Zeitschrift fur medizinische Physik最新文献

{"title":"Performance evaluation of the Biograph Trinion EP2 PET/CT system according to NEMA NU2-2018.","authors":"Ivo Rausch, Fabian Schmidt, Martha Hoffmann, Philipp Peloschek","doi":"10.1016/j.zemedi.2026.07.009","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.07.009","url":null,"abstract":"<p><strong>Aim: </strong>This study evaluates the performance of the Siemens Biograph Trinion EP2 whole-body PET/CT system according to the NEMA NU2-2018 standard.</p><p><strong>Methods: </strong>Following the NEMA NU2-2018 standard, spatial resolution was measured using a ²²Na point source in air, sensitivity was calculated from consecutive measurements of a ¹⁸F containing line source surrounded by aluminum tubes, count rate performance, accuracy of corrections assessment and TOF resolution was based on measurements of an ¹⁸F line-source inside scatter phantom. PET-CT co-registration accuracy was assessed by radioactive and radiation dense point sources, image quality was evaluated using a NEMA IQ phantom. Measurements were done using implemented NEMA NU2-2018 acquisition protocols on a Siemens Biograph Trinion EP2 PET/CT system.</p><p><strong>Results: </strong>The Trinion EP2 showed a spatial resolution between 4.0 and 4.4 mm FWHM at the center of the FOV. Sensitivity was measured with 13.8 kBq/MBq and the peak noise equivalent count rage of 143 kcps measured at 14.8 kBq/mL with a corresponding scatter fraction of 37.5%. The maximum average error was 1.6% between 1 kBq/mL and 14.8 kBq/mL and a TOF resolution of 241 ps was measured at a clinical activity concentration. Contrast recoveries between 47.2% and 81.6% were measured in the image quality phantom when using standard reconstructions.</p><p><strong>Conclusion: </strong>The Biograph Trinion EP2 PET/CT system shows a good overall performance providing a decent image quality comparable to state-of-the-art PET/CT systems with standard axial FOV between 20 and 30 cm.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148703300","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":"A vergence-based calculation framework for optimal rotational adjustment of toric supplementary intraocular lenses to minimise residual refractive cylinder.","authors":"Achim Langenbucher, Nóra Szentmáry, Alan Cayless, Kamran M Riaz, Douglas D Koch, Jascha A Wendelstein","doi":"10.1016/j.zemedi.2026.07.005","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.07.005","url":null,"abstract":"<p><strong>Purpose: </strong>To present a transparent, physics-based, and generalisable calculation framework to predict the optimal rotational adjustment of toric supplementary intraocular lenses (SIOLs), comprising toric phakic intraocular lenses implanted in the phakic eye and toric AddOn (secondary sulcus-fixated) lenses implanted in the pseudophakic eye, quantifying the expected refractive benefit across four corneal models.</p><p><strong>Methods: </strong>A paraxial vergence-based calculation framework was implemented to predict the optimal toric axis of a misaligned SIOL. Required inputs were the measured manifest refraction at spectacle plane, corneal power (using either thin- or thick-cornea models), labelled equivalent and toric power of the SIOL, measured SIOL axis, and axial SIOL position. The effective lens position was estimated by combining the measured back-vertex position with an offset between the back-vertex plane and the image-sided principal plane, derived from legacy phakic lens design data or custom template SIOL models. Forward and backward spherocylindrical vergence transformations were embedded in a nonlinear sequential quadratic programming optimisation to identify the SIOL axis that minimised residual refractive cylinder. The method was demonstrated in four representative clinical scenarios, including phakic, pseudophakic , keratoplasty, and prior laser vision correction eyes.</p><p><strong>Results: </strong>In all examples, the model predicted a specific rotational adjustment of the SIOL (16-18°) that substantially reduced refractive cylinder. Absolute reductions ranged from 1.7 to 2.4 D, corresponding to relative cylinder reductions of 67-94%. The framework successfully accommodated different corneal models and lens types, and provided predicted postoperative refraction and quantitative performance metrics.</p><p><strong>Conclusions: </strong>This framework enables individualised planning of toric SIOL realignment across diverse corneal models and lens geometries. Explicitly defining optical assumptions and vergence transformations allows reproducible prediction of both optimal rotation and expected refractive benefit using routine clinical inputs. Prospective clinical validation is warranted.