Abstract
BACKGROUND
With the development of the CT technology, multi-energy technology is applied to CT imaging, which improves the time resolution, spatial resolution and density resolution of CT system. It enables the CT imaging system to achieve clearer image display under safe and low-dose conditions, so that the disease can be displayed more quickly, and the disease can be identified more early and more clearly.
METHODS
38 non-small cell lung cancer patients were selected for energy spectral scanning. All energy spectral images obtained were transferred to the DiscoverTM CT post-processing workstation to generate 40 keV, 60 keV, 80 keV, 100 keV, 120 keV, and 140 keV single-energy images. Then the single-energy images were imported to Eclipse, and the oncologist contours the target area and organs at risk (OARs) on the single-energy images described above, and then the physicist designed radiotherapy plans to perform statistical analysis on the tissue CT value and target volume of each single-energy image, and to compare dosimetry of different plans about the organs at risk and the target area.
RESULTS
The CT values of GTV, heart, lung, and spinal cord of different energy CT images are statistically different (P < 0.05). Among them, the CT value of each tissue obtained in the 40 keV group is the largest, and the CT value decreases with the increase of energy. There were no statistically significant differences in the homogeneity index(HI), the conformity index(CI), the maximum dose, the minimum dose and the average dose of the gross tumor volume (GTV) delineated on CT images of different energy (P > 0.05), as well as the organs at risk.
CONCLUSIONS
When CT images of different energies obtained from energy spectral CT scans are used in the design of radiotherapy planning, there are no significant differences in target area outlines and doses caused by energy factors, but the differences in tissue CT values have statistical significant.