Zeitschrift fur medizinische Physik最新文献

{"title":"Erratum to \"Multiple direction needle-path planning and inverse dose optimization for robotic low-dose rate brachytherapy\" [Z Med Phys 32 (2022) 173-187].","authors":"Philipp Aumüller, Andreas Rothfuss, Martin Polednik, Yasser Abo-Madyan, Michael Ehmann, Frank A Giordano, Sven Clausen","doi":"10.1016/j.zemedi.2024.07.009","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.07.009","url":null,"abstract":"","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142127878","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":"Erratum to \"Investigation of biases in convolutional neural networks for semantic segmentation using performance sensitivity analysis\" [Z Med Phys 32 (2022) 346-360].","authors":"Daniel Güllmar, Nina Jacobsen, Andreas Deistung, Dagmar Timmann, Stefan Ropele, Jürgen R Reichenbach","doi":"10.1016/j.zemedi.2024.07.007","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.07.007","url":null,"abstract":"","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142127877","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":"Erratum to \"Tumour volume distribution can yield information on tumour growth and tumour control\" [Z Med Phys 32 (2022) 143-148].","authors":"Uwe Schneider, Jürgen Besserer","doi":"10.1016/j.zemedi.2024.07.010","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.07.010","url":null,"abstract":"","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142117030","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":"Reducing electromagnetic interference in MR thermometry: A comparison of setup configurations for MR-guided microwave ablations.","authors":"Simon Schröer, Daniel Düx, Josef Joaquin Löning Caballero, Julian Glandorf, Thomas Gerlach, Dominik Horstmann, Othmar Belker, Moritz Gutt, Frank Wacker, Oliver Speck, Bennet Hensen, Marcel Gutberlet","doi":"10.1016/j.zemedi.2024.07.004","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.07.004","url":null,"abstract":"<p><p>Magnetic Resonance (MR) thermometry is used for the monitoring of MR-guided microwave ablations (MWA), and for the intraoperative evaluation of ablation regions. Nevertheless, the accuracy of temperature mapping may be compromised by electromagnetic interference emanating from the microwave (MW) generator. This study evaluated different setups for improving magnetic resonance imaging (MRI) during MWA with a modified MW generator. MWA was performed in 15 gel phantoms comparing three setups: The MW generator was placed outside the MR scanner room, either connected to the MW applicator using a penetration panel with a radiofrequency (RF) filter and a 7 m coaxial cable (Setup 1), or through a waveguide using a 5 m coaxial cable (Setup 2). Setup 3 employed the MW generator within the MR scan room, connected by a 5 m coaxial cable. The coaxial cables in setups 2 and 3 were modified with custom shielding to reduce interference. The setups during ablation (active setup) were compared to a reference setup without the presence of the MW system. Thermometry and thermal dose maps (CEM43 model) were compared for the three configurations. Primary endpoints for assessment were signal-to-noise ratio (SNR), temperature precision, Sørensen-Dice-Coefficient (DSC), and RF-noise spectra. Setup 3 showed highly significant electromagnetic interference during ablation with a SNR decrease by -60.4%±13.5% (p<0.001) compared to reference imaging. For setup 1 and setup 2 no significant decrease in SNR was measured with differences of -2.9%±9.8% (p=0.6) and -1.5%±12.8% (p=0.8), respectively. SNR differences were significant between active setups 1 and 3 with -51.2%±16.1% (p<0.001) and between active setups 2 and 3 with -59.0%±15.5% (p<0.001) but not significant between active setups 1 and 2 with 19.0%±13.7% (p=0.09). Furthermore, no significant differences were seen in temperature precision or DSCs between all setups, ranging from 0.33 °C ± 0.04 °C (Setup 1) to 0.38 °C ± 0.06 °C (Setup 3) (p=0.6) and from 87.0%±1.6% (Setup 3) to 88.1%±1.6% (Setup 2) (p=0.58), respectively. Both setups (1 and 2) with the MW generator outside the MR scanner room were beneficial to reduce electromagnetic interference during MWA. Moreover, provided that a shielded cable is utilized in setups 2 and 3, all configurations displayed negligible differences in temperature precision and DSCs, indicating that the location of the MW generator does not significantly impact the accuracy of thermometry during MWA.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918507","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":"Non-contrast free-breathing liver perfusion imaging using velocity selective ASL combined with prospective motion compensation.","authors":"Ke Zhang, Simon M F Triphan, Mark O Wielpütz, Christian H Ziener, Mark E Ladd, Heinz-Peter Schlemmer, Hans-Ulrich Kauczor, Oliver Sedlaczek, Felix T Kurz","doi":"10.1016/j.zemedi.2024.06.