Application of recording and processing of energy‐filtered image sequences for the elemental mapping of biological specimens: Imaging‐Spectrum

Abstract

Summary Computerized energy‐filtered transmission electron microscope (EFTEM) permits the recording and the processing of energy‐filtered images, allowing a part of an electron energy‐loss spectrum for each picture element to be obtained. This method, called ‘Imaging‐Spectrum’, uses a Zeiss CEM902 coupled to several image analysis systems. The actual configuration records sequences of 48 images, 256 × 256 pixels, in steps of the energy loss, ΔE. Processing these sequences results in part of a core‐loss EELS‐spectrum for each pixel. This approach produces elemental maps with a short processing time. We have implemented three kinds of background calculation for the image subtraction. The influence of the irradiation dose and of the energy selecting slit width on the quality of the spectra is investigated. The method is applied to the analysis of some biological specimens (pericellular coat behaviour during adhesion between macrophages and red blood cells and location of calcite microcrystals in dental pulp cells). The Imaging‐Spectrum method appears to be suitable for the analysis of large areas.