Abstract
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 language | English (US) |
|---|---|
| Pages (from-to) | 1093-1098 |
| Number of pages | 6 |
| Journal | International Journal of Radiation Oncology, Biology, Physics |
| Volume | 22 |
| Issue number | 5 |
| DOIs | |
| State | Published - 1992 |
| Externally published | Yes |
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Keywords
- Dose-volume histogram
- Meningioma
- Optic nerve
- Optic nerve sheath
- Radiation therapy
- Technique
ASJC Scopus subject areas
- Oncology
- Radiology Nuclear Medicine and imaging
- Radiation
Cite this
Precision radiation therapy for optic nerve sheath meningiomas. / Eng, Tony Y.; Albright, N. W.; Kuwahara, G.; Akazawa, C. N.; Dea, D.; Chu, G. L.; Hoyt, W. F.; Wara, W. M.; Larson, D. A.
In: International Journal of Radiation Oncology, Biology, Physics, Vol. 22, No. 5, 1992, p. 1093-1098.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Precision radiation therapy for optic nerve sheath meningiomas
AU - Eng, Tony Y.
AU - Albright, N. W.
AU - Kuwahara, G.
AU - Akazawa, C. N.
AU - Dea, D.
AU - Chu, G. L.
AU - Hoyt, W. F.
AU - Wara, W. M.
AU - Larson, D. A.
PY - 1992
Y1 - 1992
N2 - 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.
AB - 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.
KW - Dose-volume histogram
KW - Meningioma
KW - Optic nerve
KW - Optic nerve sheath
KW - Radiation therapy
KW - Technique
UR - http://www.scopus.com/inward/record.url?scp=0026766090&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026766090&partnerID=8YFLogxK
U2 - 10.1016/0360-3016(92)90814-X
DO - 10.1016/0360-3016(92)90814-X
M3 - Article
C2 - 1555959
AN - SCOPUS:0026766090
VL - 22
SP - 1093
EP - 1098
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
SN - 0360-3016
IS - 5
ER -