An apparatus for the measurement of -radiation from the human body

Abstract

The design and construction of a total-body gamma-monitor are described. It employs 4 long, high-pressure ionization chambers connected differentially with 4 similar chambers to reduce the background intensity. The chambers are mounted in a water-filled steel tank, to provide shielding against local gamma-radiation. The differential current develops a potential across a stable high-value resistor, and this potential is amplified by a vibrating reed electrometer. The amplified output is displayed on an electro-mechanical recorder and the mean out-of-balance current is determined automatically. The errors are such that a 2-hour measurement of body radioactivity enables the K content of a subject to be determined with a probability error of about 17% under ideal conditions.