VADER: a variable dose-rate external 137Cs irradiator for internal emitter and low dose rate studies

Abstract

In the long term, 137Cs is probably the most biologically important agent released in many accidental (or malicious) radiation disasters. It can enter the food chain, and be consumed, or, if present in the environment (e.g. from fallout), can provide external irradiation over prolonged times. In either case, due to the high penetration of the energetic γ rays emitted by 137Cs, the individual will be exposed to a low dose rate, uniform, whole body, irradiation. The VADER (VAriable Dose-rate External 137Cs irradiatoR) allows modeling these exposures, bypassing many of the problems inherent in internal emitter studies. Making use of discarded 137Cs brachytherapy seeds, the VADER can provide varying low dose rate irradiations at dose rates of 0.1 to 1.2 Gy/day. The VADER includes a mouse “hotel”, designed to allow long term simultaneous residency of up to 15 mice. Two source platters containing ~ 250 mCi each of 137Cs brachytherapy seeds are mounted above and below the “hotel” and can be moved under computer control to provide constant low dose rate or a varying dose rate mimicking 137Cs biokinetics in mouse or man. We present the VADER design and characterization of its performance over 18 months of use.

Biofluid Metabolomics of Mice Exposed to External Low-Dose Rate Radiation in a Novel Irradiation System, the Variable Dose-Rate External 137Cs Irradiator

“…The VADER was designed to deliver controlled dose rates in the range 0.1–1 Gy/d to a cohort of up to 15 mice . The VADER uses ∼0.5 Ci of retired 137 Cs brachytherapy seeds that are arranged in two platters placed above and below a “mouse hotel”.…”

“…In this study, we examined the effects of variable LDR IR on mouse urine and serum small-molecule signatures using a liquid chromatography–mass spectrometry (LC–MS) global metabolomic approach. Mice were placed in the VAriable Dose-rate External 137 Cs irradiatoR (VADER), a custom-built irradiation system designed to model LDR 137 Cs exposures from both fallout and internal emitters. Mice were then removed at a single time point within a 30 d period (1–30 d) to represent different accumulated doses (1–9.7 Gy) at different dose rates (∼1–0.1 Gy/d).…”

The Flash Irradiator at the Radiological Research Accelerator Facility

“…Experiments with a large cohort of volunteers is under way to investigate age and sex effects on the dose rate response of dicentric yields, using both high dose rates, using this platform, and very low dose rates, mimicking fallout [11].…”

“…Having recently developed irradiation platforms to study low dose rate effects [11,12], we describe here a dedicated FLASH irradiator, that we have implemented at the Radiological Research Accelerator Facility (RARAF). The irradiator is based on a decommissioned medical linear accelerator (linac), similar to the platforms developed at Stanford [13] and Dartmouth [14].…”

Gene expression for biodosimetry and effect prediction purposes: promises, pitfalls and future directions – key session ConRad 2021

“…In an effort to further study such variable dose-rates, an external 137 Cs irradiator was used for long-term low dose rate studies (Garty et al 2020). Interestingly, sex-specific differences were found in the applied murine model when looking at the relative response of different blood cell subtypes.…”