Flattening Filter Free
Also written as: FFF — Flattening Filter Free
Linear accelerator beam delivery mode without flattening filters, producing higher dose rates with beam profile variations.
Full Definition
Flattening Filter Free (FFF) beams are produced by removing the flattening filter from the linear accelerator beam path, resulting in a forward-peaked photon fluence profile rather than the traditionally flat beam profile. This configuration allows for significantly higher dose rates, reduced beam hardening, and lower out-of-field dose due to reduced head scatter. FFF beams are particularly advantageous for stereotactic treatments where high dose rates enable shorter treatment times and potentially improved patient comfort and setup reproducibility.
Usage
Usage note: Commonly abbreviated as FFF; ensure distinction from filtered beams.
In Context
- "The flattening filter free beam enabled delivery of the SBRT treatment in under 15 minutes." — Treatment delivery report
- "FFF beam commissioning required modified dose calculation algorithms to account for the peaked profile." — Physics commissioning document