RT Journal Article SR Electronic T1 Early Retardation of 99mTc-DTPA Radioaerosol Transalveolar Clearance in Irradiated Canine Lung JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 292 OP 299 VO 42 IS 2 A1 Suga, Kazuyoshi A1 Alderson, Philip O. A1 Mitra, Avijit A1 Domingues, Carlos A1 Rescigno, John A1 Smith, Lewis G. A1 Ogasawara, Nobuhiko A1 Matsunaga, Naofumi A1 Sasai, Kazuhiko YR 2001 UL http://jnm.snmjournals.org/content/42/2/292.abstract AB The alteration of 99mTc-labeled diethylenetriaminepentaacetic acid (DTPA) transalveolar clearance in an initial phase of radiation lung injury was experimentally investigated. Methods: Fourteen dogs were irradiated to the hemithorax with a single dose of 20 Gy. A DTPA radioaerosol study was performed before irradiation and on day 12 after irradiation. On day 14, the DTPA study was repeated again, with seven animals undergoing the study after inhalation of an aerosolized synthetic surfactant. The penetration index (P.I.) and clearance half-time (T1/2) of DTPA were measured in each lung. To evaluate the changes in lung surfactant after irradiation, alveolar lipids were stained in the resected lungs (n = 14), and the amounts of alveolar surfactant phospholipid and protein were measured by a bronchoalveolar lavage study in another six irradiated dogs. Results: In all of the 14 irradiated animals, DTPA radioaerosol distributed uniformly throughout the lungs without significant changes in P.I. The T1/2 values in irradiated lungs were significantly prolonged compared with the matched baseline values and those in nonirradiated lungs (P < 0.05 and 0.001, respectively). The aerosolized synthetic surfactant retarded the DTPA clearance both in the irradiated and in the nonirradiated lungs (P < 0.001) without significant changes in P.I. The histologic and bronchoalveolar lavage studies revealed an increase of alveolar surfactant materials in the irradiated lungs without substantial histologic changes in the alveolar structures. Conclusion: DTPA transalveolar clearance was retarded soon after irradiation. Increased alveolar surfactant may be partly responsible for this retarded DTPA clearance because the aerosolized synthetic surfactant also prolonged the clearance in nonirradiated lungs. A DTPA clearance test is sensitive for the early detection of radiation lung injury and seems helpful for clarifying the association of epithelial integrity changes and lung surfactant in radiation lung injury.