Institut für Medizintechnik und Medizininformatik
Dauerhafte URI für die Sammlunghttps://irf.fhnw.ch/handle/11654/23
Listen
300 Ergebnisse
Ergebnisse nach Hochschule und Institut
Publikation Technical note: development of a simulation framework, enabling the investigation of locally tuned single energy proton radiography(IOP Publishing, 07.02.2024) Lundberg, Måns; Meijers, Arturs; Souris, Kevin; Deffet, Sylvain; Weber, Damien C; Lomax, Antony; Knopf, AntjeRange uncertainties remain a limitation for the confined dose distribution that proton therapy can offer. The uncertainty stems from the ambiguity when translating CT Hounsfield Units (HU) into proton stopping powers. Proton Radiography (PR) can be used to verify the proton range. Specifically, PR can be used as a quality-control tool for CBCT-based synthetic CTs. An essential part of the work illustrating the potential of PR has been conducted using multi-layer ionization chamber (MLIC) detectors and mono-energetic PR. Due to the dimensions of commercially available MLICs, clinical adoption is cumbersome. Here, we present a simulation framework exploring locally-tuned single energy (LTSE) proton radiography and corresponding potential compact PR detector designs. Based on a planning CT data set, the presented framework models the water equivalent thickness. Subsequently, it analyses the proton energies required to pass through the geometry within a defined ROI. In the final step, an LTSE PR is simulated using the MCsquare Monte Carlo code. In an anatomical head phantom, we illustrate that LTSE PR allows for a significantly shorter longitudinal dimension of MLICs. We compared PR simulations for two exemplary 30 × 30 mm2proton fields passing the phantom at a 90° angle at an anterior and a posterior location in an iso-centric setup. The longitudinal distance over which all spots per field range out is significantly reduced for LTSE PR compared to mono-energetic PR. In addition, we illustrate the difference in shape of integral depth dose (IDD) when using constrained PR energies. Finally, we demonstrate the accordance of simulated and experimentally acquired IDDs for an LTSE PR acquisition. As the next steps, the framework will be used to investigate the sensitivity of LTSE PR to various sources of errors. Furthermore, we will use the framework to systematically explore the dimensions of an optimized MLIC design for daily clinical use.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation In situ minimally invasive 3D printing for bone and cartilage regeneration - a scoping review(De Gruyter, 14.09.2024) Maintz, Michaela; Tomooka, Yukiko; Eugster, Manuela; Gerig, Nicolas; Sharma, Neha; Thieringer, Florian M.; Rauter, GeorgAdvancements in personalized medicine, three-dimensional (3D) printing, miniaturization, and robot-assistedsurgery are driving innovation in tissue engineering. A novelapproach, known asin situprinting, focuses on the direct depo-sition of materials at the surgical site. Using thein situprintingapproach, bone and/or cartilage defects can be addressed withhigh precision. Furthermore, highly customized 3D printed tis-sue constructs or implants can be deposited directly insidethe body. Currently, most applications ofin situprinting arelimited to areas near the skin or open surgeries. Even thougha minimally invasive approach would bring clinical benefits,only a few research groups have focused on this field. In thisscoping review, we provide an overview of the current stateofin situminimally invasive 3D printing technology for boneand cartilage regeneration and discuss its advantages and cur-rent challenges.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Imaging in article therapy. Current practice and future trends(IOP Publishing, 06/2024) Paganelli, Chiara; Gianoli, Chiara; Knopf, Antje; Paganelli, Chiara; Gianoli, Chiara; Knopf, AntjeThe benefits of particle therapy (PT), stemming from its physical and radiobiological advantages, necessitate the use of dedicated imaging technologies and approaches to ensure precise treatment planning and delivery. This book endeavors to establish a fundamental understanding of imaging within the context of PT, alongside exploring current research and clinical perspectives on its role. The focus is directed towards examining near-room, in-room, and in-beam technologies, both