Zeitschrift fur Medizinische Physik最新文献

{"title":"Intraoperative molecular imaging – it’s all about advancing surgical decision making and improving dexterity","authors":"Fijs W.B. van Leeuwen,&nbsp;Tessa Buckle","doi":"10.1016/j.zemedi.2026.01.002","DOIUrl":"10.1016/j.zemedi.2026.01.002","url":null,"abstract":"<div><div>Clinical implementation of intraoperative molecular imaging has accelerated by incorporating molecular image-guided decision making into minimal invasive robotic surgery. The resulting digital surgery concepts combine precise molecular image-guided decision making with increased dexterity, with the aim to achieve value-based medicine. In this review several surgically encountered challenges and the technological innovations the field of intraoperative molecular imaging and molecular image-guided robotics, that include navigation in preoperative imaging roadmaps, dosing, imaging and sensing and performance assessment are discussed. Herein specific focus is placed on physical trade-offs between key issues such as penetration depth, spatial resolution and background signal, as well as integration of hybrid tracers and multimodal strategies.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 3","pages":"Pages 261-267"},"PeriodicalIF":4.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146021103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-of-flight: The last frontier in positron emission tomography instrumentation","authors":"Georgios Konstantinou,&nbsp;Paul Lecoq","doi":"10.1016/j.zemedi.2026.03.003","DOIUrl":"10.1016/j.zemedi.2026.03.003","url":null,"abstract":"<div><div>Positron emission tomography (PET) instrumentation has seen significant advances over the last 20 years. In particular, substantial improvement in electronics and scalability have allowed new clinical scanners to combine high gamma stopping power and patient geometrical coverage in the total body PET paradigm. Similarly, spatial resolution has almost reached its physical limit imposed by the uncertainty caused by the positron range and acollinearity of emitted annihilation gamma rays. Time-of-flight (ToF) offers an improvement to effective sensitivity, proportional to the reverse square of detector timing resolution. In contrast to the aforementioned, this is a development direction that has not yet been sufficiently harnessed, with state of the art remaining far from the physical limit of ToF resolution. Nevertheless, existing scanners offer a glimpse of the advantages of ToF for imaging and diagnosis. In this review, analyse the limiting factors; describe the motivation for enhancing detector ToF capabilities; explore the physical mechanisms related to ToF application; describe the state-of-the-art in clinical, prototyping and laboratory stages; offer insights on emerging approaches and their capabilities to provide scalable, and cost-effective ToF; and finally envision the future of medicine, once ultraToF of the order of 10 ps has become the standard in clinically deployed scanners.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 3","pages":"Pages 315-325"},"PeriodicalIF":4.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147825458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of a quantitative method for measuring the spatial resolution of a gamma camera using a bar phantom","authors":"Jule Maack,&nbsp;Christian Schütze","doi":"10.1016/j.zemedi.2026.02.004","DOIUrl":"10.1016/j.zemedi.2026.02.004","url":null,"abstract":"<div><div>The method developed by Hander et al. (1997) [1] enables a quantitative determination of spatial resolution by analysing planar images of a lead bar phantom. The method is based on the determination of the modulation transfer function (MTF) and the full width at half maximum (FWHM) solely on the basis of the mean value and standard deviation within a region of interest (ROI). To assess the applicability of this method for constancy checks with extrinsic measurements, the influence of the phantom-to-collimator distance, the total counts and the matrix size was evaluated. In addition, the constancy of the method for repeated measurements under repositioning was analysed.</div><div>The phantom-to-collimator distance significantly affects the determined resolution, with the <em>FWHM</em> increasing by approximately 0.4 mm per centimetre of distance. The matrix size also influences the determined values, leading to up to 20% lower <em>MTF</em> values for the larger bars (4 and 5 mm) when decreasing the matrix from a 1024 × 1024 to a 256 × 256 matrix. The total number of counts does not affect the <em>MTF</em> or <em>FWHM</em> values, provided that at least 3·10⁶ counts are acquired. However, this applies only to the larger bars (4 and 5 mm); if reliable values are required for all four quadrants, the total number of counts should be increased further. Under constant measurement conditions, variations below 2.4% were observed for the bars of 4 and 5 mm width. For the smaller bars of 2 and 3 mm width the variations were below 9%.