TOPOGRAPHIC SAMPLING METHOD FOR QUANTITATIVE RADIOTRACER EVALUATION IN BONES AND TEETH

¹ Harvard School of Dental Medicine, Boston, Mass.

A selective grinding method for sampling bones and teeth of rhesus monkeys and rats has been described and found to be especially useful where the distribution of radioisotope varied greatly from one region of calcified tissue to another. The method was evaluated following radiophosphorus and radiosodium injection in monkeys in order to determine whether reproducible results could be obtained between bilaterally symmetrical teeth and between various bones.

In monkeys, good reproducibility was observed in both radiophosphorus uptake and total phosphorus content between bilaterally symmetrical teeth within the same arch, and in different samples of alveolar bone and cementum of the same arch. Comparable radiophosphorus uptakes were observed between the shafts of the right and left humeri of the same animal and also between the shafts of the right and left femurs. Similarly, there was good agreement in radiosodium uptake between teeth that were in the same state of development and function.

In rats that received subcutaneous radiosodium injections 24 hours before sacrifice, reproducible results were obtained in the relative uptake of isotope in enamel and dentin from the 4 jaw quadrants within each animal and also between animals of the same litter. Comparable results were obtained in the comparison of the right and left femurs.