Automation of a Beckman liquid scintillation counter for data capture and data-base management

A software package for the automation of a Beckman LS9000 liquid scintillation counter is presented. The package provides effective on-line data capture (with a Perkin Elmer 3230 32-bit minicomputer), database management, audit trail and archiving facilities. Key features of the package are rapid andJlexible data entry, background subtraction, half-life correction, ability to queue several sample sets pending scintillation.counting, and formatted report generation. A brief discussion is given on the development of customized data processing programs. a4C and 3H radioisotopes have been frequently used in metabolism studies of drugs and other xenobiotics. They are also useful in comparing the relative absorption of a given compound from different routes of administration. Incorporation of either or both radioisotopes in the test compound allows for highly specific and sensitive deter-minations of the test compound and metabolites in the body tissues and excreta. Liquid scintillation counting (LSC) is the method of choice in measuring such weak beta-emitting radioiso-topes as 3H and 14C. The scintillation process involves interactions between a test sample containing beta emitters and the scintillation cocktail (a mixture of organic solvent and scintillator) leading to the emission of photons, which are measured by photomultiplier tubes in the LS counter. Following a typical metabolism or bioavailability study in our laboratory, measurements of radioactivity in collected samples are effectively carried out with a Beckman LS9000 counter. It is equipped with three counting channels and with microprocessors that automatically correct for background and counting efficiency. However, the steps that follow which include data entry, record keeping, documentation, and quality assurance of numerous quantities of LSC data are laborious and time-consuming and in need of obvious automation.