Zeitschrift fur medizinische Physik最新文献

{"title":"Time course of transimpedances is affected by cochlea implant surgical technique.","authors":"Luise Wagner, Stefan K Plontke, Torsten Rahne, Anna C Kopsch","doi":"10.1016/j.zemedi.2025.04.006","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.04.006","url":null,"abstract":"<p><strong>Background: </strong>For cochlear implant (CI) users after subtotal cochlectomy for removal of intracochlear schwannomas, significantly different intracochlear potentials can be observed compared with cochleae of CI patients after round window electrode insertion. The time course of this difference after surgery is so far unknown.</p><p><strong>Purpose: </strong>The change of intracochlear potentials over time and differences between surgical approaches are investigated.</p><p><strong>Methods: </strong>In a retrospective study of cochlear implant recipients, the electrode transimpedances were measured and compared between 19 patients after subtotal cochlectomy and 20 patients after round window insertion. Transimpedances were measured with pulse widths of 37 µs and current units of 100 CL to 110 CL using a monopolar stimulation and recording mode (MP2). For each patient, at least three time points over a period of up to four years were used for time course analysis.</p><p><strong>Results: </strong>The transimpedances of patients after subtotal cochlectomy were significantly smaller than those of the round window group. The largest transimpedance changes over time were observed for basal electrode contacts in patients after round window insertion.</p><p><strong>Conclusions: </strong>For the interpretation of transimpedances, it is relevant to consider the time since surgery and the CI insertion technique. The width of the electric field may be related to loss of intracochlear conductive fluid due to surgical trauma and fibrotic processes.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144003198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative analysis of open-source against commercial AI-based segmentation models for online adaptive MR-guided radiotherapy.","authors":"Dominik Langner, Marcel Nachbar, Monica Lo Russo, Simon Boeke, Cihan Gani, Maximilian Niyazi, Daniela Thorwarth","doi":"10.1016/j.zemedi.2025.04.008","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.04.008","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Background and purpose: &lt;/strong&gt;Online adaptive magnetic resonance-guided radiotherapy (MRgRT) has emerged as a state-of-the-art treatment option for multiple tumour entities, accounting for daily anatomical and tumour volume changes, thus allowing sparing of relevant organs at risk (OARs). However, the annotation of treatment-relevant anatomical structures in context of online plan adaptation remains challenging, often relying on commercial segmentation solutions due to limited availability of clinically validated alternatives. The aim of this study was to investigate whether an open-source artificial intelligence (AI) segmentation network can compete with the annotation accuracy of a commercial solution, both trained on the identical dataset, questioning the need for commercial models in clinical practice.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Materials and methods: &lt;/strong&gt;For 47 pelvic patients, T2w MR imaging data acquired on a 1.5 T MR-Linac were manually contoured, identifying prostate, seminal vesicles, rectum, anal canal, bladder, penile bulb, and bony structures. These training data were used for the generation of an in-house AI segmentation model, a nnU-Net with residual encoder architecture featuring a streamlined single image inference pipeline, and re-training of a commercial solution. For quantitative evaluation, 20 MR images were contoured by a radiation oncologist, considered as ground truth contours (GTC) and compared with the in-house/commercial AI-based contours (iAIC/cAIC) using Dice Similarity Coefficient (DSC), 95% Hausdorff distances (HD95), and surface DSC (sDSC). For qualitative evaluation, four radiation oncologists assessed the usability of OAR/target iAIC within an online adaptive workflow using a four-point Likert scale: (1) acceptable without modification, (2) requiring minor adjustments, (3) requiring major adjustments, and (4) not usable.