Zeitschrift fur Medizinische Physik最新文献

{"title":"Evaluation of RADIANCE Monte Carlo algorithm for treatment planning in electron based Intraoperative Radiotherapy (IOERT)","authors":"Charoula Iliaskou,&nbsp;Giulio Rossi,&nbsp;Ilias Sachpazidis,&nbsp;Vasilios Boronikolas,&nbsp;Mark Gainey,&nbsp;Dimos Baltas","doi":"10.1016/j.zemedi.2023.12.002","DOIUrl":"10.1016/j.zemedi.2023.12.002","url":null,"abstract":"<div><h3>Purpose</h3><div>To perform experimental as well as independent Monte Carlo (MC) evaluation of the MC algorithm implemented in RADIANCE version 4.0.8, a dedicated treatment planning system (TPS) for 3D electron dose calculations in intraoperative radiation therapy (IOERT).</div></div><div><h3>Methods and materials</h3><div>The MOBETRON 2000 (IntraOp Medical Corporation, Sunnyvale, CA) IOERT accelerator was employed. PDD and profiles for five cylindrical plastic applicators with 50–90 mm diameter and 0°, 30° beveling were measured in a water phantom, at nominal energies of 6, 9 and 12 MeV. Additional PDD measurements were performed for all the energies without applicator. MC modeling of the MOBETRON was performed with the user code BEAMnrc and egs_chamber of the MC simulation toolkit EGSnrc. The generated phase space files of the two 0°-bevel applicators (50 mm, 80 mm) and three energies in both RADIANCE and BEAMnrc, were used to determine PDD and profiles in various set-ups of virtual water phantoms with air and bone inhomogeneities. 3D dose distributions were also calculated in image data sets of an anthropomorphic tissue-equivalent pelvis phantom. Image acquisitions were realized with a CT scanner (Philips Big Bore CT, Netherlands). Gamma analysis was applied to quantify the deviations of the RADIANCE calculations to the measurements and EGSnrc calculations. Gamma criteria normalized to the global maximum were investigated between 2%, 2 mm and 3%, 3 mm.</div></div><div><h3>Results</h3><div>RADIANCE MC calculations satisfied the gamma criteria of 3%, 3 mm with a tolerance limit of 85% passing rate compared to in- water phantom measurements, except for the dose profiles of the 30° beveled applicators. Mismatches lay in surface doses, in umbra regions and in the beveled end of the 30° applicators. A very good agreement to the EGSnrc calculations in heterogeneous media was observed. Deviations were more pronounced for the larger applicator diameter and higher electron energy. In 3D dose comparisons in the anthropomorphic phantom, gamma passing rates were higher than 96 % for both simulated applicators.</div></div><div><h3>Conclusions</h3><div>RADIANCE MC algorithm agrees within 3%, 3 mm criteria with in-water phantom measurements and EGSnrc MC dose distributions in heterogeneous media for 0°-bevel applicators. The user should be aware of missing scattering components and the 30° beveled applicators should be used with attention.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 3","pages":"Pages 282-291"},"PeriodicalIF":4.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139107067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of NEMA protocols to verify GATE models based on the Digital Biograph Vision and the Biograph Vision Quadra scanners","authors":"Miriam Magela Peña-Acosta,&nbsp;Sergio Gallardo,&nbsp;María Lorduy-Alós,&nbsp;Gumersindo Verdú","doi":"10.1016/j.zemedi.2024.01.005","DOIUrl":"10.1016/j.zemedi.2024.01.005","url":null,"abstract":"<div><h3>Purpose</h3><div>The Monte Carlo method is an effective tool to simulate and verify PET systems. Furthermore, it can help in the design and optimization of new medical imaging devices and algorithms. In this framework, the goal of this work is to verify the GATE toolkit performance when applied to simulate two Siemens Healthineers PET scanners: a standard axial field-of-view Biograph Vision scanner and the new long axial field-of-view Biograph Vision Quadra scanner.