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Leibold, D. (author), Schaart, D.R. (author), Goorden, M.C. (author)Cone-beam computed tomography (CBCT) and X-ray projection radiography are commonly used in the proton therapy workflow for the verification of patient positioning. The prospect of using the CBCT images for dose calculation purposes is attractive but currently hampered by the poorer image quality compared to the planning (fan-beam) CT. Ideally...conference paper 2024
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van Blaaderen, J.J. (author), van der Sar, S.J. (author), Onggo, Djulia (author), Sheikh, Md Abdul K. (author), Schaart, D.R. (author), Birowosuto, Muhammad D. (author), Dorenbos, P. (author)Due to recent development in detector technology, photon-counting computed tomography (PCCT) has become a rapidly emerging medical imaging technology. Current PCCT systems rely on the direct conversion of X-ray photons into charge pulses, using CdTe, CZT, or Si semiconductor detectors. Indirect detection using ultrafast scintillators coupled...journal article 2023
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Pastor Serrano, O. (author), Habraken, S.J.M. (author), Hoogeman, M.S. (author), Lathouwers, D. (author), Schaart, D.R. (author), Nomura, Yusuke (author), Xing, Lei (author), Perko, Z. (author)Objective. In radiotherapy, the internal movement of organs between treatment sessions causes errors in the final radiation dose delivery. To assess the need for adaptation, motion models can be used to simulate dominant motion patterns and assess anatomical robustness before delivery. Traditionally, such models are based on principal...journal article 2023
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Leibold, D. (author), van der Sar, S.J. (author), Goorden, M.C. (author), Schaart, D.R. (author)X-ray detectors with photon-counting capabilities promise to revolutionise medical imaging. For an efficient comparison of detectors of various materials and with different setup choices, reliable detector performance measures are needed. The detector point spread function (PSF) is a commonly used measure, which describes the spatial response...journal article 2022
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van der Sar, S.J. (author), Brunner, Stefan (author), Schaart, D.R. (author)We investigate X-ray photon-counting scintillation detectors with silicon photomultiplier (SiPM) readout. These circumvent some drawbacks of direct-conversion detectors. We measured observed count rate (OCR) versus X-ray tube current for single-pixel detectors consisting of LYSO:Ce and YAP:Ce scintillators coupled to ultrafast SiPMs. For a 30...journal article 2022
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van der Sar, S.J. (author), Leibold, D. (author), Brunner, Stefan E. (author), Schaart, D.R. (author)We investigate fast silicon photomultiplier (SiPM)-based scintillation detectors for X-ray photon-counting applications, e.g., photon-counting computed tomography (CT). Such detectors may be an alternative to CdTe/CdZnTe (CZT) and Si detectors, which face challenges related to availability and cost-effective growth of detector-grade material,...conference paper 2022
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Kalisvaart, Gijsbert M. (author), van Velden, Floris H.P. (author), Hernández-Girón, Irene (author), Meijer, Karin M. (author), Ghesquiere-Dierickx, Laura M.H. (author), Brink, Wyger M. (author), Webb, A. (author), de Geus-Oei, Lioe-Fee (author), Slump, Cornelis H. (author), Kuznetsov, D.V. (author), Schaart, D.R. (author), Grootjans, Willem (author)Background: Accuracy and precision assessment in radiomic features is important for the determination of their potential to characterize cancer lesions. In this regard, simulation of different imaging conditions using specialized phantoms is increasingly being investigated. In this study, the design and evaluation of a modular multimodality...journal article 2022
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Schaart, D.R. (author), Schramm, Georg (author), Nuyts, Johan (author), Surti, Suleman (author)The first time-of-flight positron emission tomography (TOF-PET) scanners were developed as early as in the 1980s. However, the poor light output and low detection efficiency of TOF-capable detectors available at the time limited any gain in image quality achieved with these TOF-PET scanners over the traditional non-TOF PET scanners. The...review 2021
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Pastor Serrano, O. (author), Habraken, S.J.M. (author), Lathouwers, D. (author), Hoogeman, M.S. (author), Schaart, D.R. (author), Perko, Z. (author)Breathing interplay effects in Intensity Modulated Proton Therapy (IMPT) arise from the interaction between target motion and the scanning beam. Assessing the detrimental effect of interplay and the clinical robustness of several mitigation techniques requires statistical evaluation procedures that take into account the variability of...journal article 2021
