M.Sc. Jona Kasprzak

Institut für Medizintechnik
Universität zu Lübeck
Ratzeburger Allee 160

23562 Lübeck
Gebäude 64, Raum 024

Email:	j.kasprzak(at)uni-luebeck.de
Phone:	+49 451 3101 5428
Fax:	+451 3101 5404

Roles

Research Assistant

Research

Research Interests

Reconstruction in nuclear imaging
Development of priors for image reconstruction
The mathematics of Origin Ensemble
Theory of Relativity, Black Holes and other astronomical objects

Curriculum Vitae

JONA KASPRZAK was born in Lübeck, Germany in 1997. From 2003 to 2006 he went to primary school in Lübeck. From 2006 to 2016 he went to the Thomas-Mann-School, a Europe school, where he had bilingual lessons. In 2016 he graduated with specialization in physics. After school he studied Computational Life Science at the University of Lübeck. In 2019 he wrote his bachelor thesis about the mathematical description of special relativity at the Institute of Mathematics. During his Master studies he specialized in image computing. In 2021 he wrote his master thesis on modeling of black holes in terms of general relativity at the Institute of Mathematics. In 2021 he started to work at the Institute of Medical Engineering as a research assistant.

Publications

[ 2024 ]
[ 2023 ]

2024[ to top ]

Werner, J., Pennazio, F., Schmid, N., Fiorina, E., Bersani, D., Cerello, P., Kasprzak, J., Mosco, N., Ranjbar, S., Sacchi, R., Ferrero, V. and Rafecas, M.: Stopping power and range estimations in proton therapy based on prompt gamma timing: motion models and automated parameter optimization, Physics in Medicine & Biology, 2024, DOI: 10.1088/1361-6560/ad5d4b.
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@article{werner2024stopping, author = {Werner, Julius and Pennazio, Francesco and Schmid, Niklas and Fiorina, Elisa and Bersani, Davide and Cerello, Piergiorgio and Kasprzak, Jona and Mosco, Nicola and Ranjbar, Sahar and Sacchi, Roberto and Ferrero, Veronica and Rafecas, Magdalena}, journal = {Physics in Medicine & Biology}, keywords = {imt}, month = {06}, publisher = {IOP Publishing}, title = {Stopping power and range estimations in proton therapy based on prompt gamma timing: motion models and automated parameter optimization}, year = 2024 }
Kasprzak, J., Roser, J., Werner, J. and Rafecas, M.: Image Reconstruction with Regularized Origin Ensemble for Proton-Therapy Range Verification with a Compton Camera and Heterogeneous Targets, 2024, DOI: 10.1016/j.ejmp.2024.103920.
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@inproceedings{kasprzak2024image, author = {Kasprzak, Jona and Roser, Jorge and Werner, Julius and Rafecas, Magdalena}, booktitle = {Abstracts of the 5th European Congress of Medical Physics}, keywords = {imt}, month = {09}, title = {Image Reconstruction with Regularized Origin Ensemble for Proton-Therapy Range Verification with a Compton Camera and Heterogeneous Targets}, volume = 125, year = 2024 }
Werner, J., Schmidt, M., Pennazio, F., Roser, J., Kasprzak, J., Ferrero, V. and Rafecas, M.: An Analytical System Response Model for Spatiotemporal Emission Reconstruction from Multi-Detector Prompt Gamma Timing, 1–1, 2024, DOI: 10.1109/NSS/MIC/RTSD57108.2024.10655960.
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@inproceedings{10655960, abstract = {Particle therapy verification using induced prompt gamma radiation is a field of active research. We employ an iterative reconstruction algorithm to reconstruct the spatiotemporal emission distribution. Due to the fast emission of the prompt gamma radiation after the interaction, their spatiotemporal distribution can be used as a surrogate for the primary particle motion. Using a motion model, we extract the particle range and the stopping power, which should allow direct validation of expected values from treatment planning without additional imaging time. The reconstruction is based on Prompt Gamma Timing spectra from multiple detectors, i.e. the combination of primary particle time of flight before nuclear interaction and secondary photon time of flight until detection outside the patient. Reconstruction requires an accurate model of photon transport and detection, which we previously calculated using extensive Monte-Carlo simulations. Here, we present an analytical model that accelerates calculations by almost 200 times, while matching the Monte-Carlo implementation within 6% of the global maximum value for 99% of all non-zero entries. Furthermore, detection delay caused by secondary particles created by the photons in the detector is studied and its integration into the analytical model demonstrated. First reconstructions of spatiotemporal emission distributions from simulated data using both models show almost perfect agreement. The impact on range and stopping power estimates is currently under investigation.}, author = {Werner, Julius and Schmidt, Malte and Pennazio, Francesco and Roser, Jorge and Kasprzak, Jona and Ferrero, Veronica and Rafecas, Magdalena}, booktitle = {2024 IEEE Nuclear Science Symposium (NSS), Medical Imaging Conference (MIC) and Room Temperature Semiconductor Detector Conference (RTSD)}, keywords = {imt}, month = 10, pages = {1-1}, title = {An Analytical System Response Model for Spatiotemporal Emission Reconstruction from Multi-Detector Prompt Gamma Timing}, year = 2024 }
Roser, J., Kasprzak, J., Llosá, G., Werner, J. and Rafecas, M.: Background Reduction in Compton-Camera Based 3D Imaging by Using a Non-Uniform Discretization of the Field-of-View, 2024, DOI: 10.1016/j.ejmp.2024.104168.
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@inproceedings{roser2024background, author = {Roser, Jorge and Kasprzak, Jona and Llosá, Gabriela and Werner, Julius and Rafecas, Magdalena}, booktitle = {Abstracts of the 5th European Congress of Medical Physics}, keywords = {imt}, month = {09}, title = {Background Reduction in Compton-Camera Based 3D Imaging by Using a Non-Uniform Discretization of the Field-of-View}, volume = 125, year = 2024 }
Werner, J., Ferrero, V., Aglietta, M., Cerello, P., Fiorina, E., Kasprzak, J., Mas Milian, F., Mostardi, F., Pullia, M., Roser, J., Schmid, N., Pennazio, F. and Rafecas, M.: In-beam measurement of stopping power using multi-detector Prompt Gamma Timing in proton therapy, 2024, DOI: 10.1016/j.ejmp.2024.103890.
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@inproceedings{werner2024inbeam, author = {Werner, Julius and Ferrero, Veronica and Aglietta, Marco and Cerello, Piergiorgio and Fiorina, Elisa and Kasprzak, Jona and Mas Milian, Felix and Mostardi, Franco and Pullia, Marco and Roser, Jorge and Schmid, Niklas and Pennazio, Francesco and Rafecas, Magdalena}, booktitle = {Abstracts of the 5th European Congress of Medical Physics}, keywords = {imt}, month = {09}, title = {In-beam measurement of stopping power using multi-detector Prompt Gamma Timing in proton therapy}, volume = 125, year = 2024 }
Roser, J., Kasprzak, J., Llosá, G., Werner, J. and Rafecas, M.: Background reduction of Compton-camera based 3D imaging for range verification in proton therapy, 1–1, 2024, DOI: 10.1109/NSS/MIC/RTSD57108.2024.10655232.
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@inproceedings{10655232, abstract = {Low signal-to-background ratio and subsequent image degradation limits the performance of Compton cameras and hinder their application for range verification in hadron therapy. While several approaches have been explored to improve the signal-to-background ratio via event selection (e.g. with neural networks, energy cuts or using dedicated hardware), background reduction within the 3D image reconstruction process has been hitherto overlooked. In this work we present three such background reduction techniques, and show their potential for image-quality improvement by using simulated data. The explored techniques are shown to reduce image noise-edge artifacts, as well as improve the image contrast and/or be quantitatively closer to the ground truth spatial emission distribution. Such promising results encourage further study on their implementation and impact on range verification.}, author = {Roser, Jorge and Kasprzak, Jona and Llosá, Gabriela and Werner, Julius and Rafecas, Magdalena}, booktitle = {2024 IEEE Nuclear Science Symposium (NSS), Medical Imaging Conference (MIC) and Room Temperature Semiconductor Detector Conference (RTSD)}, keywords = {imt}, month = 10, pages = {1-1}, title = {Background reduction of Compton-camera based 3D imaging for range verification in proton therapy}, year = 2024 }

