SU-E-T-676: Impact of Carbon Fiber Couchtop On TrueBeam Flattening-Filter-Free (FFF) SRS/SBRT Radiation Therapy.

PURPOSE To evaluate the attenuation of Flattening-Filter-Free (FFF) SRS/SBRT beams resulting from transmission through the Exac Trac carbon fiber couchtop and to validate the couchtop model in Eclipse Ver.11. METHODS A cylindrical phantom of 8cm-diameter was scanned with an ion chamber placed in the center. Radiation doses of static fields (3×3, 5×5, and… (More)