Dynamic renal studies were performed with 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA). The results were analyzed by the method of mathematical deconvolution in order to obtain the impulse response function of the kidney. Regional analysis of the kidney was attempted by evaluating the independent responses of the renal parenchyma and renal pelvis to a bolus injection of 99mTc-DTPA.