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148650057","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 additional PMMA on the calibration of X-ray multimeters for mammography radiation qualities.","authors":"Elisabeth Salomon, Peter Homolka, Istvan Csete, Paula Toroi","doi":"10.1016/j.zemedi.2026.07.004","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.07.004","url":null,"abstract":"<p><p>X-ray multimeters (XMMs) are widely used for quality control measurements in mammography, providing air kerma, half-value layer (HVL), and tube voltage from a single exposure. The energy dependence of their response was comprehensively investigated for various anode/filter combinations and software selections. However, the influence of a change in the X-ray spectrum due to additional material in the beam has not yet been systematically investigated. The aim of this study is to quantify the sensitivity of XMM calibration coefficients to changes in X-ray spectra introduced by additional polymethyl methacrylate (PMMA) of different thicknesses. Four commercially available XMMs were calibrated at the IAEA dosimetry laboratory for air kerma, HVL, and tube voltage using two anode/filter combinations (Mo/Mo and W/Al) at tube voltages ranging from 25kV to 35kV. Calibration coefficients were determined without additional filtration and with PMMA thicknesses of 2.0mm, 2.8mm, and 4.8mm placed close to the X-ray tube to modify the primary spectrum while minimizing scattered radiation reaching the detectors. In relation to the calibration coefficient determined without PMMA deviations of up to 11% were observed for air kerma rate. HVL and tube voltage calibration coefficients exhibited substantially larger deviations, reaching up to 37% and 42%, respectively. We conclude that changes in the X-ray spectra as from additional PMMA filtration, can substantially alter XMM calibration coefficients, particularly for HVL and tube voltage measurements. XMM responses are highly sensitive to spectral modifications beyond standard anode/filter combinations and tube voltage settings.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148475508","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":"CBCT dose reduction with HyperSight on an Ethos linear accelerator: A phantom-based TLD measurement study.","authors":"Svenja Ganz, Sven Knobe, Marc Ries, Jan Palm, Markus Hecht, Hendrik Auerbach","doi":"10.1016/j.zemedi.2026.07.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.07.003","url":null,"abstract":"<p><strong>Purpose: </strong>The novel HyperSight cone-beam CT (CBCT) system (Varian Medical Systems, Siemens Healthineers, Palo Alto, USA) provides image quality comparable to native CT and offers advantages for contouring in online-adaptive radiotherapy. However, daily imaging increases organ dose. This study evaluates and compares organ doses across HyperSight protocols on an O-ring Linac and calculates the effective dose and secondary cancer risk associated with daily imaging.</p><p><strong>Methods: </strong>Thermoluminescent dosimeter (TLD) measurements were performed on an anthropomorphic phantom for all pre-configured CBCT protocols in HyperSight, with TLDs placed according to each entity (head, head and neck, thorax, chest, and pelvis). The resulting imaging doses were compared across the various protocols and TLD positions, followed by the calculation of effective doses and the associated secondary cancer risk.</p><p><strong>Results: </strong>HyperSight CBCT demonstrated lower organ doses compared with previous systems. Mean bladder and rectum dose was 10mGy versus 27mGy for OBI Version 1.4.13, while mean head dose was 2mGy compared with 1.2mGy for Halcyon 3.0. A left-right dose asymmetry was observed due to partial gantry rotation, resulting in higher exposure in beam-facing organs. Imaging dose varied considerably between protocols. Low Dose protocols reduced exposure by up to 55%, whereas slow and large protocols increased dose by 40-60%.</p><p><strong>Conclusion: </strong>HyperSight provides high-quality imaging with lower dose levels than previous CBCT generations. The observed beam geometry-related asymmetry should be considered in clinical use, and individualized protocol selection is essential to minimize unnecessary exposure in image guided and adaptive radiotherapy under ALARA principles.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148458128","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":"Toward clinical harmonization of radiobiological modeling in particle-based radiotherapy: a translational review of proton, heavy-ion, and BNCT frameworks.","authors":"Nanjie Xiao, Tingting Cao, Tingting Liu, Zhitao Dai","doi":"10.1016/j.zemedi.2026.07.