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Patient-individual annotations were generated in a median [range] time of 23 [16-34] s for iAIC and 152 [121-198] s for cAIC, respectively. OARs showed a maximum median DSC of 0.97/0.97 (iAIC/cAIC) for bladder and minimum median DSC of 0.78/0.79 (iAIC/cAIC) for anal canal/penile bulb. Maximal respectively minimal median HD95 were detected for rectum with 17.3/20.6 mm (iAIC/cAIC) and for bladder with 5.6/6.0 mm (iAIC/cAIC). Overall, the average median DSC/HD95 values were 0.87/11.8mm (iAIC) and 0.83/10.2mm (cAIC) for OAR/targets and 0.90/11.9mm (iAIC) and 0.91/16.5mm (cAIC) for bony structures. For a tolerance of 3 mm, the highest and lowest sDSC were determined for bladder (iAIC:1.00, cAIC:0.99) and prostate in iAIC (0.89) and anal canal in cAIC (0.80), respectively. Qualitatively, 84.8% of analysed contours were considered as clinically acceptable for iAIC, while 12.9% required minor and 2.3% major adjustments or were classed as unusable. Contour-specific analysis showed that iAIC achieved the highest mean scores with 1.00 for the anal canal and the lowest w","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144056741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of nozzle configurations on radiobiological effects in carbon ion radiation therapy estimated using GATE/Geant4.","authors":"Hermann Fuchs, Alessio Parisi, Keith M Furutani, Dietmar Georg, Chris J Beltran","doi":"10.1016/j.zemedi.2025.04.004","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.04.004","url":null,"abstract":"<p><strong>Background: </strong>Carbon Ion Radiation Therapy (CIRT) has been used in Europe and in Asia for several decades. The first treatment facility in America is now under construction at Mayo Clinic Florida (MCF) in Jacksonville. CIRT is known to have a variable relative biological effectiveness (RBE) which depends on the microdosimetric spectra and consequently the kinetic energy spectra.</p><p><strong>Purpose: </strong>CIRT centers from different vendors exist around the world with different accelerators, delivery, and nozzle designs. Although nominally they provide comparable energies and beam qualities, this study investigates how the different nozzle designs might affect radiation quality and the consequent RBE.</p><p><strong>Methods: </strong>The impact of three nozzle designs, the upcoming MCF (Jacksonville, USA), MedAustron Ion Therapy Center (Wiener Neustadt, Austria), and the Osaka HIMAK (Osaka, Japan), on the RBE was investigated using OpenGATE10. The microdosimetric spectra were determined using the abridged microdosimetric distribution methodology (AMDM) and input into the MCF microdosimetric kinetic model (MKM) to determine spectral and RBE dependence on nozzle design. Monoenergetic carbon ion beams having a range in water of 3 and 27 cm were simulated. For the 27 cm beams, a simulated water-based range shifter was inserted before the phantom, reducing the range to 3 cm. Furthermore, a shallow spread-out Bragg peak (SOBP) (5-10 cm) and a deep SOBP (15-21 cm), were simulated for all nozzles and the resulting integrated dose profiles compared.</p><p><strong>Results: </strong>For all nozzle geometries, the range at 80% dose fall-off (R80) agreed within 0.1 mm. The lineal energy and the RBE agreed very well until the Bragg peak, after which some differences could be observed. For the SOBPs, the agreement was similar with an agreement in the biological dose before and at the SOBP within 0.7%. For the thick nozzle of Osaka HIMAK, small differences were observed, mostly in the fragmentation tail.</p><p><strong>Conclusion: </strong>The AMDM was successfully integrated into OpenGATE10 and used to compute the RBE with the MCF MKM. It was shown that the nozzle design itself had only a minor effect on the radiation quality and consequently the RBE. A small difference in RBE is observed mostly after the Bragg peak and SOBP in the fragmentation tail and depends on the nozzle water equivalent tissue (WET), when it is a change of more than 24 mm.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144065547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a TLD-100 based set up for in vivo dosimetry in Intraoperative Electron Beam Radiation Therapy (IOERT): an experimental and clinical evaluation.","authors":"Charoula Iliaskou, Mark Gainey, Benedikt Thomann, Michael Kollefrath, Rainer Saum, Eleni Gkika, Uwe A Wittel, Dietrich A Ruess, Anca-Ligia Grosu, Dimos Baltas","doi":"10.1016/j.zemedi.2025.04.007","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.04.007","url":null,"abstract":"<p><strong>Purpose: </strong>This study presents an in-house developed set-up enabling the placement of multiple TLDs over the target region, for in vivo dosimetry in intraoperative electron beam radiotherapy (IOERT).