The Role of Imaging in Radiation Therapy Planning: Past, Present, and Future

Table 1

Accelerator voltage	Mean photon energy	Classification
10–150 kV	3–50 keV	Superficial
150–500 kV	50–166 keV	Orthovoltage
500–1000 kV	166–333 keV	Supervoltage
>1000 kV (1 MV)	>333 keV (0.33 MeV)	Megavoltage