Author: Chuxiong Ding, Xuejun Gu, Heejung Kim, Weiguo Lu, Yang Kyun Park, Yulong Yan 👨🔬
Affiliation: Medical Artificial Intelligence and Automation (MAIA) Lab, Department of Radiation Oncology, UT Southwestern Medical Center, UT Southwestern Medical Center, University of Texas Southwestern Medical Center, Department of Radiation Oncology, Stanford University School of Medicine 🌍
Purpose: The purpose of this study was to develop and evaluate a Monte Carlo (MC) dose calculation software (DosemanCK) for secondary dose verification of CyberKnife (CK) treatment plans. Unlike traditional independent dose verification methods that use point dose comparisons, DosemanCK calculates a 3D dose distribution, enabling a more comprehensive evaluation of the CK treatment plan’s accuracy.
Methods: The DosemanCK software was developed to perform MC-based secondary dose verification for CK treatment plans. This MC calculation utilizes the patient's planning CT, structures, and plan data to independently compute a 3D dose distribution. A total of 39 CK treatment cases were analyzed using the 3%/1mm gamma criterion for 3D dose comparison. The point dose difference at the reference point was evaluated, and the gamma passing rate was calculated for each case.
Results: DosemanCK generates a total of 8 pages of reports, including point dose difference, gamma passing rate, dose distribution at the reference point, DVHs, and dose profiles. A tolerance of 10% was applied for point dose differences, and 90% was used for the gamma passing rate. Results exceeding these tolerances were flagged by DosemanCK, with the corresponding result boxes in the report form highlighted in red for easy identification. The signed point dose difference at the reference point showed an average difference of 0.0%, while the absolute point dose difference averaged 1.4%. The gamma passing rate, based on the 3%/1mm criterion, showed an average value of 98.6% across all cases. These results indicate a strong agreement between the MC dose calculation and the planned dose, demonstrating the accuracy of DosemanCK for secondary dose verification in CK treatment plans.
Conclusion: DosemanCK provides a novel approach for independent secondary dose verification in CyberKnife treatments, offering more comprehensive and accurate 3D dose distribution comparisons compared to traditional point dose methods.