Physica Medica-European Journal of Medical Physics最新文献

Comparison of two biologically effective dose calculation models applied to single fraction stereotactic radiosurgery 两种生物有效剂量计算模型在单次分次立体定向放射手术中的应用比较

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-27 DOI: 10.1016/j.ejmp.2024.104820

{"title":"Comparison of two biologically effective dose calculation models applied to single fraction stereotactic radiosurgery","authors":"","doi":"10.1016/j.ejmp.2024.104820","DOIUrl":"10.1016/j.ejmp.2024.104820","url":null,"abstract":"<div><h3>Background</h3><div>Recent studies suggest strong correlations between Biologically Effective Doses (BED) and single fraction stereotactic radiosurgery treatment outcomes, as demonstrated for vestibular schwannomas (VS), arterio-venous malformations and pituitary adenomas. The BEDs calculated in these studies consider an uniform dose delivery where the spatio-temporal aspects of dose delivery were neglected.</div></div><div><h3>Purpose</h3><div>The aim of the study is to quantify the discrepancies between the BED values calculated with a simplified model of uniform dose delivery against the more complex model that incorporates the temporo-spatial incrementation of dose delivery and the bi-exponential effect of the sub-lethal damage repair.</div></div><div><h3>Methods</h3><div>A software tool that computes the BED distributions based on individual isocenter dose matrices extracted from the GammaPlan (Elekta) treatment planning was developed. Two cohorts 5 VS and 5 jugular foramen schwannoma cases of various tumor volumes and isocenter number were utilized to benchmark the method. Their BEDs covering 98% of tumor volumes were compared against those determined with the uniform delivery model.</div></div><div><h3>Results</h3><div>The BEDs covering 98% of the tumor volumes as calculated with both models show an approximately linear dependency with the treatment time. For all studied cases, the uniform delivery model overestimates the BEDs calculated with the full spatio-temporal delivery model. This discrepancy seems to accentuate with the tumor volume and treatment complexity.</div></div><div><h3>Conclusions</h3><div>Despite their resemblance, the BED distributions provide a plethora of BED measures more suitable to characterize clinical outcomes than the unique peripheral BED value calculated with the simplified model of uniform dose delivery.</div></div>","PeriodicalId":56092,"journal":{"name":"Physica Medica-European Journal of Medical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

LatticeOpt: An automatic tool for planning optimisation of spatially fractionated stereotactic body radiotherapy LatticeOpt：空间分割立体定向体放射治疗规划优化自动工具

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-26 DOI: 10.1016/j.ejmp.2024.104823

{"title":"LatticeOpt: An automatic tool for planning optimisation of spatially fractionated stereotactic body radiotherapy","authors":"","doi":"10.1016/j.ejmp.2024.104823","DOIUrl":"10.1016/j.ejmp.2024.104823","url":null,"abstract":"<div><h3>Purpose</h3><div>Lattice radiotherapy (LRT) is a three dimensional (3D) implementation of spatially fractionated radiation therapy, based on regular spatial distribution of high dose spheres (vertices) inside the target. Due to tumour shape heterogeneity, finding the best lattice arrangement is not trivial.</div><div>The aim of this study was to develop the LatticeOpt tool to generate the best lattice structures on clinical cases for treatment planning.</div></div><div><h3>Methods</h3><div>Developed in MATLAB, LatticeOpt finds the 3D-spatial configurations that maximize the number of vertices within the gross target volume (GTV). If organs at risk (OARs) are considered, it chooses the solution that minimizes the overlapping volume histograms (OVH). Otherwise, the lattice structure with the minimum Hausdorff distance between vertices and GTV boundary is chosen to avoid unpopulated regions.</div><div>Different lattice structures were created for 20 patients, with (OVHopt) and without (OVHunopt) OVH minimization. Imported into TPS (Eclipse, Varian), corresponding plans were generated and evaluated in terms of OAR mean and maximum doses, GTV vertex coverage and dose gradients, as well as pre-clinical plan dosimetry.</div></div><div><h3>Results</h3><div>Plans based on an optimized lattice structure (OVHopt, OVHunopt) had similar dose distributions in terms of vertex coverage and gradient index score. OAR sparing was observed in all patients, with a 4 % and 9 % difference for mean and max dose (both p-values <0.01), respectively. The best vertices dimensions and their relative distances were patient dependent.</div></div><div><h3>Conclusions</h3><div>LatticeOpt was able to reduce the time-consuming procedures of LRT, as well as to achieve standardized and reproducible results, useful for multicentre studies.</div></div>","PeriodicalId":56092,"journal":{"name":"Physica Medica-European Journal of Medical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323358","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

Advanced mathematical modeling for preciseestimation of CT energy spectrum using a calibration phantom 利用校准模型精确估算 CT 能谱的高级数学模型

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-26 DOI: 10.1016/j.ejmp.2024.104819

