能谱纯化管电压对头部CT扫描辐射剂量及图像质量影响的体模研究

The Effect of Selected Photon Shield Tube Voltage on Radiation Dose and Image Quality in Head CT:A Phantom Study

目的通过体模实验探讨不同的能谱纯化(SPS)管电压对头部CT扫描辐射剂量及图像质量的影响。方法利用三个头部仿真体模(CIRS公司1岁、5岁、成人),分别采用原始协议、Sn 100 kV、Sn 110 kV、Sn 120 kV四种协议进行成像;测量并比较不同体模不同扫描协议眼晶状体、脑实质的吸收剂量,以及脑实质区域的噪声水平。结果相比原始协议组,1岁体模-Sn 100 kV协议组、5岁体模-Sn 110 kV协议组、成人体模-Sn 120 kV协议组的眼晶状体剂量分别降低71.40%、53.81%、53.31%,成人体模降低管电压至Sn 110 kV可使晶状体剂量进一步降低至69.17%。不同体模不同扫描协议脑实质的噪声水平,差异有统计学意义(F=122.42至81.25,P<0.05);与原始协议相比,1岁、5岁、成人体模脑实质的噪声水平对应的在Sn 100 kV、Sn 110 kV、Sn 110 kV/Sn 120 kV协议组下仅见少量增加(<1.92 HU)。结论在所有的体模中,采用与原始协议相同的SPS管电压可在维持一定图像质量的同时,显著降低头部CT扫描的辐射剂量,可用于临床头部CT的低剂量成像;而针对成人体模,可在与原始协议相同的SPS管电压的基础上通过进一步降低管电压来降低辐射剂量。

Objective The aim of this study was to investigate the effect of different selected photon shield(SPS)tube voltage on the radiation dose and image quality for head CT scan.Methods Three anthropomorphic head phantoms(CIRS 1-yr-old,5-yr-old and adult)were scanned by default protocol,Sn 100 kV,Sn 110 kV and Sn 120 kV protocols,respectively.Radiation dose of lens and the brain,Noise level of the brain in different phantoms were measured and compared underwent different imaging protocols.Results Compared with default protocol,the lens dose of 1-year-old-Sn 100 kV,5-year-old-Sn 110 kV and adult phantom-Sn 120 kV was reduced by 71.40%,53.81%and 53.31%,respectively.The lens dose of adult phantom could be further reduced to 69.17%by decreasing the tube voltage to Sn 110 kV.The noise level of brain in different phantoms under different scanning protocols was statistically significant(F=122.42-81.25,P<0.05).Compared with the default protocol,the noise level of 1-year-old,5-year-old and adult phantoms was only slightly increased(<1.92 HU)under Sn 100 kV,Sn 110 kV and(Sn 110 kV/Sn 120 kV)protocols,respectively.Conclusions In all phantoms,using the same SPS tube voltage as the default protocol can significantly reduce the radiation dose of head CT scan while maintaining image quality,which can be used for low-dose imaging of clinical head CT examination.For adult phantom,the radiation dose can be reduced by further decreasing tube voltage on the basis of the same SPS tube voltage as the default protocol.