Speaker
Description
Objective:
Hadron therapy, particularly carbon-ion therapy, delivers a sharp, highly localized dose via the Bragg peak, however, this same sharpness makes treatment outcomes sensitive to range uncertainties arising from anatomical variation [6]. Ion beams interaction in tissue involves both electromagnetic processes, responsible for energy deposition, and nuclear interactions that lead to the production of positron-emitting fragments produced by stable ¹²C or proton beams such as ¹¹C, ¹⁵O, and ¹³N [3]. These isotopes form the basis for positron emission-based range monitoring techniques. Positron emission tomography (PET), based on β+-emitting fragments, is the most widely used in-vivo range verification method, but suffers with low count rates and broad activity distributions which limit its precision to a few millimeters [4]. Radioactive ion beams (RIBs), such as ¹¹C, have been proposed to substitute the stable ion beams to directly increase the PET activity signals, since every primary ion itself contributes to the measurable annihilation signal [5]. The annihilation map produced by ¹¹C beams closely tracks the real dose fall-off position, and that this could allow meaningful reduction of clinical range margin [7].
Methods:
Monte Carlo simulations are performed using GATE (Geant4 Application for Tomographic Emission) leveraging the principle of modular Jagiellonian Positron Emission Tomography (J-PET) technology based on plastic scintillators, as a cost-effective tool. One can indirectly verify the range of beams within the patient [2]. Our proposed approach allows for in vivo monitoring whether the dose will be delivered exactly where intended, compensating for anatomical variations or setup uncertainties.
Results:
The results from the simulations used to characterize the activity and dose distributions to determine the achievable range-monitoring precision and to quantify the difference between the activity-based and dose-based range estimates. This is aimed to the feasibility of detecting the annihilation signal with a modular J-PET configuration in an upright treatment geometry.
Outlook & Discussion:
The study evaluates the emerging interest in monitoring beams range in the upright position. Positioning patients in the upright position, that is sitting or standing, allows for significant reductions in treatment cost, increased patient comfort, and even therapeutic benefits resulting from physiological alignment and better anatomical separation of critical structures [1]. The study aims to provide a more direct estimate of the practical, achievable precision of RIBs therapy, in an upright treatment geometry for range verification with J-PET.
Keywords: Upright hadron therapy, Radioactive ion beams (RIBs) range verification, Bragg peak, Positron-emitting isotopes, Jagiellonian Positron Emission Tomography (J-PET) Scanner.
Funded by:
The UPLIFT project is funded by the European Union under Grant Agreement No. 101168955.
Acknowledgements:
We acknowledge the support of the National Science Centre (NCN), Poland, under grant nos. 2021/42/A/ST2/00423, 2021/43/B/ST2/02150, 2022/47/I/NZ7/03112, and 2023/50/E/ST2/00574; the Polish Ministry of Science and Higher Education (MNiSW), under grant nos. IAL/SP/596235/2023 and SPUB/SP/627733/2025; the SciMat and qLife Priority Research Areas; and the ERC Advanced Grant POSITRONIUM (No. 101199807).
References
[1] K. Brzeziński et al., Physics in Medicine & Biology 68 (2023) 145016
[2] P. Moskal et al., Science Advances 10 (2024) eadp2840
[3] I. Kadenko et al., Bio-Algorithms and Med-Systems 19 (2023) 139–143
[4] A.C. Kraan et al., Frontiers in Oncology 5 (2015) 150
[5] M. Durante et al., Frontiers in Physics 8 (2020) 326
[6] O. Sokol et al., Scientific Reports 12 (2022) 21792
[7] M. Krämer et al., Physics in Medicine & Biology 45 (2000) 3299