title: Dosimetric benefit of adaptive re-planning in pancreatic cancer stereotactic body radiotherapy.
abstract: Stereotactic body radiotherapy (SBRT) shows promise in unresectable pancreatic cancer, though this treatment modality has high rates of normal tissue toxicity. This study explores the dosimetric utility of daily adaptive re-planning with pancreas SBRT. We used a previously developed supercomputing online re-planning environment (SCORE) to re-plan 10 patients with pancreas SBRT. Tumor and normal tissue contours were deformed from treatment planning computed tomographies (CTs) and transferred to daily cone-beam CT (CBCT) scans before re-optimizing each daily treatment plan. We compared the intended radiation dose, the actual radiation dose, and the optimized radiation dose for the pancreas tumor planning target volume (PTV) and the duodenum. Treatment re-optimization improved coverage of the PTV and reduced dose to the duodenum. Within the PTV, the actual hot spot (volume receiving 110% of the prescription dose) decreased from 4.5% to 0.5% after daily adaptive re-planning. Within the duodenum, the volume receiving the prescription dose decreased from 0.9% to 0.3% after re-planning. It is noteworthy that variation in the amount of air within a patient׳s stomach substantially changed dose to the PTV. Adaptive re-planning with pancreas SBRT has the ability to improve dose to the tumor and decrease dose to the nearby duodenum, thereby reducing the risk of toxicity.
authors.affiliation: Department of Engineering Physics, Tsinghua University, Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, China; Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Yongbao
authors.initials: Y
authors.lastname: Li
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA.
authors.forename: Jeremy D P
authors.initials: JD
authors.lastname: Hoisak
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA.
authors.forename: Carrie
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tian
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Gautier
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA.
authors.forename: Masoud
authors.initials: M
authors.lastname: Zarepisheh
authors.affiliation: Department of Engineering Physics, Tsinghua University, Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, China.
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Engineering Physics, Tsinghua University, Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, China.
authors.forename: Yaqiang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Xun
authors.initials: X
authors.lastname: Jia
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA.
authors.forename: Jona
authors.initials: J
authors.lastname: Hattangadi-Gluth
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA.
authors.forename: Loren K
authors.initials: LK
authors.lastname: Mell
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Steve
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Center for Advanced Radiotherapy Technologies University of California San Diego, La Jolla, CA; Department of Radiation Oncology, University of California San Diego, La Jolla, CA. Electronic address: j2murphy@ucsd.edu.
authors.forename: James D
authors.initials: JD
authors.lastname: Murphy
mesh_terms: D006801:Humans; D010190:Pancreatic Neoplasms / Q000532:radiotherapy*; D010865:Pilot Projects; D016634:Radiosurgery; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies
keywords: CBCT; Interfraction anatomic changes; Online adaptive re-planning; Pancreatic cancer; SBRT