Program Information
Study On Application of Beam Angle Optimization for Multiple Intracranial Metastases
X Lin , t sun*, Y Yin , shandong cancer hospital, Jinan, shandong
Presentations
SU-E-T-713 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose:To study the dosimetric impact of different angle fields IMRT and the feasibility of beam angle optimization (BAO) for multiple intracranial metastases.
Methods:11 patients with multiple intracranial metastases were included in this analysis. In Varian Eclipse TPS two treatment techniques were designed for each patient: the 7 equal spaced fields and 7 fields by beam angle optimization IMRT. Two plans were designed for each patient with the same dose-volume constraints and prescription dose. All plans were normalized to the mean dose to PTV. The dose distribution in the target, the dose to the organs at risk and normal brain tissues and total MU in two techniques were compared to explore the dosimetric differences.
Results:For the target dose, conformity and homogeneity in PTV, no statistically differences were observed in the two plans. Compared to 7 equal spaced fields IMRT plans, IMRT plans with BAO reduced the maximum dose to left and right lens by an average of 45%, 37%, the mean dose to left and right eyes were reduced by an average of 42.6% ,44.5% .The maximum dose of the right optic nerve and the mean dose of normal brain tissue were reduced by an average of 23%,3% respectively. The above data were statistically significant. IMRT plans with BAO reduced the maximum dose of the brainstem and the optic chiasm, the number of MU, but the result were not statistically significant (p> 0.05).
Conclusion:Compared to 7 equal spaced fields IMRT plans, IMRT plans with BAO showed the similar target dose and reduced the dose of the organs at risk. For multiple intracranial metastases, IMRT plans with BAO were feasible and beneficial.
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