X-ray fluorescence tissue analysis during tumor growth

The authors discuss trace element content of tissue specimens obtained during growth of the murine Lewis lung tumor and the murine hepatoma BW7756 determined by radioisotope-induced X-ray fluorescence analysis. Elements from calcium, Z=20, to molybdenum, Z-=42, were monitored using the 22 Kev Aq X-ray emission from Cd-109 as the primary radiation source. The Compton Scatter peak, the shape and location of which is dependent on sample geometry and weight, was used to normalize spectral element X-ray yield data so deviations from normal healthy values could be routinely determined. X-ray yields from the tissues of tumor-bearing mice were compared directly with those obtained from the analysis of the same type as normal tissue in order to obtain disease/healthy concentration ratios as a function of days posttransplant. Results show that there are large fluctuations in zinc, bromine, and rubidium concentrations in organ and tumor tissues at critical points in the Lewis lung tumor life cycle. A comparison is made between these findings and analyses of tissues from mice with the BW7756 hepatoma