The prescription dose was delivered as follows : gross target volume ( GTVnx ) @-@ Gy in @-@ fractions , positive neck lymph nodes ( GTVln-R/L ) @-@ Gy in @-@ fractions , high-risk clinical target volume ( CTV@ ) @-@ Gy , low-risk clinical target volume ( CTV@ ) @-@ Gy , and clinical target volume of cervical lymph node regions ( CTVln ) @-@ Gy .