BR, RB, ZN, FE, SE AND K IN BLOOD OF COLORECTAL PATIENTS BY INAA AND PIXE

A preliminary study was conducted on blood samples and blood fractions of 11 colorectal patients and 10 healthy subjects (controls) in Belgi um, in order to determine the concentration of some vital trace elemen ts. Two non destructive analytical methods were used for the determina tion: INAA and PIXE. The agreement between PIXE and INAA was within ab out +/- 10% for plasma, but for Rb, Se and Fe in whole blood and red c ells a difference of +/- 20% was noted; part of the discrepancy may be due to self absorption problems in PIXE, and for Rb, spectral interfe rences also may have contributed. The precision of the INAA method for the elements studied was found to be +/- 3% for whole blood and red c ells and +/- 5% for plasma; the accuracy for Br, Rb and Zn was better than +/- 10% and +/- 17% for Se. The ratios of the concentrations in w hole blood to red cells and whole blood to plasma were not significant ly different for normals and cancer cases and, therefore, in future st udies analysis of whole blood only may be sufficient. The mean values for Br, Rb, Br/Rb ratio, K, Fe and Se were significantly lower for can cer cases than for healthy individuals, and this might be applicable a s an additional parameter for differentiating normals from malignant c ases.