The application of multi-slice low-dose CT in the chest

Objective The aim this study was to explore rationality and possibility of multi-slice low-dose in the chest. Methods 1) X - ray radiance dose measurement: To use 120kV tube VoltageN0. 75s/ rotation,8mm,5mm,3mm,1mm sections and the tube current setting 115mAs, 75mAs,40mAs,25mAs,7.5mAs were employed in every section. The X - ray radiation dose were measured and conducted statistics management. 2) water- model measurement: The technical parameters were 120kV,0.75s,8mm,5mm,3mm sections, The every slice was scanned to use tube current 115mAs,40mAs,25mAs. The every image were measured six same region of interest. 3) The multi-slice low-dose CT in patients: The mass and patcly in the lung of patients each twenty cases were selected randomly .The technical parameters were 120kV,0.75s,8mm slice thinkness. In same lamia were employed 115mAs,40mAs,25mAs,15mAs,7.5mAs tube current. Otherwise five cases had been helical scan to use 190mAsx 150mAs, 40mAs,25mAs,15mAs tube current .The images of MIP,MPR,CVR, HRCI,3D CT virtual endoscopy and variety of interval reconstruction were compared. 4) Evaluation image Duality: According to three degree the four doctors had used single-blind to evaluated CT images, normity image (0) ;few artifact ( + ); excessive artifact ( + + ). To account result. Results 1) The dose 115mAs tube current exceed 75mAs,40mAs,25mAs about 1.5times,3times,5times,14times. 2) The water-model measurement show the CT value of 115mAs and 40mAs; 115mAs and 25mAs in 8mm and 115mAs and 40mAs in 5mm were no significant difference (p 0.05) . That other CT value of dose had difference (p0.05). 3) Result of e-valuation image quality : The percentage of the normity image was no significant difference in 115mAs,40mAs,25mAs. Other image of dose have difference. Conclusion When multi- slice low-dose CT technology was correctly employed that may availably protect the patients and guarantee image quality.