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Acceptance Testing and Commissioning of  Robotic Intensity-Modulated Radiation Therapy M6 System Equipped with InCiseTM2 Multileaf Collimator
Prog. Med. Phys. 2018;29(1):8-15
Published online March 31, 2018
© 2018 Korean Society of Medical Physics.

Jeongmin Yoon, Kwangwoo Park, Jin Sung Kim, Yong Bae Kim, Ho Lee

Department of Radiation Oncology, Seoul National University Hospital, Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea
Correspondence to: Ho Lee(
Tel: 82-2-2228-4363
Fax: 82-2-2227-7823
Received March 24, 2018; Revised March 26, 2018; Accepted March 26, 2018.
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.
This work reports the acceptance testing and commissioning experience of the Robotic Intensity-Modulated Radiation Therapy (IMRT) M6 system with a newly released InCiseTM2 Multileaf Collimator (MLC) installed at the Yonsei Cancer Center. Acceptance testing included a mechanical interdigitation test, leaf positional accuracy, leakage check, and End-to-End (E2E) tests. Beam data measurements included tissue-phantom ratios (TPRs), off-center ratios (OCRs), output factors collected at 11 field sizes (the smallest field size was 7.6 mm×7.7 mm and largest field size was 115.0 mm×100.1 mm at 800 mm source-to-axis distance), and open beam profiles. The beam model was verified by checking patient-specific quality assurance (QA) in four fiducial-inserted phantoms, using 10 intracranial and extracranial patient plans. All measurements for acceptance testing satisfied manufacturing specifications. Mean leaf position offsets using the Garden Fence test were found to be 0.01±0.06 mm and 0.07±0.05 mm for X1 and X2 leaf banks, respectively. Maximum and average leaf leakages were 0.20% and 0.18%, respectively. E2E tests for five tracking modes showed 0.26 mm (6D Skull), 0.3 mm (Fiducial), 0.26 mm (Xsight Spine), 0.62 mm (Xsight Lung), and 0.6 mm (Synchrony). TPRs, OCRs, output factors, and open beams measured under various conditions agreed with composite data provided from the manufacturer to within 2%. Patient-specific QA results were evaluated in two ways. Point dose measurements with an ion chamber were all within the 5% absolute-dose agreement, and relative-dose measurements using an array ion chamber detector all satisfied the 3%/3 mm gamma criterion for more than 90% of the measurement points. The Robotic IMRT M6 system equipped with the InCiseTM2 MLC was proven to be accurate and reliable.
Keywords : Robotic IMRT, InCiseTM2 MLC, Commissioning 

December 2018, 29 (4)