Simultaneous measurement of lung clearance rates for Tc- and In-DTPA in normal and damaged lungs
We investigated the relative clearance rates for /sup 99m/Tc-labeled diethylenetriamine-pentaacetate (Tc-DTPA) and /sup 113m/In-labeled DTPA (In-DTPA) when they were inhaled and deposited together within the lungs of same animal. Submicronic aerosols containing Tc-DTPA and In-DTPA were simultaneously generated by different nebulizers and collected within the same anesthetic bag. The combined aerosols were insufflated into piglets. Clearances for both compounds were measured simultaneously in normal lungs and when the lungs were damaged by intravenous oleic acid or by a presumed oxidant agent, intravenous or intratracheal phorbol myristate acetate (PMA). A medium-energy collimator and a computer-assisted gamma camera were used to calculate clearances. Correction was made for downscatter from the In photopeak into the Tc window. Marked lung injury occurred as evidenced by increases in lung water content and decreases in arterial PO/sub 2/. The clearance of In-DTPA was slightly but significantly slower than for Tc-DTPA in each group of animals. The correlation (r = 0.93) between clearances for Tc-DTPA and In-DTPA was good, even though in vitro studies demonstrated that Tc-DTPA, but not In-DTPA, slowly dissociated at room and body temperatures. Oleic acid increased, but surprisingly, PMA had no effect on clearance rates for both In-DTPA and Tc-DTPA. We recommend continued use of Tc-DTPA for these measurements in view of its lower cost, requirement for only low-energy collimation, better imaging characteristics, and widespread availability. The overlap between control and injured lungs and the lack of increased clearance rates after PMA suggest this technique does not always detect acute lung injury.
- Research Organization:
- Hospital for Sick Children, Toronto, Ontario (Canada)
- OSTI ID:
- 5702489
- Journal Information:
- J. Appl. Physiol.; (United States), Vol. 66:5
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
DTPA
LUNG CLEARANCE
LUNGS
PATHOLOGICAL CHANGES
PHORBOL ESTERS
TOXICITY
COLLIMATORS
COMPARATIVE EVALUATIONS
GAMMA CAMERAS
INDIUM 113
ISOMERIC NUCLEI
OLEIC ACID
RESPIRATORY SYSTEM DISEASES
SWINE
TECHNETIUM 99
TRACER TECHNIQUES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CAMERAS
CARBOXYLIC ACIDS
CARCINOGENS
CHELATING AGENTS
CLEARANCE
DISEASES
DOMESTIC ANIMALS
DRUGS
ESTERS
EXCRETION
HOURS LIVING RADIOISOTOPES
INDIUM ISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MONOCARBOXYLIC ACIDS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
RESPIRATORY SYSTEM
STABLE ISOTOPES
TECHNETIUM ISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques
560300 - Chemicals Metabolism & Toxicology