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 3","pages":"Pages 376-380"},"PeriodicalIF":4.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146230294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DNA damage induction and repair in peripheral blood mononuclear cells induced by internal ex vivo irradiation with β- and γ-emitting radionuclides","authors":"Sarah Schumann,&nbsp;Isabella Strobel,&nbsp;Johanna Hahn,&nbsp;Alberto Meca Zapata,&nbsp;Michael Lassmann,&nbsp;Harry Scherthan,&nbsp;Uta Eberlein","doi":"10.1016/j.zemedi.2026.03.010","DOIUrl":"10.1016/j.zemedi.2026.03.010","url":null,"abstract":"<div><div>Purpose: Aim of the study was to investigate DNA damage induction and repair in peripheral blood mononuclear cells (PBMCs) after internal <em>ex vivo</em> irradiation with short-lived radionuclides with varying emission properties.</div><div>Methods: Blood samples from healthy volunteers were irradiated with different activity concentrations for 1 h, resulting in absorbed doses to the blood from nominally 3 to 100 mGy. DNA double-strand breaks (DSBs) in PBMCs were assessed by quantifying radiation-induced γ-H2AX+53BP1-positive foci (RIF). In part A of the study, four different radionuclides (¹⁷⁷Lu, ⁹⁰Y, ^99mTc and ⁶⁸Ga) were used to test for radionuclide dependence. In part B, blood samples were exposed to ¹⁷⁷Lu and cells were fixed at three different time points (directly, 4 h and 24 h after irradiation) to investigate DSB repair and its dependence on the absorbed dose.</div><div>Results: The number of RIF increases linearly with the absorbed dose to the blood, independent of the radionuclide used for irradiation. The decline in RIF after irradiation can be described by an exponential function, with a trend towards higher repair rates at higher absorbed doses to the blood, i.e. (0.20±0.12) h⁻¹ for 25 mGy, (0.22±0.04) h⁻¹ for 50 mGy, and (0.37±0.06) h⁻¹ for 100 mGy.</div><div>Conclusion: Our results show a clear relationship between absorbed dose and DSB foci induced by internal irradiation in blood cells, independent of the emission properties of the particular radionuclide used. A better understanding of DNA damage repair dynamics after internal irradiation can improve future nuclear medicine therapies.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 3","pages":"Pages 399-406"},"PeriodicalIF":4.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147505968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Delayed convergence of iterative reconstruction in dopamine transporter SPECT with multiple-pinhole collimators","authors":"Loreen Jedid,&nbsp;Thomas Buddenkotte,&nbsp;Ivayla Apostolova,&nbsp;Laurin Bruer,&nbsp;Erik Jámbor,&nbsp;Susanne Klutmann,&nbsp;Melinda Szolikova,&nbsp;Attila Forgács,&nbsp;Svend Hvidsten,&nbsp;Ralph Buchert","doi":"10.1016/j.zemedi.2025.10.006","DOIUrl":"10.1016/j.zemedi.2025.10.006","url":null,"abstract":"&lt;div&gt;&lt;h3&gt;Background&lt;/h3&gt;&lt;div&gt;Multiple-pinhole (MPH) collimators for brain SPECT improve the resolution-sensitivity tradeoff compared with conventional parallel-hole and fan-beam collimators. The system count sensitivity profile with MPH collimators exhibits a peak at the center of the field-of-view and significant decline in count sensitivity toward the periphery. In MPH SPECT with [&lt;sup&gt;123&lt;/sup&gt;I]FP-CIT, this makes the difference in relative statistical noise between the striatum and extrastriatal (reference) regions even bigger. This could slow down the convergence of iterative reconstruction compared with [&lt;sup&gt;123&lt;/sup&gt;I]FP-CIT using conventional collimators. This study evaluated the impact of the effective number of reconstruction iterations in [&lt;sup&gt;123&lt;/sup&gt;I]FP-CIT SPECT with MPH collimators.