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.07.001","url":null,"abstract":"<p><p>Particle-based radiotherapy, including proton therapy, heavy-ion therapy, and boron neutron capture therapy (BNCT), enables conformal dose delivery but introduces model-dependent biological-dose uncertainty. This uncertainty reflects variations in relative biological effectiveness (RBE), linear energy transfer (LET), oxygenation, microdosimetric spectra, and boron distribution, so identical nominal prescriptions may not yield equivalent biological effects. This review summarizes representative clinical, secondary-review, and investigational model families, including fixed and variable-RBE proton models, the local effect model (LEM) and microdosimetric kinetic model (MKM) families for heavy ions, and compound biological effectiveness (CBE), photon-isoeffective-dose, microdosimetric, and nanodosimetric BNCT frameworks. We compare their assumptions, input descriptors, validation status, clinical readiness, and implementation barriers. We further distinguish prescription-embedded clinical systems from secondary-review models and investigational mechanistic frameworks to clarify the current level of clinical evidence supporting each model family. Published experimental and model-comparison studies indicate that proton RBE may increase in high-LET distal-edge regions, that LEM- and MKM-based carbon-ion systems can yield clinically relevant, site- and endpoint-dependent differences in RBE-weighted dose interpretation, and that BNCT biological dose is strongly affected by component-dose and boron-distribution assumptions. We propose an evidence-informed four-layer harmonization perspective, rather than a formal consensus guideline, consisting of minimum reporting, reference mapping, model-sensitivity quality assurance (QA), and registry-based clinical learning.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148439500","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 intracochlear voltage matrix analysis explain the occurrence of electrically evoked vestibular responses in cochlear implant users?","authors":"Ahmed Salha, Luise Wagner, Sebastian Strieth, Klaus W G Eichhorn, Laura Fröhlich","doi":"10.1016/j.zemedi.2026.06.004","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.06.004","url":null,"abstract":"<p><strong>Background: </strong>This study examined how intracochlear voltage distributions obtained from impedance field telemetry (IFT) in cochlear implant (CI) users with straight lateral wall electrodes related to electrically evoked cervical and ocular vestibular myogenic responses (e-cVEMPs and e-oVEMPs).</p><p><strong>Methods: </strong>e-cVEMPs and e-oVEMPs were recorded in adult MED-EL Synchrony CI users by stimulating at intracochlear electrodes E3, E6, E10 and E11. IFT provided voltage matrices characterizing intracochlear electric field distribution. Voltage data were adjusted using a current-dependent scaling factor to account for stimulation-level differences, and both qualitative and quantitative analyses were performed to compare participants with and without e-VEMP responses and to assess spatial dependencies between voltage profiles and vestibular activation.</p><p><strong>Results: </strong>The study included 18 implanted ears of 17 participants. Qualitative evaluation of the difference matrices across all stimulation electrodes revealed local variations within individual stimulation sites, but no consistent group-specific pattern that persisted across electrodes for either e-cVEMPs or e-oVEMPs. Quantitative analysis of voltage line graphs showed higher voltages and e-oVEMP thresholds across all sites in participants with e-oVEMPs, reaching significance only at E3. For e-cVEMPs, analysis showed no significant group differences. Detection rates demonstrated a spatial trend, with e-cVEMPs occurring predominantly during basal stimulation and e-oVEMPs during apical stimulation.</p><p><strong>Conclusion: </strong>These data suggest that there could be different current pathways for saccular and utricular co-stimulation. Intracochlear electric field distributions could not be directly correlated with e-VEMP occurrence. Spatial dependencies and voltage decay patterns suggest separate mechanisms, possibly related to differences in local field orientation and tissue conductivity, which have to be further examined with respect to anatomical data.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148388375","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":"Limitations of Mono-Exponential Individual Fitting as a Reference Model for Single-Time-Point Dosimetry in [¹⁷⁷Lu]Lu-PSMA-617 Therapy.","authors":"Fulki Fiarka, Assyifa Rahman Hakim, Indra Budiansah, Abdurrahman Aziz Wicaksono, Jaja M Jabar, Steffie M B Peters, Bastiaan M Prive, James Nagarajah, Mark W Konijnenberg, Syahril Siregar, Deni Hardiansyah, Gerhard Glatting","doi":"10.1016/j.zemedi.2026.06.005","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.06.005","url":null,"abstract":"<p><strong>Purpose: </strong>To examine whether mono-exponential individual fitting (Mono-IFIT) is an adequate reference model for validating single-time-point (STP) renal dosimetry in [¹⁷⁷Lu]Lu-PSMA-617 therapy, and to compare the resulting STP accuracy rankings with those obtained using population-based model selection with non-linear mixed-effects modelling (PBMS NLMEM).