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.06.001","url":null,"abstract":"<p><strong>Purpose: </strong>To apply velocity selective arterial spin labeling (VSASL) combined with a navigator-based (NAV) prospective motion compensation method for a free-breathing liver perfusion measurement without contrast agent.</p><p><strong>Methods: </strong>Sinc-modulated Velocity Selective Inversion (sinc-VSI) pulses were applied as labeling and control pulses. In order to account for respiratory motion, a navigator was employed in the form of a single gradient-echo projection readout, located at the diaphragm along the inferior-superior direction. Prior to each transverse imaging slice of the spin-echo EPI based readouts, navigator and fat suppression were incorporated. Motion data was obtained from the navigator and transmitted back to the sequence, allowing real-time adjustments to slice positioning. The sinc-VSI without velocity-selective gradients during the control condition but with velocity-selective gradients along all three directions during labeling was chosen for the VSASL. The VSASL was compared with pseudo-continuous ASL (pCASL) methods, which selectively tagged the moving spins using a tagging plane placed at the portal vein and hepatic artery.</p><p><strong>Results: </strong>The motion caused by respiratory activity was effectively computed using the navigator signal. The coefficients of variation (CoV) of average liver voxel in NAV were significantly decreased when compared to breath-hold (BH), with an average reduction of 29.4 ± 18.44% for control images, and 29.89 ± 20.83% for label images (p < 0.001). The resulting maps of normalized ASL signal (normalized to M₀) showed significantly higher perfusion weightings in the NAV-compensated VSASL, when compared to the NAV-compensated pCASL techniques.</p><p><strong>Conclusions: </strong>This study demonstrates the feasibility of using a navigator-based prospective motion compensation technique in conjunction with VSASL for the measurement of liver perfusion without the use of contrast agents while allowing for free-breathing.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500136","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":"Comparison of iterative reconstruction implementations for multislice helical CT.","authors":"Zsolt Adam Balogh, Zsofia Barna, Eva Majoros","doi":"10.1016/j.zemedi.2024.04.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.04.001","url":null,"abstract":"<p><p>The most mature image reconstruction algorithms in multislice helical computed tomography are based on analytical and iterative methods. Over the past decades, several methods have been developed for iterative reconstructions that improve image quality by reducing noise and artifacts. In the regularization step of iterative reconstruction, noise can be significantly reduced, thereby making low-dose CT. The quality of the reconstructed image can be further improved by using model-based reconstructions. In these reconstructions, the main focus is on modeling the data acquisition process, including the behavior of the photon beams, the geometry of the system, etc. In this article, we propose two model-based reconstruction algorithms using a virtual detector for multislice helical CT. The aim of this study is to compare the effect of using a virtual detector on image quality for the two proposed algorithms with a model-based iterative reconstruction using the original detector model. Since the algorithms are implemented using multiple GPUs, the merging of separately reconstructed volumes can significantly affect image quality. This issue is often referred to as the \"long object\" problem, for which we also present a solution that plays an important role in the proposed reconstruction processes. The algorithms were evaluated using mathematical and physical phantoms, as well as patient cases. The SSIM, MS-SSIM and L₁ metrics were utilized to evaluate the image quality of the mathematical phantom case. To demonstrate the effectiveness of the algorithms, we used the CatPhan 600 phantom. Additionally, anonymized patient scans were used to showcase the improvements in image quality on real scan data.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140855011","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":"High-energy X-ray diffraction experiment employing a compact synchrotron X-ray source based on inverse Compton scattering.","authors":"Johannes Melcher, M. Dierolf, Benedikt Günther, K. Achterhold, Daniela Pfeiffer, Franz Pfeiffer","doi":"10.1016/j.zemedi.2024.03.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.03.003","url":null,"abstract":"","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":"83 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140765320","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":"Intra-fractional lung tumor motion monitoring using arbitrary gantry angles during radiotherapy treatment.","authors":"S. Hatamikia, Soraya Elmirad, H. Furtado, G. Kronreif, Elisabeth Steiner, W. Birkfellner","doi":"10.1016/j.zemedi.2024.03.004","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.03.004","url":null,"abstract":"","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":"68 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140764797","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":"Explorative study using ultrasound time-harmonic elastography for stiffness-based quantification of skeletal muscle function.","authors":"Yang Yang, Mehrgan Shahryari, Tom Meyer, Stephan Rodrigo Marticorena Garcia, Steffen Görner, Mahsa Salimi Majd, Jing Guo, Jürgen Braun, Ingolf Sack, Heiko Tzschätzsch","doi":"10.1016/j.zemedi.2024.03.