{"title":"Advanced mathematical modeling for preciseestimation of CT energy spectrum using a calibration phantom","authors":"","doi":"10.1016/j.ejmp.2024.104819","DOIUrl":"10.1016/j.ejmp.2024.104819","url":null,"abstract":"<div><h3>Purpose</h3><div>This research aims to develop an advanced mathematical model using a CT calibration phantom to accurately estimate the CT energy spectrum in clinical settings, enhancing imaging quality and patient dose management.</div></div><div><h3>Methods</h3><div>Data were collected from a CT scanner using a CT calibration phantom at various energy levels (80, 100, 120, and 135 kVp). The data was optimized to refine the energy spectrum model, followed by cross-validation with Monte Carlo simulations.</div></div><div><h3>Results</h3><div>The developed model demonstrated high precision in estimating the CT energy spectrum at all tested energy levels, with R-squared values above 0.9738 and an R-squared value of 0.9829 at 100 kVp. The model also showed low Normalized Root Mean Square Deviation (NRMSD) ranging from 0.6698 % to 1.8745 %. The Mean Energy Difference (ΔE) between the estimated and simulated spectrum consistently remained under 0.01 keV. These results were comparable to recent studies, which reported higher NRMSD and ΔE.</div></div><div><h3>Conclusions</h3><div>This study presents a significantly improved model for estimating the CT energy spectrum, offering greater accuracy than existing models. Its strengths include high precision and the use of standard equipment and algorithmic values. While the current use of 13 plugs is adequate, incorporating plugs with varied densities could enhance accuracy. This model has potential for improving imaging quality and optimizing patient dosing in clinical applications. Future trends may include extending energy spectrum estimation to megavoltage domains and integrating technologies like EPID and MVCT for better dose distribution prediction in high-energy photon beam therapy.</div></div>","PeriodicalId":56092,"journal":{"name":"Physica Medica-European Journal of Medical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323357","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

Investigate potential clinical benefits and linear energy transfer sparing utilizing proton arc therapy for hepatocellular carcinoma 研究利用质子弧疗法治疗肝细胞癌的潜在临床优势和线性能量转移间隔

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-25 DOI: 10.1016/j.ejmp.2024.104816

{"title":"Investigate potential clinical benefits and linear energy transfer sparing utilizing proton arc therapy for hepatocellular carcinoma","authors":"","doi":"10.1016/j.ejmp.2024.104816","DOIUrl":"10.1016/j.ejmp.2024.104816","url":null,"abstract":"<div><h3>Purpose</h3><div>To investigate the potential clinical benefits and dose-averaged Linear Energy Transfer (LET<sub>d</sub>) sparing, utilizing proton arc plan for hepatocellular carcinoma (HCC) patients in comparison with Intensity Modulated Proton Therapy (IMPT).</div></div><div><h3>Methods</h3><div>Ten HCC patients have been retrospectively selected. Two planning groups were created: Proton Arc plans using Monaco ver. 6 and the clinical IMPT plan. Both planning groups used the same robustness parameters. The prescription dose is 67.5 Gy (RBE) in 15 fractions of the Clinical Target Volume (CTV). Robustness evaluations were performed to ensure dose coverage. Normal Tissue Complicated Probability (NTCP) model was utilized to predict the possibility of Radiation-Induced Liver Disease (RILD) and evaluate the potential benefit of proton arc therapy. LET<sub>d</sub> calculation and evaluation were performed as well.</div></div><div><h3>Results</h3><div>Proton arc plan has shown better dosimetric improvements of most Organ-At-Risks (OARs). More specifically, the liver mean dose has been significantly reduced from 14.7 GyE to 10.62 GyE compared to the IMPT plan. The predicted possibility of RILD has also been significantly reduced for cases with a large and deep liver target where healthy liver tissue sparing is a challenge. Additionally, proton arc therapy could increase the average LET<sub>d</sub> in the target and reduce LET<sub>d</sub> in adjacent OARs.</div></div><div><h3>Conclusions</h3><div>The potential clinical benefit of utilizing proton arc therapy HCC varies depending on the patient-specific geometry. With more freedom, proton arc therapy can offer a better dosimetric plan quality in the challenge cases, which might not be feasible using the current IMPT technique.</div></div>","PeriodicalId":56092,"journal":{"name":"Physica Medica-European Journal of Medical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320100","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

Development of a Monte Carlo simulation platform for the systematic evaluation of photon-counting detector-based micro-CT 开发蒙特卡洛模拟平台，用于系统评估基于光子计数探测器的微型计算机断层显微技术

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-25 DOI: 10.1016/j.ejmp.2024.104824

