Orthovoltage X-Rays (Paperback)

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Orthovoltage X-rays are produced by X-ray generators operating at voltages in the 200-500 kV range, and therefore an energy in the 200-500 keV range (see external beam radiotherapy for an explanation of the maximum and mean energies as a function of voltage). When used to treat patients, radiation oncologists find that they penetrate to a useful depth of about 4-6 cm. That makes them good for treating skin, superficial tissues, and ribs, but not for deeper structures such as lungs or pelvic organs. Orthovoltage X-rays are sometimes termed "deep" X-rays (DXR). Historically, as radiation machines were improved in the 1930s-'40s, the beam energy (and so its penetration) were increased. So as the new 200-500 kV beams became available, they were considered 'deep'.