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SU‐GG‐T‐229: Intensity Modulated Arc Therapy for Pediatric Brain Tumors
Author(s) -
Gray J,
Beltran C
Publication year - 2010
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3468620
Subject(s) - medicine , nuclear medicine , intensity (physics) , magnetic resonance imaging , radiology , physics , quantum mechanics
Purpose: Investigate the benefits of intensity modulated arc therapy (IMAT) for pediatric brain tumors over non‐coplanar IMRT. Method and Materials: Nine pediatric patients with posterior fossa tumors, mean age 9.6 years (6.1–15.1), were treated with IMRT within the past year at our institution. For this study, each was re‐planned with 54Gy to the PTV with five different methods; 8 field non‐coplanar IMRT, single coplanar IMAT, double coplanar IMAT, single non‐coplanar IMAT, and double non‐coplanar IMAT. For each method, the dose to 95% of the PTV was held constant and the dose to surrounding critical structures were minimized. The plans were compared based on conformality index (CI), MUs, and dose to surrounding normal tissue. Results: The body V 5 and brain D 50 for IMAT and double IMAT were reduced (p<0.01) compared to NC‐IMRT. The body V 50 and D 50 to the cochleae were increased (p<0.01). For IMAT, the CI and MU were decreased (p=0.01). For NC‐IMAT, the V 5 was increased (p=0.01) but the D 50 to the right cochlea and both temporal lobes was decreased (p=0.01). For double NC‐IMAT, the body V 50 , D 50 to both cochleae and temporal lobes were decreased (p<0.01), however the body V 5 and MU were increased (p<0.01). The CI for the double NC‐IMAT was also improved (p=0.05). Four patients had NC‐IMRT plans where both cochleae received greater than 25Gy; the average for these patients was 27.9Gy. The average dose was increased for the IMAT (32.7Gy p=0.01) and double IMAT (31.0Gy p=0.05). For the NC‐IMAT, the dose decreased to 22.5Gy (p=0.03) and double NC‐IMAT was also decreased (20.0Gy p<0.01). Conclusion: Double NC‐IMAT can improve treatment for pediatric posterior fossa tumors over non‐coplanar IMRT, and this option may be able to provide dose reduction to certain critical structures. This method has merit and should be considered alongside IMRT for these patients.