M.Sc. Julius Friedemann Werner

Institut für Medizintechnik
Universität zu Lübeck
Ratzeburger Allee 160
23562 Lübeck
Gebäude 64, Raum 024

Email:	friedemann.werner(at)uni-luebeck.de
Phone:	+49 451 3101 5446

Roles

Research Assistant

Research

Research Interests

Image Reconstruction
Particle Therapy Verification
Prompt Gamma Timing

Involved Projects

Image Reconstruction for Range Verification in Particle Therapy

Curriculum Vitae

JULIUS FRIEDEMANN WERNER was born in Oranienburg, Germany in 1998. He received his Bachelor of Science in Medical Engineering in 2019 followed by his Master of Science in Medical Engineering from the University of Lübeck in 2022. He wrote his master thesis in collaboration with the Turin section of the Italian National Institute for Nuclear Physics (INFN). During his studies he was mainly interested in image processing and reconstruction with a focus on particle therapy verification. Since February 2022 he is a research assistant at the Institute of Medical Engineering in the field of nuclear imaging.

Publications

[ 2023 ]
[ 2022 ]

2023[ to top ]

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.
- [ BibTeX ]
- [ URL ]
@inproceedings{10337908, abstract = {Many efforts have been made to fully exploit charged particles' specific features in terms of dose delivered to the target and sparing of healthy tissues. Although the dose maximum, defined by the Bragg peak, can be well characterized for materials of known composition and physical properties, uncertainties in its determination are encountered in the clinical practice. To mitigate these uncertainties, treatment verification techniques based on the detection of secondaries have gained importance, but a clinical device integrated in the patient routine is yet to be available. We present here the first experimental results of the spatio-temporal emission reconstruction for treatment verification in proton therapy. With a multi-detector prompt-gamma timing system, we are able to simultaneously reconstruct the spatial and temporal distribution of the emitted prompt photons. This distribution is correlated to both the primary particle range and their motion inside the target. A detector prototype comprising two LaBr3:Ce-based detectors and an Ultra Fast Silicon detector was developed within the MERLINO (Measurement of the EneRgy Loss for IN-vivo Optimization in particle therapy) project for the technique proof-of-concept. Experimental measurements of a 227 MeV proton beam impinging on an homogeneous phantom were taken at the National Center for Oncological Hadrontherapy in Italy. First comparisons between data and simulation show excellent agreement, with a 98% average correlation of the prompt gamma timing distributions. A preliminary reconstruction of the prompt photons spatio-temporal emission is here reported for the first time for experimental data. The corresponding simulation was carried out with the FLUKA Monte Carlo tool. The results shown here represent the first step towards the experimental validation of the technique.}, author = {Ferrero, V. and Werner, J. and Aglietta, M. and Cerello, P. and Fiorina, E. and Mas Milian, F. and Mostardi, F. and Pennazio, F. and Pullia, M. and Sacchi, R. and Vignati, A. 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 = {Proton therapy treatment verification: a spatio-temporal emission reconstruction with experimental data}, year = 2023 }
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.
- [ BibTeX ]
- [ URL ]
@article{Ferrero_2023, author = {Ferrero, V. and Aglietta, M. and Cerello, P. and Fiorina, E. and Rafecas, M. and Vignati, A. and Werner, J. and Pennazio, F.}, journal = {Physica Medica}, keywords = {IMT}, month = 11, pages = 102698, publisher = {Elsevier BV}, title = {A NEW APPROACH TO EVALUATE THE STOPPING POWER OF CLINICAL BEAMS FOR PROTON THERAPY OPTIMIZATION}, volume = 115, year = 2023 }
Vo, H., Seeger, S., Werner, J. and Rafecas, M.: Towards Full-body Small Aquatic Animal PET: a Simulation Study of MERMAID-v2, 1–1, 2023, DOI: 10.1109/NSSMICRTSD49126.2023.10338525.
- [ BibTeX ]
@inproceedings{10338525, author = {Vo, H.P. and Seeger, S. and Werner, J. and Rafecas, M.}, booktitle = {2023 IEEE Nuclear Science Symposium, Medical Imaging Conference and International Symposium on Room-Temperature Semiconductor Detectors (NSS MIC RTSD)}, keywords = {SeegerSteven}, pages = {1-1}, title = {Towards Full-body Small Aquatic Animal PET: a Simulation Study of MERMAID-v2}, year = 2023 }
Seeger, S., Vo, H., Florack, C., Werner, J., Schmidt, C. and Rafecas, M.: First Images from MERMAID, a Small Aquatic Animal PET Scanner Prototype, 1–1, 2023, DOI: 10.1109/NSSMICRTSD49126.2023.10338697.
- [ BibTeX ]
@inproceedings{10338697, author = {Seeger, S. and Vo, H.P. and Florack, C. and Werner, J. and Schmidt, C. and Rafecas, M.}, booktitle = {2023 IEEE Nuclear Science Symposium, Medical Imaging Conference and International Symposium on Room-Temperature Semiconductor Detectors (NSS MIC RTSD)}, keywords = {MERMAID}, pages = {1-1}, title = {First Images from MERMAID, a Small Aquatic Animal PET Scanner Prototype}, year = 2023 }
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.
- [ BibTeX ]
- [ URL ]
@inproceedings{10337946, 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 }

