To what dose do you treat enlarged, but PET negative lymph nodes in laryngeal SCC?

If a node meets criteria for involvement by physical examination (firm, stuck to surrounding structures), or CT (enhancing, loss of fatty hilum, rounded), I give the node (+ 3mm for PTV) 70 Gy in 35 fx. Level II would also be a first-echelon node, raising my suspicion. The remaining level II region ...