</p><p><strong>Methods: </strong>Kidney biokinetic data were analysed using a training dataset of 500 virtual patients generated from a six-parameter sum-of-exponentials function previously identified within the PBMS NLMEM framework, and an external testing dataset comprising 10 clinical patients with low-volume metastatic hormone-sensitive prostate cancer. Reference absorbed doses were calculated with Mono-IFIT and PBMS NLMEM. Four STP methods (STP_NLMEM, STP_MLR, STP_H, and STP_M) were evaluated at (47.7±2.2) h post-injection. Accuracy was assessed using relative deviation (RD), mean absolute percentage error (MAPE), and root mean square error (RMSE).</p><p><strong>Results: </strong>The selected PBMS NLMEM model provided a better description of the renal time-activity data than Mono-IFIT according to predefined goodness-of-fit criteria and Akaike-weight-based model selection. STP performance rankings depended strongly on the chosen reference model. Against Mono-IFIT, STP_M and STP_H showed the smallest deviations (mean RD -2.3% and 3.3%; MAPE 3.5% and 4.5%; RMSE 4.6% and 5.3%, respectively), whereas STP_NLMEM showed the largest deviation (mean RD 16.0%; MAPE 16.0%; RMSE 17.9%). Against PBMS NLMEM, STP_NLMEM showed the closest agreement (mean RD -2.5%; MAPE 6.6%; RMSE 9.3%), whereas STP_MLR, STP_H and STP_M underestimated absorbed dose (mean RD -14.1%, -13.1% and -17.8%; MAPE 15.2%, 13.1% and 17.8%; RMSE 17.3%, 14.8% and 19.1%, respectively).</p><p><strong>Conclusion: </strong>The apparent accuracy of STP methods is highly dependent on the reference model. For [¹⁷⁷Lu]Lu-PSMA-617 renal dosimetry, Mono-IFIT should not be considered the preferred reference for method validation. In this dataset, PBMS NLMEM provided the better reference framework, and STP_NLMEM showed the closest agreement with it. To ensure broader applicability, this approach should also be evaluated for salivary glands and tumours, which may require tailored fitting strategies, thereby supporting the development of a generalisable STP method for personalised treatment. Prospective validation in larger cohorts remains necessary.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148383458","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":"Determination of long-range resistance from high resolution impedance spectroscopy in human cadaveric heads.","authors":"Mit B Bhavsar, Merle Sehlmeyer, Nils Prenzler, Andrej Kral, Stefan Zimmermann, Hannes Maier","doi":"10.1016/j.zemedi.2026.06.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.06.003","url":null,"abstract":"<p><p>Long-range resistance (R_t) reflects the resistive component of current flow through intracochlear fluids, surrounding tissues, and bone before it returns to the extracochlear return electrode (RE). Unlike near-field resistances, which mainly capture the local tissue-electrode interface, R_t captures the global tissue pathway and therefore represents how efficiently stimulation current spreads throughout the cochlea and surrounding anatomical structures. In this study, we have determined the long-range resistance (R_t) between a stimulation electrode (SE) and the extracochlear RE from precision impedance spectroscopic measurements in three human cadaveric heads involving six sequentially cochlear implanted ears with the MED-EL FLEX28 and the Cochlear Ltd. CI622 electrode arrays. Equivalent electrical circuit (EEC) modelling, combined with finite element method (FEM)-based correction, was employed to separate the biological impedance components from non-biological artefacts arising from the measurement setup. Principal Component Analysis (PCA) was applied to detect and remove atypical impedance responses due to malfunctioning electrodes. Missing electrode values were interpolated using cubic splines to maintain continuity. Across both array types, R_t consistently increased from basal to apical electrode positions, consistent with the progressively smaller scala tympani cross-section in the apical turn. The overall trend of R_t observed in the present study also aligns with trends reported in in vivo telemetry studies, supporting the translational relevance of the measurements.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148371562","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":"Patient-specific quality assurance in stereotactic radiotherapy: clinical practice in absence of guidelines - status and new approach from the DGMP working group for physics and technology in stereotactic radiotherapy.","authors":"H Gottschlag, B Bathen, E Beckers, T Gauer, D Schmitt, O Blanck","doi":"10.1016/j.zemedi.2026.04.