Optimized planning target volume margin in helical tomotherapy for prostate cancer: Is there a preferred method?

Yuan Jie Cao, Suk Lee, Kyung Hwan Chang, Jang Bo Shim, Kwang Hyeon Kim, Min Sun Jang, Won Sup Yoon, Dae Sik Yang, Young Je Park, Chul Yong Kim

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2 Citations (Scopus)


We compare the dosimetrical differences between plans generated for helical tomotherapy by using the 2D or 3D the margining technique for the treatment of prostate cancer. Ten prostate cancer patients were included in this study. For 2D plans, the planning target volume (PTV) was created by adding 5 mm (lateral/anterior-posterior) to the clinical target volume (CTV). For 3D plans, a 5-mm margin was added not only lateral/anterior-posterior, but also superior-inferior, to the CTV. Various dosimetrical indices, including the prescription isodose to target volume (PITV) ratio, conformity index (CI), homogeneity index (HI), target coverage index (TCI), modified dose homogeneity index (MHI), conformation number (CN), critical organ scoring index (COSI), and quality factor (QF) were determined to compare the different treatment plans. Differences between the 2D and the 3D PTV indices were not significant except for the CI (p = 0.023). 3D margin plans (11195 MUs) resulted in higher (13.0%) monitor units than 2D margin plans (9728 MUs). There were no significant differences in any organs at risk (OARs) between the 2D and the 3D plans. Overall, the average dose for the 2D plan was slightly lower than that for the 3D plan dose. Compared to the 2D plan, the 3D plan increased the average treatment time by 1.5 minutes; however, this difference was not statistically significant (p = 0.082). We confirmed that the 2D and the 3D margin plans were not significantly different with regard to various dosimetric indices such as the PITV, CI, and HI for PTV and the OARs with tomotherapy.

Original languageEnglish
Pages (from-to)26-32
Number of pages7
JournalJournal of the Korean Physical Society
Issue number1
Publication statusPublished - 2015 Jul 31


  • 2D and 3D margin
  • Biological index
  • Dosimetrical index
  • Prostate cancer
  • Tomotherapy

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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