DoseRight技术下定位像的选择对儿童胸部CT检查辐射剂量及图像质量的影响

Impact of the selection of scout view image on radiation dose and image quality in thoracic CT of children under DoseRight technology

目的比较在DoseRight技术条件下采用单一正位定位像、单一侧位定位像和正侧位双定位像进行儿童胸部CT检查时的图像质量和辐射剂量的差异。方法前瞻性地选取行胸部CT检查的367例0~16岁患儿为研究对象,按年龄分为A组(n=120)、B组(n=120)及C组(n=127)。再根据定位像的选择情况对每一组患儿随机分为单一正位定位像者、单一侧位定位像者和正侧位双定位像者。使用飞利浦128iCT进行数据采集,记录患儿的扫描范围(L)、CTDIVOL及DLP,并测量患儿胸部前后径和左右径,计算其有效直径。对胸部CT图像质量进行主客观评价。结果 A1者L显著大于A2、A3者大(P<0.05),A2、A3者差异不明显(P>0.05);B1者L显著大于B2、B3者大(P<0.05),B2、B3者间差异不明显(P>0.05);C1者L显著大于C2、C3者(P<0.05),C2、C3者差异不明显(P>0.05)。A1者CTDIVOL、DLP高于A2者,A2者高于A3(均P<0.05);B1者CTDIVOL、DLP高于B2者,B2者高于B3者(均P<0.05);C1者CTDIVOL、DLP高于C2者,C2者高于C3(均P<0.05)。结论进行儿童胸部CT检查时,采用正侧位双定位像扫描能更精确控制扫描范围,降低辐射剂量,并保证图像质量。

Objective To compare the difference of image quality and radiation dose in children’s chest CT examination with single AP, single AP and dual AP in DoseRight technique.Methods 367 children aged 0-16 years who underwent chest CT examination were prospectively selected as the subjects of study. They were divided into group A(n=120), group B(n=120) and group C(n=127) according to their ages. According to the selection of location image, each group of children was randomly divided into single location image, single location image and double location image. The data were collected with Philips 128 iCT, and the scan range(L), CTDIVOL and DLP were recorded. The anterior and posterior chest diameters, left and right chest diameters were measured, and the effective diameters were calculated. The quality of chest CT image was evaluated subjectively and objectively. Results L of A1 was significantly larger than that of A2 and A3(P<0.05). There was no significant difference between A2 and A3(P>0.05). The L of B1 was significantly higher than that of B2 and B3(P<0.05), but there was no significant difference between B2 and B3(P>0.05). L of C1 was significantly higher than that of C2 and C3(P < 0.05), but there was no significant difference between C2 and C3(P>0.05). The CTDI, Vol and DLP of A1 were higher than those of A2, and those of A2 were higher than those of A3(P<0.05). The CTDI, Vol and DLP of B1 were higher than those of B2, and those of B2 were higher than those of B3(P<0.05). CTDI, Vol and DLP of C1 were higher than those of C2, and those of C2 were higher than those of C3(P<0.05). Conclusion T In CT examination of children’s chest, the use of positive and lateral double location image scanning can control the scanning range more accurately, reduce the radiation dose, and ensure the image quality.