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目的对比分析食道异物CT低剂量与常规剂量CT扫描的辐射剂量比以及低剂量扫描对图像质量的影响。方法对30例食道异物(食源性)患者作食道CT扫描,分为20 mA,40 mA,200 mA 3种剂量扫描,评价3种剂量扫描的图像质量,分别记录3种剂量扫描CT剂量容积(CTD Ivol),剂量长度乘积DLP(mGy.cm)。结果与常规剂量200 mA扫描比较,40 mA扫描对食道异物显示的清晰度影响很小,没有影响到对其图像的观察诊断;20mA扫描时影响观察诊断随着扫描剂量减低,图像颗粒增粗,组织结构分辨率下降,以200mA为标准,20mA,40mA组的CTD Ivol和DLP量分别为常规剂量的10.03%、10%,19.96%、20%。结论40 mA低剂量CT扫描对食道异物显示没有明显影响,不影响观察诊断,其X射线辐射剂量是常规剂量的1/5,完全可应用于食道异物术前诊断。
Objective To compare and analyze the radiation dose ratio of low dose esophageal CT scanning with conventional CT scanning and the effect of low dose scanning on image quality. Methods Thirty esophageal foreign body (food-borne) patients underwent esophageal CT scans. They were divided into 3 doses of 20 mA, 40 mA and 200 mA to evaluate the image quality of 3 kinds of dose scanning. Three dose scanning CT dose volumes (CTD Ivol), dose length product DLP (mGy.cm). Results Compared with the conventional 200 mA scan, the 40 mA scan had little effect on the clarity of the esophageal foreign body, which did not affect the observational diagnosis of the images. The impact of the 20 mA scan on the diagnosis was observed. With the decrease of the scanning dose and the thickening of the image particles, The resolution of tissue structure decreased to 200mA as the standard. The CTD Ivol and DLP of 20mA and 40mA groups were 10.03%, 10%, 19.96% and 20% of the conventional dose respectively. Conclusion The 40 mA low-dose CT scan has no obvious effect on esophageal foreign body, does not affect the observation and diagnosis, and its X-ray dose is 1/5 of the conventional dose, which is completely applicable to the preoperative diagnosis of esophageal foreign body.