S Barna, C Meouchi, A F Resch, G Magrin, D Georg, Anatoly Rozenfeld, Linh T Tran, H Palmans
{"title":"Microdosimetry of a clinical carbon-ion pencil beam at MedAustron, Part 2: Monte Carlo simulation.","authors":"S Barna, C Meouchi, A F Resch, G Magrin, D Georg, Anatoly Rozenfeld, Linh T Tran, H Palmans","doi":"10.1016/j.zemedi.2025.04.005","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.04.005","url":null,"abstract":"<p><strong>Context: </strong>A first benchmark of the Monte Carlo (MC) code GATE was performed for microdosimetry in carbon ion beams. A validated MC model can, in turn, be used to calculate the radiation quality in lineal energy for any number of energies or treatment plans.</p><p><strong>Materials and methods: </strong>Measurements were performed at five depths along a carbon ion pencil beam with a nominal energy of 284.7 MeV/u, with additional offside central axis (off-CAX) measurements at four depths. The silicon-on-insulator detector used was modeled with a simplified sensitive volume geometry in the Monte Carlo (MC) toolkit GATE. The source code of GATE was modified to allow the scoring of lineal energy for slab sensitive volumes.</p><p><strong>Results: </strong>On average, the difference between the measured and simulated spectra (assuming the same keVµm<sup>-1</sup> cut-off value) was 15 % and 13 % for the frequency-mean and dose-mean lineal energy, respectively. By applying a shift in depth of 500µm towards the beam nozzle, the differences decreased to 10 % and 5 %, mostly affecting the positions in and the fall-off after the Bragg peak. The position in the fragmentation tail showed an edge at a different position than the expected carbon ion edge, which was determined through theoretical (stopping power tables) as well as computational (MC) means to be caused by boron ions.</p><p><strong>Conclusion: </strong>MC is a powerful tool for any potential future clinical application of microdosimetry, provided the beam model has been benchmarked with experimental data. The detector geometry can be approximated with its sensitive volume if the water equivalent thickness of the detector is well known.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236394","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}
Lotte Wilke, Sebastian M Christ, Riccardo Dal Bello, Elizabeth Denney, Silvia Fabiano, Hubert S Gabryś, Klara Kefer, Michael Mayinger, Ina Nilo, Sophie Perryck, Jens von der Grün, Matthias Guckenberger, Stephanie Tanadini-Lang
{"title":"Safety in MR-enhanced daily adaptive SBRT Radiotherapy using a conventional C-arm linear accelerator: An FMEA approach.","authors":"Lotte Wilke, Sebastian M Christ, Riccardo Dal Bello, Elizabeth Denney, Silvia Fabiano, Hubert S Gabryś, Klara Kefer, Michael Mayinger, Ina Nilo, Sophie Perryck, Jens von der Grün, Matthias Guckenberger, Stephanie Tanadini-Lang","doi":"10.1016/j.zemedi.2025.05.002","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.05.002","url":null,"abstract":"<p><strong>Background and purpose: </strong>MR-guided adaptive Radiotherapy has the potential to compensate for interfractional changes in patient anatomy. Modern hybrid devices, which combine MR and linear accelerator technologies, have been clinically implemented but their costs may prevent broad adoption. To accelerate the adoption of MR-guided adaptive radiotherapy, we developed a workflow for MR-enhanced daily adaptive Radiotherapy on a C-arm linac using a dedicated MR simulator and a patient transfer shuttle system. A failure mode and effects analysis (FMEA) was performed to identify possible risks in this newly developed workflow.</p><p><strong>Materials and methods: </strong>A workflow for MR-enhanced daily adaptive SBRT (MEDAS) on a Varian Truebeam linac was developed using a stand-alone 1.5T MR-simulator and patient transfer using a shuttle system. The different process steps were conceptualized in a multidisciplinary team and an FMEA of the different process steps was performed as well as measures for mitigation of possible risks were discussed.