</div></div><div><h3>Methods</h3><div>The simulation toolkit GATE is based on GEANT4, comprising its main functionalities and a set of domain-specific features in the field of medical physics. To accomplish our purpose, the guidelines described in the NEMA NU 2-2018 protocol are reproduced. Then the simulated results are compared to experimental data available in the literature for both PET scanners. The assessment of the models includes different studies of sensitivity, count rate performances, spatial resolution and image quality. These tests are intended to evaluate the image quality of PET devices.</div></div><div><h3>Results</h3><div>In the spatial resolution test, relative errors lower than 8% are obtained between the experiments and GATE models. The sensitivity is 17.2 cps/kBq (Vision) and 175.9 cps/kBq (Quadra), representing relative differences with the experiment of 6% and 0.3%, respectively. Deviations from peak NECR are less than 9%. In the Image Quality test, the contrast recovery coefficient for hot spheres, with 8 iterations and 5 subsets, ranges between 57–83% for Vision and 54–86% for Quadra. These values represent a maximum deviation between the simulations and the experiments of 10% for the Quadra scanner. In the case of the Vision scanner, the highest difference is observed for the 10 mm sphere (∼38%) due to the higher contrast recovery of the experiment caused by the Gibbs artifact from the use of PSF reconstruction.</div></div><div><h3>Conclusions</h3><div>The results of the simulations have provided evidence of a good agreement between the experimental data and the results obtained with GATE. Thus, this work supports the capability of this MC toolkit to accurately simulate the models of the Vision and Quadra scanners. This study has laid the basis for further research in this field and has identified several areas that could be explored.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 3","pages":"Pages 318-330"},"PeriodicalIF":4.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139716810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of the maximum ring difference on image quality and noise characteristics of a total-body PET/CT scanner","authors":"Fabian P. Schmidt ,&nbsp;Julia G. Mannheim ,&nbsp;Pia M. Linder ,&nbsp;P. Will ,&nbsp;Lena Sophie Kiefer ,&nbsp;Maurizio M. Conti ,&nbsp;Christian la Fougère ,&nbsp;Ivo F. Rausch","doi":"10.1016/j.zemedi.2023.09.001","DOIUrl":"10.1016/j.zemedi.2023.09.001","url":null,"abstract":"<div><div>The sensitivity of a PET system highly depends on the axial acceptance angle or maximum ring difference (MRD), which can be particularly high for total-body scanners due to their larger axial field of views (aFOVs). This study aims to evaluate the impact on image quality (IQ) and noise performance when MRD85 (18°), the current standard for clinical use, is increased to MRD322 (52°) for the Biograph Vision Quadra (Siemens Healthineers).</div></div><div><h3>Methods</h3><div>Studies with a cylindrical phantom covering the 106 cm aFOV and an IEC phantom filled with ¹⁸F, ⁶⁸Ga and ⁸⁹Zr were performed for acquisition times from 60 to 1800 s and activity concentrations from 0.4 to 3 kBq/ml to assess uniformity, contrast recovery coefficients (CRCs) and to characterize noise by coefficient of variation (CV). Spatial resolution was compared for both MRDs by sampling a quadrant of the FOV with a point source. Further IQ, CV, liver SUV_mean and SUV_max were compared for a cohort of 5 patients scanned with [¹⁸F]FDG (3 MBq/kg, 1 h p.i.) from 30 to 300 s.</div></div><div><h3>Results</h3><div>CV was improved by a factor of up to 1.49 and is highest for short acquisition times, peaks at the center field of view and mitigates parabolic in axial direction with no difference to MRD85 beyond the central 80 cm. No substantial differences between the two evaluated MRDs in regards to uniformity, SUV_mean or CRC for the different isotopes were observed. A degradation of the average spatial resolution of 0.9 ± 0.2 mm in the central 40 cm FOV was determined with MRD322. Depending on the acquisition time MRD322 resulted in a decrease of SUV_max between 23.8% (30 s) and 9.0% (300 s).