Detection and discrimination of neutron capture events for NCEPT dose quantification
Abstract Neutron Capture Enhanced Particle Therapy (NCEPT) boosts the effectiveness of particle therapy by capturing thermal neutrons produced by beam-target nuclear interactions in and around the treatment site, using tumour-specific $$^{10}$$ 10 B or $$^{157}$$ 157 Gd-based neutron capture agents....
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2022-04-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-022-09676-x |
| _version_ | 1811272488334655488 |
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| author | Andrew Chacon Marissa Kielly Harley Rutherford Daniel R. Franklin Anita Caracciolo Luca Buonanno Ilenia D’Adda Anatoly Rosenfeld Susanna Guatelli Marco Carminati Carlo Fiorini Mitra Safavi-Naeini |
| author_facet | Andrew Chacon Marissa Kielly Harley Rutherford Daniel R. Franklin Anita Caracciolo Luca Buonanno Ilenia D’Adda Anatoly Rosenfeld Susanna Guatelli Marco Carminati Carlo Fiorini Mitra Safavi-Naeini |
| author_sort | Andrew Chacon |
| collection | DOAJ |
| description | Abstract Neutron Capture Enhanced Particle Therapy (NCEPT) boosts the effectiveness of particle therapy by capturing thermal neutrons produced by beam-target nuclear interactions in and around the treatment site, using tumour-specific $$^{10}$$ 10 B or $$^{157}$$ 157 Gd-based neutron capture agents. Neutron captures release high-LET secondary particles together with gamma photons with energies of 478 keV or one of several energies up to 7.94 MeV, for $$^{10}$$ 10 B and $$^{157}$$ 157 Gd, respectively. A key requirement for NCEPT’s translation is the development of in vivo dosimetry techniques which can measure both the direct ion dose and the dose due to neutron capture. In this work, we report signatures which can be used to discriminate between photons resulting from neutron capture and those originating from other processes. A Geant4 Monte Carlo simulation study into timing and energy thresholds for discrimination of prompt gamma photons resulting from thermal neutron capture during NCEPT was conducted. Three simulated $$300\times 300\times 300$$ 300 × 300 × 300 mm $$^3$$ 3 cubic PMMA targets were irradiated by $$^4$$ 4 He or $$^{12}$$ 12 C ion beams with a spread out Bragg peak (SOBP) depth range of 60 mm; one target is homogeneous while the others include $$10\times 10\times 10$$ 10 × 10 × 10 mm $$^3$$ 3 neutron capture inserts (NCIs) of pure $$^{10}$$ 10 B or $$^{157}$$ 157 Gd located at the distal edge of the SOBP. The arrival times of photons and neutrons entering a simulated $$50\times 50\times 50$$ 50 × 50 × 50 mm $$^3$$ 3 ideal detector were recorded. A temporal mask of 50–60 ns was found to be optimal for maximising the discrimination of the photons resulting from the neutron capture by boron and gadolinium. A range of candidate detector and thermal neutron shielding materials were simulated, and detections meeting the proposed acceptance criteria (i.e. falling within the target energy window and arriving 60 ns post beam-off) were classified as true or false positives, depending on their origin. The ratio of true/false positives ( $$R_{TF}$$ R TF ) was calculated; for targets with $$^{10}$$ 10 B and $$^{157}$$ 157 Gd NCIs, the detector materials which resulted in the highest $$R_{TF}$$ R TF were cadmium-shielded CdTe and boron-shielded LSO, respectively. The optimal irradiation period for both carbon and helium ions was 1 µs for the $$^{10}$$ 10 B NCI and 1 ms for the $$^{157}$$ 157 Gd NCI. |
| first_indexed | 2024-04-12T22:41:12Z |
| format | Article |
| id | doaj.art-21d5cb55f3024fd8a2f264b79ff42613 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-12T22:41:12Z |
