Room: AAPM ePoster Library
Purpose: compare the radiobiological dose of multi-stage SRS treatment planning technique to fractionated SBRT treatment for liver tumor using universal survive curve.
Methods: A patient who was treated with fractionated SBRT for liver tumor(62.60cm³) was retrospectively included in this study. A total prescription dose of 48Gy was used for three staged SRS and three fractionated SBRT treatment. A Cyberknife treatment plan was optimized for the target volume to achieve at least 97% coverage of the prescription dose with minimized normal tissue dose. This plan was used to generate both multi-stage and fractionated treatment schemes to ensure that both treatment schemes deliver same physical dose. For multi-stage plans, the target was segmented into three sub-targets having similar volumes. Dose matrices for each plan were export in DICOM format and used to calculate biological equivalent dose distributions using universal survive curve.
Results: Multi-stage plan and fractionated SBRT plans had an average Biological Equivalent Dose (BED) to the target of 194.73Gy and 144.21Gy, respectively. The surround liver had an average BED of 38.23Gy and 27.94Gy, respectively.
Conclusion: The multi-stage treatment provided increased biologically effect on target compared to the multi-fraction SBRT treatments.
Not Applicable / None Entered.