2022[ to top ]

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.
- [ BibTeX ]
- [ URL ]
@article{ferrero2022estimating, abstract = {Objective. We introduce a new treatment verification technique to estimate the primary particle's stopping power from prompt gamma timing measurements in proton therapy. Approach. The starting point is the Spatio-temporal Emission Recostruction technique, which provides the time-depth distribution of the emitted prompt photons with a multiple Prompt-Gamma Timing detector setup based on Lanthanum Bromide crystals. A dedicated formalism based on an analytical approximation of the stopping power is developed to obtain the desired information. Its performance is evaluated in a proof of concept configuration via Monte Carlo simulations of monochromatic proton beams impinging on a homogeneous PMMA phantom. Main Results. Results indicate stopping power estimations as good as 3.8% with respect to NIST values, and range estimations within 0.3 cm (standard deviation), when considering 250 ps FWHM timing resolution. Significance. The current study shows, for the first time, the feasibility of evaluating the stopping power of primary beams with a technique that can be performed in-vivo, opening up new possibilities in the field of treatment verification and therapy optimization.}, author = {Ferrero, Veronica and Werner, Julius and Cerello, Piergiorgio and Fiorina, Elisa and Vignati, Anna and Pennazio, Francesco and Rafecas, Magdalena}, editor = {Vasquez Osorio, Eliana Maria}, journal = {Frontiers in Physics}, keywords = {imt}, month = {09}, publisher = {Frontiers}, title = {Estimating the stopping power distribution during proton therapy: A proof of concept}, type = {article}, year = 2022 }
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.
- [ BibTeX ]
@inproceedings{10399204, abstract = {Prompt Gamma Timing is a technique proposed for range monitoring in proton therapy. The experimental measurements so far are limited to a single secondary proton detector. In this study we present an innovative technique to merge the information from many detectors in different positions into a unique estimation of the beam particle motion in the spatiotemporal domain. We test the proposed method by means of Monte Carlo simulations, with various beam ranges and a number of primaries interesting for proton therapy monitoring (107). The method is based on the Maximum Likelihood Expectation Maximization algorithm, and we show its applicability with both MeV-range gamma detectors as well as lower energy detectors such as PET detectors. The preliminary results shown indicate a range resolution of about 5 mm. The ultimate goal of this study is to provide a robust mathematical instrument to expand the significance of Prompt Gamma Timing measurements, to be useful for the prototypes presently under construction by the treatment monitoring community.}, author = {Pennazio, Francesco and Werner, Julius and Aglietta, Marco and Cerello, Piergiorgio and Fiorina, Elisa and Garbolino, Sara and Monaco, Vincenzo and Vignati, Anna and Wheadon, Richard and Ferrero, Veronica and Rafecas, Magdalena}, booktitle = {2022 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)}, keywords = {IMT}, month = 11, title = {Proton Therapy Treatment Monitoring: Prompt Gamma Emission Reconstruction in the Time and Space Domain}, year = 2022 }
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.
- [ BibTeX ]
