New approaches for biological monitoring of radiation workers.

Methods for measuring somatic mutation and chromosome aberration in humans are currently advancing and provide important new opportunities for biologic dosimetry of nuclear workers. Methods to test somatic mutation in four human genes (hprt, hla-a, glycophorin A, and beta globin) are reviewed briefly and evaluated for their applicability to biological radiation dosimetry of nuclear workers. Two somatic mutation tests can be currently recommended: an HPRT method applied to recently exposed workers and the glycophorin A method applied to workers exposed over their working lifetime. A new method of chromosome analysis using DNA hybridization with chromosome-specific gene libraries allows one to paint single or multiple chromosome pairs in standard metaphase preparations. This method is ideal for rapid and reliable detection of reciprocal translocations, the key lesion for the evaluation of long-term radiation exposure. Both mutational and aberrational approaches should be fostered in the expectation that they will complement other forms of dosimetry and will improve our ability to clarify whether or not significant health effects are dosimetrically related.