Do you routinely re-image all craniopharyngioma patients during radiotherapy?  

Yes, typically weekly. Ideally with MRI. HASTE MRI is often sufficient. If the cyst wall has enough calcifications and MRI authorization is a challenge, I will sometimes substitute a CT head (often as a re-sim using the treatment mask).

I was taught to do this weekly. Realistically though, we end up doing a mid treatment MRI to assess for any enlargement due to logistics and authorization reasons.