[Liquid scintillation counting of 51chromium. Application to a micromethod of cell-mediated cytotoxic assay (author's transl)].

Detection of gamma emitting isotopes is achieved conventionally by using a gamma spectrometer, or in some cases by liquid scintillation counting. We applied these two methods to the detection of 51 Chromium released in a lymphocyte-mediated cytotoxic reaction. Detection in liquid scintillation appeared more efficient than conventional gamma detection: 16.74% vs 1,11%. It is therefore possible to reduce by a factor of 10 the number of target cells in the cytotoxic assay if liquid scintillation counting is used. Either method gave the same results when applied on the same samples. Liquid scintillation counting is to be preferred when high sensitivity is needed. In addition it offers the advantage of using the same apparatus for detection of gamma or beta emitting isotopes.