Zhiyong Yang1, Yu Chang2, Kristy K Brock3, Guillaume Cazoulat3, Eugene J Koay4, Albert C Koong4, Joseph M Herman4, Peter C Park5, Falk Poenisch5, Qin Li2, Kunyu Yang2, Gang Wu2, Brian Anderson3, Andrea N Ohrt3, Yupeng Li5, X Ronald Zhu5, Xiaodong Zhang5, Heng Li6. 1. Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, United States. 2. Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. 3. Department of Image Physics, The University of Texas MD Anderson Cancer Center, Houston, United States. 4. Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, United States. 5. Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, United States. 6. Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, United States. Electronic address: hengli@mdanderson.org.
Abstract
PURPOSE: To evaluate the effect of setup uncertainties including uncertainties between different breath holds (BH) and inter-fractional anatomical changes under CT-guided BH with intensity-modulated proton therapy (IMPT) in patients with liver cancer. METHODS AND MATERIALS: This retrospective study considered 17 patients with liver tumors who underwent feedback-guided BH (FGBH) IMRT treatment with daily CT-on-rail imaging. Planning CT images were acquired at simulation using FGBH, and FGBH CT-on-rail images were also acquired prior to each treatment. Selective robust IMPT plans were generated using planning CT and re-calculated on each daily CT-on-rail image. Subsequently, the fractional doses were deformed and accumulated onto the planning CT according to the deformable image registration between daily and planning CTs. The doses to the target and organs at risk (OARs) were compared between IMRT, planned IMPT, and accumulated IMPT doses. RESULTS: For IMPT plans, the mean of D98% of CTV for all 17 patients was slightly reduced from the planned dose of 68.90 ± 1.61 Gy to 66.48 ± 1.67 Gy for the accumulated dose. The target coverage could be further improved by adjusting planning techniques. The dose-volume histograms of both planned and accumulated IMPT doses showed better sparing of OARs than that of the IMRT. CONCLUSIONS: IMPT with FGBH and CT-on-rail guidance is a robust treatment approach for liver tumor cases.
PURPOSE: To evaluate the effect of setup uncertainties including uncertainties between different breath holds (BH) and inter-fractional anatomical changes under CT-guided BH with intensity-modulated proton therapy (IMPT) in patients with liver cancer. METHODS AND MATERIALS: This retrospective study considered 17 patients with liver tumors who underwent feedback-guided BH (FGBH) IMRT treatment with daily CT-on-rail imaging. Planning CT images were acquired at simulation using FGBH, and FGBH CT-on-rail images were also acquired prior to each treatment. Selective robust IMPT plans were generated using planning CT and re-calculated on each daily CT-on-rail image. Subsequently, the fractional doses were deformed and accumulated onto the planning CT according to the deformable image registration between daily and planning CTs. The doses to the target and organs at risk (OARs) were compared between IMRT, planned IMPT, and accumulated IMPT doses. RESULTS: For IMPT plans, the mean of D98% of CTV for all 17 patients was slightly reduced from the planned dose of 68.90 ± 1.61 Gy to 66.48 ± 1.67 Gy for the accumulated dose. The target coverage could be further improved by adjusting planning techniques. The dose-volume histograms of both planned and accumulated IMPT doses showed better sparing of OARs than that of the IMRT. CONCLUSIONS: IMPT with FGBH and CT-on-rail guidance is a robust treatment approach for liver tumor cases.