Impact of optimization algorithms on the intensity map in IMRT treatment planning

Mari Shimada, Mitsuhiro Nakamura, Yuki Miyabe, Tokihiro Yamamoto, Teruki Teshima, Yuichiro Narita, Takashi Mizowaki, Yasushi Nagata, Masahiro Hiraoka

Research output: Contribution to journalArticle

Abstract

In inverse planning of IMRT, optimum intensity maps are generated using an optimization algorithm. In this paper, impacts of two different optimization algorithms on the intensity map in IMRT treatment planning were evaluated. These were from the steepest descent (SD) and simulated annealing (SA) methods. The following five patterns were compared: [1] SD with calculation time of 5 min; [2] SD with the terminal criterion based on cost function; [3] SA with calculation time of 5 min; [4] SA with the terminal criterion; and [5] SA with the terminal criterion using a smoothing filter. Differences of D(95%) for the planning target volume, V(70Gy) for the rectum wall and the bladder wall were up to 0.5, 1.8 and 3.2 %, respectively in all patterns. The dosimetric impact was negligible. In contrast, generated intensity maps were sensitive to the algorithms. Intensity maps generated by SA tended to have much fluctuation due to numerical artifacts compared to those generated by SD. The difference in the profile was over 7 % between the algorithms. The smoothing filter decreased the fluctuation in intensity maps of SA. In conclusion, it is important to understand impacts of optimization algorithms on the intensity map and the dose distribution.

Original languageEnglish (US)
Pages (from-to)97-107
Number of pages11
JournalIgaku butsuri : Nihon Igaku Butsuri Gakkai kikanshi = Japanese journal of medical physics : an official journal of Japan Society of Medical Physics
Volume26
Issue number3
StatePublished - 2006
Externally publishedYes

ASJC Scopus subject areas

  • Medicine(all)

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