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.03.001","url":null,"abstract":"<p><p>Time-harmonic elastography (THE) is an emerging ultrasound imaging technique that allows full-field mapping of the stiffness of deep biological tissues. THE's unique ability to rapidly capture stiffness in multiple tissues has never been applied for imaging skeletal muscle. Therefore, we addressed the lack of data on temporal changes in skeletal muscle stiffness while simultaneously covering stiffness of different muscles. Acquiring repeated THE scans every five seconds we quantified shear-wave speed (SWS) as a marker of stiffness of the long head (LHB) and short head (SHB) of biceps brachii and of the brachialis muscle (B) in ten healthy volunteers. SWS was continuously acquired during a 3-min isometric preloading phase, a 3-min loading phase with different weights (4, 8, and 12 kg), and a 9-min postloading phase. In addition, we analyzed temporal SWS standard deviation (SD) as a marker of muscle contraction regulation. Our results (median [min, max]) showed both SWS at preloading (LHB: 1.04 [0.94, 1.12] m/s, SHB: 0.86 [0.78, 0.94] m/s, B: 0.96 [0.87, 1.09] m/s, p < 0.001) and the increase in SWS with loading weight to be muscle-specific (LHB: 0.010 [0.002, 0.019] m/s/kg, SHB: 0.022 [0.017, 0.042] m/s/kg, B: 0.039 [0.019, 0.062] m/s/kg, p < 0.001). Additionally, SWS during loading increased continuously over time by 0.022 [0.004, 0.051] m/s/min (p < 0.01). Using an exponential decay model, we found an average relaxation time of 27 seconds during postloading. Analogously, SWS SD at preloading was also muscle-specific (LHB: 0.018 [0.011, 0.029] m/s, SHB: 0.021 [0.015, 0.027] m/s, B: 0.024 [0.018, 0.037] m/s, p < 0.05) and increased by 0.005 [0.003, 0.008] m/s/kg (p < 0.01) with loading. SWS SD did not change over loading time and decreased immediately in the postloading phase. Taken together, THE of skeletal muscle is a promising imaging technique for in vivo quantification of stiffness and stiffness changes in multiple muscle groups within seconds. Both the magnitude of stiffness changes and their temporal variation during isometric exercise may reflect the functional status of skeletal muscle and provide additional information to the morphological measures obtained by conventional imaging modalities.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140178578","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":"Assessment of attenuation properties for SLA and SLS 3D-printing materials in X-ray imaging and nuclear medicine.","authors":"Stefan Weber, Andreas Block, Felix Bärenfänger","doi":"10.1016/j.zemedi.2024.02.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.02.003","url":null,"abstract":"<p><p>In recent years, access to 3D printers has become increasingly affordable. Alongside industrial and private applications, the significance of 3D printing in the clinical context is also growing. For instance, 3D printing processes enable the production of individual anatomical models that can be used to support patient communication or aid in surgical planning. While filament 3D printing is common, stereolithography (SLA) and selective laser sintering (SLS) printing processes offer higher precision. For the use of 3D printing materials in radiology, understanding their attenuation properties concerning ionizing radiation is crucial. Polymethyl methacrylate (PMMA) serves as an important reference material for radiological applications in this regard. In this research, linear- and mass attenuation coefficients of 38 SLA-/SLS-materials from Formlabs (Somerville, Massachusetts, USA) and PMMA will be determined through intensity measurements in nuclear medicine for the radionuclides technetium-99 m and iodine-131, as well as for X-ray imaging in the range of 60 kVp - 110 kVp tube voltage. Based on the mass attenuation coefficients, correction factors in respect to PMMA will be calculated for each material. A significant number of materials exhibit a deviance within approximately ±5% in respect to PMMA regardless of radiation energy. However, certain materials from the dental and industrial application show deviances up to +500% at the lower end of radiation energy spectrum. In conclusion, most materials can be considered equivalent to PMMA with only minor adjustments required. Materials with high deviances can be utilized as high-contrast materials in custom X-ray phantoms.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140121807","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}