Conjunctival transport of technetium-99m pertechnetate

Using a gamma camera coupled to a computer and a tape unit the transport of pertechnetate (Tc99m) across the conjunctiva was determined by the 'region of interest' technique in human subjects. In 11 patients with their lacrimal sacs removed a fractional turnover rate of 0.021 min-1 was found. In 21 patients with inflammed conjunctiva due to chronic dacryocystitis a fractional turnover rate of 0.027 min-1 was found, whereas the value in 11 normal individuals was 0.015 min-1. Neglecting the relatively small transcorneal route of disappearance, the values found for technetium disappearance could be regarded as representative for the transconjunctival transport of the radioisotope. This assumption was confirmed by correlating the radioactivity in the blood with the fractional turnover rate.