</p><p><strong>Results: </strong>The FMEA identified 23 failure modes across eight process steps, with the majority occurring during base plan preparation and adaptive planning. Seventeen (74%) failure modes were classified as low risk, while six (26%) were assessed as medium risk. No high-risk failure modes were identified. Risk mitigation measures, including workflow automation and checklist enhancements, successfully reduced all failure modes to low risk while not introducing new risks CONCLUSION: We developed a workflow for MEDAS on a conventional C-Arm linac. In this process, an FMEA was performed in a multidisciplinary team. The FMEA identified and addressed six medium-risk failure modes within the MEDAS workflow. Through further automation and adaption of existing checklists, the occurrence- and discover probability was successfully reduced, such that these failure modes are decreased to a low risk.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144218098","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}
Florian Amstutz, Björn Zobrist, Peter Manser, Michael K Fix
{"title":"Deformable image registration (DIR) in Swiss radiotherapy: Usage patterns survey and multi-institutional deformable dose accumulation comparison.","authors":"Florian Amstutz, Björn Zobrist, Peter Manser, Michael K Fix","doi":"10.1016/j.zemedi.2025.05.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.05.001","url":null,"abstract":"<p><strong>Background and purpose: </strong>Deformable image registration (DIR) enables advanced applications for image-guided and adaptive radiotherapy. However, DIR has not yet been widely adopted in clinical settings. This study addresses two challenges: (1) evaluating DIR practices and identifying barriers through a survey of Swiss radiotherapy institutes, providing Swiss-specific insights, and (2) assessing multi-institutional deformable-based dose accumulation (DDA) uncertainties by analyzing dose discrepancies on the accumulated dose. These findings aim to inform consensus guidelines, quantify DDA uncertainties, and support standardized future DIR integration into routine RT.</p><p><strong>Material and methods: </strong>All Swiss radiotherapy institutes with available contact details were invited to participate in the study's two parts: a survey and a multi-institutional DDA evaluation. The survey consisted of 25 questions and was conducted from August 23 to October 31, 2024. Survey results were compared to surveys from other countries. For the DDA evaluation, participants used shared datasets, including a lung cancer case with two dose distributions, one conventional VMAT dose and one artificially created cuboid dose, to perform DIR and accumulate doses. The cuboid dose was used to have a standardized dose with a \"perfect\" dose gradient. The level of inter-institutional dose discrepancies was assessed visually and by calculating dose differences on a voxel level.</p><p><strong>Results: </strong>Eighteen out of 26 institutes (69%) completed the survey. All 18 institutes use rigid image registration (RIR) clinically, 11 (61.1%) use DIR. Five of those institutes use DIR in research projects. RIR is primarily applied for image fusion (100% of the institutes), patient positioning (88.9%), and as a preliminary step to DIR or adaptive RT (55.6%). DIR use cases include image fusion, dose accumulation, and adaptive workflows. Barriers to DIR adoption in clinical routine include software limitations and a lack of quality management methods. Standardized quality management of DIRs is largely missing in Swiss radiotherapy institutes so far. Six institutes participated in the dose accumulation part, submitting dose accumulation results for a VMAT and a cuboid dose distribution. Visual inspection revealed inter-institutional differences, particularly in steep dose gradient areas. Quantitative analysis showed average voxel-wise absolute differences of 0.01-0.03 Gy (VMAT), corresponding to 0.1%-0.3%, and 0.18-0.45 Gy (cuboid), corresponding to 1.8%-4.5%, for a total dose of 10 Gy. Differences were more pronounced in steep dose gradients and, consequently, in proximity to the PTV. The voxel-wise maximum-minimum analysis highlighted variability in gradient regions, even for the same algorithms used by different institutes, emphasizing the impact of software, software usage, and workflow choices on dose accumulation outcomes. The cuboid dose showed increase","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144145176","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}
