scholarly journals Relative biological effectiveness of alpha particles and protons varies with biological criteria, and values are mutually correlated in thermal neutron exposure

2010 ◽  
Vol 60 (2) ◽  
pp. 121-129
Author(s):  
Yasuo Ukai ◽  
Atsushi Yamashita
Keyword(s):  
Thermal Neutron ◽  
Relative Biological Effectiveness ◽  
Alpha Particles ◽  
Biological Criteria ◽  
Biological Effectiveness ◽  
Neutron Exposure

scholarly journals Thermal neutron Relative Biological Effectiveness factors for Boron Neutron Capture Therapy from In Vitro Irradiations

2020 ◽  
Author(s):  
María Pedrosa-Rivera ◽  
Javier Praena ◽  
Ignacio Porras ◽  
Manuel Pedro Sabariego ◽  
Ulli Köster ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Thermal Neutron ◽  
Boron Neutron Capture Therapy ◽  
Neutron Capture ◽  
Relative Biological Effectiveness ◽  
Neutron Capture Therapy ◽  
Tumor Cell Lines ◽  
Boron Neutron Capture ◽  
Effectiveness Factors ◽  
Biological Effectiveness

The experimental determination of the relative biological effectiveness of thermal neutron factors is fundamental in Boron Neutron Capture Therapy. Present values have been obtained using mixed beams consisting of both neutrons and photons of various energies. A common weighting factor has been used for both thermal and fast neutron doses, although such an approach has been questioned. At the nuclear reactor of the Institut Laue-Langevin a pure low-energy neutron beam has been used to determine thermal neutron relative biological effectiveness factors. Different tumor cell lines, corresponding to glioblastoma, melanoma, and head and neck squamous cell carcinoma, and non-tumor cell lines (lung fibroblast and embryonic kidney) have been irradiated using an experimental arrangement designed to minimise neutron-induced secondary gamma radiation. Additionally, the cells were irradiated with photons at a medical linear accelerator, providing reference data for comparison with that from neutron irradiation. Survival and proliferation were studied after irradiation, yielding the Relative Biological Effectiveness corresponding to the damage of thermal neutrons for the different tissue types.

scholarly journals High-Accuracy Relative Biological Effectiveness Values Following Low-Dose Thermal Neutron Exposures Support Bimodal Quality Factor Response with Neutron Energy

2022 ◽  
Vol 23 (2) ◽  
pp. 878
Author(s):  
Laura C. Paterson ◽  
Amy Festarini ◽  
Marilyne Stuart ◽  
Fawaz Ali ◽  
Christie Costello ◽  
...  
Keyword(s):  
Dna Damage ◽  
Thermal Neutron ◽  
Quality Factor ◽  
Neutron Energy ◽  
Relative Biological Effectiveness ◽  
High Energy ◽  
Weighting Factor ◽  
Radiological Protection ◽  
Thermal Neutrons ◽  
Biological Effectiveness

Theoretical evaluations indicate the radiation weighting factor for thermal neutrons differs from the current International Commission on Radiological Protection (ICRP) recommended value of 2.5, which has radiation protection implications for high-energy radiotherapy, inside spacecraft, on the lunar or Martian surface, and in nuclear reactor workplaces. We examined the relative biological effectiveness (RBE) of DNA damage generated by thermal neutrons compared to gamma radiation. Whole blood was irradiated by 64 meV thermal neutrons from the National Research Universal reactor. DNA damage and erroneous DNA double-strand break repair was evaluated by dicentric chromosome assay (DCA) and cytokinesis-block micronucleus (CBMN) assay with low doses ranging 6–85 mGy. Linear dose responses were observed. Significant DNA aberration clustering was found indicative of high ionizing density radiation. When the dose contribution of both the 14N(n,p)14C and 1H(n,γ)2H capture reactions were considered, the DCA and the CBMN assays generated similar maximum RBE values of 11.3 ± 1.6 and 9.0 ± 1.1, respectively. Consequently, thermal neutron RBE is approximately four times higher than the current ICRP radiation weighting factor value of 2.5. This lends support to bimodal peaks in the quality factor for RBE neutron energy response, underlining the importance of radiological protection against thermal neutron exposures.

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