I didn't see a biopsy of the right posterior tongue, unless omitted? The BOT can go to both sides of neck if cancer was close to the midline. As David mentioned, you will probably get around that range 70-72Gy, some other areas lesser.
Other base-line tests before treatment is an eye exam, hearing test, TSH, hemoglobin and creatinine, the last two are on the CBC, complete blood count, which is taken before chemo infusions.
Good luck.