Accuracy Assessment of Cone-Beam CT Images for Pelvic Tumor Dose Calculation

Objective To evaluate the feasibility and accuracy of cone-beam CT (CBCT) images for radiotherapy dose calculation in pelvic tumors.

Methods An improved volumetric density coverage method was used to establish CT value-relative electron density (RED) curves for CBCT images. The planning CT plans were transferred to the CBCT images, and the constructed density curves were applied to calculate doses for CBCT plans while maintaining the optimization parameters unchanged. Dose calculation deviations between the two plans were analyzed.

Results The mean differences in dosimetric parameters for the target volume and organs at risk (OAR) between the two plans were less than 1% and 1.5%, respectively. The target conformity index (CI), homogeneity index (HI), and gamma passing rates were highly consistent, with no statistically significant differences.

Conclusion CBCT images corrected by this method can be used for dose calculation in pelvic tumor radiotherapy planning.