Winston Lutz couch shift conventions

I’m using a Winston Lutz module with a Truebeam and the up/down instructions seem reversed:

print(wl.bb_shift_instructions(couch_vrt=3.5, couch_lng=34.92, couch_lat=-0.01))
: When I follow the suggested couch positions, I only get farther from the field center.
Is it possible to modify the directions?


The couch position should be passed in centimeters. That’s probably an inconsistency as everything else is in mm. When I create mock images of a BB 2mm high the instructions seem correct:

print(wl.bb_shift_instructions(couch_vrt=3.5, couch_lng=0, couch_lat=0))

LEFT 0.00mm; IN 0.00mm; DOWN 2.01mm
New couch coordinates (mm): VRT: 3.30; LNG: 0.00; LAT: -0.00

WL 2mm (189 KB)