Zeitschrift fur medizinische Physik最新文献

{"title":"Improvement of perceived cochlear implant sound quality through individualized psychoacoustic-based frequency fitting.","authors":"Tobias Rader, Lisa Lippl, Joachim Müller","doi":"10.1016/j.zemedi.2025.02.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.02.001","url":null,"abstract":"<p><strong>Objective: </strong>In recent years, there has been a trend toward more individualization in the fitting of cochlear implants (CI). Here, a new individualized approach to frequency band allocation was used. This approach is based on binaural perceptual pitch matching.</p><p><strong>Patient: </strong>The patient had congenital bilateral progressive sensorineural hearing loss due to Usher Syndrome. He had used hearing aids in both ears since the age of 4 years. In his mid-40s, he received a CI on his right ear and, ten months later, a second CI on the left ear.</p><p><strong>Intervention: </strong>Adjustments to the frequency band allocations were made, guided by the binaural perceptual pitch matching of piano notes. For the first CI, pitch matching was performed using the contralateral ear as the reference, which had preserved low-frequency residual hearing (bimodal pitch matching). For the second CI, pitch matching was performed using the first implanted side as the reference (bilateral electrical pitch matching).</p><p><strong>Results: </strong>The final frequency band allocation adjustments were always shifted toward lower frequencies relative to the default band allocations. The adjustments were larger in magnitude for the second CI compared to the first CI. Speech perception scores generally increased over the course of rehabilitation and were higher with the individualized fitting compared to the default fitting. The subjective sound quality was reportedly greatly improved with the individualized fitting.</p><p><strong>Conclusions: </strong>Individualized psychoacoustic frequency-based fitting can yield improvements in the perceived sound quality with a CI. However, this method requires significant residual hearing in at least one ear, and the patient must have relatively fine pitch discrimination abilities.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532032","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":"Development of an MR-only radiotherapy treatment planning workflow using a commercial synthetic CT generator for brain and head & neck tumor patients.","authors":"Martin Buschmann, Harald Herrmann, Manuela Gober, Aleksandra Winkler, Nicole Eder-Nesvacil, Franziska Eckert, Joachim Widder, Dietmar Georg, Petra Trnková","doi":"10.1016/j.zemedi.2025.01.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.01.003","url":null,"abstract":"<p><strong>Background: </strong>In magnetic resonance (MR)-only radiotherapy (RT) workflows, synthetic computed tomography images (sCT) are needed as a surrogate for a dose calculation. Commercial and certified sCT algorithms became recently available, but many have not been evaluated in a clinical setting, especially in the head and neck tumor (HN) region. In this study, an MRI-only workflow using a commercial sCT generator for photon beam therapy in brain and HN body sites was evaluated in terms of dose calculation accuracy, modelling of immobilization devices, as well as usability for autosegmentation.</p><p><strong>Methods: </strong>For 13 brain and 10 HN cancer patients, MR scans using T1W mDIXON sequences were retrospectively collected. Four brain and all HN patients were scanned in RT treatment position with immobilization devices. All MRIs were converted to a sCT using the MRCAT algorithm (Philips, Eindhoven, The Netherlands). All patients underwent standard planning CT (pCT) for clinical segmentation and VMAT treatment planning. The sCT was rigidly registered to the pCT and clinical contours were transferred to the sCT. For dosimetric evaluation of sCT based dose calculation, all VMAT plans were recalculated on the sCT. D_1% and D_mean were compared for all structures between pCT and sCT, but D_95%, D_98% for targets only. For MR-invisible RT immobilization device modelling, MR-visible markers were placed into sCT and a geometric robustness analysis was performed based on the same target dose-volume parameters. For organs-at-risk (OARs) autosegmentation, both pCT and sCT were autosegmented with a clinically established CT-based autocontouring software. The agreement of contours on pCT and sCT was analyzed by similar dose-volume parameters and dice similarity (DSC) and Hausforff distance (HD).