A method for in vivo analysis of platinum after chemotherapy with cisplatin

A method to quantify the concentration of platinum in vivo by x-ray fluorescence (XRF) analysis is described. The measurement system consists of a roentgen apparatus, operated at 155 kV and 25 mA, and a high-purity germanium detector. In order to reduce the amount of scattered radiation in the detector the connecting links between the roentgen tube and scatterer, scatterer and patient, patient and detector, are arranged in a three-axial geometry with mutually orthogonal directions. With this system, quantification of platinum can be achieved with a minimum detectable concentration of 8 micrograms/g, for a measuring time of 30 min and an organ depth of 4 cm. The method can be used to follow the uptake and retention of platinum in patients treated with cisplatin, a frequently used cytostatic agent for tumour therapy.