Algorithms and Modelling for Particle Therapy Verification and Theranostics

In particle therapy, beams of energetic protons or certain ions are used to irradiate tumors or other types of diseased tissue. The interaction of therapeutic particle beams in matter is characterized by a very well-defined range, a high-dose deposition localized in a small region (the Bragg peak), and a steep dose gradient at the distal edge of the Bragg peak. These features imply that possible uncertainties in the determination of the particle range might have severe consequences, such as tumor under-dosage, or the irradiation of healthy tissue. Therefore, safety margins are applied to ensure full treatment of the tumor.

These safety margins could be reduced if the actual dose deposition is quantified with high precision. For this purpose, verification methods aimed to determine the range of the particle beam are under investigation worldwide. Most of these methods are based on the detection of secondary radiation. For example, positron emitting nuclei are created along the beam path; their decay and subsequent annihilation of the emitted positrons give rise to two annihilation photons, which can be detected using similar technology as in Positron Emission Tomography (PET). Another important effect is the excitation of nuclei along the particle path; these nuclei return to their ground state by emitting single gamma rays. Due to the very short half-life of these excited states, these gamma rays are also called prompt gamma radiation.

Our research activities focus on image reconstruction for particle range verification, mainly tomographic Prompt Gamma Imaging (PGI) using Compton cameras, but also in-beam PET. To that end, we employ our in-house implementations of the Maximum-Likelihood Expectation-Maximization (ML-EM) and statistical Origin-Ensemble (OE) algorithms, as well as Bayesian reconstruction approaches. Furthermore, we are investigating novel reconstruction techniques based on Prompt Gamma Timing (PGT) measurements to indirectly determine the particle range and other physical quantities like the stopping power.

