Is this what you mean?
while($vak=mysql_fetch_array($result))
{ print("<input type=\"radio\" value=\"$vak[0]\" name=\"group1\"> $vak[1]\n");
}
BTW getting your variables in the manner of $vak[1] isn't a very good idea. If you ever have to drop or add a column the numbers might get scrambled and none of your code would work.
Also don't try to do a select * . . . just select what you need
select VakId as VALUE1, VakNaam as Value2
Then fetch, then $vak['VALUE1']
Just my 2 euro cents
PS: You can reply in Dutch if that would be easier 🙂