Table 2.

Dose-volume histogram data for planning target volumes in the 749 patients with NPC

Variate	Volume (mL)	Dmax (Gy)	Dmin (Gy)	Mean dose (Gy)
PTV-P	51.89 (2.60–287.48)	79.91 (70.47–93.95)	59.79 (50.58–71.16)	73.11 (68.16–78.48)
PTV1	97.35 (13.78–494.77)	79.67 (72.81–86.08)	58.86 (49.13–67.32)	67.94 (56.66–74.48)
PTV2	368.97 (106.36–685.58)	78.99 (70.04–86.74)	45.28 (43.12–61.47)	60.55 (53.64–72.13)

PTV-P planning target volume of the primary tumor, PTV1 PTV of the high-risk clinical target volume, PTV2 PTV of the low-risk clinical target volume, D _max maximum dose, D _min minimum dose. All data are presented as median with range in parentheses