Smoothing intensity-modulated beam profiles to improve the efficiency of delivery Journal Article


Authors: Spirou, S. V.; Fournier-Bidoz, N.; Yang, J.; Chui, C. S.; Ling, C. C.
Article Title: Smoothing intensity-modulated beam profiles to improve the efficiency of delivery
Abstract: Intensity-modulated beam profiles are generated by an inverse planning or optimization algorithm, a process that, being computationally complex and intensive, is inherently susceptible to noise and numerical artifacts. These artifacts make delivery of the beams more difficult, oftentimes for little, if any, observable improvement in the dose distributions. In this work we examine two approaches for smoothing the beam profiles. The first approach is to smooth the beam profiles subsequent to each iteration in the optimization process (method A). The second approach is to include a term within the objective function that specifies the smoothness of the profiles as an optimization criterion (method B). The two methods were applied to a phantom study as well as three clinical sites: paraspinal, nasopharynx, and prostate. For the paraspinal and nasopharynx cases, which have critical organs with low tolerance doses in close proximity, method B produced sharper dose gradients, better target dose homogeneity, and more critical organ sparing. In the less demanding prostate case, the two methods give similar results. In addition, method B is more efficient during optimization, requiring fewer iterations, but less efficient during DMLC delivery, requiring a longer beam-on time. © 2001 American Association of Physicists in Medicine.
Keywords: radiotherapy; algorithms; dose-response relationship, radiation; prostatic neoplasms; prostate; algorithm; head and neck neoplasms; models, statistical; spine; spinal neoplasms; intermethod comparison; radiotherapy planning, computer-assisted; radiotherapy, conformal; phantom; radiation beam; phantoms, imaging; nasopharyngeal neoplasms; radiation dose distribution; artifact reduction; intensity-modulated radiation therapy; nasopharynx; optimization; radiation absorption; inverse planning; humans; human; male; priority journal; article; filtering; savitzky-golay; smoothing
Journal Title: Medical Physics
Volume: 28
Issue: 10
ISSN: 0094-2405
Publisher: American Association of Physicists in Medicine  
Date Published: 2001-10-01
Start Page: 2105
End Page: 2112
Language: English
DOI: 10.1118/1.1406522
PUBMED: 11695772
PROVIDER: scopus
DOI/URL:
Notes: Export Date: 21 May 2015 -- Source: Scopus
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MSK Authors
  1. C Clifton Ling
    331 Ling
  2. Jie Yang
    50 Yang
  3. Chen Chui
    144 Chui
  4. Spiridon Spirou
    34 Spirou