▲ 9 r/MedicalPhysics
Reproducibility of MLC Hancock test
For Elekta users who perform the Hancock MLC test on Agility: have you noticed a lack of reproducibility with variations close to 1 mm in some positions between sucesive executions of the test? Like, you do it the first time and one of the segments appears with -0.4 mm absolute deviation, you repeat it after a while and you get about +0.4 mm in the same region, but in other segments the position does not change...
Since each one of the three bands is actually the combination of two images, small differences between the upper and the lower half are not surprising, but differences between consecutive tests seem higher than desirable (even although the absolute deviation is within 0.5 mm for most leaves). I have seen this in three linacs.
u/ClinicFraggle — 1 day ago