Quantitative Ga-67 Scintigraphy in patients with Silicosis: Comparison with Chest X-ray and Pulmonary Function

Shin, Kwang Hyun; Sohn, Hyung Sun; Chung, Yong An

Abstract

PURPOSE:The International Labor Organization (ILO) has established an international standard for chest X-ray diagnosis of pneumoconiosis since 1980. However, there is a need for improved diagnosis and staging in occupational disease. We evaluated Ga-67 citrate scintigraphy quantitatively and correlated the scintigraphic findings with pulmonary function tests and chest X-ray result.
MATERIALS AND METHODS
Twenty-five patients underwent whole body scintigraphy with additional chest and abdomen images 48 hrs after intravenous injection of 185 MBq of Ga-67 citrate. Ten normal controls were also studied. Regions of interest (ROI) were drawn on the posterior image to measure counts from the liver and lungs (Lung/Liver Ratio).
RESULTS
L/L ratio according to the stages of chest X-ray classification were as follows; stage 0 (normal, n=10): 0.3948+/-0.0692, stage 1 (n=10): 0.5763+/-0.1837, stage 2 (n=11): 0.6849+/-0.1459, stage 3 (n=4): 0.9913+/-0.0712. There was a significant correlation between the scintigraphic L/L ratio and the X-ray stage (r=0.618, p<0.05). However, no significant correlation between L/L ratio and pulmonary function tests were observed (p>0.05).
CONCLUSION
Quantitative Ga-67 scintigraphy can be a useful method for staging of silicosis. However, it is not a method to assess pulmonary functional impairment.