单双定位图对腰椎间盘序列扫描剂量的比较

Comparison of radiation doses between single and double localizer radiographies in lumber disc CT scan

目的探讨单次侧位定位图扫描与双次定位图扫描对腰椎间盘CT(computed tomography)的辐射剂量和图像质量的影响。方法选取临床怀疑腰椎间盘突出的患者112例,随机分成单定位组53例和双定位组59例,单定位组使用常规单次侧位定位图进行常规椎间盘序列扫描,双定位组使用侧位和正位双次定位图进行常规椎间盘序列扫描,均使用自动曝光控制技术。比较2组扫描辐射剂量和轴位图像质量。结果双定位组L_(1～2)、L_(2～3)、L_(3～4)、L_(4～5)、L_5～S_1的辐射剂量低于单定位组(P<0.05)。秩相关分析结果显示,体重指数与单定位图和双定位图的扫描剂量均呈正相关(P<0.05)。2组主观评价图像质量差异无统计学意义(P>0.05)。双定位图L_5～S_1脂肪客观评价图像质量噪声和信噪比高于单定位图,差异有统计学意义(P<0.05),2组余间盘客观评价图像质量指标差异均无统计学意义(P>0.05)。结论对于腰椎间盘序列扫描的检查,选用双次正侧位定位图并配合自动曝光控制技术可降低受检者的辐射剂量。

Objective To investigate the effects of single-lateral localizer radiography and doubl-localizer radiography images on the radiation dose and image quality of lumbar intervertebral disc computed tomography(CT). Methods One hundred and twelve patients with suspected lumbar intervertebral disc herniation were divided into two groups randomly: 53 cases in single-localizer group used a conventional single lateral-localizer radiography scan, 59 cases in double-localizer group used lateral-orthotopic-localizer radiography scan. Then these two groups performed routine intervertebral disc sequence scanning by 128 slices spiral CT, respectively. Automatic exposure control(AEC) technology was used. The radiation doses of all scans and the corresponding axial image qualities were analyzed. Results The CT dose of double-localizer group of the five variables of L1-2, L2-3, L3-4, L4-5 and L5-S1 were significantly lower than that of single-localizer group(P<0.05). The results of rank correlation analysis showed that there was a positive correlation between body mass index and scan doses of two groups(P<0.05). There was no significant difference in the evaluation of image quality between two groups, except that in L5-S1 of noise and signal-to-noise ratio of fat measurement of double-localizer group was higher than single-localizer group(P<0.05). Conclusion For the examination of the lumbar intervertebral disc sequence CT scanning, the lateral-orthotopic double-localizer radiography images with AEC technology can reduce the radiation dose of the subjects.