Evaluation of Cyberknife Treatment Planning for Prostate Cancer using the Conformal Index and the Tumor Control Probability

Chia Chun Kuo, Hsiao-Wei Yu, Kuang Wei Huang, Chiu-Ping Chen, Tao Sang Chung, Jeng-Fong Chiou, Jo-Ting Tsai

Research output: Contribution to journalArticle


Purpose: This study was to evaluate the feasibility of dose conformity and tumor control probability calculated for CyberKnife(superscript ®) hypofractionated planning for prostate cancer.
Materials and Methods: Six patients with early prostate cancer were included in this retrospective study. They received stereotactic hypofractionation radiotherapy by CyberKnife(superscript ®). The dose prescriptions were 37.5 Gy in 5 fractions, 42 Gy in 5 fractions, or 32 Gy in 4 fractions. Dose conformity was calculated with three parameters: the conformity index (CI), the new conformity index (nCI) and the modified conformal index (mCOIN). A statistical analysis of the tumor control probability (TCP) was also calculated.
Results: The CI and nCI of the CyberKnife(superscript ®) treatment planning system are all under 1.483. All the calculated TCP values were greater than 98.3%. We added the factors pertaining to the critical organ and obtained the mCOINs. The mCOIN values were listed to compare the quality of treatment plans.
Conclusion: The conformity index value can be used to evaluate the quality of radiosurgery planning. The mCOIN values are also feasible to compare the plans.
Original languageEnglish
Pages (from-to)301-310
Number of pages10
Issue number4
Publication statusPublished - 2008



  • Conformity index
  • Tumor control probability
  • Stereotactic radiosurgery
  • CyberKnife

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