Research Of The Influence Of Background Factors On Measurement Of The CT Numbers Of Small Nodules

Objective: To research the influence of background factors on measurement of the CT numbers of softy tissue density nodules in 1.5cm diameter. Methods: Establish the experimental model: Take a 10cm diameter cylindrical thin wall plastic container as the model body, set a spherical nodules at the center of the model container, which was about 1.5cm diameter sealed with rubber membrane. The model container was filled with 15 different densities substances distinctively as the nodule's background and scanned with the same scanning parameter. The background substances were divided into 15 groups from low density to high. The nodule's CT numbers each of the 15 groups were measured, and all the data was analyzed with SPSS16.0 Statistical software, a changing curve of the nodule's CT numbers varied with the different backgrounds was drawn. Results: There are different CT numbers a nodule in different density substance backgrounds. It is the lowest and relatively stabilized in similar density background. The higher the background density is, the lower the nodule's CT number in lower density substance backgrounds, while the higher the background density is, the higher the nodule's CT number in higher density substance backgrounds. Conclusion:There are certain influences on the nodule's CT numbers in different homogeneous density substance backgrounds. The bigger the difference between the nodule's density and its background is, the higher the nodule's CT number is.