@inproceedings{10399132, abstract = {The precision of charged particle therapy dose deposition is its main advantage to conventional radiotherapy and its weakness when encountering range uncertainties in clinical practice. We offer a new perspective on treatment verification by introducing a technique to estimate electronic stopping power during the treatment from the measurement of time between particle target entry and prompt gamma detection (TOF-ULET). For the estimation of electronic stopping power, we developed a lightweight analytical model for axial particle motion inside the patient. We used Monte Carlo simulations of a homogenous PMMA phantom as a first test of our method, achieving 6 % estimation errors for 170 MeV and 189 MeV protons. The in-beam estimation of electronic stopping power opens up new opportunities in treatment adaptation between fractions by not only indicating significant deviations from the treatment plan, but also offering a current estimate of the patients’ anatomy along the beam path and – using conversion models – the delivered dose.}, author = {Werner, Julius and Ferrero, Veronica and Aglietta, Marco and Cerello, Piergiorgio and Fiorina, Elisa and Bolke, Andreas and Kasprzak, Jona and Vignati, Anna and Pennazio, Francesco and Rafecas, Magdalena}, booktitle = {2022 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)}, keywords = {IMT}, month = 11, title = {TOF-ULET: In-beam Stopping Power Estimation using Prompt Gamma Timing towards Adaptive Charged Particle Therapy}, year = 2022 }
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.
- [ BibTeX ]
- [ URL ]
@article{Ferrero_2022, abstract = {The MERLINO project is developing a multi-detector setup with the goal of evaluating the beam stopping power from Prompt-Gamma-Timing measurements in proton therapy. The detectors are based on the cerium-doped lanthanum bromide crystal, LaBr3:Ce, coupled to photo-multiplier tubes. The system characterization is ongoing and the first calibration measurements with two detectors showed 124 ps σ and σ E/E = 3% for the timing and energy resolution, respectively. The measured experimental parameters were then used to carry out a preliminary estimation of the stopping power. Results from the simulation of a 189 MeV proton beam impinging on an homogeneous phantom are presented for the optimisation of the MERLINO detector setup.}, author = {Ferrero, V. and Werner, J. and Aglietta, M. and Cerello, P. and Fiorina, E. and Gorgi, A. and Vignati, A. and Rafecas, M. and Pennazio, F.}, journal = {Journal of Instrumentation}, keywords = {imt}, month = 11, number = 11, pages = {C11013}, publisher = {IOP Publishing}, title = {The MERLINO project:characterization of LaBr3:Ce detectors for stopping power monitoring in proton therapy}, volume = 17, year = 2022 }
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.
- [ BibTeX ]
- [ URL ]
@article{Pennazio_2022, author = {Pennazio, Francesco and Ferrero, Veronica and D'Onghia, Grazia and Garbolino, Sara and Fiorina, Elisa and Villarreal, Oscar Ariel Marti and Milian, Felix Mas and Monaco, Vincenzo and Monti, Valeria and Patera, Alessandra and Werner, Julius and Wheadon, Richard and Rafecas, Magdalena}, journal = {Physics in Medicine & Biology}, keywords = {imt}, month = {03}, number = 6, pages = {065005}, publisher = {{IOP} Publishing}, title = {Proton therapy monitoring: spatiotemporal emission reconstruction with prompt gamma timing and implementation with {PET} detectors}, volume = 67, year = 2022 }

Theses

Julius J. Friedemann Werner, Iterative Rekonstruktion der Energiespektren prompter Gammastrahlung mittels Compton-Kameras für die Anwendung in der Partikeltherapie, Bachelor thesis, Institute of Medical Engineering, University of Lübeck, 2019

Julius J. Friedemann Werner, Stopping power estimation from prompt gamma timing data for particle therapy verification, Master thesis, Institute of Medical Engineering, University of Lübeck, 2022