</p><p><strong>Results: </strong>The overall median deviation (± interquartile range) of dosimetric parameters between sCT and pCT including the immobilization model was 1.1 ± 0.4% for brain target volumes, 1.3 ± 1.2% for brain OAR, 0.4 ± 0.7% for HN target volumes and 0.4 ± 0.9% for HN OAR. The median geometric agreement over all sCT autocontours compared to pCT autocontours resulted in DSC = 0.82 for brain OAR and DSC = 0.79 for HN OAR.</p><p><strong>Conclusion: </strong>MR-only RT planning using MRCAT software package was feasible for brain and HN tumors, with acceptable clinical accuracy. The MR-invisible immobilization devices could be modelled in the planning system and the autosegmentation on sCTs using a CT-based autosegmentation tool was feasible.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434902","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":"Impact of the corneal epithelium on the corneal power using 3D raytracing with OCT data.","authors":"Achim Langenbucher, Nóra Szentmáry, Alan Cayless, Peter Hoffmann, Jascha Wendelstein","doi":"10.1016/j.zemedi.2025.01.002","DOIUrl":"https://doi.org/10.1016/j.zemedi.2025.01.002","url":null,"abstract":"<p><strong>Purpose: </strong>To study the effects of corneal imaging and focusing using a raytracing simulation with 2 and 3 surface corneal models based on customized surface representations of corneal tomography data .</p><p><strong>Methods: </strong>Raytracing simulation using surface data for the epithelium (S1), stroma (S2) and endothelium (S3) extracted from MS-39 anterior segment tomographer CSV export files. Customized surface representations were derived using Gaussian Process Predictors, and rays traced through the cornea and a 3.5 mm aperture stop located 3.66 mm behind the corneal apex. 4 clinical examples were evaluated: A) after hyperopic LASIK, B) after myopic LASIK, C) keratoconus, and D) after PRK with postoperatively developed Salzmann nodules.</p><p><strong>Results: </strong>The raytracing based bundle focus and wavefront focus distances of the 2 surface (S1 and S3) and 3 surface cornea models (S1, S2 and S3) were comparable, whereas the paraxial focus derived from a 1 surface cornea (S1), 2 (S1 and S3) or 3 surface cornea (S1, S2 and S3) using floating best fit sphere representations for S1, S1 and S3 showed systematically lower / higher focal distance with B) / C) indicating an overestimation / underestimation of corneal power with paraxial calculations.</p><p><strong>Conclusions: </strong>The clinical examples in this study exhibited only minor differences between the mono- and dual layer cornea models. We recommend verification in a larger clinical study. Three surface corneal raytracing models could be of clinical relevance in intraocular lens calculations and LASIK ablation nomograms, offering potential improvements over paraxial calculations especially in cases with surface irregularities.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412155","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":"Imaging dose and image quality of kilovoltage imaging implemented on a helical tomotherapy unit.","authors":"Eric D Ehler, Parham Alaei","doi":"10.1016/j.zemedi.2024.12.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.12.003","url":null,"abstract":"<p><p>The purpose of this work was to evaluate the imaging dose for the Accuray Radixact ClearRT system. Low-contrast resolution and CT number consistency was evaluated as well. CTDI measurements were compared to vendor supplied values, and similar measurements were done on a Varian TrueBeam kV cone-beam CT (CBCT) and a Philips Big Bore CT scanner. In-field imaging doses were measured using various protocols in an anthropomorphic phantom, while out-of-field doses were measured 10 cm from the imaging field edge. Comparison of the CTDI and the in-field doses showed considerable disagreement when the patient anatomy size was not congruent with the size of the CTDI phantom. While that is an expected outcome, this work provides an estimate of the differences for a variety of ClearRT protocols when this situation arises. The CNR was measured for all combinations of ClearRT settings for comparisons within the system, as well as for a comparison with a CBCT and fan-beam CT system. The CNR and dose information provided in this work can be used to aid in selecting a ClearRT imaging protocol. The CT number stability was tracked over 27 months; two instances where the CT number constancy exceeded tolerance were observed after service.