Lidia Strigari, David Menichelli, Elisa Lodi Rizzini, Arber Golemi, Gian Mauro Sacchetti, Lucia Leva, Cristina Nanni, Paolo Castelucci, Stefano Fanti, Alessio Giuseppe Morganti, Roberta Matheoud
{"title":"Advancing risk management in nuclear medicine diagnostic and therapy through incident-driven risk management tools.","authors":"Lidia Strigari, David Menichelli, Elisa Lodi Rizzini, Arber Golemi, Gian Mauro Sacchetti, Lucia Leva, Cristina Nanni, Paolo Castelucci, Stefano Fanti, Alessio Giuseppe Morganti, Roberta Matheoud","doi":"10.1016/j.zemedi.2025.03.004","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.03.004","url":null,"abstract":"<p><p>Accidental or unintended exposures in nuclear medicine present significant risks, demanding proactive and systematic risk management strategies. This study explores the development and implementation of a novel software tool that integrates Failure Modes and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) into a unified platform tailored for nuclear medicine. The tool addresses the complexities of risk assessment across diagnostic and therapeutic workflows, offering customizable templates and a streamlined process for identifying, prioritizing, and mitigating failure modes. A multicenter study involving nuclear medicine departments of various sizes demonstrated the tool's efficacy in standardizing risk analysis and enhancing interdisciplinary collaboration. Key scenarios, such as errors in radiopharmaceutical preparation and administration, were assessed, with rankings assigned based on a refined Risk Priority Number (RPN) system. The results underscore the transformative potential of combining FMEA and FTA in nuclear medicine, addressing the limitations of standalone methodologies. This approach improves workflow efficiency and ensures a robust framework for patient safety. Future directions include expanding the tool's applications, refining templates, and fostering a proactive culture of risk assessment. These advancements pave the way for safer, more efficient practices in nuclear medicine, benefiting patients and professionals alike.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144121900","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}
Luise Wagner, Stefan K Plontke, Torsten Rahne, Anna C Kopsch
{"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}
Dominik Langner, Marcel Nachbar, Monica Lo Russo, Simon Boeke, Cihan Gani, Maximilian Niyazi, Daniela Thorwarth
{"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":"<p><strong>Background and purpose: </strong>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.</p><p><strong>Materials and methods: </strong>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.</p><p><strong>Results: </strong>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}
Hermann Fuchs, Alessio Parisi, Keith M Furutani, Dietmar Georg, Chris J Beltran
{"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}
Charoula Iliaskou, Mark Gainey, Benedikt Thomann, Michael Kollefrath, Rainer Saum, Eleni Gkika, Uwe A Wittel, Dietrich A Ruess, Anca-Ligia Grosu, Dimos Baltas
{"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}
Jaime A Peña, Reinhard Barkmann, Stefan Reinhold, Timo Damm, Tobias Fricke, Jan Bastgen, Felix Thomsen, Claus-C Glüer
{"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":"<p><strong>Purpose: </strong>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.</p><p><strong>Materials and methods: </strong>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<sub>CCC</sub>) 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.</p><p><strong>Results: </strong>After cross-calibration the overall ex vivo mean Tb.BMD across CT-scanners was basically maintained, changing only from 119.0 mgHA/cm<sup>3</sup> to 119.4 mgHA/cm<sup>3</sup>. The mean Ct.BMD raised from 420.4 mgHA/cm<sup>3</sup> to 441.1 mgHA/cm<sup>3</sup>. Tb.BMD showed a small variability (SD of means) across centers of 2.7 mgHA/cm<sup>3</sup>. For Ct.BMD additional kernel related thickness correction reduced this variability from 31.7 mgHA/cm<sup>3</sup> to 22.4 mgHA/cm<sup>3</sup>. 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<sub>ccc</sub> [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}
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
{"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 cm<sup>2</sup> vs 150 Gy cm<sup>2</sup> 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}