Smoothing intensity modulated beam profiles to facilitate delivery Conference Paper
| Authors: | Spirou, S. V.; Yang, J.; Chui, C. S.; Ling, C. C. |
| Editor: | Enderle, J. D. |
| Title: | Smoothing intensity modulated beam profiles to facilitate delivery |
| Conference Title: | 22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society |
| Abstract: | Intensity-modulated radiation therapy (IMRT) is rapidly gaining ground as a means of delivering dose distributions that conform more closely to the target and provide greater organ-sparing. The optimization algorithms that determine the IM beam profiles are computationally complex and intensive. Moreover, for reasons of efficiency, these algorithms often contain simplifications, such as the use of partial scattering. Consequently, the resulting IM beam profiles are inherently uncertain and noisy, often exhibiting narrow and sharp peaks and valleys. Such profiles are difficult to generate, requiring long treatment times, while affecting the final dose distribution only marginally. In this work we discuss techniques of smoothing the beam profiles. The simplest approach is to smooth at the end of each iteration. Alternatively, penalty terms for the "unsmoothness" of the beam profiles can be included within the objective function used to drive the optimization process. The functional form of these terms is similar to those used in the first approach, thus essentially applying the same filter. The latter method achieves better dose distributions in situations where a low-tolerance critical organ is in the middle of the field, with much sharper dose gradients at the interfaces between the critical organ and the target. In addition, it is more efficient, requiring fewer iterations, because the process of smoothing does not undo the process of optimization, as the case is in the former method. |
| Keywords: | intensity modulated radiation therapy; radiotherapy; algorithms; dosimetry; biological organs; intensity-modulated radiation therapy; biomedical engineering; optimization; filtering; savitzky-golay; smoothing; least-squares; least squares approximations |
| Journal Title | IEEE Engineering in Medicine and Biology Society. Annual International Conference. Proceedings |
| Volume: | 1 |
| Conference Dates: | 2000 Jul 23-28 |
| Conference Location: | Chicago, IL |
| ISBN: | 1094-687X |
| Publisher: | IEEE |
| Location: | Chicago, IL |
| Date Published: | 2000-01-01 |
| Start Page: | 445 |
| End Page: | 448 |
| Language: | English |
| PROVIDER: | scopus |
| DOI: | 10.1109/IEMBS.2000.900771 |
| DOI/URL: | |
| Notes: | Annu Int Conf IEEE Eng Med Biol Proc -- Conference code: 58178 -- Export Date: 18 November 2015 -- CODEN: CEMBA -- 23 July 2000 through 28 July 2000 -- Source: Scopus |
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