Comparison of Simultaneous Integrated Boost-IMRT Dose Distributions: Classic Versus 18F-FLT PET–Guided
| Parameter | Classic | 18F-FLT PET–guided |
|---|---|---|
| Organs at risk | ||
| Left parotid gland (Gy) | 25.4 | 25.4 |
| Right parotid gland (Gy) | 24.8 | 24.8 |
| Maximum dose, spinal cord (Gy) | 48.2 | 48.1 |
| PTV> | ||
| Mean dose (Gy) | 52.2 | 52.1 |
| Volume receiving 90% of prescribed dose (%) | 99.5 | 99.5 |
| Volume receiving 95% of prescribed dose (%) | 96.7 | 96.4 |
| PTV< | ||
| Mean dose (Gy) | 68.7 | 69.0 |
| Volume receiving 90% of prescribed dose (%) | 99.7 | 99.6 |
| Volume receiving 95% of prescribed dose (%) | 96.9 | 96.8 |
| PTV≪ | ||
| Mean dose, first subvolume (Gy) | NA | 73.6 |
| Mean dose, second subvolume (Gy) | NA | 74.5 |
| Mean dose, overlap subvolumes (Gy) | NA | 74.7 |
PTV = planning target volume; PTV> = PTV encompassing electively treated volume, i.e., lymph node regions at risk of subclinical metastatic disease; PTV< = PTV encompassing primary tumor; PTV≪ = PTV for dose escalation defined by repetitive 18F-FLT PET (see “Materials and Methods”); NA = not available.