胰腺多层螺旋CT照射剂量与噪声的关系分析

Analysis of the relationship between the exposure dose and noise of multi-slice spiral CT of pancreas

目的：采用预设的两组照射剂量分别对正常胰腺患者进行CT增强扫描,探讨CT照射剂量与正常胰腺图像噪声的关系。方法：搜集2009年1-8月正常胰腺患者60例,随机分为A、B两组,每组30例。A、B两组固定其它扫描参数,分别采用150 mAs和125 mAs进行多期扫描,扫描结束后分别选择胰腺动脉期头、体和尾中心层面进行3点感兴趣区CT值与标准差测量,其3点标准差的平均值等视同胰腺图像噪声值,A、B两组噪声值行统计学分析。结果：A、B两组噪声值分别为10.58±1.94和11.01±1.62。统计结果显示两组间差异无显著性意义（P〉0.05）。结论：在确保胰腺图像质量的前提下,适度接受噪声有利患者辐射防护。

Objective：To explore the relationship between exposure dose and noise of multi-slice spiral CT in normal pancreas with administration of contrast agents using two sets of predetermined exposure dose.Methods：Sixty normal pancreas subjects from our hospital（from January 2009 to August 2009） were randomly divided into two groups（A and B）,each having 30 cases.With fixed other scan parameters,150mAs and 125mAs multi-phase scannings were applied to group A and group B,respectively.After scanning,the central plane of the head,body,and tail of pancreas during arterial phase were chosen to measure the CT values and standard deviations of the three regions of interest.The mean value of standard deviations of the three regions in both groups was regarded as image noise values of the pancreas,which were statistically analyzed.Results：The image noise values of group A and group B were 10.58±1.94 and 11.01±1.62,respectively,having no statistically significant difference between the two groups.Conclusion：As long as the imaging quality of pancreas at MSCT is assured,accepting proper image noise is beneficial to protect patients from radiation.