Investigation of pulmonary deposition of a nebulized radiopharmaceutical agent in awake cats

Objective - To determine whether conscious, unsedated cats will inhale a nebulized material administered via a facemask and whether this material will reach the lower airways. Animals - 20 healthy adult cats. Procedure - Technetium Tc 99m-diaminetriaminopentaacetic acid (^99mTc-DTPA) was nebulized into a spacer and administered to the cats via a closely fitting facemask. By use of a gamma camera, images were then immediately obtained to determine the distribution of ⁹⁹mTc-DTPA within the lower airways. Results - Images obtained by use of the gamma camera revealed that all 20 cats had inhaled ^99mTc-DTPA from the facemask. In each cat, deposition of the radiopharmaceutical agent was evident throughout the lung fields. Conclusions and Clinical Relevance - Awake cats that were not used to the application of a facemask did inhale substances from such a device. Aerosolization of medications may be a feasible route of administration for cats with lower airway disease.