GEANT4 calculations of neutron dose in radiation protection using a homogeneous phantom and a Chinese hybrid male phantom

Geng, Changran; Tang, Xiaobin; Guan, Fada; Johns, Jesse; Vasudevan, Latha; Gong, Chunhui; Shu, Diyun; Chen, Da

doi:10.1093/rpd/ncv364

Cited by 21 publications

(6 citation statements)

References 11 publications

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“…Thus, the supposed impact of neutrons on the LET needs to be investigated further. However, the neutrons are difficult to be detected directly because the CR-39 detectors are not sensitive to uncharged particles; and the Geant4 simulation results of neutrons are related to the physical models as well as cross-section library [30]. As the biological effect of heavy ion is determined by the total effect of the dose contributed from the ions with different LET components, the LET d is commonly used in proton and carbon ions radiobiological studies [5].…”

Section: Discussionmentioning

confidence: 99%

Changes of the linear energy transfer (LET) and beam width of therapeutic carbon ion beam in density heterogeneous phantoms

Yang¹,

Zhao²,

Zhuo³

et al. 2022

J. Radiol. Prot.

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This work aims to investigate the changes in the linear energy transfer (LET) spectra distribution and the beam spot width of a therapeutic carbon ion beam in density heterogeneous phantoms. Three different heterogeneous phantoms were fabricated using a combination of solid water, lung, and bone tissue slabs and irradiated by a single energy carbon beam (276.5 MeV/u). CR-39 detectors were used for experimental measurements and the Monte Carlo toolkit Geant4 was employed for theoretical simulations. The results demonstrated that the measured LET spectra agree well with the simulation results. The lung and bone tissues displayed no obvious effect on the spectral distribution of LET. The dose-average LET was invariant and showed no obvious difference in the different materials, while the track-average LET increased in the lung and decreased in the bone materials. Similarly, the beam spot size increased in the lung, and decreased in the bone materials. Additionally, the fluence of the secondary fragments varied in different tissues. These findings are expected to provide cross-validation data for the quality assurance of carbon ion therapy and to be beneficial for validating the base data in treatment planning systems.

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Section: Discussionmentioning

confidence: 99%

Changes of the linear energy transfer (LET) and beam width of therapeutic carbon ion beam in density heterogeneous phantoms

Yang¹,

Zhao²,

Zhuo³

et al. 2022

J. Radiol. Prot.

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“…Specifically, G4EMStandardPhysics was used to simulate the electromagnetic process, including photoelectric effect, Compton scattering, pair production, multiple scattering, ionization, and bremsstrahlung for photons and electrons; G4DecayPhysics was used for modelling decays of unstable particles defined in the physics list; G4RadioactiveDecayPhysics was used to simulate radioactive decays of nuclei based on ENSDF data [37]. To speed up the simulation and reduce memory usage, the G4PhantomParameterisation class was used to create the parameterized volume representing the voxelized scomber japonicus phantom, and deposited energy was scored by organ/tissue index in each particle tracking step instead of scoring the three-dimensional dose distribution [38]. The Geant4 toolkit version 11.0.3 was used in the present work.…”

Section: Monte Carlo Simulationmentioning

confidence: 99%

Voxelized scomber japonicus phantom and its application for internal dose evaluation by Monte Carlo calculations

Gong,

Dao,

Guo

et al. 2023

Environ. Res. Commun.

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This study developed a voxelized scomber japonicus phantom through CT scanning images for the purpose of radiation protection in the environment, which gives a realistic description of the scomber japonicus’s anatomy. The absorbed fraction (AF) values of the voxelized scomber japon-icus phantom were calculated for photons and electrons in the energies of 0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 MeV using Monte Carlo toolkit Geant4. Furthermore, the S-factor values for four radionuclides (134Cs, 137Cs, 131I and 90Sr) in the organs/tissues were evaluated using the monoenergetic AF values based on the radioisotope decay data, and compared with that obtained directly through whole emission spectra simulation. The voxelized scomber japonicus phantom would be a good candidate for dosimetry in non-human biota for the environmental dosimetry, and the built database of AF values can be used for dose calculations of any radioactive contaminations.

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“…It not only retains all the features of Geant4 in terms of speed, accuracy, and flexibility but also provides standardised basic physics. The physical model 'g4em-standar-d_opt4,' 'thermalphp physics,' 'g4decay,' 'g4ion-binarycascade,' 'g4h-elastic_HP,' 'g4stopping,' and 'g4em-extra' were adopted in this research as described in previous studies [21]. The number of simulated particles was 1×10 9 , and the Monte Carlo uncertainty was less than 3%, ensuring the accuracy of the simulation results.…”

Section: Monte Carlo Simulation and Dose Calculationmentioning

confidence: 99%

Assessment of long-term risks of secondary cancer in paediatric patients with brain tumours after boron neutron capture therapy

et al. 2019

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This study firstly explored the risks of secondary cancer in healthy organs of Chinese paediatric patients with brain tumours after boron neutron capture therapy (BNCT). Three neutron beam irradiation geometries (i.e. right lateral, top to bottom, posterior to anterior) were adopted in treating patients with brain tumours under the clinical environment of BNCT. The concerned organs in this study were those with high cancer morbidity in China (e.g. lung, liver and stomach). The equivalent doses for these organs were calculated using Monte Carlo and anthropomorphic paediatric phantoms with Chinese physiological features. The risk of secondary cancer, characterised by the lifetime attributable risk (LAR) factor given in the BEIR VII report, was compared among the three irradiation geometries. The results showed that the LAR was lower with the PA irradiation geometry than with the two other irradiation geometries when the 2 cm diameter tumour was at a depth of 6 cm on the right side of the brain. Under the PA irradiation geometry, the LAR in the organs increased with increasing tumour volume and depth because of the long irradiation time. As the patients aged from 10–15 years old, the LAR decreased, which was related to the increased patient height and shortened life expectancy. Female patients had a relatively higher risk of secondary cancer than male patients in this study, which could be due to the thinner body thickness and the weaker protective effect on the internal organs of the female patients. In conclusion, the risks of secondary cancer in organs were related to irradiation geometries, gender, and age, indicating that the risk of secondary cancer is a personalised parameter that needs to be evaluated before administering BNCT, especially in patients with large or deep tumours.

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GEANT4 calculations of neutron dose in radiation protection using a homogeneous phantom and a Chinese hybrid male phantom

Cited by 21 publications

References 11 publications

Changes of the linear energy transfer (LET) and beam width of therapeutic carbon ion beam in density heterogeneous phantoms

Changes of the linear energy transfer (LET) and beam width of therapeutic carbon ion beam in density heterogeneous phantoms

Voxelized scomber japonicus phantom and its application for internal dose evaluation by Monte Carlo calculations

Assessment of long-term risks of secondary cancer in paediatric patients with brain tumours after boron neutron capture therapy

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