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.04.001","url":null,"abstract":"<p><strong>Introduction: </strong>Guidelines on how to perform patient-specific quality assurance (PSQA) in stereotactic radiotherapy (SRT) are currently not available. In this context, guidelines for modulated techniques like IMRT or IMAT do include descriptions of PSQA. However, commonly used quality assurance (QA) devices, methods, and evaluation metrics are not sufficiently suitable for small-field conditions. Consequently, these guidelines cannot generally be applied to stereotactic radiotherapy. The aim of this work is to assess the limitations of current clinical practice and provide guidance on choosing QA methods given the extensive QA requirements. Additionally, we will present a method for evaluating comprehensive PSQA programs, identifying blind spots, and supporting the selection of suitable devices and methods to overcome them.</p><p><strong>Methods/results: </strong>We reviewed available literature, especially guidelines, and identified main issues in today's PSQA practice for SRT by performing surveys among users and vendors. Current QA equipment, software, and methods were assessed and analyzed. Independently, we defined the scope of an appropriate PSQA for SRT. Subsequently, we related this to available devices and methods in a vendor-neutral manner, resulting in a toolkit for evaluation of site-specific PSQA programs in SRT. The approach and result were reviewed by a group of experts.</p><p><strong>Discussion/conclusion: </strong>No single QA solution or method can account for all PSQA needs for SRT. In addition, properly choosing PSQA evaluation metrics is key for a meaningful verification process. The heterogeneity of SRT implementations throughout different sites encompasses different needs and hinders the creation of a static guideline. In the absence of such, we derived a best option decision-making toolkit for optimizing a PSQA program to be used in the environment of stereotactic radiotherapy.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148364632","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":"Evaluation of PET/CT Artificial Intelligence Image Reconstructions VS Harmonized Clinical Reconstruction.","authors":"Panayiotis Hadjitheodorou, Michalis Sotiriou, Kyriaki Kyrou, Giorgos Adamou, Michalis Eleftheriou, Kyriaki Konstantinidou, Alexis Vrachimis","doi":"10.1016/j.zemedi.2026.06.002","DOIUrl":"https://doi.org/10.1016/j.zemedi.2026.06.002","url":null,"abstract":"<p><strong>Background: </strong>This study focuses on evaluating how SubtlePET™, an artificial intelligence (AI)-based image enhancement algorithm, produced PET/CT images compare against EARL Standard-2 harmonized images, and to assess its impact on quantitative accuracy and workflow in a clinical setting.</p><p><strong>Methods: </strong>A NEMA IEC PET Body Phantom with 10:1 (EARL protocol) and 4:1 (NEMA NU2-2018 protocol) sphere-to-background ratios were scanned using a General Electric Discovery™ IQ Gen-2 PET/CT system. Data were acquired in list mode for 10 minutes per bed position and retrospectively reconstructed to simulate reduced scan duration. Images were reconstructed with and without SubtlePET^TM (phantom image trained) using EARL Standard-2 accredited reconstruction. Recovery coefficients (SUV_mean,_max,_peak) were calculated and compared to EARL standard-2 along with their repeatability. Additionally, 23 patient datasets acquired for 3-minutes per bed-position were reconstructed to simulate reduced acquisition time both by SubtlePET^TM (human image trained) and EARL Standard-2 reconstruction parameters. Lesions were segmented semi-automatically to assess SUV and volume metrics. Statistical comparisons were performed using a two-sample t-test assuming equal variances.</p><p><strong>Results: </strong>SubtlePET^TM reconstructions achieved 91% compliance with EARL standard-2. SUV_peak remained the most robust metric across scan duration. Patient data showed no significant differences in SUV_peak or volume for SubtlePET^TM at half the acquisition time. Minor deviations were noted in SUV_max and SUV_mean for smaller lesions at 1-min/bed.</p><p><strong>Conclusion: </strong>SubtlePET™ preserves quantitative performance comparable to EARL Standard 2-compliant reconstructions, particularly when SUVpeak is used, although deviations associated with reduced acquisition time persist. These findings support the potential for reduced scan duration, which may facilitate lower radiation exposure or increased patient throughput without compromising diagnostic quality. Further validation across different scanners and clinical settings is warranted.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148298335","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}