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Methods&lt;/h3&gt;&lt;div&gt;671 patients (43.8% females, 67.3±11.3y) were included retrospectively. Projection data were acquired with a triple-head camera (Mediso AnyScan Trio) equipped with 2&lt;sup&gt;nd&lt;/sup&gt; generation general-purpose brain MPH collimators. MPH projections from 12 min total scan duration were reconstructed with the iterative 3d Tera-Tomo Monte Carlo algorithm of the system software. The effective number of iterations was varied between 12 and 300. To evaluate the impact of the iteration number on diagnostic performance, a data-driven Gaussian mixture model approach was used to assess the power of the putaminal specific binding ratio (SBR) for differentiation between reduced and normal scans. In a subset of 72 patients, reconstructed images were visually evaluated twice by 7 independent readers with respect to parkinson-like reduction of striatal [&lt;sup&gt;123&lt;/sup&gt;I]FP-CIT uptake using a Likert 6-score (-3=clearly reduced, …, 3=clearly normal). The impact of the iteration number on the Likert 6-score was tested using repeated measure analysis of variance (ANOVA) with iteration number, reader and session as within-subject factors. The majority vote binary classification (reduced, normal) was taken into account as between-subject factor. Within- and between-readers agreement of visual scoring were characterized by Cohen’s and Fleiss’ kappa.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;div&gt;Iterative reconstruction converged much slower in the extrastriatal reference region than in the striatum and its subregions. Considerable improvement of spatial resolution with increasing iteration number came with an acceptable increase of statistical noise. The discriminative power of the putaminal SBR was highest with 300 effective iterations. There was a small but significant reduction of reader confidence and between-readers agreement with 300 compared to 24 iterations, particularly in normal cases (Likert 6-score 2.325 versus 2.468, p &lt; 0.001).&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Conclusions&lt;/h3&gt;&lt;div&gt;300 iterations provide a good compromise between spatial resolution, robustness and diagnostic power of semi-quantitative SBR analyses on one side versus statistical ","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 3","pages":"Pages 381-389"},"PeriodicalIF":4.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145461133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep learning-based restoration of PET images from a dual-panel breast dedicated scanner","authors":"Hamid Nezampour,&nbsp;Mehdi Amini,&nbsp;Amirhossein Sanaat,&nbsp;Habib Zaidi","doi":"10.1016/j.zemedi.2026.01.001","DOIUrl":"10.1016/j.zemedi.2026.01.001","url":null,"abstract":"<div><div>Positron Emission Tomography (PET) is important for breast cancer diagnosis and monitoring, but high costs restrict access. Dual-panel scanners can reduce costs, though they typically produce lower quality images with quantitative bias compared to full-ring systems. In this study, we investigated the use of deep learning (DL) to address these limitations and improve image quality in a dedicated dual-panel breast PET scanner. Monte Carlo simulations were performed with the GATE toolkit to model both dual-panel and full-ring scanners. The dual-panel configuration included two detector heads separated by 21 cm, each consisting of 3×4 blocks of 13×13 crystals, while the full-ring system comprised 14 detector blocks in four rings with a 21 cm diameter. During acquisition, the dual panel system was rotated by 90 degrees (step and shoot, no data acquisition during motion) to increase angular sampling<em>.</em> Clinical data from 51 ¹⁸F-FDG breast PET/CT cases were used as activity and attenuation maps for the simulations. A SwinUNETR architecture was trained to synthesize full-ring–equivalent images from dual-panel data. Performance was evaluated with structural similarity index (SSIM), peak signal-to-noise ratio (PSNR), root mean square error (RMSE), and voxelwise correlation. The dual-panel and full-ring scanners achieved spatial resolutions of 3.2 mm and 1.6 mm, and sensitivities of 8.9 and 14.2 cps/kBq, respectively. Compared with dual-panel images, AI-enhanced outputs showed improvements of 2.65% in PSNR, 26.4% in SSIM, and 12.1% in RMSE. Voxelwise correlation increased markedly (R² increased from 0.75 to 0.96). These findings highlight the potential of DL-based approaches to generate higher quality, artifact-reduced breast PET images, allowing cost-effective dual-panel systems to approach the performance of full-ring scanners.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 3","pages":"Pages 366-375"},"PeriodicalIF":4.