Michael Tallhamer, MSC, DABR
We don’t have C-Series linacs here (only TrueBeams with Align RT) but we did do clinical testing of the Move Couch feature for the Neasden release and my understanding of the modifications to the Move Couch workflow are more or less safety modifications as it relates to how Align RT is seen by the Varian machines.
Since the machine is using the MMI interface provided by Varian and AlignRT is using the Varian defined ADI dialect to communicate over that interface there are inherent limitations as to how things are done.
- MMI from the Varian side tends to see third party devices as “sudo” CBCT type objects. This is how Varian chooses to see these objects not necessarily how these objects see themselves so there is a slight disconnect there in definition.
- The connected device (AlignRT in our case) only gets ADI messages at certain points in the process so information about the machine setup is only known at discreet points in the workflow.
- Because of the above 2 conditions there were workflow issues that could arise where information sent over MMI by align RT through the ADI communication protocol to the Varian machine was not interpreted as intended. This resulted in the device (AlignRT) manufacturer (Vision RT) needing to impose a priori conditional limitations on the communication conditions so that these workflow and communication frame of reference (see 1 and 2 above) related issues can be avoided.
From our experience the Move Couch feature still works as intended with a couple additional safety related limitations which prevent some of the reported workflow related errors from the previous release.
If you would like to discuss further I would be happy to talk with you over the phone or it can remain on the forums (either way). Send me a private email (firstname.lastname@example.org) if you would prefer a phone call and I’ll send you my cell number.