The Preparation of Bromine-82 and Iodine-131 Labelled Polystyrene Microspheres With Diameters from 0·1 to 30 Microns

Abstract

Methods are described for producing radioactive spherical particles of substituted polystyrene with diameters in the range 0·1–30 μm. Small particles (0·1–2 μm) are produced by the emulsion polymerisation of ¹³¹I-labelled 2,4-iodostyrene. Larger particles (1–30 μm) are produced with a spinning disc aerosol generator using a xylene solution of either ⁸²Br-labelled polymerised 3-bromostyrene or ¹³¹I-labelled iodinated polystyrene. Particles produced by both techniques are spherical and the standard deviations of preparations compare well with those of commercially prepared suspensions of polymers. The radioactivity, being chemically bound to the polymer, is resistant to leaching and the leaching rates, determined both in vitro and in vivo, are less than 0·1 per cent/day. The use of these labelled particles in investigations of human lung dynamics is discussed.