Orthovoltage

Orthovoltage X-rays (also sometimes called superficial x-rays) refers to therapeutic x-rays in the range of 50-500 kVp, and have been employed in radiation therapy for over 100 years. X-rays in this range can be uniquely suitable for extremely superficial lesions. Once common in cancer therapy, orthovoltage units are now relatively rare. With the advent of Megavoltage-producing linear accelerators, many centers now use electron beams for superficial treatments. In certain cases orthovoltage is an excellent choice. In particular, unlike electron beams, orthovoltage beams begin depositing energy (and therefore providing therapeutic effect) at the very surface. If skin sparing is desired this would not be desirable, but if skin treatment is needed, it can be ideal.

An orthovoltage unit is a relatively simple device requiring less shielding and service than a linear accelerator. Customized patient positioning and field shaping is also simpler and quicker than the comparable process required for electron beam treatment. This can result in a less rigorous treatment experience for patients for whom orthovoltage is an appropriate choice.