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143026273","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":"Black-blood MRI at 7T using 2D RARE MRI: In vitro testing and in vivo demonstration.","authors":"Eva Peschke, Mariya S Pravdivtseva, Olav Jansen, Naomi Larsen, Jan-Bernd Hövener","doi":"10.1016/j.zemedi.2024.11.002","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.11.002","url":null,"abstract":"<p><p>Vessel walls play a crucial role in many inflammatory vascular diseases. Vessel wall imaging (VWI) using mangnetic resonance imaging (MRI) is one of the few methods by which vessel walls and inflammation can be visualized noninvasively, in vivo, and without ionizing radiation. VWI is based on black-blood (BB) MRI, where the signal from flowing blood is suppressed and contrast agent accumulation in the (inflamed) vessel wall is highlighted. Here, high resolution, T1 weighting, suppression of fat and flowing spins is essential. Whereas VWI is often applied in humans, only very few reports describe its use in small animals. Here, we investigated whether BB MRI for rodents can be implemented using a state-of-the-art, but commercially available, preclinical MRI system and imaging sequence. We identified 2D spin-echo (RARE)-based BB-MRI as a promising sequence that is widely available and not vendor dependent. First, we investigated the properties of the sequence in vitro with respect to image contrast, resolution, the suppression of signal of flowing spins and fat using a newly developed, 3D-printed model setup (cylindrical model with exchangeable nuclear magnetic resonance tubes and flow tube in agarose, printed with stereolithography). For example, good signal-to-noise ratio, BB and T1 contrast were obtained for TE = 5 ms for slice thickness equal or below 0.352 mm or slice thickness = 0.8 mm with TE at least 25 ms. In vivo, we obtained a pronounced BB effect for both intracranial and abdominal vessels of healthy rats down to a 0.25 mm diameter in no more than 1:36 min with TE = 12 ms, TR = 750 ms, voxel 156 × 156 × 800 µm³, and 11 slices. Compared to in vitro, we were able to reduce TE without apparent artifacts likely because the flow was faster in vivo than in vitro. Additionally, we needed to increase the resolution to image small vessels. Thus, we found that BB-MRI with 2D spin-echo sequences is feasible on rodents with state-of-the-art, commercially available preclinical MRI systems. We believe that these results will facilitate the development and application of rodent VWI in longitudinal studies, which, in comparison to histology, may reduce the number of needed animals and intersubject variability at the same time.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142776194","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":"Systematizing the risk management process in clinical radiotherapy practice: Recommendations of the working group on risk management of the DGMP.","authors":"Dominik Kornek, Cordelia Hoinkis, Natasa Milickovic, Ailine Lange, Alena Knak, Manuel März, Mieke L Möller, Markus Buchgeister","doi":"10.1016/j.zemedi.2024.11.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.11.001","url":null,"abstract":"<p><strong>Purpose: </strong>The Deutsche Gesellschaft für Medizinische Physik [German Society of Medical Physics] has recently published two coherent reports, No. 25 and No. 28, detailing the design and implementation of a risk management (RM) process for German radiotherapy (RT) departments. This study offers an overview and background of the efforts behind these reports.</p><p><strong>Methods and materials: </strong>For three years, up to nine medical physicists (MPs) with practical RM experience held weekly meetings to develop recommendations for a clinical RM process. Care was taken to ensure that the recommendations were equally applicable to RT departments of various sizes. A process-based method derived from the failure mode and effects analysis (FMEA) was created to identify and address risks from unintentional radiation exposure. This method was applied to exemplarily analyze the hazardous scenarios in breast RT using surface guidance and deep inspiration breath hold (DIBH) techniques. Three common criticality methods-risk matrix, risk priority number, and action priority-were applied, and each step was schematically explained for first-time users. Each report was peer-reviewed by two radiation oncologists and 11 MPs.</p><p><strong>Results: </strong>In report No. 25, basic requirements were outlined for running the RM process, conducting risk assessments, and monitoring clinical procedures. A three-year plan-do-check-act cycle was proposed for continuous improvement. In report No. 28, general process lists for external beam radiotherapy (EBRT), brachytherapy, and radionuclide therapy were designed. Based on the EBRT process list, 45 hazardous scenarios in the surface-guided breast RT in DIBH were identified. Two scenarios were used to illustrate handling instructions for the three criticality methods.