</p><p><strong>Methods and materials: </strong>TLD-100 (LiF:MgTi) rods were calibrated at 10 Gy and their response was determined for the nominal electron energies of the Mobetron LINAC within the dose range from 4 Gy to 20 Gy. Irradiation of various set-ups was performed using the ionisation chambers (IC) ROOS parallel plate 34001 (PTW, Freiburg) and 3D Semiflex 31021 (PTW, Freiburg), a microdiamond detector 60019 (PTW, Freiburg) and EBT3 films (Ashland™) to investigate beam perturbations that may result due to the structure of the set up. EGSnrc Monte Carlo (MC) simulations evaluated the response of the TLDs in clinical beams of the available electron energies, the influence of the catheter to the TLD dose scoring and the depth dependence of the TLD dose assessment. TLD measurements in-phantoms and in patient in vivo were realised and compared to the expected doses estimated using data of water phantom measurements and 3D MC electron dose calculations of a dedicated IOERT treatment planning system (Radiance TPS- GmV, Tres Cantos, Madrid).</p><p><strong>Results: </strong>MC and measurements verified that no energy correction is needed for the used electron beams. Correction factors for the dose non-linear response were evaluated. High resolution dose measurements showed local hot spots beneath the flap. However, there are no significant perturbations of the electron beam or on the dose delivery to the targeted volume. MC simulations demonstrated no signal attenuation due to the catheter and 1 % effect of the depth of TLD measurement relative to the depth of calibration was noted. TLD measurements in phantom set-ups agreed with expected doses with less than 2.6 % in phantoms and by 1 % in patient in vivo.</p><p><strong>Conclusions: </strong>Our results demonstrate the suitability of using the implemented TLD-based workflow for in vivo dosimetry purposes in the operation room (OR) environment.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144060322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Standardization of bone mineral density and microstructure from high-resolution CT-scans of the spine in a multicenter setting.","authors":"Jaime A Peña, Reinhard Barkmann, Stefan Reinhold, Timo Damm, Tobias Fricke, Jan Bastgen, Felix Thomsen, Claus-C Glüer","doi":"10.1016/j.zemedi.2025.04.002","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.04.002","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Purpose: &lt;/strong&gt;Quantitative Computed Tomography (QCT) has not fully addressed the need to reduce intra- and inter-scanner variability for Osteoporosis and bone-related studies, which can lead to inaccuracies when pooling data from different CT manufacturers, models, devices, or protocols. In this context, the aim of this work was to develop ex vivo methods for the standardization of bone mineral density and microstructural parameters.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Materials and methods: &lt;/strong&gt;Six human vertebral body specimens embedded in poly-methyl methacrylate (PMMA) were scanned ex vivo inside an anthropomorphic abdomen phantom in eight different CT-scanners. We measured 3D trabecular and cortical bone mineral density (Tb.BMD and Ct.BMD at the peeled spongiosa and the vertical cortex, respectively), trabecular separation (Tb.Sp) and cortical thickness (Ct.Th). Standardization of Tb.BMD and Ct.BMD across CT-scanners was conducted by correcting for the influence of PMMA and kernel related differences in the segmented cortical volume. For Tb.BMD and Ct.BMD two CT-scanners, where the majority of the patients were scanned, were used as reference. For Tb.Sp standardization we accounted for the image binarization threshold and used high-resolution peripheral QCT (HR-pQCT) as reference. Cross-calibration factors were obtained for each CT-scanner from which the cross-calibrated measures xTb.BMD, xCt.BMD and xTb.Sp were computed both ex vivo and in vivo. Agreement of the ex vivo measurements with respect to the references was quantified with Lin's concordance correlation coefficient (r&lt;sub&gt;CCC&lt;/sub&gt;) before and after standardization. For the clinical in vivo part of the study, 152 patients (24M, 128F) undergoing long-term bisphosphonate treatment had their T12 or L1 vertebrae scanned with the same CT-scanners and protocols as for ex vivo. Statistical bone fracture models were conducted before and after cross-calibration to assess the performance of the standardization procedure in vivo.