A Feasibility Investigation: Radiotherapy Dose Calculation On KV Cone-Beam CT Image for Lung Tumor
C Ma*,SU-E-T-16 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
Purpose: To eveluate the performance of the KV CBCT image data used for dose calculation with precise calibration of Hounsfield units(HU)to electron density(HU-density).
Methods:The CBCT calibration was analysed with different field angle in this study. A clinical treatment planning system was employed for plan CT and KV CBCT image to dose calculations and subsequent comparisons. Two HU-density tables generated using the Computerized Imaging Reference Systems(CIRS) phantom. By performing dose comparision between CT and CBCT image-based plans.
Results:The results showed that a max of about 4% dose discrepancy was observed for inserts.The sigle field isodose curves were very close and less discrepant. The lung clinical patient study indicated that the volume of lung tumor achieved the prescribed dose in CBCT was lower than the CT plan.
Conclusion:Our study showed that the dosimetric accuracy of CBCT-based dose calculation for lung tumor is acceptable only for the purpose of dosimetric checks with calibration applied. KV CBCT images can not replace the traditional CT images for accuracy dose calculation.