</div></div><div><h3>Conclusion</h3><div>Patient and phantom studies revealed that scan time could be lowered by approximately a factor of two with MRD322 while maintaining similar noise performance. The moderate degradation in spatial resolution for MRD322 is worth to exploit the full potential of the Quadra by either shorten scan times or leverage noise performance in particular for low count scenarios such as ultra-late imaging or dynamic studies with high temporal resolution.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 3","pages":"Pages 292-303"},"PeriodicalIF":4.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49695836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiation-induced double-strand breaks by internal ex vivo irradiation of lymphocytes: Validation of a Monte Carlo simulation model using GATE and Geant4-DNA","authors":"Maikol Salas-Ramirez ,&nbsp;Lydia Maigne ,&nbsp;Giovanna Fois ,&nbsp;Harry Scherthan ,&nbsp;Michael Lassmann ,&nbsp;Uta Eberlein","doi":"10.1016/j.zemedi.2023.07.007","DOIUrl":"10.1016/j.zemedi.2023.07.007","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study describes a method to validate a radiation transport model that quantifies the number of DNA double-strand breaks (DSB) produced in the lymphocyte nucleus by internal &lt;em&gt;ex vivo&lt;/em&gt; irradiation of whole blood with the radionuclides &lt;sup&gt;90&lt;/sup&gt;Y, &lt;sup&gt;99m&lt;/sup&gt;Tc, &lt;sup&gt;123&lt;/sup&gt;I, &lt;sup&gt;131&lt;/sup&gt;I, &lt;sup&gt;177&lt;/sup&gt;Lu, &lt;sup&gt;223&lt;/sup&gt;Ra, and &lt;sup&gt;225&lt;/sup&gt;Ac in a test vial using the GATE/Geant4 code at the macroscopic level and the Geant4-DNA code at the microscopic level.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Methods&lt;/h3&gt;&lt;div&gt;The simulation at the macroscopic level reproduces an 8 mL cylindrical water-equivalent medium contained in a vial that mimics the geometry for internal &lt;em&gt;ex vivo&lt;/em&gt; blood irradiation. The lymphocytes were simulated as spheres of 3.75 µm radius randomly distributed, with a concentration of 125 spheres/mL. A phase-space actor was attached to each sphere to register all the entering particles. The simulation at the microscopic level for each radionuclide was performed using the Geant4-DNA tool kit, which includes the &lt;em&gt;clustering&lt;/em&gt; example centered on a density-based spatial clustering of applications with noise (DBSCAN) algorithm. The irradiation source was constructed by generating a single phase space from the sum of all phase spaces. The lymphocyte nucleus was defined as a water sphere of a 3.1 µm radius. The absorbed dose coefficients for lymphocyte nuclei (d&lt;sub&gt;Lymph&lt;/sub&gt;) were calculated and compared with macroscopic whole blood absorbed dose coefficients (d&lt;sub&gt;Blood&lt;/sub&gt;). The DBSCAN algorithm was used to calculate the number of DSBs. Lastly, the number of DSB∙cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt; (simulation) was compared with the number of radiation-induced foci per cell and absorbed dose (RIF∙cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt;) provided by experimental data for gamma and beta emitting radionuclides. For alpha emitters, d&lt;sub&gt;Lymph&lt;/sub&gt; and the number of α-tracks∙100 cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt; and DSBs∙µm&lt;sup&gt;−1&lt;/sup&gt; were calculated using experiment-based thresholds for the α-track lengths and DSBs/track values. The results were compared with the results of an &lt;em&gt;ex vivo&lt;/em&gt; study with &lt;sup&gt;223&lt;/sup&gt;Ra.