Modelling PET radionuclide production in tissue and external targets using Geant4

[摘要] The Proton Therapy Facility in TRIUMF provides 74 MeV protons extracted from a 500 MeV H-cyclotron for ocular melanoma treatments. During treatment, positron emitting radionuclides such as1C,15O and13N are produced in patient tissue. Using PET scanners, the isotopic activity distribution can be measured for in-vivo range verification. A second cyclotron, the TR13, provides 13 MeV protons onto liquid targets for the production of PET radionuclides such as18F,13N or68Ga, for medical applications. The aim of this work was to validate Geant4 against FLUKA and experimental measurements for production of the above-mentioned isotopes using the two cyclotrons. The results show variable degrees of agreement. For proton therapy, the proton-range agreement was within 2 mm for11C activity, whereas13N disagreed. For liquid targets at the TR13 the average absolute deviation ratio between FLUKA and experiment was 1.9±2.7, whereas the average absolute deviation ratio between Geant4 and experiment was 0. 6±0.4. This is due to the uncertainties present in experimentally determined reaction cross sections.

[发布机构] University of Huddersfield, Huddersfield; HD1 3DH, United Kingdom^1;European Organization for Nuclear Research, Geneva 23, Switzerland^2;TRIUMF, Vancouver; BC; V6T 2A3, Canada^3

[关键词] Activity distribution;Average absolute deviation;Liquid target;Ocular melanoma;PET scanner;Proton therapy;Range verifications;Reaction cross-sections