Radiation and Cancer Physics

PD 06 - Physics 2 - Poster Discussion - Treatment Delivery

1048 - Analysis of Beam Delivery Times and Dose Rates for the Treatment of Mobile Tumors Using Real Time Image Gated Spot-Scanning Proton Beam Therapy

Monday, October 22
11:03 AM - 11:09 AM
Location: Room 217 C/D

Analysis of Beam Delivery Times and Dose Rates for the Treatment of Mobile Tumors Using Real Time Image Gated Spot-Scanning Proton Beam Therapy
S. Shimizu1,2, T. Yoshimura3, N. Katoh1,4, T. Inoue4, T. Hashimoto5, K. Nishioka2, S. Takao4, T. Matsuura1,6, N. Miyamoto4, Y. M. Ito7, K. Umegaki6, and H. Shirato1,5; 1Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan, 2Department of Radiation Oncology, Faculty of Medicine, Hokkaido University, Sapporo, Japan, 3Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Japan, 4Department of Radiation Oncology, Hokkaido University Hospital, Sapporo, Japan, 5Department of Radiation Medicine, Faculty of Medicine, Hokkaido University, Sapporo, Japan, 6Division of Quantum Science and Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan, 7Department of Biostatistics, Hokkaido University Faculty of Medicine, Sapporo, Japan

Purpose/Objective(s): Spot-scanning technique ensures the precise delivery of a dose to the clinical target volume (CTV); however, the existence of interplay effects in proton scanning must be considered. One method for mitigating the influence of organ motion is the use of real-time image gating. The use of gating during beam delivery may prolong the treatment time. In this study, we analyzed the clinical feasibility of a real-time-image gated proton beam therapy (RGPT) system regarding beam delivery times and dose rates for the treatment of mobile tumors.

Materials/Methods: Thirty-six patients were treated using the RGPT system from October 2016 to October 2017, and their data were included in this analysis. The locations of the targets for treatment were obtained through Au fiducial markers of either 1.5 or 2.0 mm diameter inserted around the CTV. The coordinates of the fiducial marker were calculated using the system at a frequency of either 30 or 15 Hz, and the proton beam was automatically controlled and delivered according to the pre-set gating window of ±2 mm. The parameters for beam delivery and nominal dose rates for each treatment port were also examined and analyzed.

Results: Among the patients treated using the RGPT system, 33 liver cases and 3 lung cases were evaluated. The doses delivered to 99% of the CTV were 76 GyE/20Fr (n = 8), 74 GyE/37Fr (n = 6), 72.6 GyE/22Fr (n = 15), and 66 GyE/10Fra (n = 4) for the liver cases, whereas a dose of 70 GyE/10Fr (n = 3) was administered for the lung cases. The number of treatment ports and dose rates for each treatment plan, according to the disease, were as follows: liver, two ports (n = 28): 0.60 ± 0.45 GyE/min, three ports (n = 4): 0.49 ± 0.13 GyE/min, and four ports (n = 1): 0.94 ± 0.06 GyE/min, and lung, three ports (n = 3): 0.92 ± 0.38 GyE/min. The ratio of the treatment time for the delivery of the therapeutic proton beam using RGPT to each port against the QA mode beam delivery time required for non-gating beam delivery were 2.21 ± 1.08 (two ports: 2.34 ± 1.83, three ports: 2.04 ± 1.08, and four ports: 1.63 ± 0.33) for liver cases, and 1.88 ± 0.83 for lung cases. Irradiation of the mobile target with gating function was possible within a reasonable time for clinical usage using RGPT.

Conclusion: The use of RGPT for mobile tumors can deliver a treatment beam within reasonable treatment time using a +/- 2 mm gating window.
Without Gating (Data from QA) RGPT Time Ratio
Port no. (n) Min GyE/min Min GyE/min [Gate/Non-gate]
Liver 2 (27) 2.15 1.18 4.71 0.60 ± 0.45 2.34 ± 1.83
3 ( 4) 1.50 0.89 2.62 0.49 ± 0.13 2.04 ± 1.08
4 ( 1) 1.15 1.50 1.83 0.94 ± 0.06 1.63 ± 0.33
Lung 3 ( 3) 1.74 1.50 3.36 0.92 ± 0.38 1.88 ± 0.83

Author Disclosure: S. Shimizu: Research Grant; Hitachi Ltd. Patent/License Fees/Copyright; Radiotherapy control apparatus and radiotherapy control program, US9616249 B2, Charged particle beam system, US 14/524,495. T. Yoshimura: None. N. Katoh: None. K. Nishioka: None. S. Takao: Patent/License Fees/Copyright; Radiotherapy control apparatus and radiotherapy control program, US9616249 B2. T. Matsuura: Patent/License Fees/Copyright; Radiotherapy control apparatus and radiotherapy control program, US9616249 B2. H. Shirato: Research Grant; Hitachi Ltd, Shimadzu Corporation. Patent/License Fees/Copyright; Moving body pursuit irradiating device and positioning method using this device, Charged particle beam system, US 14/524,495.

Shinichi Shimizu, MD, PhD

Disclosure:
Compensation
Hitachi Ltd.: Research Grants

Ownership
Charged particle beam system, US 14/524,495: Patent/License Fees/Copyright; Radiotherapy control apparatus and radiotherapy control program, US9616249 B2: Patent/License Fees/Copyright

Biography:
Shinichi Shimizu, M.D., Ph.D.
Professor, Department of Radiation Oncology, Hokkaido University Faculty of Medicine.

Department of Radiation Oncology, Hokkaido University Faculty of Medicine North-15 West-7 Sapporo, Hokkaido. Japan
Tel/Fax: +81(11) 706-7798/ +81(11)706-7799 e-mail: sshing@med.hokudai.ac.jp

EDUCATION
April 1989 - March 1995, M.D. Hokkaido University School of Medicine, Sapporo, Japan
Degree-Granting Education
April 1995 - September 1999, Ph.D. Hokkaido University Graduate School of Medicine, Sapporo, Japan

Postgraduate Training
April 1995 - September 2000, Department of Radiology, Hokkaido University Hospital. Sapporo, Japan
CREDENTIALS
Board Certification Board-certified Fellow of Japan Radiological Society, (#4060), 2002 Board Certified Fellow of the Japanese Society for Therapeutic Radiology and Oncology, (#395), 2003
Licensure Full Medical License (Japan), #371445, 1995

EXPERIENCE/SERVICE
Academic Appointments
April 2017 – Present Vice dean of Hokkaido University Graduate School of Biomedical Science and Engineering
October 2016 – Present Professor of Department of Radiation Oncology, Hokkaido University Graduate School of Medicine
October 2014–September 2016 Associate Professor of Department of Radiation Oncology, Hokkaido University Graduate School of Medicine
December 2007 - July 2008 Research Associate Professor of Department of Radiology, Hokkaido University Graduate School of Medicine
July 2007 - November 2007 Lecturer of Department of Radiology, Hokkaido University Graduate School of Medicine

Other Appointments/Responsibilities
June 2003 - June 2007 Radiation Oncologist-in-Chief, Department of Radiation Oncology, Keiyukai Sapporo Hospital
April 2003 - May 2003 Staff of Radiation Therapy Hokkaido University Hospital
October 2000 - March 2003 Radiation Oncologist-in-sub-Chief, Hakodate City Hospital

HONORS AND AWARDS
1) Hokkaido University Graduate School of Medicine, Horita Memorial Award (Hokkaido University, 2014)
2) 6th Techno-Economic Innovation award, 2017 (Japan Techno-Economics Scciety)

Presentation(s):

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