锥形束CT灰度值与密度相关性的研究

目的:研究锥形束CT灰度值与体外已知密度参考模型的相关性,并分析锥形束CT不同拍摄条件对密度测量值的影响。方法:将已知密度分别为:1.0、1.5、2.0、2.5 g/cm³的小球固定在模型上,该模型分别放置在直径约为14 cm和16 cm盛满水的圆柱形玻璃烧杯内,并在不同拍摄条件下进行锥形束CT扫描测得小球灰度值。结果:采用线性回归分析方法得出在不同环境及不同拍摄参数下样本小球密度与灰度值相关系数均大于0.95,样本小球密度与灰度值之间呈明显线性相关。结论:样本小球密度和灰度值呈明显线性相关关系,拍摄环境及参数对其相关性影响较小,锥形束CT可以作为密度测量及评估的一种方法。

The correlation between gray scale value and density of cone beam computed tomography

Objective:The aim is to study the correlation between the gray value of cone beam computed tomography(CBCT)and the reference model of known density in vitro,and analyze the influence of different shooting conditions of CBCT on the density measurement value.Methods:Fix small balls with known densities:1.0,1.5,2.0,2.5 g/cm~3 on the model.Then place the model in a cylindrical glass beaker filled with water with a diameter of approximately 14 cm and 16 cm,and perform CBCT scanning under different shooting conditions and measure the gray value of the small ball.Results:Using linear regression analysis method,the correlation coefficient of sample ball density and gray value under different environment and different shooting parameters are all greater than 0.95,and there is an obvious linear correlation between sample ball density and gray value.Conclusion:The sample ball density and gray value are obviously linearly correlated,and the shooting environment and parameters have no statistical difference in their correlation.CBCT can be used as a method for density measurement and evaluation.