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;After cross-calibration the overall ex vivo mean Tb.BMD across CT-scanners was basically maintained, changing only from 119.0 mgHA/cm&lt;sup&gt;3&lt;/sup&gt; to 119.4 mgHA/cm&lt;sup&gt;3&lt;/sup&gt;. The mean Ct.BMD raised from 420.4 mgHA/cm&lt;sup&gt;3&lt;/sup&gt; to 441.1 mgHA/cm&lt;sup&gt;3&lt;/sup&gt;. Tb.BMD showed a small variability (SD of means) across centers of 2.7 mgHA/cm&lt;sup&gt;3&lt;/sup&gt;. For Ct.BMD additional kernel related thickness correction reduced this variability from 31.7 mgHA/cm&lt;sup&gt;3&lt;/sup&gt; to 22.4 mgHA/cm&lt;sup&gt;3&lt;/sup&gt;. Non-standardized Tb.Sp showed a mean of 2.63 mm across CT-scanners, which after standardization was corrected to 1.18 mm. Agreement to the reference measurements was markedly improved after standardization (before: the r&lt;sub&gt;ccc&lt;/sub&gt; [min, max] for Tb.BMD, Ct.BMD and Tb.Sp was [0.64, 0.92], [0.40, 0.89] and [0.57, 0.99], respectively; after standardization: [0.98, 0.99], [0.96, 0.99] and [0.78, 0.99], respectively). For in vivo, Tb.BMD and Ct.BMD showed","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144016205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinical radiation audits as a tool for the optimization of radiation exposure in cardiac electrophysiology procedures.","authors":"Lorraine Sazgary, Eleni Theano Samara, Anja Stüssi, Natalia Saltybaeva, Matthias Guckenberger, F Ruschitzka, Thomas Wolber, Nadine Molitor, Fu Guan, Gonca Suna, Julia Hermes-Laufer, Alexander Breitenstein, Corinna B Brunckhorst, Firat Duru, Ardan M Saguner","doi":"10.1016/j.zemedi.2025.04.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.04.003","url":null,"abstract":"<p><strong>Background: </strong>Clinical radiation audits are useful to reduce ionizing radiation in clinical practice. The first Swiss radiation audit in Cardiology took place at the University Heart Center Zurich in 2019.</p><p><strong>Objectives: </strong>To compare local diagnostic reference levels (DRLs) in cardiac electrophysiology (EP) procedures to the currently available national DRLs and to examine patient radiation exposure before and after the clinical radiation audit.</p><p><strong>Methods: </strong>Retrospective study including 775 patients undergoing EP procedures from 2018- 2020. Main recommendations of the clinical audit were the regular use of collimation, semitransparent filters, the reduction of cine images and frame rates. Patient radiation exposure was evaluated with cumulative doses, fluoroscopy times and dose-area product (DAP). Secondary endpoints were acute procedural success rates and 30-day complications.</p><p><strong>Results: </strong>447 (57.5%) patients prior to, and 328 (42.3%) after the audit were included. Cryoballoon pulmonary vein isolation (PVI) was performed in 14.1%, PVI radiofrequency (RF) ablation in 26.8%, RF ablation of right-sided supraventricular tachycardia in 32.1%, other procedures in 27% of cases. Local DRLs for the DAP were below national DRLs (1 Gy cm² vs 150 Gy cm² for AVNRT/AVRT ablation). After the audit, there was a significant radiation reduction for right-sided supraventricular tachycardia ablation (cumulative dose: 4.8 mGy vs 2.1 mGy and fluoroscopy times: 210 seconds vs 107 seconds, p < 0.001) and PVI with RF (50.4 mGy vs 29.5 mGy, and 378 seconds vs 191 seconds, p < 0.003; respectively). No significant differences were found in acute procedural success rates or 30-day complications.</p><p><strong>Conclusions: </strong>The clinical radiation audit was associated with a significant reduction of patient radiation exposure for right-sided supraventricular tachycardia ablation and PVI with RF.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144060098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparing the Achievable Sensitivity Limits of Synchrotron-based X-ray Fluorescence Imaging versus conventional X-ray absorption imaging and comparing absorbed dose levels including PET/SPECT.","authors":"Florian Grüner, Jan Scheunemann, Christoph Hoeschen, Thorsten Frenzel, Theresa Staufer","doi":"10.1016/j.zemedi.2025.04.