EFFECTIVE PENETRATION OF THE LUNG PERIPHERY USING RADIOACTIVE AEROSOLS - CONCISE COMMUNICATION

  • 1 January 1982
    • journal article
    • research article
    • Vol. 23  (10) , 872-877
Abstract
Radioactive microspheres could offer several advantages over gases in the investigation of pulmonary ventilation. Monodisperse microspheres of human serum albumin were produced using a spinning-disc generator, and kits were prepared for subsequent labeling with 99mTc. The average labeling efficiency was 88% and unlabeled 99mTc was removed before aerosol delivery. A simple system was constructed to nebulize and deliver dry monodisperse microspheres. The ventilation images obtained were compared quantitatively with the corresponding 81mKr images, subdividing the lung regions into inner, central and peripheral zones. No significant difference was found in the proportions of the total counts for any lung region. There was good agreement between the distributions of microspheres obtained on separate days (r = 0.97, P < 0.001). An aerosol penetration index was defined as the ratio of the peripheral to the inner counts for the microspheres normalized by the corresponding ratio of 81mKr. The mean value of this index for 16 normal subjects was 0.98 .+-. 0.23, indicating that the microspheres had achieved penetration of the lung periphery. For patients with chronic obstructive lung disease, more localized defects were observed with the microspheres than with 81mKr. The mean penetration index for this group was only 0.69 .+-. 0.21. This was significantly different from the value for normal subjects (P < 0.002).

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