棒性。与商业参考线圈相比，我们测量了6个解剖目标区域中4个的信噪比增益和6个解剖目标区域中2个的相似信噪比。在髋关节和颈部成像方面，ModFlex的并行成像能力与标准线圈相当，但在踝关节和脊柱成像方面，ModFlex的性能优于标准线圈。高信噪比结合高加速度的可能性，实现更快的成像工作流程和/或高分辨率MR采集。线圈的多功能性有利于不同受试者大小的用例，可以提高患者的舒适度。

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