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145985551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large axial field of view PET/CT – Not just a longer PET gantry","authors":"Mathias R. Steffner,&nbsp;Tim Felgenhauer,&nbsp;Bastian Szermerski,&nbsp;Johanna Diekmann,&nbsp;Frank M. Bengel,&nbsp;Sibylle I. Ziegler,&nbsp;Lilli Geworski","doi":"10.1016/j.zemedi.2026.03.008","DOIUrl":"10.1016/j.zemedi.2026.03.008","url":null,"abstract":"<div><div>Positron Emission Tomography (PET) has undergone disruptive advancements in the past two decades. One of the most impactful technological developments is the introduction of Large Axial Field-of-View PET/CT (LAFOV PET/CT). These systems are transforming clinical routine by enabling dramatically shorter acquisition times and substantially higher sensitivity, thereby influencing all related workflows. Established procedures gain new diagnostic potential thanks to image quality and detection accuracy that surpass the limits of conventional PET/CT. Beyond routine clinical applications, advanced methods such as parametric imaging or system-based network analyses particularly benefit from LAFOV PET/CT, as the extended field of view allows for the simultaneous observation of all relevant organs in a single bed position. This review highlights the main system features of LAFOV PET/CT and their potential in clinical use.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 3","pages":"Pages 326-331"},"PeriodicalIF":4.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147523597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial Board + Consulting Editorial Board","authors":"","doi":"10.1016/S0939-3889(26)00029-2","DOIUrl":"10.1016/S0939-3889(26)00029-2","url":null,"abstract":"","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 2","pages":"Page iii"},"PeriodicalIF":4.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148477984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","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,&nbsp;Jan Scheunemann,&nbsp;Christoph Hoeschen,&nbsp;Thorsten Frenzel,&nbsp;Theresa Staufer","doi":"10.1016/j.zemedi.2025.04.001","DOIUrl":"10.1016/j.zemedi.2025.04.001","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 2","pages":"Pages 212-225"},"PeriodicalIF":4.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144060952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design, implementation and evaluation of non-contact in vivo confocal microscopy for capturing the human corneal endothelium from the central to near-limbal regions","authors":"Karsten Sperlich,&nbsp;Alois Gottschlich,&nbsp;Karsten Winter,&nbsp;Florian Worsch,&nbsp;Oliver Stachs,&nbsp;Sebastian Bohn","doi":"10.1016/j.zemedi.2025.12.001","DOIUrl":"10.1016/j.zemedi.2025.12.001","url":null,"abstract":"<div><h3>Purpose</h3><div>Current imaging techniques for assessing the human corneal endothelium are constrained by drawbacks related to corneal contact, imaging artifacts, and a restricted field of view (FOV). We present a non-contact in vivo confocal microscopy (IVCM) configuration enabling cellular-resolution endothelial imaging.</div></div><div><h3>Methods</h3><div>A commercially available scanning laser ophthalmoscope was modified with a long-working-distance microscope objective enabling non-contact IVCM of the corneal endothelium. Central endothelial images were obtained in one healthy volunteer using the novel non-contact IVCM and two established modalities: contact IVCM and specular microscopy. A cell segmentation algorithm was applied to compare modalities. For the non-contact IVCM, near-limbal images were obtained in a second volunteer demonstrating far-peripheral imaging. For demonstration purposes, additional five healthy volunteers were imaged.</div></div><div><h3>Results</h3><div>The non-contact IVCM achieved a lateral resolution below 2.2 µm, while offering a larger FOV. Obtained quantitative metrics - including endothelial cell density, mean cell area, and polygonality - were consistent across modalities. The system also enabled high-quality imaging of peripheral and near-limbal endothelial regions with resolution and contrast similar to central areas.</div></div><div><h3>Conclusion</h3><div>This non-contact IVCM system delivers cellular-resolution imaging of the human corneal endothelium across central to near-limbus without topical anesthesia or corneal contact. It preserves the quantitative consistency of contact confocal microscopy yet offers greater comfort and a larger sampling area. To our knowledge, the herein presented IVCM is currently the only non-contact, high-resolution imaging modality demonstrating endothelial imaging in the limbal region in vivo. These results offer a patient-friendly alternative for routine quantitative endothelial assessment.</div></div>","PeriodicalId":54397,"journal":{"name":"Zeitschrift fur Medizinische Physik","volume":"36 2","pages":"Pages 144-150"},"PeriodicalIF":4.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145795883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}