| publishDate | 2022-04-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-21d5cb55f3024fd8a2f264b79ff426132022-12-22T03:13:42ZengNature PortfolioScientific Reports2045-23222022-04-0112111410.1038/s41598-022-09676-xDetection and discrimination of neutron capture events for NCEPT dose quantificationAndrew Chacon0Marissa Kielly1Harley Rutherford2Daniel R. Franklin3Anita Caracciolo4Luca Buonanno5Ilenia D’Adda6Anatoly Rosenfeld7Susanna Guatelli8Marco Carminati9Carlo Fiorini10Mitra Safavi-Naeini11Australian Nuclear Science and Technology Organisation (ANSTO)Australian Nuclear Science and Technology Organisation (ANSTO)Australian Nuclear Science and Technology Organisation (ANSTO)Faculty of Engineering and IT, University of Technology SydneyDipartimento di Elettronica, Informazione e BioingegneriaDipartimento di Elettronica, Informazione e BioingegneriaDipartimento di Elettronica, Informazione e BioingegneriaCentre for Medical Radiation Physics, University of WollongongCentre for Medical Radiation Physics, University of WollongongDipartimento di Elettronica, Informazione e BioingegneriaDipartimento di Elettronica, Informazione e BioingegneriaAustralian Nuclear Science and Technology Organisation (ANSTO)Abstract Neutron Capture Enhanced Particle Therapy (NCEPT) boosts the effectiveness of particle therapy by capturing thermal neutrons produced by beam-target nuclear interactions in and around the treatment site, using tumour-specific $$^{10}$$ 10 B or $$^{157}$$ 157 Gd-based neutron capture agents. Neutron captures release high-LET secondary particles together with gamma photons with energies of 478 keV or one of several energies up to 7.94 MeV, for $$^{10}$$ 10 B and $$^{157}$$ 157 Gd, respectively. A key requirement for NCEPT’s translation is the development of in vivo dosimetry techniques which can measure both the direct ion dose and the dose due to neutron capture. In this work, we report signatures which can be used to discriminate between photons resulting from neutron capture and those originating from other processes. A Geant4 Monte Carlo simulation study into timing and energy thresholds for discrimination of prompt gamma photons resulting from thermal neutron capture during NCEPT was conducted. Three simulated $$300\times 300\times 300$$ 300 × 300 × 300 mm $$^3$$ 3 cubic PMMA targets were irradiated by $$^4$$ 4 He or $$^{12}$$ 12 C ion beams with a spread out Bragg peak (SOBP) depth range of 60 mm; one target is homogeneous while the others include $$10\times 10\times 10$$ 10 × 10 × 10 mm $$^3$$ 3 neutron capture inserts (NCIs) of pure $$^{10}$$ 10 B or $$^{157}$$ 157 Gd located at the distal edge of the SOBP. The arrival times of photons and neutrons entering a simulated $$50\times 50\times 50$$ 50 × 50 × 50 mm $$^3$$ 3 ideal detector were recorded. A temporal mask of 50–60 ns was found to be optimal for maximising the discrimination of the photons resulting from the neutron capture by boron and gadolinium. A range of candidate detector and thermal neutron shielding materials were simulated, and detections meeting the proposed acceptance criteria (i.e. falling within the target energy window and arriving 60 ns post beam-off) were classified as true or false positives, depending on their origin. The ratio of true/false positives ( $$R_{TF}$$ R TF ) was calculated; for targets with $$^{10}$$ 10 B and $$^{157}$$ 157 Gd NCIs, the detector materials which resulted in the highest $$R_{TF}$$ R TF were cadmium-shielded CdTe and boron-shielded LSO, respectively. The optimal irradiation period for both carbon and helium ions was 1 µs for the $$^{10}$$ 10 B NCI and 1 ms for the $$^{157}$$ 157 Gd NCI.https://doi.org/10.1038/s41598-022-09676-x |
| spellingShingle | Andrew Chacon Marissa Kielly Harley Rutherford Daniel R. Franklin Anita Caracciolo Luca Buonanno Ilenia D’Adda Anatoly Rosenfeld Susanna Guatelli Marco Carminati Carlo Fiorini Mitra Safavi-Naeini Detection and discrimination of neutron capture events for NCEPT dose quantification Scientific Reports |
| title | Detection and discrimination of neutron capture events for NCEPT dose quantification |
| title_full | Detection and discrimination of neutron capture events for NCEPT dose quantification |
| title_fullStr | Detection and discrimination of neutron capture events for NCEPT dose quantification |
| title_full_unstemmed | Detection and discrimination of neutron capture events for NCEPT dose quantification |
| title_short | Detection and discrimination of neutron capture events for NCEPT dose quantification |
| title_sort | detection and discrimination of neutron capture events for ncept dose quantification |
| url | https://doi.org/10.1038/s41598-022-09676-x |
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