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Irradiator Commissioning and Dosimetry for Assessment of LQ α and β Parameters, Radiation Dosing Schema, and in vivo Dose Deposition
Published on: March 11, 2021
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Dose conversion coefficients for neutron external exposures with five postures: walking, sitting, bending, kneeling,
Yeon Soo Yeom1, Keith Griffin1, Haegin Han2
1Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA.
Radiation and Environmental Biophysics
|March 11, 2021
Summary
This study calculated neutron dose coefficients for non-standing postures using computational phantoms. Posture significantly impacts organ and effective dose calculations, highlighting the need for posture-specific data in radiation protection.
Area of Science:
- Radiation Dosimetry
- Computational Phantoms
- Nuclear Physics
Background:
- Previous research established posture-dependent dose coefficients for photon external exposures.
- The International Commission on Radiological Protection (ICRP) reference computational phantoms (MRCPs) were used.
- Five non-standing postures (walking, sitting, bending, kneeling, squatting) were previously studied for photons.
Purpose of the Study:
- To establish a dose coefficient (DC) dataset for external neutron exposures in non-standing postures.
- To perform Monte Carlo simulations using adult male and female MRCPs in five non-standing postures.
- To compare posture-dependent DCs with those of standing postures.
Main Methods:
- Conducted Monte Carlo radiation transport simulations.
- Utilized adult male and female ICRP reference computational phantoms (MRCPs).
- Simulated five non-standing postures: walking, sitting, bending, kneeling, and squatting.
- Calculated dose coefficients for 29 organs/tissues and effective doses.
- Covered neutron energies from 10-9 to 104 MeV.
- Investigated six irradiation geometries: antero-posterior (AP), posteroanterior (PA), left-lateral (LLAT), right-lateral (RLAT), rotational (ROT), and isotropic (ISO).
Main Results:
- Significant differences were observed between non-standing and standing posture dose coefficients.
- Lateral irradiation geometries showed up to a factor of 4 overestimate in breast DCs for squatting vs. standing.
- Lateral geometries showed up to 17 times underestimate in gonad DCs for standing vs. squatting.
- Impact on effective doses was generally less than organ doses but still significant.
- Standing MRCPs overestimated bending MRCP effective doses by 20% (AP, <50 MeV).
- Standing MRCPs underestimated kneeling MRCP effective doses by up to 40% (lateral, <0.1 MeV).
Conclusions:
- Posture-dependent dose coefficients are crucial for accurate external neutron exposure assessments.
- The established dataset provides essential data for radiation protection in various occupational and environmental scenarios.
- Differences in arm and leg positions significantly influence organ dose estimations across postures.
Keywords:
Dose coefficientsExternal exposuresMesh-type reference computational phantomsNeutronsPosturesMore Related Videos
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