A SENSITIVE NONINVASIVE ANALYSIS OF PT IN EXTERNAL TISSUES - FOLLOW-UP OF PT DEPOSITION FOLLOWING CISPLATIN TREATMENT

Noninvasive analysis of heavy elements in external tissues by diagnost ic-x-ray spectrometry (DXS) is presented. Pt can be detected accuratel y with sensitivity below 1 mug/g wet weight of tissue. In the present paper the possibility to monitor Pt accumulation and clearance in the external tissues of cancer patients treated with cisplatin [Cis-diammi nedichloro-platinum (II)-cDDP] chemotherapy is reported. The DXS metho d is based on x-ray fluorescence analysis. Heavy elements in the small skin area of interest are analyzed by their excitation with a monochr omatic soft x-ray beam of 14.6 KeV. Spectral L lines of heavy metals s uch as Pt are detected with minimum interference by other elements in the tissues. Skin Pt levels up to about 6 mug/g were observed followin g several courses of cDDP treatment. The Pt seemed to be homogeneously distributed in different skin areas with similar levels in the dermis and epidermis. The rate of clearance of Pt from the skin (50% in abou t 30 days) was slower by three orders of magnitude than its clearance from plasma. Further studies may use DXS to establish the accurate kin etics of Pt deposition and clearance in tissues of cDDP treated patien ts, as well as the exact relation between tissue Pt levels and the dev elopment of the drug related late complications.