Terence T Sio1, Kenneth W Merrell2, Chris J Beltran2, Jonathan B Ashman3, Kathleen A Hoeft2, Robert C Miller3, Thomas J Whitaker2, Stephanie K Wurgler2, Erik J Tryggestad4. 1. Department of Radiation Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55901, USA; Department of Radiation Oncology, Mayo Clinic Hospital, 5777 E. Mayo Blvd., Phoenix, AZ 85054, USA. 2. Department of Radiation Oncology, Mayo Clinic, 200 First St. SW, Rochester, MN 55901, USA. 3. Department of Radiation Oncology, Mayo Clinic Hospital, 5777 E. Mayo Blvd., Phoenix, AZ 85054, USA. 4. Department of Radiation Oncology, Mayo Clinic Hospital, 5777 E. Mayo Blvd., Phoenix, AZ 85054, USA. Electronic address: Tryggestad.Erik@mayo.edu.
Abstract
PURPOSE: We explored the dosimetric potential of spot-scanned stereotactic body proton therapy (SBPT) for pancreatic cancer. METHODS: We compared SBPT to stereotactic body intensity-modulated radiotherapy (SB-IMRT) in 10 patients. We evaluated 3 variables in SBPT planning: (1) 4 and 6 mm spot size; (2) single vs. multi-field optimization (SFO vs. MFO); and (3) optimization target volume (OTV) expansion. Robustness analysis was performed with unidirectional isocenter shifts of ±3 mm in x, y, and z and ±3% stopping power uncertainties. RESULTS: SBPT plans had lower V10Gy for the stomach and small and large bowels. Under static robustness, a 5 mm OTV and SFO-6 mm spot size represented the best compromise between target and normal structure. A 4-mm spot-size and 3 mm OTV resulted in significant target underdosing with deformable dose accumulation analysis. CONCLUSIONS: This study provides a critical basis for clinical translation of spot size, optimization technique, and OTV expansion for pancreatic SBPT.
PURPOSE: We explored the dosimetric potential of spot-scanned stereotactic body proton therapy (SBPT) for pancreatic cancer. METHODS: We compared SBPT to stereotactic body intensity-modulated radiotherapy (SB-IMRT) in 10 patients. We evaluated 3 variables in SBPT planning: (1) 4 and 6 mm spot size; (2) single vs. multi-field optimization (SFO vs. MFO); and (3) optimization target volume (OTV) expansion. Robustness analysis was performed with unidirectional isocenter shifts of ±3 mm in x, y, and z and ±3% stopping power uncertainties. RESULTS:SBPT plans had lower V10Gy for the stomach and small and large bowels. Under static robustness, a 5 mm OTV and SFO-6 mm spot size represented the best compromise between target and normal structure. A 4-mm spot-size and 3 mm OTV resulted in significant target underdosing with deformable dose accumulation analysis. CONCLUSIONS: This study provides a critical basis for clinical translation of spot size, optimization technique, and OTV expansion for pancreatic SBPT.
Authors: Chenbin Liu; Steven E Schild; Joe Y Chang; Zhongxing Liao; Shawn Korte; Jiajian Shen; Xiaoning Ding; Yanle Hu; Yixiu Kang; Sameer R Keole; Terence T Sio; William W Wong; Narayan Sahoo; Martin Bues; Wei Liu Journal: Int J Radiat Oncol Biol Phys Date: 2018-02-14 Impact factor: 7.038
Authors: Krishan R Jethwa; Erik J Tryggestad; Thomas J Whitaker; Broc T Giffey; Bret D Kazemba; Michelle A Neben-Wittich; Kenneth W Merrell; Michael G Haddock; Christopher L Hallemeier Journal: Adv Radiat Oncol Date: 2018-04-13