A Versatile Plutonium-238 Irradiator for Radiobiological Studies with α-particles

TLDR

The irradiator is particularly suitable for in vitro studies of α‑particle biological effects at energies and LETs comparable to those encountered in vivo from radionuclides such as radon and actinides. The device uses ~1.2 × 10⁹ Bq of ²³⁸Pu on a platinum disc in a He‑filled chamber, delivering 3.26 ± 0.22 MeV α‑particles (LET 121 keV µm⁻¹) to cell monolayers at selectable dose rates from ~2 Gy min⁻¹ down to <10⁻⁴ Gy min⁻¹, with energy and LET tunable from 0.8–4.2 MeV and 266–102 keV µm⁻¹, and includes incubation and gassing for prolonged irradiation. It has been successfully used to investigate a range of α‑particle‑induced effects in diverse cell types, both as attached monolayers and thin suspensions.

Abstract

SummaryA versatile irradiator has been constructed for in vitro irradiation of mammalian cells with α-particles of well-defined energy, LET, direction, dose and dose rate. It is based on ∼ 1·2 × 109 Bq of 238Pu (on a platinum disc) contained in a He-filled chamber. In a standard configuration, monolayers of cells grown in 10 Hostaphan-based dishes are irradiated with 3·26 ± 0·22 MeV α-particles (LET 121 keV μm−1) at selectable dose rates from ∼ 2 Gy min−1 down to < 10−4 Gy min−1 (i.e. fluence rates of 1 × 107 cm−2 min−1 to 3 × 102 cm−2 min−1). Single dishes can be irradiated at dose rates up to 24 Gy min−1 (fluence rate 1 × 108 cm−2 min−1). Incident energy and LET can be varied from 0·8 to 4·2 MeV and 266 to 102 keV μm−1, respectively. The irradiator has full incubation and gassing facilities for protracted irradiations. The irradiator is particularly suitable for in vitro analytical studies of the biological effects of α-particles of energies and LETs similar to those which cells may receive in vivo from radionucleides such as radon and the actinides. It has been used successfully for investigations of a variety of α-particle-induced effects in different cell types irradiated either as attached monolayers or as very thin suspensions.