Impact of multileaf collimator leaf positioning accuracy on intensity modulated radiation therapy.

Motoharu Sasaki, Masahide Tominaga, Hitoshi Ikushima, Taro Kishi, Tetsuya Kawashita, Yasuo Hara, Yukiko Fukunaga, Masashi Kimura, Yasufumi Shitakubo, Satoru Takashi, Masataka Oita

Research output: Contribution to journalArticlepeer-review


In multileaf collimator (MLC)-based intensity modulated radiation therapy (IMRT), the dose is influenced by the uncertainty of MLC driving control. In this study, we examined the influence of MLC driving control accuracy on dose evaluation (gamma analysis) by evaluating 60-day MLC driving control accuracy (stationary positioning accuracy and positioning reproducibility) once a week as well as measuring IMRT dose distribution. The MLC positioning accuracy accompanied variation over time and tended to expand by 0.1 to 0.15 mm in one week and about 1 mm in 60 days. In terms of reproducibility, errors were within 0.2 mm for more than 95%. For prostate IMRT, when MLC stationary positioning accuracy was around 1 mm, no significant difference was observed in the pass rate in gamma analysis. Therefore, the results suggest that regular maintenance by setting a permissible value determined by the MLC positioning accuracy test can be an effective indicator in the future for maintaining the safety of IMRT.

Original languageEnglish
Pages (from-to)497-506
Number of pages10
JournalNihon Hoshasen Gijutsu Gakkai zasshi
Issue number5
Publication statusPublished - 2011
Externally publishedYes

ASJC Scopus subject areas

  • Medicine(all)


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