Automated scanning electron microscopic characterization of particulate inclusions in biological tissues

Rapid individual particle characterization by computer assisted scanning electron microscopy and x-ray energy spectroscopy is now routinely available to many analysts. Its potential in the area of biological microanalysis is substantial. This paper details how these procedures work; showing how computers are interfaced to SEM/XES systems and how the resultant data may be processed for feature classification. The advantages and disadvantages of automated image analysis techniques are contrasted. A specific example of biological microanalysis of the calcium-phosphorus rich concretions in the kidney of marine bivalve molluscs is presented. Concretions were isolated by tissue homogenization and density gradient centrifugation. With the aid of discriminant analysis of the object vectors, a classification scheme for these features was developed. The advantage of computer suppression of artifact particles is demonstrated in this analysis. Results showed that individual heavy metals, as opposed to combinations, were associated with the concretions.