Grants

Cooperations

Publications

2025[ to top ]
  • Kasprzak, J., Roser, J., Werner, J., Kohlhase, N., Bolke, A., Kaufmann, L.-M. and Rafecas, M.: Regularized origin ensemble with a beam prior for range verification in particle therapy with Compton-camera data, Physics in Medicine & Biology, 2025, DOI: 10.1088/1361-6560/adbfd8.
2024[ to top ]
  • 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.
  • 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.
  • 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.
  • Data, E., Milian, F. M., Abujami, M., Bersani, D., Cerello, P., Donetti, M., Fadavi Mazinani, M., Ferrero, V., Fiorina, E., Garbolino, S., Hosseini, M. A., Montalvan-Olivares, D. M., Pennazio, F., Pullia, M., Ranjbar, S., Werner, J., Wheadon, R. J., Vignati, A., Cirio, R., Sacchi, R. and Giordanengo, S.: A novel detector for 4D tracking in particle therapy, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 169690, 2024, DOI: 10.1016/j.nima.2024.169690.
  • 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.
  • Fiorina, E., Mas Milian, F., Bersani, D., Cerello, P., Cirio, R., Data, E., Donetti, M., Ferrero, V., Fadavi Mazinani, M., Hosseini, M. A., Lombardo, E., Montalvan-Olivares, D. M., Pennazio, F., Pullia, M., Ranjbar, S., Vignati, A., Werner, J., Sacchi, R. and Giordanengo, S.: Innovative Integrated Beam Monitor and Range Verification System Designed for a Superconducting Multi-Ion Gantry for Particle Therapy, 2024, DOI: 10.1016/j.ejmp.2024.103884.
  • 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.
  • Ranjbar, S., Data, E., Milian, F. M., Bersani, D., Cerello, P., Cirio, R., Ferrero, V., Mazinani, M. F., Giordanengo, S., Hosseini, M. A., Lombardo, E., Montalvan-Olivares, D. M., Pullia, M., Savazzi, S., Sacchi, R., Vignati, A., Werner, J., Pennazio, F. and Fiorina, E.: First Prompt Gamma Timing measurements with carbon ions, 1–1, 2024, DOI: 10.1109/NSS/MIC/RTSD57108.2024.10655573.
  • Roser, J., Hetzel, R., Clement, P., Fenger, A., Kasper, J., Kercz, M., Kołodziej, M., Mielke, L., Rusiecka, K., Stahl, A., Wrońska, A. and Rafecas, M.: Range Monitoring Capabilities with the SiFi-CC Detector: Spectral-spatial Imaging with Monte Carlo-simulated Data, 1, 2024, DOI: 10.5506/aphyspolbsupp.17.7-a9.
  • 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.
2023[ to top ]
  • Ferrero, V., Aglietta, M., Cerello, P., Fiorina, E., Rafecas, M., Vignati, A., Werner, J. and Pennazio, F.: A new approach to evaluate the stopping power of clinical beams for proton therapy optimization, Physica Medica, 115, 102698, 2023, DOI: 10.1016/j.ejmp.2023.102698.
  • Ferrero, V., Werner, J., Aglietta, M., Cerello, P., Fiorina, E., Mas Milian, F., Mostardi, F., Pennazio, F., Pullia, M., Sacchi, R., Vignati, A. and Rafecas, M.: Proton therapy treatment verification: a spatio-temporal emission reconstruction with experimental data, 2023, DOI: 10.1109/NSSMICRTSD49126.2023.10337908.
  • 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.
  • Hetzel, R., Urbanevych, V., Bolke, A., Kasper, J., Kercz, M., Kołodziej, M., Magiera, A., Mueller, F., Müller, S., Rafecas, M., Rusiecka, K., Schug, D., Schulz, V., Stahl, A., Weissler, B., Wong, M.-L. and Wrońska, A.: Near-field coded-mask technique and its potential for proton therapy monitoring, Physics in Medicine & Biology, 68(24), 245028, 2023, DOI: 10.1088/1361-6560/ad05b2.
  • Llosá, G. and Rafecas, M.: Hybrid PET/Compton-camera imaging: an imager for the next generation, The European Physical Journal Plus, 138(3), 214, 2023.
2022[ to top ]
  • Pennazio, F., Ferrero, V., D’Onghia, G., Garbolino, S., Fiorina, E., Villarreal, O. A. M., Milian, F. M., Monaco, V., Monti, V., Patera, A., Werner, J., Wheadon, R. and Rafecas, M.: Proton therapy monitoring: spatiotemporal emission reconstruction with prompt gamma timing and implementation with PET detectors, Physics in Medicine & Biology, 67(6), 065005, 2022, DOI: 10.1088/1361-6560/ac5765.
  • Ferrero, V., Werner, J., Aglietta, M., Cerello, P., Fiorina, E., Gorgi, A., Vignati, A., Rafecas, M. and Pennazio, F.: The MERLINO project:characterization of LaBr3:Ce detectors for stopping power monitoring in proton therapy, Journal of Instrumentation, 17(11), C11013, 2022, DOI: 10.1088/1748-0221/17/11/C11013.
  • Werner, J., Ferrero, V., Aglietta, M., Cerello, P., Fiorina, E., Bolke, A., Kasprzak, J., Vignati, A., Pennazio, F. and Rafecas, M.: TOF-ULET: In-beam Stopping Power Estimation using Prompt Gamma Timing towards Adaptive Charged Particle Therapy, 2022, DOI: 10.1109/NSS/MIC44845.2022.10399132.
  • Pennazio, F., Werner, J., Aglietta, M., Cerello, P., Fiorina, E., Garbolino, S., Monaco, V., Vignati, A., Wheadon, R., Ferrero, V. and Rafecas, M.: Proton Therapy Treatment Monitoring: Prompt Gamma Emission Reconstruction in the Time and Space Domain, 2022, DOI: 10.1109/NSS/MIC44845.2022.10399204.
  • Ferrero, V., Werner, J., Cerello, P., Fiorina, E., Vignati, A., Pennazio, F. and Rafecas, M.: Estimating the stopping power distribution during proton therapy: A proof of concept, Frontiers in Physics, 2022, DOI: 10.3389/fphy.2022.971767.
2021[ to top ]
  • Rusiecka, K., Hetzel, R., Kasper, J., Kozani, M. K., Kohlhase, N., Kolodziej, M., Lalik, R., Magiera, A., Migdal, W., Rafecas, M., Stahl, A., Urbanevych, V., Wong, M. and Wrońska, A.: A systematic study of LYSO:Ce, LuAG:Ce and GAGG:Ce scintillating fibers properties, Journal of Instrumentation, 16(11), P11006, 2021, DOI: 10.1088/1748-0221/16/11/p11006.
2020[ to top ]
  • Kohlhase, N., Stille, M., Bolke, A., Zvolský, M. and Rafecas, M.: Compton Camera Image Reconstruction with A-Priori Information from a Beam Tagging Hodoscope, 1–4, 2020, DOI: 10.1109/NSS/MIC42677.2020.9507820.
  • Kohlhase, N., Wegener, T., Schaar, M., Bolke, A., Etxebeste, A., Sarrut, D. and Rafecas, M.: Capability of MLEM and OE to Detect Range Shifts with a Compton Camera in Particle Therapy, IEEE Transactions on Radiation and Plasma Medical Sciences, 4(2), 233–242, 2020, DOI: 10.1109/TRPMS.2019.2937675.
2019[ to top ]
  • Ferrero, V., Pennazio, F., Cerello, P., Fiorina, E., Garbolino, S., Monaco, V., Wheadon, R. and Rafecas, M.: Evaluation of in-beam PET treatment verification in proton therapy with different reconstruction methods, IEEE Transactions on Radiation and Plasma Medical Sciences, 2019, DOI: 10.1109/TRPMS.2019.2942713.
  • Kohlhase, N., Wegener, T., Schaar, M., Bolke, A. and Rafecas, M.: Bildrekonstruktion von Compton-Kamera Daten unter Verwendung eines Hodoskops für die Reichweitenverifikation in der Partikeltherapie, 317, 2019.
  • Wegener, T., Kohlhase, N., Schaar, M., Bolke, A. and Rafecas, M.: Stochastic behavior of the Origin-Ensemble Algorithm – effect on ange verification in proton therapy using Compton-Cameras, 240, 2019.
2018[ to top ]
  • Ferrero, V., Cerello, P., Fiorina, E., Monaco, V., Rafecas, M., Wheadon, R. and Pennazio, F.: Innovation in online hadrontherapy monitoring: An in-beam PET and prompt-gamma-timing combined device, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2018, DOI: 10.1016/j.nima.2018.08.065.