FFF beam profile parameters

With TrueBeam linear accelerator it is possible to acquire images of FFF beams with the MV imager in normal clinical treatment mode. Following a feasibility study, both Epiqa configuration and Epiqa main software were enhanced in order to have full Epiqa functionality also with FFF beam. Implementation includes some ad-hoc corrections to overcome actual limitation of portal dosimetry of FFF beams in terms of imager and dosimetric calibration in the TrueBeam environment. See also FFF-RapidArc patient QA

Example of open FFF field evaluation

This image displays the analysis results of open beam 10 MV FFF with the comparison of calculated dose distribution in water phantom (in depth of Dmax) and measured dose provided by EPID and GLAaS algorithm.

Example of FFF profile analysis

Results can be printed in a FFF profile report                                                         Download FFF brochure

Supported modes of measurement

Machine QA for RapidArc :
SDD = 100 cm
Dose rate max 800 MU/min for both energies.

Open beams & IMRT QA:
SDD = 100 cm
Dose rate max 800 MU/min for both energies.

SDD = 150 cm
Any dose rate for both energies (up to 2400 MU/min).
Maximum detectable fields size = 27×21 cm².

RapidArc QA:
SDD = 150 cm
Any dose rate for both energies (up to 2400 MU/min).
Maximum detectable fields size = 27×21 cm².

Last update on 15. April 2013