Markus,
I am in the UK and had surgery follwed by six weeks of radiotherapy (30 sessions), along with weekly cisplatin - each Thursday, taking about 6 hours to complete, largely because of the fluids used before and after the bag of cisplatin. I'm sorry that I can't tell you the dosage - it took about two hours to go through the line in my hand. I was given anti-nausea meds before and aferwards and in my case, there were no adverse side effects, (other than, whisper it, a little constipation!) - that I have become a person who says such things to strangers!!
I really don't know whether this is standard over here, but there were other H&N patients receiving weekly cisplatin at the same time. I was told that it works to improve the efficacy of the radiotherapy and would also act as a general 'flush'.
Sorry if this is a bit wishy washy and vague.
Good luck,
Georgia