New operational quantities (RBE × D p lens/Φ) for eye lens neutron dosimetry as a function of energy and angle of incidence in the ICRU 95 formalism

This paper is a continuation of a study published recently by the authors. It presents and discusses computed personal absorbed dose in the lens of the eye (Dp lens/ Φ), and a relative biological effectiveness (RBE)-weighted absorbed dose (in terms of an newly proposed operational quantity RBE × Dp lens/Φ), conversion coefficients for the lens of the eye for neutron exposure at incident energies from thermal to ∼20 MeV and at angles of incidence from 0° to 90° in 15° increments, at 180° and for rotational incidence irradiation geometry (from 0° to 360° in 5° increments). These conversion coefficients were obtained from a simulation model developed for this study that contains the stylised eye model, embedded in the adult UF-ORNL mathematical ph antom, whereby the previously stated RBE-weighted absorbed dose was obtained using the proposed RBE versus neutron energy distribution compiled in a previous paper by the authors. The simulations carried out for this study using the Monte Carlo N-Particle transport code version 6.2, were conducted i n a realistic human eye model, for the left and right sensitive and whole volume of the lens of the eye, considering the recent proposed redefinition of the operational quantities for external radiation exposure in International Commission on Radiation Units and Measurements (ICRU) report 95. A comp rehensive set of tabulated data for neutron fluence-to-dose conversion coefficients (Dp lens/Φ in pGy cm2) and RBE-weighted absorb...

Source: Journal of Radiological Protection - September 10, 2023 Category: Physics Authors: Salah Djeffal, Jacques Dubeau, Jiansheng Sun and Fawaz Ali Source Type: research