A voltage in the region of millions of volts.(noun)
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Use "megavoltage" in a sentence
"External X-ray megavoltage beam irradiation is quite often indicated in view of the closeness of the surgical margin of resection."
"However, megavoltage imaging also has significant disadvantages."
"According to Star-Lack, it is possible to greatly reduce the distortions by using very high energy (megavoltage) x-rays that better penetrate the metal."