those already in clinical use and those in the developmental stage, which play pivotal roles in treatment planning, delivery, and verification processes, enabling adjustments either offline or online. Concurrently, the text addresses methodological solutions derived from these imaging modalities to effectively address challenges such as range uncertainties, anatomical variations, and biological properties, thereby enhancing the accuracy of treatment modeling and adaptation.03 - SammelbandPublikation Conclusions and future perspectives of imaging in particle therapy(IOP Publishing, 06/2024) Paganelli, Chiara; Gianoli, Chiara; Knopf, Antje; Paganelli, Chiara; Gianoli, Chiara; Knopf, AntjeIn this chapter, we will consolidate the concluding remarks presented throughout the preceding chapters, with a specific emphasis on the technical and methodological advancements in image-guided particle therapy, as well as elucidating the future trajectory of this field.04A - Beitrag SammelbandPublikation Treatment verification in particle therapy(IOP Publishing, 01.06.2024) Gianoli, Chiara; De Simoni, M.; Knopf, Antje; Paganelli, Chiara; Gianoli, Chiara; Knopf, AntjeTo make the most of the physical and biological potentials of Particle Therapy (PT), it would be extremely desirable to verify dose deposition in vivo. In this chapter, we describe and compare in vivo range verification methods currently being proposed, developed or clinically implemented, including PET and prompt gamma imaging. The potential of other emerging techniques for indirect treatment verification will be also cited.04A - Beitrag SammelbandPublikation Integration of imaging in clinical protocols of particle therapy(IOP Publishing, 06/2024) Trnkova, P.; Bolsi, Alessandra; Knopf, Antje; Hoffmann, A.; Paganelli, Chiara; Gianoli, Chiara; Knopf, Antje04A - Beitrag SammelbandPublikation Intracoronary ECG ST-segment shift remission time during reactive myocardial hyperemia. A new method to assess hemodynamic coronary stenosis severity(American Physiological Society, 01.10.2024) Bigler, Marius Reto; Kieninger-Gräfitsch, Andrea; Rohla, Miklos; Corpateaux, Noé; Waldmann, Frédéric; Wildhaber, Reto; Häner, Jonas; Seiler, ChristianFractional flow reserve (FFR) measurements are recommended for assessing hemodynamic coronary stenosis severity. Intracoronary ECG (icECG) is easily obtainable and highly sensitive in detecting myocardial ischemia due to its close vicinity to the myocardium. We hypothesized that the remission time of myocardial ischemia on icECG after a controlled coronary occlusion accurately detects hemodynamically relevant coronary stenosis. This retrospective, observational study included patients with chronic coronary syndrome undergoing hemodynamic coronary stenosis assessment immediately following a strictly 1-min proximal coronary artery balloon occlusion with simultaneous icECG recording. icECG was used for a beat-to-beat analysis of the ST-segment shift during reactive hyperemia immediately following balloon deflation. The time from coronary balloon deflation until the ST-segment shift reached 37% of its maximum level, i.e., icECG ST-segment shift remission time (τ-icECG in seconds), was obtained by an automatic algorithm. τ-icECG was tested against the simultaneously obtained reactive hyperemia FFR at a threshold of 0.80 as a reference parameter. From 120 patients, 139 icECGs (age, 68 ± 10 yr old) were analyzed. Receiver operating characteristic (ROC) analysis of τ-icECG for the detection of hemodynamically relevant coronary stenosis at an FFR of ≤0.80 was performed. The area under the ROC curve was equal to 0.621 (P = 0.0363) at an optimal τ-icECG threshold of 8 s (sensitivity, 61%; specificity, 67%). τ-icECG correlated inversely and linearly with FFR (P = 0.0327). This first proof-of-concept study demonstrates that τ-icECG, a measure of icECG ST segment-shift remission after a 1-min coronary artery balloon occlusion accurately detects hemodynamically relevant coronary artery stenosis according to FFR at a threshold of ≥8 s.