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.04.001","url":null,"abstract":"<p><p>The field of X-ray Fluorescence Imaging (XFI) is relatively new, with recent breakthroughs in preclinical applications using synchrotron radiation, whereas X-ray tube-based absorption imaging, such as CT, is a very well-known and widely used imaging technique. Thus, the question arises how XFI and conventional X-ray imaging compare, in particular in terms of achievable detection sensitivity. In this article we briefly summarize the state of the art of XFI with the special focus on shedding light onto the reasons for why XFI has an intrinsically higher sensitivity than any other form of X-ray based absorption imaging. Since the issue of applied radiation dose limits needs to be taken into account as well, we kept the absorbed dose levels, when comparing XFI with absorption imaging, the same, but will also compare the XFI-required dose level with the levels in PET/SPECT to also allow for a quantitative comparison with these ultra-high sensitivity nuclear imaging modalities.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144060952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Can multiparametric FDG-PET/MRI analysis really enhance the prediction of myocardial recovery after CTO revascularization? A machine learning study.","authors":"Alberto Villagran Asiares, Teresa Vitadello, Osvaldo M Velarde, Sylvia Schachoff, Tareq Ibrahim, Stephan G Nekolla","doi":"10.1016/j.zemedi.2025.03.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.03.003","url":null,"abstract":"<p><strong>Purpose: </strong>To comprehensively evaluate the effectiveness of FDG-PET/MRI multiparametric analysis in predicting myocardial wall motion recovery following revascularization of chronic coronary total occlusions (CTO), incorporating both traditional and machine learning approaches.</p><p><strong>Methods: </strong>This retrospective study assessed fluorine-18 fluorodeoxyglucose uptake (FDG), late gadolinium enhanced MR imaging (LGE), and MR wall motion abnormalities (WMA) of the left ventricle walls of a clinical cohort with 21 CTO patients (62 ± 9 years, 20 men). All patients were examined using a PET/MRI prior to revascularization and a follow-up cardiac MRI six months later. Prediction models for wall motion recovery after perfusion restoration were developed using linear and nonlinear algorithms as well as multiparametric variables. Performance and prediction explainability were evaluated in a 5x2 cross-validation framework, using ROC AUC and McNemar's test modified for clustered matched-pair data, and Shapley values.</p><p><strong>Results: </strong>Based on 79 CTO-subtended myocardial wall segments with wall motion abnormalities at baseline, the reference logistic regression model LGE + FDG obtained 0.55(SE = 0.07) in the clustered ROC AUC (cROC AUC) and 0.17(0.05) in the Global Absolute Shapley value. The reference outperformed FDG standalone in cROC AUC (-35(17) %, p < 0.0001), but not LGE standalone (11(12) %, p > 0.05). There were no statistically significant differences between the marginal probabilities of success of these three models. Moreover, no significant improvements (differences < 10 % in cROC AUC, and < 20 % in Global Absolute Shapley, p > 0.05) were found when using mixed effects logistic regression, decision tree, k-nearest neighbor, Naive Bayes, random forest, and support vector machine, with multiparametric combinations of FDG, LGE, and/or WMA.</p><p><strong>Conclusion: </strong>In this clinical cohort, adding more complex interactions between PET/MRI imaging of cardiac function, infarct extension, and/or metabolism did not enhance the prediction of wall motion recovery after perfusion restoration. This finding raises the question whether multiparametric FDG-PET/MRI analysis has demonstrable benefits in risk stratification for CTO revascularization. Further studies with larger cohorts and external validation datasets are crucial to clarify this question and refine the role of multiparametric imaging in this context.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144047745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Robustness assessment of radiotherapy treatment plans in Switzerland.","authors":"Hannes A Loebner, Jenny Bertholet, Paul-Henry Mackeprang, Werner Volken, Michael K Fix, Peter Manser","doi":"10.1016/j.zemedi.2025.03.002","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.03.002","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Purpose: &lt;/strong&gt;Robustness assessment is an essential part of radiotherapy plan quality assessment. However, it is often not evaluated in photon-based radiotherapy. This study aims to conduct a robustness audit to establish a baseline for the role of plan robustness in Switzerland by assessing and comparing robustness across plans from and clinical workflows in multiple institutions.