DISCORDANT FINDINGS BETWEEN KRYPTON-81M GAS AND TC-99M LABELED ULTRAFINE AEROSOL LUNG VENTILATION SPECT IN 2 PATIENTS WITH IDIOPATHIC PULMONARY FIBROSIS
N. Watanabe et al., DISCORDANT FINDINGS BETWEEN KRYPTON-81M GAS AND TC-99M LABELED ULTRAFINE AEROSOL LUNG VENTILATION SPECT IN 2 PATIENTS WITH IDIOPATHIC PULMONARY FIBROSIS, Clinical nuclear medicine, 20(4), 1995, pp. 315-317
Technegas, a newly developed ultra-fine dry dispersion of Tc-99m label
ed carbon with a particle size of approximately 5 nm to 20 nm, possess
es the properties for lung ventilation imaging using SPECT. The author
s observed a discrepancy between krypton-81m gas and technegas lung ve
ntilation SPECT in two patients with idiopathic pulmonary fibrosis who
demonstrated heterogeneously decreased distribution of technegas with
out regions of high count density (focal hot spots) of tracer in their
lungs in spite of the almost homogenous distribution of krypton-81m g
as, This finding could be explained by the duration of radioactive gas
inhalation. Technegas lung ventilation SPECT images reflected lung ve
ntilation with tidal breathing, Conversely, Kr-81m gas lung ventilatio
n SPECT images reflected not only lung ventilation, but also lung volu
mes, These two radioactive agents for lung ventilation SPECT show diff
erent findings.