{"title":"Development of a Monte Carlo simulation platform for the systematic evaluation of photon-counting detector-based micro-CT","authors":"","doi":"10.1016/j.ejmp.2024.104824","DOIUrl":"10.1016/j.ejmp.2024.104824","url":null,"abstract":"<div><h3>Purpose</h3><div>This study aimed to develop a photon-counting detector (PCD) based micro-CT simulation platform for assessing the performance of three different PCD sensor materials: cadmium telluride (CdTe), gallium arsenide (GaAs), and silicon (Si). The evaluation encompasses the components of primary and scatter signals, performance of imaging contrast agents, and detector efficiency.</div></div><div><h3>Methods</h3><div>Simulations were performed using the Geant4 Monte Carlo toolkit, and a micro-PCD-CT system was meticulously modeled based on realistic geometric parameters. Results.</div><div>The simulation can obtain HU values consistent with measured results for iodine and calcium hydroxyapatite contrast agents. The two major components of scatter signals for CdTe and GaAs based PCD are fluorescent X-ray photons and photoelectrons, whereas for Si, the components are photoelectrons and Compton electrons. Scattering counts of CdTe and GaAs sensors can be effectively reduced by using energy thresholds, whereas those of Si sensor are insensitive to the applied threshold. The optimal threshold values for CdTe and GaAs are 30 and 15 keV, respectively. For contrast agent imaging, GaAs exhibits enhanced sensitivity to low photon energies compared to CdTe, while it’s contrast-to-noise ratio (CNR) values are slightly lower than those of CdTe at the same contrast agent concentration. Among the three sensor materials, Si has the lowest CNR and detector efficiency; CdTe exhibits the highest efficiency, except in low-energy ranges (< 45 keV), where GaAs has superior efficiency.</div></div><div><h3>Conclusions</h3><div>The proposed methods are expected to benefit PCD optimization and applications, including energy threshold selection, scattering correction, and may reduce the need for large-scale experiments.</div></div>","PeriodicalId":56092,"journal":{"name":"Physica Medica-European Journal of Medical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319425","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

Open LEARN: Open access linear accelerator education and augmented reality Navigator 开放 LEARN：开放式直线加速器教育和增强现实导航仪

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-13 DOI: 10.1016/j.ejmp.2024.104515

{"title":"Open LEARN: Open access linear accelerator education and augmented reality Navigator","authors":"","doi":"10.1016/j.ejmp.2024.104515","DOIUrl":"10.1016/j.ejmp.2024.104515","url":null,"abstract":"<div><h3>Purpose</h3><p>To create an open-access Linear Accelerator Education and Augmented Reality Navigator (Open LEARN) via 3D printable objects and interactive augmented reality assets.</p></div><div><h3>Methods</h3><p>This study describes an augmented reality linear accelerator (linac) model accessible through a QR code and a smartphone to address the challenges of medical physics and radiation oncology trainees in low-to-middle-income countries.</p></div><div><h3>Results</h3><p>Major components of a generic linear accelerator are modeled as individual objects. These objects can be 3D printed for hands-on learning and used as interactive 3D assets within the augmented reality app. In the AR app, descriptions are displayed to navigate the components spatially and textually. Items modeled include the treatment couch, klystron, circulator, RF waveguides, electron gun, waveguide, beam steering assemblies, target, collimators, multi-leaf collimators, and imaging systems. The linear accelerator is rendered at nearly 100% of its actual size, allowing users to change magnification and view objects from different angles.</p></div><div><h3>Conclusions</h3><p>The augmented reality linear accelerators and 3D-printed objects make these complex machines easily accessible with smartphones and 3D-printing technologies, facilitating education and training through physical and virtual interaction.</p></div>","PeriodicalId":56092,"journal":{"name":"Physica Medica-European Journal of Medical Physics","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S112017972401072X/pdfft?md5=f497fa19cc1be003b9ea9e63e12176b0&pid=1-s2.0-S112017972401072X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142229948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

SC14.04 ISODOSE-CONSTRAINED AUTOMATIC TREATMENT PLANNING WITH MULTICRITERIA RATING BASED ON PHYSICAL EVALUATION OF PREDICTED DOSE FOR NASOPHARYNGEAL CANCER SC14.04 基于物理评估鼻咽癌预测剂量的多标准评级的等剂量约束自动治疗规划

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-01 DOI: 10.1016/j.ejmp.2024.103484

引用次数: 0

SC22.03 COMPARISON OF BREAST POPULATION DOSE ESTIMATION BETWEEN OLD AND NEW DOSIMETRY FOR DIGITAL MAMMOGRAPHY (DM) AND DIGITAL BREAST TOMOSYNTHESIS (DBT) SC22.03 数字乳腺 X 射线照相术（DM）和数字乳腺断层合成术（DBT）新旧剂量测量法对乳腺群体剂量估算的比较

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-01 DOI: 10.1016/j.ejmp.2024.103513

引用次数: 0

SC20.07 STATUS OF DIAGNOSTIC RADIOLOGY MEDICAL PHYSICIST RECOGNITION: RESULTS OF A EUROPEAN SURVEY SC20.07 放射诊断医学物理学家的认可状况：欧洲调查的结果

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-01 DOI: 10.1016/j.ejmp.2024.103504

引用次数: 0

SC21.05 NOVEL SPHERICAL IN-BEAM PET SCANNER FOR ONLINE RANGE MONITORING IN SMALL ANIMAL RADIATION RESEARCH sc21.05 用于小动物辐射研究在线范围监测的新型球形束内宠物扫描仪

IF 3.3 3区医学

Physica Medica-European Journal of Medical Physics Pub Date : 2024-09-01 DOI: 10.1016/j.ejmp.2024.103509

引用次数: 0