Medical Radiology and Radiation Safety. 2024. Vol. 69. № 6
DOI:10.33266/1024-6177-2024-69-6-87-93
G.G. Shimchuk, A.V. Skobliakov, A.A. Golubev, A.V. Kantsyrev, Gr.G. Shimchuk
Assessment of the Possibility of Verification of Proton Dose Distributions by the Method of Induced Positron Activity in Human Tissue
National Research Center “Kurchatov Institute”
Contact person: G.G. Shimchuk, e-mail: Этот адрес электронной почты защищен от спам-ботов. У вас должен быть включен JavaScript для просмотра.
ABSTRACT
A computational assessment was made of the possibility of verifying dose distributions during proton radiation therapy using PET imaging of positron activity in human tissues, which was formed as a result of proton irradiation. To compare the dose distribution of a particle energy-modulated proton beam with a diameter of 10 mm with an initial particle energy of 100 MeV, ensuring uniform irradiation of the target in a 13 mm zone (at the level of 90 % of the radiation dose) at the end of the particle path, with a map of induced activity from the radionuclides 11C, 13N and 15O, numerical calculations were performed in a Monte–Carlo code using the Geant4 simulation program. In the modeling process, a volume with dimensions of 50 × 50 × 100 mm was used, simulating soft tissues of the human body with a density of 1 g/cm3, consisting of hydrogen atoms (62 %), carbon (12 %), oxygen (24 %) and nitrogen (1.1 %). The cross sections for the formation of radionuclides 11C, 13N and 15O in the reactions 12C(p, pn)11C, 14N(p, α)11C, 16O(p, αpn)11C, 14N(p, pn)13N, 16O(p, α)13N, 16O(p, pn)15O have been calculated, which were used to calculate the distributions of positron activity in the irradiated volume. Taking into account the short half-lives of the radionuclides under consideration (primarily oxygen-15), calculations of isoactivities and depth distributions of accumulated radioactivities were performed for various time intervals after irradiation.
The performed computational modeling of the distributions of activities of radionuclides 11C, 13N and 15O during the passage of a modulated proton beam, taking into account the decay of produced radionuclides after irradiation, shows that by recording for 15 minutes the induced activity of PET radionuclides 2 minutes after irradiation, it is possible to obtain data on the compliance of the planned and irradiation of tumors performed during proton therapy. However, small levels of generated activity (at a level of 2 Gy for finely fractionated irradiations) require a device with high efficiency in recording annihilation radiation and high spatial resolution at the level of 1.5–2.0 mm.
Key words: proton irradiation, radionuclides, induced activity, PET, dose fields, verification
For citation: Shimchuk GG, Skobliakov AV, Golubev AA, Kantsyrev AV, Shimchuk GrG. Assessment of the Possibility of Verification of Proton Dose Distributions by the Method of Induced Positron Activity in Human Tissue. Medical Radiology and Radiation Safety. 2024;69(6):87–93. (In Russian). DOI:10.33266/1024-6177-2024-69-6-87-93
References
1. Goitein M. Radiation Oncology –A Physicist’s Eye View. New York, Springer, 2008.
2. Koehler AM, Schneider RJ, Sisterson JM. Flattening of Proton Dose Distributions for Large-Field Radiotherapy. Med. Phys. 1977;4:297–301.
3. Grusell E, et al. A general Solution to Charged Particle Beam Flattening Using an Optimized Dual-Scattering-Foil Technique, with Application to Proton Therapy Beams. Phys. Med. Biol. 1994;39:2201–16.
4. Kanai T, et al. Spot Scanning System for Proton Radiotherapy. Med. Phys. 1980;7:365–9.
5. Pedroni E, et al. The 200-MeV Proton Therapy Project at the Paul Scherrer Institute: Conceptual Design and Practical Realization. Med. Phys. 1995;22:37–53
6. Kraft G. Tumortherapy with Ion Beams. Nucl. Instrum. and Methods Phys. Res. A. 2000;454:1–10.
7. Zenklusen S, Pedroni E, Meer D. A Study on Repainting Strategies for Treating Moderately Moving Targets with Proton Pencil Beam Scanning for the New Gantry 2 at PSI. Phys. Med. Biol. 2010;55:5103–21.
8. Geant 4: User’s Guide for Application Developers. URL: https://geant4-userdoc.web.cern.ch/UsersGuides/ForApplicationDeveloper/fo/BookForApplicationDevelopers.pdf
9. Wen Luo, Hao-yang Lan, Yi Xu, Dimiter L. Balabanski. Implementation of the n-Body Monte-Carlo Event Generator into the Geant4 toolkit for Photonuclear Studies. Nuclear Instruments and Methods in Physics Research A. 2017;849:49-54. doi: 10.1016/j.nima.2017.01.010
10. Jae Won Shin. A Data-Based Photonuclear Reaction Model for GEANT4. Nuclear Instruments and Methods in Physics Research B. 2015;358:194-200.
11. TALYS. URL: https://www-nds.iaea.org/talys/
12. Geant 4: Physics List Guide. URL: https://geant4- userdoc.web.cern.ch/UsersGuides/PhysicsListGuide/fo/ PhysicsListGuide.pdf
13. Geant 4: User’s Guide for Toolkit Developers. URL: https://geant4userdoc.web.cern.ch/UsersGuides/ForToolkitDeveloper/fo/BookForToolkitDeveloper.pdf
14. Geant 4 Physics: Physics Reference Manual. URL: https://geant4- userdoc.web.cern.ch/UsersGuides/PhysicsReferenceManual/fo/ PhysicsReferenceManual.pdf
15. LibInterpolate. URL: https://github.com/CD3/libInterpolate.
PDF (RUS) Full-text article (in Russian)
Conflict of interest. The authors declare no conflict of interest.
Financing. The work was carried out as part of the fulfillment of the state task of the Kurchatov Institute Research Center.
Contribution. Article was prepared with equal participation of the authors.
Article received: 20.07.2024. Accepted for publication: 25.09.2024.