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Possible association of dose rate and the development of late visual toxicity for patients with intracranial tumours treated with pencil beam scanned proton therapy(BioMed Central, 17.06.2024) Meijers, Arturs; Daartz, Juliane; Knopf, Antje; Van Heerden, Michelle; Bizzocchi, Nicola; Vazquez, Miriam Varela; Bachtiary, Barbara; Pica, Alessia; Shih, Helen A.; Weber, Damien CharlesBackground and purpose Rare but severe toxicities of the optic apparatus have been observed after treatment of intracranial tumours with proton therapy. Some adverse events have occurred at unusually low dose levels and are thus difficult to understand considering dose metrics only. When transitioning from double scattering to pencil beam scanning, little consideration was given to increased dose rates observed with the latter delivery paradigm. We explored if dose rate related metrics could provide additional predicting factors for the development of late visual toxicities. Materials and methods Radiation-induced intracranial visual pathway lesions were delineated on MRI for all index cases. Voxel-wise maximum dose rate (MDR) was calculated for 2 patients with observed optic nerve toxicities (CTCAE grade 3 and 4), and 6 similar control cases. Additionally, linear energy transfer (LET) related dose enhancing metrics were investigated. Results For the index cases, which developed toxicities at low dose levels (mean, 50 GyRBE), some dose was delivered at higher instantaneous dose rates. While optic structures of non-toxicity cases were exposed to dose rates of up to 1 to 3.2 GyRBE/s, the pre-chiasmatic optic nerves of the 2 toxicity cases were exposed to dose rates above 3.7 GyRBE/s. LET-related metrics were not substantially different between the index and non-toxicity cases. Conclusions Our observations reveal large variations in instantaneous dose rates experienced by different volumes within our patient cohort, even when considering the same indications and beam arrangement. High dose rate regions are spatially overlapping with the radiation induced toxicity areas in the follow up images. At this point, it is not feasible to establish causality between exposure to high dose rates and the development of late optic apparatus toxicities due to the low incidence of injury.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Organ motion in particle therapy and the role of imaging(IOP Publishing, 06/2024) Paganelli, Chiara; Molinelli, Silvia; Knopf, Antje; Paganelli, Chiara; Gianoli, Chiara; Knopf, AntjeOrgan motion is one of the main challenges to account for in particle therapy to plan and deliver an accurate treatment. In this chapter, we will explain the concept of organ motion in terms of inter- and intra-fraction variations. The current inter- and intra-fraction motion compensation techniques demanding for imaging will be also reported.04A - Beitrag SammelbandPublikation Machine learning for precision diagnostics of autoimmunity(Nature, 13.11.2024) Kruta, Jan; Carapito, Raphael; Trendelenburg, Marten; Martin, Thierry; Rizzi, Marta; Voll, Reinhard E.; Cavalli, Andrea; Natali, Eriberto; Meier, Patrick; Stawiski, Marc; Mosbacher, Johannes; Mollet, Annette; Santoro, Aurelia; Capri, Miriam; Giampieri, Enrico; Schkommodau, Erik; Miho, EnkelejdaEarly and accurate diagnosis is crucial to prevent disease development and define therapeutic strategies. Due to predominantly unspecific symptoms, diagnosis of autoimmune diseases (AID) is notoriously challenging. Clinical decision support systems (CDSS) are a promising method with the potential to enhance and expedite precise diagnostics by physicians. However, due to the difficulties of integrating and encoding multi-omics data with clinical values, as well as a lack of standardization, such systems are often limited to certain data types. Accordingly, even sophisticated data models fall short when making accurate disease diagnoses and presenting data analyses in a user-friendly form. Therefore, the integration of various data types is not only an opportunity but also a competitive advantage for research and industry. We have developed an integration pipeline to enable the use of machine learning for patient classification based on multi-omics data in combination with clinical values and laboratory results. The application of our framework resulted in up to 96% prediction accuracy of autoimmune diseases with machine learning models. Our results deliver insights into autoimmune disease research and have the potential to be adapted for applications across disease conditions.01A - Beitrag in wissenschaftlicher Zeitschrift