Development and validation of a monte carlo modeling of millennium MLC

Y. Ishihara, Tokihiro Yamamoto, Y. Miyabe, T. Mizowaki, Y. Narita, S. Yano, T. Teshima, M. Hiraoka

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Most of the commercial treatment planning systems doesn't take into account multileaf collimator (MLC) design which causes the leakage radiation, the tongue-and-groove effect, beam hardening and rounded leaf tip effect in intensity-modulated radiotherapy (IMRT) field. We were to develop an integrated Monte Carlo (MC) dose calculation system called MCRTV (Monte Carlo for Radiotherapy Treatment plan Verification) as a routine verification tool of radiotherapy. In this study we try to construct accurate model of the Varian Millennium 120-leaf MLC and validate the model using the EGS4/PRESTA MC code. Leakage, picket fence, and sliding window tests were calculated using well-commissioned 15MV photon beam. These results were compared and validated measured dataes. All MC simulations matched measured ones less than 2.0 %. Leaf leakage radiation was 1.38% on average. Tongue-and-groove design caused 8.3% underdose on average. According to these results, we could constructed precise Millennium model and accuracy were validated to develop a MCRTV for IMRT.

Original languageEnglish (US)
Title of host publicationProceedings of the 15th EGS Users' Meeting in Japan
Number of pages7
StatePublished - 2008
Externally publishedYes
Event15th EGS Users' Meeting in Japan 2008 - Tsukuba, Japan
Duration: Aug 6 2008Aug 8 2008


Other15th EGS Users' Meeting in Japan 2008

ASJC Scopus subject areas

  • Software


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