ABSTRACT
OBJECTIVE: To explore the effects of different doses of chest multislice spiral computed tomography( MSCT) in screening pneumoconiosis. METHODS: Forty workers exposed to coal dust and silica dust were selected by random sampling method,and scanned by conventional dose( 130 k V,25. 0-75. 0 m As) and low-dose of MSCT which included program 1( 110 k V,50. 0 m As),program 2( 110 k V,16. 0 m As) and program 3( 80 k V,16. 0 m As) respectively. Comparative analysis was given to the reconstructions of high-resolution 1. 5 mm thin-section,5. 0 mm of ordinary-section and the maximum intensity projection of 5. 0 mm coronary position respectively. RESULTS: Program 1 and program 2 exceeded program 3 in both image quality scores and low-dose MSCT image evaluation score( P < 0. 01). Both program 1 and 2 were able to show the p,q,s and t small shadows of 40 cases,and had no statistical significant difference in small shadow scores compared with those of conventional dose group( P > 0. 02),except the t small shadow scores of program 2;program 3 distinctly showed fewer images of the 4 kinds of small shadow and more false images,its images of p,q and t small shadow scores were lower than those of conventional dose group( P < 0. 01). We evaluated the radiation dose indexes including the CT dose index volume,CT dose index weighted,dose length product and the average effective dose,and all the results showed the following trend sequence from high to low: the conventional dose group > program 1 > program 2 >program 3 group( P < 0. 05). CONCLUSION: All low doses of MSCT schemes can meet the demands of pneumoconiosis screening. Using the program of 110 k V,16. 0 m As can not only achieve better quality image,but also effectively reduce the radiation doses that patients receive in screening.