TITLE:
Application of Variance Component Analysis (ANOVA) in Setup Errors and PTV Margins for Lung Cancer with Stereotactic Body Radiation Therapy (SBRT)
AUTHORS:
Xiaotian Huang, Jun Zhang, Conghua Xie, Yunfeng Zhou, Hong Quan
KEYWORDS:
SBRT, KV-CBCT, PTV Margin, Setup Errors, DVH
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.7 No.4,
November
20,
2018
ABSTRACT: Purpose: To
investigate the feasibility of applying ANOVA newly proposed by Yukinori to
verify the setup errors, PTV (Planning Target Volume) margins, DVH for lung
cancer with SBRT. Methods: 20 patients receiving SBRT to 50 Gy in 5
fractions with a Varian iX linear acceleration were selected. Each patient was
scanned with kV-CBCT before the daily treatment to verify the setup position.
Two other error calculation methods raised by Van Herk and Remeijer were also compared
to discover the statistical difference in systematic errors (Σ), random errors (σ), PTV margins and DVH. Results: Utilizing two PTV margin calculation formulas (Stroom, Van Herk), PTV
calculated by Yukinori method in three directions were (5.89 and 3.95), (5.54
and 3.55), (3.24 and 0.78) mm; Van Herk method were (6.10 and 4.25), (5.73 and
3.83), (3.51 and 1.13) mm; Remeijer method were (6.39 and 4.57), (5.98 and
4.10), (3.69 and 1.33) mm. The volumes of PTV using Yukinori method were
significantly smaller (P 0.05) among three methods. Conclusions: In lung SBRT treatment, due to fraction reduction and high level
of dose per fraction, ANOVA was able to offset the effect of random factors in
systematic errors, reducing the PTV margins and volumes. However, no distinct
dose distribution improvement was founded in target volume and organs at risk.