Radiation safety in the laboratory

Use of radioactive substances carries with it varying degrees of risk. With the correct care and protection these risks can be reduced considerably. The degree of protection required will depend on the radionucleotide being used. For practical purposes, we will confine ourselves to some of beta and gamma emitters most commonly found in life science laboratories. Beta emissions of 32P, 35P and 14C can be blocked effectively by using 10 mm thick ICI Perspex acrylic. The obvious advantage in using this material is that, with the optical properties of perspex being superb, visibility of the working area is not impaired. The gamma and X-ray emissions from 125I need to be shielded by metal lead sheet. The thickness of the lead sheet will be dependent on the energy level of the emitter. For 125I, a sheet 0.3 mm thick is effective. The disadvantage of using lead sheet is that the work area is hidden from the user. A new material alleviates this problem. It is a unique acrylic co-polymer resin, in which an organo-lead salt has been dispersed. This material has virtually all the normal chemical and physical properties, including visibility, of conventional acrylic. The gauge of material has a lead equivalence value of 0.5 mm. Lead-acrylic therefore, effectively blocks gamma emissions for this isotope and any gamma emitters of lesser energy. It is, however, unsuitable for use with other more energetic isotopes of iodine. (author)