Summary
The biological half-life (TB) of aerosolized 99mTc-diethylenetriaminepentaacetate was determined in 14 lung regions of 18 clinically normal Beagles. Three groups of lung regions or volumes were identified on the basis of significantly (P < 0.05) different TB. Group A (mean ± SD TB, 82 ± 21 minutes) included the transversely oriented cranial and caudal nonperihilar regions. Group B (mean ± SD, 61 ± 15 minutes) represented all sagittally oriented lung regions and the entire lung field. Group C (mean ± SD, 49 ± 11 minutes) included the transversely oriented cranial and caudal perihilar regions. Clearance of 99mTc-diethylenetriaminepentaacetate is considered a function of transepithelial transport into the blood, as well as bronchial transport via the mucociliary transport mechanism.
