Is it valid to administer a SUS questionnaire after a system training session?

We would like to do some tests to determine usability and learnability of a new system we have produced. We have a very short time period, so right now we are only looking at something quick and high-level.

We will be have a few training sessions with new users. In these training sessions they will be taught how to use the new software. (It is a very complex system requiring specific knowledge, and it's unlikely users would become adept through just the training sessions). They are required to do the training session, so I cannot really test on users who haven't done the training.

I am thinking about administering a SUS questionnaire at the end of the training sessions. Would this still produce valid results? My understanding is that it's generally used after usability tests with structured tasks (and not after being trained in the system).