. 2019 Jul 11;20(8):47–55. doi: 10.1002/acm2.12677

Table 1.

Dose–volume histogram metrics evaluated for all normal structures.

Structure	Dose metrics	Volume metrics 1	Volume metrics 2
Brainstem	D_max	V_{54 Gy}
Spinal cord	D_max	V_{45 Gy}
Expanded spinal cord	D_max	V_{45 Gy}
Right parotid	D_mean	V_{30 Gy}
High‐risk PTV^a		V_98%	V_95%
Mid‐risk PTV		V_98%	V_95%
Low‐risk PTV		V_98%	V_95%

D_max is defined as the maximum point dose to the tissue, D_mean is the mean point dose to the tissue, V_54 Gy is the volume of tissue receiving 54 Gy, V_45 Gy is the volume of tissue receiving 45 Gy, V_30 Gy is the volume of tissue receiving 30 Gy, V_98% is the volume of tissue receiving 98% of the prescription dose, and V_95% is the volume of tissue receiving 95% of the prescription dose.

Planning target volume.