A study on radiation dose and image quality of chest spectral imaging and conventional CT in anthropomorphic phantom
10.3760/cma.j.issn.0254-5098.2017.12.015
- VernacularTitle:胸部能谱成像模式与常规CT扫描的辐射剂量及图像质量的仿真体模研究
- Author:
Qiuzhen XU
1
;
Hailei SHAO
;
Yan LYU
;
Wenwen GUO
Author Information
1. 东南大学医学院 东南大学附属中大医院放射科
- Keywords:
Anthropomorphic chest phantom;
Spectral CT;
Conventional CT;
Image quality;
Radiation dose
- From:
Chinese Journal of Radiological Medicine and Protection
2017;37(12):957-961
- CountryChina
- Language:Chinese
-
Abstract:
Objective To obtain the parameters of optimal spectral scanning mode in chest spectral CT imaging,radiation doses,image quality,CNR and subjective scores are compared in spectral and conventional scan modes with anthropomorphic chest phantom.Methods An anthropomorphic chest phantom underwent both conventional scan and spectral scan using three different protocols:GSI assist mode (protocol A);GSI mode with mean tube current (protocol B);GSI mode with maximum tube current (protocol C).All above scans were performed with the noise index (NI) as 9 and 11 respectively.The radiation dose was recorded,and the SD values of adipose tissue and muscle tissue of 5 different sections were measured in regions of interest (ROls) to evaluate the image quality.All scans were subjectively scored in 5 score system by two senior radiologists on lung markings and branches with the lung window technique.Results The effective dose (E) values of conventional CT scan and protocols A,B and C were 8.0,8.5,6.2,10.4 and 5.3,5.1,4.3,6.2 mSv.When NI =9,the difference of SD values had statistically significance between conventional scan and protocols A,C (F =4.496,P ＜ 0.05).When NI =11,there was statistically significant difference of SD value between conventional scan and protocols A,B,C (F =8.425,P ＜ 0.05).In conventional chest scan,the difference of SD values was statistically significant between NI =9 and 11 (t =-2.570,P ＜ 0.05),while other protocols had no statistically significant difference (P ＞ 0.05).The difference of CNR and subjective score had no statistically significance in either the same NI different scanning modes or the same scanning mode with different NIs.Conclusions Appropriate spectral scanning mode had no significant difference with conventional CT scanning in radiation dose,yet higher image quality can be obtained.Furthermore,appropriate NI can reduce the radiation dose obviously while the similar image quality was achieved.Considering the two factors,GSI assist mode can achieve balance between radiation dose and image quality.
