Evaluation of auto contouring accuracy in 3D planning system

It is essential to input patients external contour in 3D treatment plan. We would like to see changes in depth and dose when 3D RTP is operating auto contouring when windows value (Width/Level) differs in this process. We have analyzed the results with 3D RTP after CT Scanning with round CT Phantom. We have compared and analyzed MU values according to depth changes to Isocenter changing external contour and inputting random Window value. We have watched change values according to dose optimization in 4 directions(LAO, LPO, RAO, RPO), We plan 100 case for exact analyzation. We have results changing window value random to each beam in 100 cans. It showed change between minimum and maximum value in 4 beam is Depth 0.26 mm, MU 1.2% in LAO. It showed LPO-Depth 0.13 mm, MU 0.9%, RAO-Depth 0.2 mm MU 0.8%, RPO-Depth 0.27 mm, MU 1.1%. Maximum change in depth 0.27 mm, MU error rate is according to Window change. As we can see in these results, it seems Window value change doesn't effect in treatment. However, it seems there needs to select appropriate Window value in precise treatment.