Orthovoltage X-rays
Orthovoltage X-rays are produced by X-ray tubes operating at voltages in the 100–500 kV range, and therefore the X-rays have a peak energy in the 100–500 keV range. Orthovoltage X-rays are sometimes termed "deep" X-rays (DXR). They cover the upper limit of energies used for diagnostic radiography, and are used in external beam radiotherapy to treat cancer and tumors. They penetrate tissue to a useful depth of about 4–6 cm. This makes them useful for treating skin, superficial tissues, and ribs, but not for deeper structures such as lungs or pelvic organs. The relatively low energy of orthovoltage X-rays causes them to interact with matter via different physical mechanisms compared to higher energy megavoltage X-rays or radionuclide γ-rays, increasing their relative biological effectiveness.
| Orthovoltage X-rays | |
|---|---|
A 200 kV orthovoltage X-ray tube used for radiation therapy, 1938. Orthovoltage X-ray machines are similar to diagnostic (radiography) X-ray machines, except that higher voltages are used and the X-ray tube is longer, to prevent the high voltages from arcing across the tube.
ICD10 = | |
| ICD-9 | 92.22 |
| OPS-301 code | 8-521 |