Encrypted login | home

Program Information

Multi-Institutional Comparison of Pre-Treatment Dose Calculation Verification for CyberKnife, Vero4DRT and Tomotherapy

no image available
H Tachibana

H Tachibana1*, Y Uchida1 , M Yamashita2 , H Nagata3 , A Sato4 , R Miyakawa5 , D Maruyama6 , H Okamoto7 , M Nakamura8 , S Kito9 , N Hayashi10 , R Shirata11 , S Noda12 , H Fukuma13 , T Kojima14 , R Takahashi15 , D Kawai16 , M Itano17 , (1) National Cancer Center, Kashiwa, Chiba, (2) Kobe City Medical Center General Hospital, Kobe, Hyogo, (3) Shonan Kamakura General Hospital, Kamakura, Kanagawa, (4) Itabashi Chuo Medical Center, Itabashi-ku, Tokyo, (5) Yokohamashitobu Hospital, Yokoyama, Kanagawa, (6) Japanese Red Cross Medical Center, Shibuya, Tokyo, (7) National Cancer Center Hospital, Chuo, Tokyo, (8) Kyoto University, Graduate School of Medicine, Kyoto, Kyoto, (9) Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Bunkyo, Tokyo, (10) School of Health Sciences, Fujita Health University, Toyoake, Aichi, (11) Shonan Kamakura General Hospital, Kamakura, Kanagawa, (12) Kitasato University Hospital, Sagamihara, Kanagawa, (13) Nagoya City University Hospital, Nagoya, Aichi, (14) Saitama Cancer Center, Kitaadachi, Saitama, (15) Cancer Institute Hospital of Japanese Foundation of Cancer Research, Koto, Tokyo, (16) Kanagawa Cancer Center, Yokohama, Kanagawa, (17) Funabashi Municipal Medical Center, Funabashi, Chiba


SU-I-GPD-T-471 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: There have been limited reports for independent calculation verification for CyberKnife, Vero4DRT and Tomotherapy. The first multi-institutional study for independent calculation verification for the three machines was performed to address the agreement between primary and secondary calculations in twelve institutions.

Methods: 638 treatment plans in several sites (brain, head and neck [H&N], lung, liver, prostate and others) including IMRT and VMAT were retrospectively analyzed using a modified Clarkson-based commercial verification program considering multileaf collimator transmission and dosimetric leaf gap. At first, the dose deviations between an ionization chamber measurement and the verification program were compared to understand the accuracy of the verification program. Next, a comparison in dose between on-site radiotherapy treatment planning systems (MultiPlan: RayTracing, Monte Carlo, iPlan: PencilBeam Convolution, X-ray Voxel Monte Carlo, Tomotherapy planning system: Collapsed cone convolution) and the verification program was performed using patient computed tomography images.

Results: For the three modalities, measurement comparison showed good agreement within 2%. Calculation comparison showed the dose deviation within 3-4% in all sites except for lung and the site including large inhomogeneous media. For the sites including inhomogeneous media, there were larger systematic and random deviations of 2.7 ± 3.7%, 4.1 ± 3.3% for CyberKnife and Vero4DRT respectively.

Conclusion: The multi-institutional comparison using a Clarkson-based algorithm would be helpful to determine the departmental action level because patient’s population and treatment site may be more limited when using the special machines. Similar to the action level of AAPM TG114, 5% would be an action level even of non-IMRT, IMRT and VMAT for CyberKnife, Vero4DRT and Tomotherapy in all sites except for lung and the sites including large inhomogeneous media. If ±5% is defined as the action level, the Clarkson method with inhomogeneous correction would be needed.

Funding Support, Disclosures, and Conflict of Interest: This study was supported in part by the research grants from the Japan Agency for Medical Research and development, No.15ck0106185h0001.

Contact Email: