73 Gy each side does seems to be a lot.
You also need to consider that this (Gy) is the energy absorbed per kg matter. If you were to get just 6 Gy whole body radiation this would be deadly. On the other hand you could have an extreme exposure of your small finger and have no "serious" problems.

M

Partial glossectomy (25%) anterior tongue. 4/6/07/. IMRT start @5/24/07 (3x) Erbitux start/end@ 5/24/07. IMRT wider field (30x) start 6/5/07. Weekly cisplatin (2x30mg/m2), then weekly carbo- (5x180mg/m2). End of Tx 19 July 07.