[en] An investigation into the use of principal components analysis in dynamic studies is described. The parameters obtained for three organs -kidneys, liver and thyroid- are compared in each case with those obtained from a standard physiological model. It is shown that the principal component parameters give better class separation than the physiological model parameters for renal and thyroid dynamic studies but with limited usefulness in the latter case. The physiological model provides better class separation for liver dynamic studies. For renal studies some measure of the degree of function can be implied from the principal components parameters