x-ray/examen de radiologie

I need to get an x-ray as soon as possible. I have a doctor's prescription, although I cannot decipher what is written on it. What is the fastest, easiest way to do this? I live in Ixelles/St Gilles and am not up to dragging myself halfway across town if possible. Are there laboratories that do this (I googled by it seemed like blood tests only)? Is an appointment required?