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Materials and methods: &lt;/strong&gt;A multi-institutional study involving 11 Swiss institutions was conducted. Each institution provided treatment plans for three cases and completed a questionnaire on treatment planning and assessment of robustness in their clinical practice. The plans were planned using the Eclipse treatment planning system and utilized intensity-modulated techniques using a 6 MV flattened photon beam for one brain case, and one unilateral and one bilateral head and neck cases, prescribed 60.0 Gy (one phase), 70.0 Gy (two phases) and 70.0 Gy (three phases) to 95% of the target volume, respectively. Institutions used their standard institutional protocols for the provided CT, structures and prescription. Dose distributions were subsequently recalculated in an in-house Monte Carlo (MC) framework incorporating clinically motivated uncertainties associated to patient setup and multi-leaf collimator (MLC) positions. The uncertainties' impact on the dosimetric plan quality was assessed by evaluating representative target and organ-at-risk (OAR) dose-volume endpoints (e.g. D98% and D2% of the target, mean dose of parallel OARs and near max dose of serial OARs).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Differences in target and OAR dose-volume endpoints in the presence of random patient setup uncertainties (Gaussian distributed with σ = 0.2 cm in the three translational and σ = 0.5° in the three rotational axes) were smaller than ±0.5 Gy. Exceptions were the near max dose-volume endpoints of structures near the target with differences up to ±2.2 Gy for the optic nerve in the brain case. Systematic rotational patient setup uncertainties of ≤3° in either pitch, yaw or roll had similar impact as translational uncertainties ≤0.3 cm in either left-right, superior inferior or anterior-posterior direction with maximal differences in most investigated dose-volume endpoints of 9.0 Gy. Systematic MLC uncertainties of +0.5 mm of all leaves led to an average increase of up to 3.0 Gy in the dose-volume endpoints. The questionnaire revealed diverse practices in terms of planning and assessment for robustness: all institutions use target and OAR margins, 2/11 use robust optimization and 5/11 regularly perform robustness assessments of treatment plans by recalculating the dose distribution including uncertainties. The importance of robustness in treatment planning was rated ≥8 out of 10 (10 as most important) by 6/11 institutions. The need for better commercial tools to assess or integrate robustness into treatment planning was expressed by 9/11 institutions","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144016576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"4D CT acquisition methods and their anticipated effects on image quality in dynamic CT-scanning of the wrist.","authors":"Eveline van den Bergh, Iwan Dobbe, Geert J Streekstra","doi":"10.1016/j.zemedi.2025.03.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.03.001","url":null,"abstract":"<p><p>Four dimensional computed tomography (4D CT) has shown to be of value in the diagnosis of motion related wrist joint pathologies. 4D CT can be performed with a variety of acquisition methods. However, the usability of 4D CT is affected by motion and image artifacts associated with the specific acquisition method used. In this literature review we inventorize which acquisition methods exist for 4D-CT imaging at different positions of the human body and what the advantages and disadvantages of each method are. Based on this assessment we formulate recommendations for the 4D CT imaging approach for diagnosing motion related wrist pathologies. We also address future perspectives of image acquisition in 4D CT of the wrist joint. We found that scanning in volumetric mode eliminates irregularity artifacts, while reducing acquisition time per frame reduces blurring artifacts. A reduced acquisition time can be achieved with short gantry rotation times, dual source CT and Reconstruction based on Partial Gantry Rotation (RPGR). However, the effect of RPGR on RPGR-specific artifacts and the effect of different acquisition times on apparent object displacements may be investigated in future research.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144053842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}