SU-E-T-50: A Multi-Institutional Study of Independent Dose Verification Software Program for Lung SBRT

Journal Article · Mon Jun 15 04:00:00 EDT 2015 · Medical Physics

DOI:https://doi.org/10.1118/1.4924411· OSTI ID:22545181

Kawai, D ^[1]; Takahashi, R; Kamima, T ^[2]; Baba, H ^[3]; Yamamoto, T; Kubo, Y ^[4]; Ishibashi, S; Higuchi, Y ^[5]; Takahashi, H ^[6]; Tachibana, H ^[7]

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1. Kanagawa Cancer Center, Yokohama, Kanagawa-prefecture (Japan)
2. The Cancer Institute Hospital of JFCR, Koutou-ku, Tokyo (Japan)
3. The National Cancer Center Hospital East, Kashiwa-city, Chiba prefecture (Japan)
4. Otemae Hospital, Chuou-ku, Osaka-city (Japan)
5. Sasebo City General Hospital, Sasebo, Nagasaki (Japan)
6. St Lukes International Hospital, Chuou-ku, Tokyo (Japan)
7. National Cancer Center Hospital East, Kashiwa, Chiba (Japan)

Purpose: The accuracy of dose distribution depends on treatment planning system especially in heterogeneity-region. The tolerance level (TL) of the secondary check using the independent dose verification may be variable in lung SBRT plans. We conducted a multi-institutional study to evaluate the tolerance level of lung SBRT plans shown in the AAPM TG114. Methods: Five institutes in Japan participated in this study. All of the institutes used a same independent dose verification software program (Simple MU Analysis: SMU, Triangle Product, Ishikawa, JP), which is Clarkson-based and CT images were used to compute radiological path length. Analytical Anisotropic Algorithm (AAA), Pencil Beam Convolution with modified Batho-method (PBC-B) and Adaptive Convolve (AC) were used for lung SBRT planning. A measurement using an ion-chamber was performed in a heterogeneous phantom to compare doses from the three different algorithms and the SMU to the measured dose. In addition to it, a retrospective analysis using clinical lung SBRT plans (547 beams from 77 patients) was conducted to evaluate the confidence limit (CL, Average±2SD) in dose between the three algorithms and the SMU. Results: Compared to the measurement, the AAA showed the larger systematic dose error of 2.9±3.2% than PBC-B and AC. The Clarkson-based SMU showed larger error of 5.8±3.8%. The CLs for clinical plans were 7.7±6.0 % (AAA), 5.3±3.3 % (AC), 5.7±3.4 % (PBC -B), respectively. Conclusion: The TLs from the CLs were evaluated. A Clarkson-based system shows a large systematic variation because of inhomogeneous correction. The AAA showed a significant variation. Thus, we must consider the difference of inhomogeneous correction as well as the dependence of dose calculation engine.

• OSTI ID: 22545181
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 6 Vol. 42; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
61 RADIATION PROTECTION AND DOSIMETRY
ACCURACY
ALGORITHMS
ANISOTROPY
BEAMS
COMPUTER CODES
COMPUTERIZED TOMOGRAPHY
CORRECTIONS
ERRORS
IMAGE PROCESSING
IONIZATION CHAMBERS
LUNGS
PATIENTS
PHANTOMS
PLANNING
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
VERIFICATION