Radiation therapy

There are 4 university hospitals in Brussels - Erasmus, CHB Brussels, UZ Brussel and St Luc. All should be a good choice. So would UZ Leuven.
Personally, I would choose whichever is easiest to get to.

An odd question. Surely her oncologist has an opinion on this, which would be more reliable than asking a bunch of strangers?

Well, I agree with CM that the oncologist ought to be pointing the patient in the right direction. Not all hospitals have the equipment. I am under treatment at Hopital Brugmann and could choose UZ Jette or Institut Bordet for 19 sessions of radiotherapy, I chose to go to Bordet since sessions are daily, and for me easier to get to by public transport.

Be careful looking for "the most modern equipment and techniques".

I have a relative who I can only describe as being exploited by the system here in Belgium. Over almost a decade was the subject in numerous clinical trials, once in a dosing trial, almost to the point of death. We ended up taking them out of the country.

Sometimes good care, given by competent and caring medical staff is better than the latest fashionable and fancy kit.

@yttap. Best of luck with your treatment.