幼猪头颅低剂量螺旋CT扫描参数优化研究

Objective To optimize the scanning parameters for CT with lower radiation dose on the infant pigs' brain which mimic the baby's head of human being. Methods Five pigs underwent CT scan using regular X-ray dose I. E. , 400 mAs, and other dose including 300,250, 200,150 and 100 mAs respectively, and the other parameters were the same. Each pig was scanned 12 times repeatedly with each of the six X-ray doses, which obtained 960 image. Anatomic details and the confidence level in reaching a diagnosis were evaluated by three radiologists respectively in a double-blinded manner using a 4-point scoring system. The CTDI of every group were compared. All Results were analyzed by Chi-square test and analysis of variance. Results The CTDI of 400,300,250,200,150,100 mAs was (55.5±0.1),(41.9±0.0), (34.7±0.0), (27.8±0.0), (20.9±0.0), (12.2±0.0) mGy respectively, there was a significant difference(F = 214872.0,P < 0.05)among the six groups. There was no significant difference in the quality of images obtained from the conventional 400 mAs scanning and low dose group of 300,250,200, 150 mAs scanning images, the total score was (3.7±0.5), (3.7±0.5), (3.6±0.3), (3.6±0.5), (3.6±0.5) respectively,which was more than 3 points, while the 100 mAs group showed low quality (2.1±0.5) which was less than 3 points. In the 100 mAs group, there were 215 in 960 images >3 points, 745 images < 3 points, and regular doses of 400 mAs group (934 image > 3 points). Image quality difference was statistically significant (χ2=3289.9,P <0.05). Conclusion The low-dose scanning (120 kV, 150 mAs, 20.8 mGy)would be practical in diagnosing in normal infant pigs' brain.

Optimization of parameters for low dose CT scanning on infant pig brain