2023[ to top ]

Kasprzak, J., Werner, J., Schadow, L. and Rafecas, M.: Regularisation of the Origin-Ensemble algorithm with a "Beam Prior" for Particle-Range Verification, 2023, DOI: 10.1109/NSSMICRTSD49126.2023.10337946.
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@inproceedings{kasprzak2023regularisation, abstract = {In particle therapy, potential range uncertainties prevent the full exploitation of ion-beam dose distribution in matter. Tomographic imaging methods such as in-beam PET or Compton-cameras (CC) have been proposed to infer range deviations through the detection of secondary radiation. However, very low counts, data truncation and strong background noise usually distort the reconstructed images. To mitigate these effects when using the Origin Ensemble (OE) reconstruction algorithm, we propose here to regularize OE using a priori information about the beam direction. We derive a prior term from a beam model and test the approach using Monte-Carlo simulations of therapeutic proton beams and a Compton camera. This regularisation term could be adapted to in-beam PET. We have simulated two water-filled phantoms with GATE, the second of which also contained an air cavity to induce a range shift. We reconstructed the images in 3D with various regularisation levels. The beam width required by the prior was first extracted from a reconstruction with few iterations and no regularisation. This gave results comparable to taking the ground-truth beam width. The distal edge shifts were quantified as the differences between the position of the inflection points from a sigmoid fit. First results show that OE with the beam prior can notably enhance image quality and improve the identification of the distal edge position. The outcomes were very sensitive to the regularization parameter. Medium regularization reduced the relative error of the shift from 51.7% without prior to 1.7%, but high regularisation increased the relative error again to 31.7%. Still, regularized OE outperformed conventional OE in most cases. Further studies are planned to characterize the dependencies of the results on the regularization parameter.}, author = {Kasprzak, J. and Werner, J. and Schadow, L. and Rafecas, M.}, booktitle = {2023 IEEE Nuclear Science Symposium, Medical Imaging Conference and International Symposium on Room-Temperature Semiconductor Detectors (NSS MIC RTSD)}, keywords = {IMT}, month = 11, title = {Regularisation of the Origin-Ensemble algorithm with a "Beam Prior" for Particle-Range Verification}, year = 2023 }

Theses

Jona Kasprzak, Methoden der hyperbolischen Geometrie in der speziellen Relativitätstheorie mit Anwendungen von Mathematica, Bachelor Thesis, Institut für Mathematik, Universität zu Lübeck, 2019

Jona Kasprzak, Modellierung der Raumzeit in der Nähe eines schwarzen Lochs nach der allgemeinen Relativitätstheorie durch Differentialgeometriesche Methoden mit Simulationen in MATLAB, Master Thesis, Institut für Mathematik, Universität zu Lübeck, 2021