Elemental Analyses Performed with the Karlsruhe Nuclear Microprobe

Proton induced X-rays have been used in the Karlsruhe nuclear microprobe to determine the content of some trace elements in normal and cancerously degenerated human stomach mucousa tissue. A 3 MeV proton beam produced in a single stage Van de Graaff accelerator is focussed down to 3 μm at 600 pA and swept across the specimens in a meandrous pattern. The local mass density of the specimens is determined by the yield of elastically scattered protons, which are registered in a surface barrier detector. Erythrocytes served as test objects to demonstrate the feasibility of the procedure. Specimens of stomach mucousa were prepared by two different methods of fixation. After irradiation the specimens were stained to identify the histological structure. All specimens show rather low structure in elemental concentrations except for iron. No significant shifts in the trace element contents between normal and cancerous stomach mucousa could be observed.