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Schaart, D.R. (author)The imaging performance of clinical positron emission tomography (PET) systems has evolved impressively during the last ∼15 years. A main driver of these improvements has been the introduction of time-of-flight (TOF) detectors with high spatial resolution and detection efficiency, initially based on photomultiplier tubes, later silicon...review 2021
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van der Sar, S.J. (author), Brunner, Stefan E. (author), Schaart, D.R. (author)Purpose: The implementation of photon-counting detectors is widely expected to be the next breakthrough in X-ray computed tomography (CT) instrumentation. A small number of prototype scanners equipped with direct-conversion detectors based on room-temperature semiconductors, such as CdTe and CdZnTe (CZT), are currently installed at medical...journal article 2021
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- Schaart, D.R. (author), Ziegler, Sibylle (author) journal article 2020
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Esmaeil Zadeh, I.Z. (author), Chang, J. (author), Van Staaden, Yuri J. (author), Swens, Jeroen P.E. (author), Dobrovolskiy, S.M. (author), Schaart, D.R. (author), Pereira, S.F. (author), Zwiller, Val (author), Dorenbos, S.N. (author)A broad range of scientific and industrial disciplines require precise optical measurements at very low light levels. Single-photon detectors combining high efficiency and high time resolution are pivotal in such experiments. By using relatively thick films of NbTiN (8-11 nm) and improving the pattern fidelity of the nanostructure of the...journal article 2020
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Brown, J.M.C. (author), Brunner, S. (author), Schaart, D.R. (author)Organ-specific, targeted field-of-view (FoV) positron emission tomography (PET)/magnetic resonance imaging (MRI) inserts are viable solutions for a number of imaging tasks where whole-body PET/MRI systems lack the necessary sensitivity and resolution. To meet the required PET detector performance of these systems, high count-rates and...journal article 2020
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Lens, E. (author), Jagt, Thyrza (author), Hoogeman, Mischa (author), Schaart, D.R. (author)The aim of this study was to investigate the feasibility of using prompt gamma (PG) ray emission profiles to monitor changes in dose to the planning target volume (PTV) during pencil beam scanning (PBS) proton therapy as a result of day-to-day variation in patient anatomy.
 For 11 prostate patients, we simulated treatment plan delivery...journal article 2019
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Lens, E. (author), Tolboom, Ellen (author), Schaart, D.R. (author)Various methods for in vivo range estimation during proton therapy based on the measurement of prompt gamma (PG) photons have been proposed. However, optimizing the method of detection by trial-and-error is a tedious endeavor. Here, we investigate the feasibility of using the Cramér-Rao lower bound (CRLB) to more quickly arrive at an optimum...journal article 2019
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Breedveld, Sebastiaan (author), Bennan, Amit B.A. (author), Aluwini, Shafak (author), Schaart, D.R. (author), Kolkman-Deurloo, Inger Karine K. (author), Heijmen, Ben J.M. (author)We developed a fast and fully-automated, multi-criteria treatment planning workflow for high dose rate brachytherapy (HDR-BT). In this workflow, the patient-CT with catheter reconstructions and dwell positions are imported from the clinical TPS into a novel system for automated dwell time optimisation. The optimised dwell times are then...journal article 2019
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van Dongen, K.W.A. (author), de Blécourt, A.J. (author), Lens, E. (author), Schaart, D.R. (author), Vos, F.M. (author)In proton therapy high energy protons are used to irradiate a tumor. Ideally, the delivered proton dose distribution is measured during treatment to ensure patient safety and treatment effectiveness. Here we investigate if we can use the ionoacoustic wave field to monitor the actual proton dose distribution for the two most commonly used proton...journal article 2019
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Venialgo Araujo, E. (author), Lusardi, Nicola (author), Garzetti, Fabio (author), Geraci, Angelo (author), Brunner, S. (author), Schaart, D.R. (author), Charbon-Iwasaki-Charbon, E. (author)Typically, a time-of-flight (TOF) PET block detector is built using application-specific integrated circuits (ASICs), since they integrate a high number of channels at a reasonable power consumption and into a small area. However, ASICs’ flexibility is limited and prototyping times are long because a semiconductor fabrication process is required...journal article 2018
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Cambraia Lopes Ferreira da Silva, P. (author), Serra Crespo, P. (author), Huizenga, J. (author), Schaart, D.R. (author)Much attention is currently being paid to imaging prompt gamma (PG) rays for in vivo proton range monitoring in proton therapy. PG imaging using a collimator is affected by neutron-related background. We study the effectiveness of background reduction experimentally, using a scanning parallel-slit PG collimator as a simplified model of a...journal article 2018