</p><p><strong>Conclusions: </strong>The recommendations provide clinical MPs and other health professionals with a pragmatic approach to RM, balancing both the needs of smaller practices and larger clinics in Germany. The risk of unintended exposures of patients is viewed acceptable once it has been lowered to a state that is as low as reasonably achievable.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142694093","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":"Large-field irradiation techniques in Germany: A DGMP Working Group survey on the current clinical implementation of total body irradiation, total skin irradiation and craniospinal irradiation.","authors":"Lena Heuchel, Stephan Garbe, Armin Lühr, Maya Shariff","doi":"10.1016/j.zemedi.2024.09.002","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.09.002","url":null,"abstract":"<p><p>In 2023, a Germany-wide survey on the current clinical practice of three different large field irradiation techniques (LFIT), namely total body irradiation (TBI), total skin irradiation (TSI) and craniospinal irradiation (CSI), was conducted covering different aspects of the irradiation process, e.g., the irradiation unit and technique, dosimetrical aspects and treatment planning as well as quality assurance. The responses provided a deep insight into the applied approaches showing a high heterogeneity between participating centers for all three large field irradiation techniques. The highest heterogeneity was found for TBI. Here, differences between centers were found in almost every aspect of the irradiation process, e.g., the irradiation technique, the prescription dose, the spared organs at risk and the applied treatment planning method. For TBI, the only agreement was found in the fractionation scheme (2 Gy/fraction, 2 fractions/day) and the dose reduction to the lung. TSI was the rarest of the three LFITs. For TSI, the only agreement was found in the use of 6 MeV when irradiating with electrons. The reported approaches of CSI were closest to standard radiotherapy, using no CSI-specific irradiation techniques or treatment planning methods. For CSI, the only agreement was found in the prescribed dose to the brain (50 - 60 Gy). When asking for future requirements, participating centers considered the lack of standardization as the most important future challenge and suggested to perform (retrospective) patient studies. The results of such studies can then serve as a basis for new and improved guidelines.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142485130","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":"Monte Carlo calculations of target fragments from helium and carbon ion interactions with water.","authors":"Quazi Muhammad Rashed Nizam, Asif Ahmed, Iftekhar Ahmed, Lembit Sihver","doi":"10.1016/j.zemedi.2024.09.003","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.09.003","url":null,"abstract":"<p><p>When high energetic heavy ions interact with any target, short range, high linear energy transfer (LET) target fragments are produced. These target fragments (TFs) can give a significant dose to the healthy tissue during heavy ion cancer therapy, and when cosmic radiation interacts with astronauts. This paper presents Monte Carlo simulations, using the Particle and Heavy Ion Transport code System (PHITS), to characterize target fragments from reactions of helium and carbon ions with water. The calculated ranges, LET, doses, and production cross sections are presented. It is shown that protons, deuterons, tritons, alpha particles, ³He, ⁶He, nitrogen, oxygen, and fluorine ions are the most probable target fragments when carbon and helium ions collide with water. Among the produced target fragments, alpha particles and nitrogen ions give the highest dose to the targets, since the combination of fluence and LETs of these TFs are highest among the produced fragments. The production cross sections of proton and oxygen are the highest among the target fragments cross sections when helium and carbon ions imping on water, because these TFs can be produced through more reaction channels compared to other fragments. These findings are helpful for accurate dose measurement during heavy ion cancer therapy and for shielding of space radiation.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142407375","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":"An automated pipeline for computation and analysis of functional ventilation and perfusion lung MRI with matrix pencil decomposition: TrueLung.","authors":"Orso Pusterla, Corin Willers, Robin Sandkühler, Simon Andermatt, Sylvia Nyilas, Philippe C Cattin, Philipp Latzin, Oliver Bieri, Grzegorz Bauman","doi":"10.1016/j.zemedi.2024.08.001","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.08.001","url":null,"abstract":"<p><strong>Purpose: </strong>To introduce and evaluate TrueLung, an automated pipeline for computation and analysis of free-breathing and contrast-agent free pulmonary functional magnetic resonance imaging.