Precision radiation therapy for optic nerve sheath meningiomas

Tony Y. Eng, N. W. Albright, G. Kuwahara, C. N. Akazawa, D. Dea, G. L. Chu, W. F. Hoyt, W. M. Wara, D. A. Larson

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


A more precise radiation therapy technique to treat unilateral optic nerve sheath meningioma is presented. It uses an immobilization device to align the ipsilateral optic nerve with a vertical axis and employs three small half-beam blocked fields to deliver radiation to a small conformal volume, thereby reducing the dose to the optic chiasm and the contralateral optic nerve. Three patients were successfully treated with this technique, and a fourth patient with optic nerve glioma was also treated in a similar fashion and was included in this study. The new technique irradiates a much smaller volume of tissue to high dose levels: 58 cm3 is irradiated to the 80% isodose level and only 18 cm3 to the 95% level. In contrast, the opposed lateral technique irradiates 171 and 73 cm3 to these levels, respectively. Thus, a considerable reduction in the volume of normal tissue irradiated was accomplished. Doses to the pituitary and contralateral optic nerve were 4% of the treatment dose for the new technique, whereas these doses were 40% and 100% for opposed laterals and 10% and 3% for wedged pair, respectively. The average setup error for this technique was very small, 50% of the setups measured were less than 1 mm off, and 92.5% were less than 3 mm off. However, for the conventional setups without a mask, only 21 % of the setups were less than 1 mm off and 55% less than 3 mm off. We recommend this technique for localized unilateral optic nerve sheath meningioma and other optic nerve lesions that may require radiation therapy.

Original languageEnglish (US)
Pages (from-to)1093-1098
Number of pages6
JournalInternational Journal of Radiation Oncology, Biology, Physics
Issue number5
StatePublished - 1992


  • Dose-volume histogram
  • Meningioma
  • Optic nerve
  • Optic nerve sheath
  • Radiation therapy
  • Technique

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research


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