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;div&gt;The d&lt;sub&gt;Lymph&lt;/sub&gt; values differed from the d&lt;sub&gt;Blood&lt;/sub&gt; values by −1.0% (&lt;sup&gt;90&lt;/sup&gt;Y), −5.2% (&lt;sup&gt;99m&lt;/sup&gt;Tc), −22.3% (&lt;sup&gt;123&lt;/sup&gt;I), 0.35% (&lt;sup&gt;131&lt;/sup&gt;I), 2.4% (&lt;sup&gt;177&lt;/sup&gt;Lu), −5.6% (&lt;sup&gt;223&lt;/sup&gt;Ra) and −6.1% (&lt;sup&gt;225&lt;/sup&gt;Ac). The number of DSB∙cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt; for each radionuclide was 0.014 DSB∙cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt; (&lt;sup&gt;90&lt;/sup&gt;Y), 0.016 DSB∙cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt; (&lt;sup&gt;99m&lt;/sup&gt;Tc), 0.013&lt;!--&gt; &lt;!--&gt;DSB∙cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt; (&lt;sup&gt;123&lt;/sup&gt;I), 0.012 DSB∙cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt; (&lt;sup&gt;131&lt;/sup&gt;I), and 0.012 DSB∙cell&lt;sup&gt;−1&lt;/sup&gt;∙mGy&lt;sup&gt;−1&lt;/sup&gt; (&lt;sup&gt;177&lt;/sup&gt;Lu). These values agree very well with experimental data. The number of α-tracks∙100 cells&lt;sup&gt;−1&lt;/sup&gt;","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 3","pages":"Pages 235-247"},"PeriodicalIF":4.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10088978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MPE training in Germany – Perspectives of the next generation","authors":"Tim Felgenhauer,&nbsp;Laura Garajová,&nbsp;Jonas Meyer,&nbsp;Andre Karius","doi":"10.1016/j.zemedi.2025.07.001","DOIUrl":"10.1016/j.zemedi.2025.07.001","url":null,"abstract":"","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 3","pages":"Pages 232-234"},"PeriodicalIF":4.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144746728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation, validation, and benchmarking of a commercial independent Monte Carlo calculation beam model for multi-target SRS","authors":"Justus Adamson ,&nbsp;Brett G. Erickson ,&nbsp;Chunhao Wang ,&nbsp;Yunfeng Cui ,&nbsp;Markus Alber ,&nbsp;John Kirkpatrick ,&nbsp;Fang-Fang Yin","doi":"10.1016/j.zemedi.2023.08.004","DOIUrl":"10.1016/j.zemedi.2023.08.004","url":null,"abstract":"<div><h3>Background</h3><div>Dosimetric validation of single isocenter multi-target radiosurgery plans is difficult due to conditions of electronic disequilibrium and the simultaneous irradiation of multiple off-axis lesions dispersed throughout the volume. Here we report the benchmarking of a customizable Monte Carlo secondary dose calculation algorithm specific for multi-target radiosurgery which future users may use to guide their commissioning and clinical implementation.</div></div><div><h3>Purpose</h3><div>To report the generation, validation, and clinical benchmarking of a volumetric Monte Carlo (MC) dose calculation beam model for single isocenter radiosurgery of intracranial multi-focal disease.</div></div><div><h3>Methods</h3><div>The beam model was prepared within SciMoCa (ScientificRT, Munich Germany), a commercial independent dose calculation software, with the aim of broad availability via the commercial software for use with single isocenter radiosurgery. The process included (1) definition &amp; acquisition of measurement data required for beam modeling, (2) tuning model parameters to match measurements, (3) validation of the beam model via independent measurements and end-to-end testing, and finally, (4) clinical benchmarking and validation of beam model utility in a patient specific QA setting. We utilized a 6X Flattening-Filter-Free photon beam from a TrueBeam STX linear accelerator (Siemens Healthineers, Munich Germany).</div></div><div><h3>Results</h3><div>In addition to the measured data required for standard IMRT/VMAT (depth dose, central axis profiles &amp; output factors, leaf gap), beam modeling and validation for single-isocenter SRS required central axis and off axis (5 cm &amp; 9 cm) small field output factors and comparison between measurement and simulation of backscatter with aperture for jaw much greater than MLCs. Validation end-to-end measurements included SRS MapCHECK in StereoPHAN geometry (2%/1 mm Gamma = 99.2% ± 2.2%), and OSL &amp; scintillator measurements in anthropomorphic STEEV phantom (6 targets, volume = 0.1–4.1cc, distance from isocenter = 1.2–7.9 cm) for which mean difference was −1.9% ± 2.2%. For 10 patient cases, MC for individual PTVs was −0.8% ± 1.5%, −1.3% ± 1.7%, and −0.5% ± 1.8% for mean dose, D_95%, and D_1%, respectively. This corresponded to custom passing rates action limits per AAPM TG-218 guidelines of ±5.2%, ±6.4%, and ±6.3%, respectively.