Room: AAPM ePoster Library
With the development of radiotherapy technology, CBCT has been widely used in clinic. At present, the scanning time of conventional CBCT is about 2 minutes, and the long scanning time may lead to decrease patient comfort and extend treatment time. With the fast CBCT scan mode, the maximum gantry speed is increased from the conventional 0.5rpm to 1rpm, the scan time can be shortened to 30S, but the number of fluoro-frames in this mode is only half of the normal scan mode, which may affect the image quality.This work aims to quantitatively evaluate the effect of reduced scan times on image quality and registration accuracy.
Three scan modes were used to the CBCT phantom, and the registration accuracy and image quality were quantitatively evaluated. There are 33 clinical patient data (278 CBCT sets) were used to verify the clinical effectiveness
Use of the fast mode scans had little impact on registration accuracy.For the pearson correlation analysis, the R2 values are greater than 0.90, and the P value is <0.01, which indicate that the measurement results of the all scan modes are highly correlated; for the Bland-Altman consistency test, The 95% consistency limit of the measurements is less than the 1 mm threshold, indicating that the measurement results of the all scanning modes are consistent.however the image quality was little degraded.
The fast mode has closely quality to the normal image and consistent registration results, which have faster scan speed and lower scan dose. Therefore, the fast mode is recommended as the clinical scan mode.