(Sunday, 7/14/2019)
Room: ePoster Forums
Purpose: The practice of performing a secondary dose check is recommended by the AAPM Task Group 40, ACR and other regulatory agencies. Due to the unique aspects of the Tomotherapy Hi-Art system, no secondary calculation systems had been available until recently. In March 2018 the Tomotherapy module for RadCalc ( LifeLine Software, Inc.) was released. We report agreement between RadCalc and Tomotherapy Hi-Art on 230 treatment plans for patients treated in our center in 2018.
Methods: RadCalc performs calculations that can be used to validate monitor units, treatment time, or dose calculated by the primary radiation therapy planning system. At a present time RadCalc does not use electron densities from planning CT; however, the user can create a density library for structures and can substitute the treatment couch for the diagnostic couch with preset densities. Secondary calculations were performed for 230 patients’ plans. Treatment sites varied as following: prostate (70), head and neck (61), pelvis (37), brain (30), lung (19), mediastinum (8), esophagus (5).
Results: All analyzed cases had dose differences within +/- 5 %. In 22 cases, the dose differences were more than 4% but less than 5%.
Conclusion: The new RadCalc module is a valuable tool for verification of primary dose calculations in Tomotherapy. Further modification of the program to allow inhomogeneity correction based on electron densities from the planning CT may improve the precision of dose calculation.
Funding Support, Disclosures, and Conflict of Interest: Travel grant by LifeLine Software, Inc.
Keywords
Monitor Unit Calculations, Tomotherapy, Quality Assurance
Taxonomy
TH- External beam- photons: tomotherapy
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