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Sci‐AM1 Sat ‐ 09: Embolization materials affect subsequent radiosurgery dose to AVM's
Author(s) -
Beachey D,
Scora D,
Ramani M,
AndradeSouza Y,
Schwartz M,
Tsao M,
terBrugge K
Publication year - 2005
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 - 10.1118/1.2031050
Subject(s) - lipiodol , imaging phantom , radiosurgery , collimated light , nuclear medicine , materials science , embolization , dosimetry , linear particle accelerator , glue , medicine , biomedical engineering , beam (structure) , radiology , radiation therapy , optics , physics , laser , composite material
Radiosurgery, often used as a follow‐up modality to surgical glue embolization for arterio‐venous‐malformations (AVM's), can be complicated by the polymerizing and contrast agents, Embucrilate and Lipiodol. Post the embolization attempt, these agents remain in the AVM nidus where they depart radiologically from tissue equivalence and thereby affect dose. A test phantom consisting of an array of deposits of embolization medium of both varying thickness and polymer / contrast concentration imbedded in solid water was constructed. For irradiation, the phantom is further imbedded in solid water at positions upstream and downstream relative to a fixed nominal target / film plane at 100 cm SAD (overall phantom thickness: 22cm; film depth: 7.0 cm.) The film placement relative to the glue media interfaces are upstream: −0.2 and 0.0 cm; and downstream: 0.0, 0.2, and 0.5 cm. Irradiations are conducted using a 5 MV radiosurgery beam (Linac system) in a wide (10 cm × 10 cm) SAD‐field setting to encompass the phantom's glue wells. Correspondence of results with narrower coned RS fields was verified. XV film results indicated dose downstream of the interface at 0.0, 0.2, and 0.5 cm was reduced 14% (±3%), 7% (±2%), and 2% (±1%) respectively. The Lipiodol concentrations, (80%, 50%, 20% by weight) reduced maximum dose 16% (±1%), 15% (±1%), and 10% (±1%) respectively. Glue depth and thickness yielded little relative dose effect. Radiation transport calculations and radiochromic film results will also be presented.