Evaluation of organ-at-risk dose reduction with jaw tracking technique in flattening filter-free beams in lung stereotactic body radiation therapy

•Jaw tracking allows significant organ-at-risk dose reduction even in FFF beams.•Complexity of jaw movements does not correlate with that of the MLC movements.•Complexity of jaw movements correlates with reduction rate of organ-at-risks.•Jaw tracking technique accurately followed the MLC movements in lung SBRT.