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Initial Experience of Patient-Specific QA for Wobbling and Line-Scanning Proton Therapy at Samsung Medical Center
Prog. Med. Phys. 2019;30(1):14-21
Published online March 31, 2019
© 2019 Korean Society of Medical Physics.

Kwanghyun Jo, Sung Hwan Ahn, Kwangzoo Chung, Sungkoo Cho, Eun Hyuk Shin, Seyjoon Park, Chae-Seon Hong, Dae-Hyun Kim, Boram Lee, Woojin Lee, Doo Ho Choi, Do Hoon Lim, Hong Ryull Pyo, Youngyih Han

Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
Correspondence to: Youngyih Han, (
Tel: 82-2-3410-2604, Fax: 82-2-3410-2619
Received December 14, 2018; Revised March 12, 2019; Accepted March 12, 2019.
This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Purpose: To report the initial experience of patient-specific quality assurance (pQA) for the wobbling and line-scanning proton therapy at Samsung Medical Center.
Materials and Methods: The pQA results of 89 wobbling treatments with 227 fields and 44 line-scanning treatments with 118 fields were analyzed from December 2015 to June 2016. For the wobbling method, proton range and spread-out Bragg peak (SOBP) width were verified. For the line-scanning method, output and two-dimensional dose distribution at multiple depths were verified by gamma analysis with 3%/3 mm criterion.
Results: The average range difference was −0.44 mm with a standard deviation (SD) of 1.64 mm and 0.1 mm with an SD of 0.53 mm for the small and middle wobbling radii, respectively. For the line-scanning method, the output difference was within ±3%. The gamma passing rates were over 95% with 3%/3 mm criterion for all depths.
Conclusions: For the wobbling method, proton range and SOBP width were within the tolerance levels. For the line-scanning method, the output and two-dimensional dose distribution showed excellent agreement with the treatment plans.
Keywords : Proton therapy, Patient specific QA, Wobbling, Line-scanning

June 2019, 30 (2)