离体猪肺标本低剂量高分辨率CT扫描的最佳管电流选择

Optimal tube current for low-dose HRCT scan of pig lung specimen in vitro

摘要:

目的：探讨离体猪肺标本低剂量高分辨率CT（high resolution computed tomography，HRCT）扫描的最佳管电流。方法：应用GE 公司Brightspeed Elite 16层螺旋CT对5具离体充气的新鲜猪肺标本进行常规扫描和不同低剂量HRCT扫描（常规扫描管电流为200 mAs，低剂量时管电流分别取80、60、40、20、10 mAs，其他扫描参数不变）。评价扫描图像质量，并计算每次扫描的有效辐射剂量（effective dose，ED），获得最佳管电流的低剂量容积HRCT技术方案。结果：当管电流分别为80、60、40 mAs时，辐射剂量依次降低，差异有统计学意义（F=173.90，P=0.000），图像质量均能满足诊断要求；当管电流为20 mAs时，辐射剂量更低，图像质量基本满足诊断要求；当管电流为10 mAs时，辐射剂量最低，但图像质量较差，不能满足诊断要求。结论：选择管电流在40 mAs时，能同时保证CT图像质量及有效降低辐射剂量，这对临床工作中患者肺部低剂量扫描方案的制定具有重要的参考价值。

Abstract:

Objective：To investigate the optimal tube current for low-dose high resolution computed tomography（HRCT） scan of pig lung specimen in vitro. Methods： Brightspeed Elite 16 multislice spiral CT from GE company was used to scan five fresh isolated in－flatable lungs of pig by methods of conventional scanning and different low-dose scanning（the tube current of conventional scanning was 200 mAs while the tube currents of low- dose scanning were 80，60，40，20，10 mAs；other scanning parameters were fixed）. Then the quality of the scanning images was evaluated. The quality of images was guaranteed under the premise of meeting the diagnostic requirements and obtaining low-dose volume HRCT technology solution. Effective dose（ED） per scanning was also calculated and analyzed statistically. Results： When the tube currents were 80，60，40 mAs，the radiation doses were lower gradually，with statis－tically significant differences（F=173.90，P<0.001） and the quality of scanning images can meet conventional diagnostic requirements. When the tube current was 20 mAs，the dose of radiation was lower and the quality of the image can basically meet the diagnostic requirements. When the tube current was 10 mAs，the dose of radiation was the lowest，but the quality of image can not meet the diag－nostic requirements. Conclusions：When we chose the tube current of 40 mAs，it can ensure high quality of CT images and reduce the radiation dose at the same time. So it is of significance for clinical doctors to formulate low-dose lung scanning solutions.