J. Trace Elements Med. BioI. Vol. 9, pp. 193-199 (l995) Br, Rb, Zn, Fe, Se and K in Blood of Colorectal Patients by INAA and PIXE C. SHENBERG 1 , H. FELDSTEIW, R. CORNELIS, L. MEES, J. VERSIECK*, L.VANBALLENBERGHE *, J. CAFMEYER AND W. MAENHAUT Laboratory for Analytical Chemistry, Institute for Nuclear Sciences, Proeftuinstraat 86, B-9000, Gent, Belgium *Department of Internal Medicine, Division of Gastroenterology, University Hospital, De Pintelaan 185, B-9000 Gent, Belgium (Received June/August 1995) Summary A preliminary study was conducted on blood samples and blood fractions of 11 colorectal patients and 10 healthy subjects (controls) in Belgium, in order to determine the concentration of some vital trace elements. Two non destructiv,y analytical methods were used for the determination: INAA and PIXE. The agreement be- tween PIXE and INAA was within about ± 10% for plasma, but for Rb, Se and Fe in whole blood and red cells a difference of ± 20% was noted; part of the discrepancy may be due to self absorption problems in PIXE, and for Rb, spectral interferences also may have contributed. The precision of the INAA method for the elements studied was found to be ± 3% for whole blood and red cells 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 whole blood to red cells and whole blood to plasma were not significantly different for normals and cancer cases and, therefore, in future studies analysis of whole blood only may be sufficient. The mean values for Br, Rb, BrlRb ratio, K, Fe and Se were significantly lower for cancer cases than for healthy individuals, and this might be applicable as an additional parameter for differentiating normals from malignant cases. Keywords: Trace elements, Br, K, Fe, Rb, Se, blood, colorectal cancer, INAA, PIXE. Introduction An increasing number of experimental and epidemio- logical studies suggest that trace elements play an essen- tial role in the human body 0-3). A number of sources indicate a relationship between trace elements and the in- cidence of cancer in the human population (4-8). Very lit- tle is known about Br and Rb status and their possible role in human pathology. The implication of bromine and bro- mine-containing compounds was discussed in relation to ITo whom correspondence should be addressed at the Soreq Nuclear Research Center, Yavne-81800, Israel. Temporarily on sabbatical leave in the Laboratory of Analytical Chemistry, Gent. © 1995 by Gustav Fischer Verlag Stuttgart· Jena . New York the stupor of uremic patients (9). The role of Rb in the differentiation of mononuclear cells (0) and several works relating to Rb in psychiatry, were reported (lI- B). In previous publications 04-16) we reported on trace element relative concentrations in normal and ma- lignant tissues, determined by high sensitivity X-Ray Fluorescence (XRF). Statistically significant differences in the concentrations of alkali and halogen elements were found in the normal and malignant colon tissue of 12 pa- tients suffering from colorectal cancer (CRC); in tumor- ous tissue the levels of K and Rb were increased, whereas the levels of Br and CI were decreased with respect to normal tissue (4). In an experiment with a relatively large number of mice inoculated with lung carcinoma, it