</p><p><strong>Materials and methods: </strong>Two-dimensional time-resolved ultra-fast balanced steady-state free precession acquisitions were transferred to TrueLung, which included image quality checks, image registration, and computation of perfusion and ventilation maps with matrix pencil decomposition. Neural network whole-lung and lobar segmentations allowed quantification of impaired relative perfusion (R_Q) and fractional ventilation (R_FV). TrueLung delivered functional maps and quantitative outcomes, reported for clinicians in concise documents. We evaluated the pipeline using 1.5T data from 75 children with cystic fibrosis by assessing the feasibility of functional MR imaging, average scan time, and the robustness of the functional outcomes. Whole-lung and lobar segmentations were manually refined when necessary, and the impact on R_Q and R_FV was quantified.</p><p><strong>Results: </strong>Functional imaging was feasible in all included CF children without any dropouts. On average, 7.9 ± 1.8 (mean±SD) coronal slice positions per patient were acquired, resulting in a mean scan time of 6min 20s per patient. The whole pipeline required 20min processing time per subject. TrueLung delivered the functional maps of all the subjects for radiological assessment. Quality controlling maps and segmentations lasted 1min 12s per patient. The automated segmentations and quantification of whole-lung defects were satisfying in 88% of patients (97% of slices) and the lobar quantification in 73% (93% of slices). The segmentations refinements required 16s per patient for the whole-lung, and 2min 10s for the lobe masks. The relative differences in R_FV and R_Q between fully-automated and manually refined data were 0.7% (1.2%) and 2.0% (2.9%) for whole-lung quantification (median, [third quartile]), and excluding two outliers, 1.7% (3.9%) and 1.2% (3.8%) for the lobes, indicating the refinements could be potentially omitted in several patients.</p><p><strong>Conclusions: </strong>TrueLung quickly delivers functional maps and quantitative outcomes in an objective and standardized way, suitable for radiological and pneumological assessment with minimal manual input. TrueLung can be used for clinical research in cystic fibrosis and might be applied across various lung diseases.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142305511","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 skin flap thickness on the transmission characteristics of middle ear implant audio processors.","authors":"Laura Fröhlich, Torsten Rahne, Alexander Müller, Oliver Dziemba","doi":"10.1016/j.zemedi.2024.08.002","DOIUrl":"https://doi.org/10.1016/j.zemedi.2024.08.002","url":null,"abstract":"<p><strong>Objective: </strong>To measure signal transmission characteristics for audio processors of an active middle ear implant as a function of skin flap thickness, i.e., distance between audio processor and the implant's receiver coil.</p><p><strong>Methods: </strong>Output sound pressure levels for 90 dB input sound pressure level (OSPL90), reference test gains as function of frequency for an input sound pressure level of 60 dB (RTG60), and reference test gains (RTG - high frequency averages) were recorded in a hearing aid test box for Samba 2 Hi, Samba 2 Lo, and AP404 audio processors (MED-EL, Innsbruck, Austria) positioned on an implant-in-the-box and distances of 0-10 mm between audio processors and the receiver coil.</p><p><strong>Results: </strong>For all audio processors, the OSPL90 and RTG decreased linearly with increasing distance. The effect was dependent on audio processor type and the strongest reduction was observed for Samba 2 Lo. Between distances of 0 mm and 10 mm, the relative change of RTG was - 9,9 dB for Samba 2 Hi, -10,3 dB for AP404, and -27,7 dB for Samba 2 Lo.</p><p><strong>Conclusions: </strong>Skin thickness is a clinically significant factor which has to be considered in VSB treatment. In combination with insufficient transducer coupling or in patients with hearing thresholds close to the indication criteria limit, a thick skin flap could lead to loss of transmitted energy resulting in insufficient audiological outcome with the active middle ear implant.</p>","PeriodicalId":101315,"journal":{"name":"Zeitschrift fur medizinische Physik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142305512","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}