</div></div><div><h3>Conclusions</h3><div>The beam modeling, validation, and clinical action criteria outlined here serves as a benchmark for future users of the customized beam model within SciMoCa for single isocenter radiosurgery of multi-focal disease.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 3","pages":"Pages 248-258"},"PeriodicalIF":4.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10192034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial Board + Consulting Editorial Board","authors":"","doi":"10.1016/S0939-3889(25)00095-9","DOIUrl":"10.1016/S0939-3889(25)00095-9","url":null,"abstract":"","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 3","pages":"Page iii"},"PeriodicalIF":4.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity and specificity of Monte Carlo based independent secondary dose computation for detecting modulation-related dose errors in intensity modulated radiotherapy","authors":"Matthias Kowatsch ,&nbsp;Philipp Szeverinski ,&nbsp;Patrick Clemens ,&nbsp;Thomas Künzler ,&nbsp;Matthias Söhn ,&nbsp;Markus Alber","doi":"10.1016/j.zemedi.2023.10.001","DOIUrl":"10.1016/j.zemedi.2023.10.001","url":null,"abstract":"<div><h3>Background</h3><div>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.</div></div><div><h3>Purpose</h3><div>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.</div></div><div><h3>Methods</h3><div>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.</div></div><div><h3>Results</h3><div>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 &gt; 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 &gt; 99%, sensitivity = 0.73 and specificity = 0.91 as a commonly used action level.</div></div><div><h3>Conclusions</h3><div>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.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 3","pages":"Pages 259-269"},"PeriodicalIF":4.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61567129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum physics at a historic milestone: How has it shaped medical physics?","authors":"Michael Bock ,&nbsp;Jürgen R. Reichenbach","doi":"10.1016/j.zemedi.2025.02.002","DOIUrl":"10.1016/j.zemedi.2025.02.002","url":null,"abstract":"","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 2","pages":"Pages 123-126"},"PeriodicalIF":2.4,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143574786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of log file source and data frequency on accuracy of log file-based patient specific quality assurance","authors":"Akbar Azzi ,&nbsp;Gerd Heilemann ,&nbsp;Dietmar Georg ,&nbsp;Supriyanto Ardjo Pawiro ,&nbsp;Terry Mart ,&nbsp;Wolfgang Lechner","doi":"10.1016/j.zemedi.2023.05.006","DOIUrl":"10.1016/j.zemedi.2023.05.006","url":null,"abstract":"<div><div>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 &lt; 0.001) for HN cases, PTV D_98% (r = 0.005) for brain cases, and PTV D_50% (<em>r</em> = 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 (<em>r</em> = −0.58, <em>p</em> &lt; 0.001) and strong correlation for OIS logs (<em>r</em> = −0.71, <em>p</em> &lt; 0.001). Furthermore, all doses calculated using Linac log files and OIS log data had a GPR &gt;90% for an RMS error &lt; 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.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"35 2","pages":"Pages 152-160"},"PeriodicalIF":2.4,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9680256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}