Histological evaluation of quantitative scintigraphy of the salivary glands in a primate model.

To assess the accuracy with which quantitative scintigraphy reflects the true extent of parenchymal losses in diseased salivary glands, the parotid glands of vervet monkeys were unilaterally subjected to experimental injury and studied by scintigraphy and histomorphometry. The glandular 99Tcm pertechnetate uptake, relative to a standard dose, was expressed as the ratio of operated to unoperated sides. This was compared with the equivalent ratios of the weights of various salivary component tissues, morphometrically determined at necropsy. Our results suggest that uptake levels of 99Tcm pertechnetate are influenced predominantly by the mass of acinar rather than ductal tissue present. Furthermore, in comparisons between scans, because of the inherent variability in the results, quantitative scintigraphy is sensitive only to differences exceeding 25% of the gland mass.