SGRT Forum

I am in the midst of commissioning our Align RT system with the head adjuster and I am running into inconsistencies between the coordinate system in Align RT and the coordinate system in our Varian linac (Trilogy) and treatment planning system (Eclipse). One of the inconsistencies has to do with the signs of the rotations, which do not match between the signs of the rotations indicated by the OBI, and those indicated by the RTDs (signs are opposite). Align RT is currently set to IEC61217 and Varian is set to Varian IEC. If there is one of you out there that is using Align RT with a Varian linac that does not have 6DOF couch, will you please share which coordinate systems you have both your Align RT and linac set to, and how the rotations (pitch, roll, yaw) correlate between both?

Thank you,

Jose Carlos Pichardo, Ph.D., DABR

Miami Beach, FL

After experimentation, the correct coordinate system for our linac is the 60601 OBI 1.6.

Varian IEC or (IEC 60601-2-1) is not the same as IEC 61217. The couch rotation is opposite in these coordinate systems. IEC 61217 has couch 270 on the left (looking at the gantry from the foot of couch) and 90 on the right. Varian IEC has couch 90 on the left (looking at the gantry from the foot of couch) and 270 on the right.

Hope that helps,

Mike

Sorry for the late reply and the reply at all you response didn't show up on the forum screen until after I submitted my response. My browser settigns may be an issue.

Best Regards,

Mike