Yes, you can do your doctoral studies at another university. However, you should clarify a few things in advance.

There are two different approaches:

1) If you are submitting your doctoral dissertation via your professor at another university, RWTH has nothing to do with the doctoral studies process. You are obligated to adhere to the doctoral regulations of that university and to contact them for information. This option only makes sense though, if your supervisor can support you with this.

2) If you want to submit your dissertation in Aachen later on, you must adhere to the doctoral regulations of the Faculty of Medicine in Aachen and fulfill their requirements.
This means you first need a doctoral supervisor in Aachen, ideally one who is in the same field as your dissertation topic, as a dissertation at our faculty is only possible with a professor from RWTH, which is not guaranteed. This professor must sign the supervision confirmation, which must be submitted to the Doctoral Studies Office one year before you submit your dissertation.

Doctorate