Which device uses gamma ray radiation to treat tumors, such as with a cobalt-60 source?

• A. Direct Electron Therapy
• B. External Beam
• C. Linear Accelerators
• D. Cobalt-60 Unit (Gamma Knife)

Answer: (D)

Gamma rays are high-energy photons produced by radioactive decay, and cobalt-60 provides a well-known source of these gamma rays for radiotherapy. A cobalt-60 unit, often used in Gamma Knife systems, places the radioactive source around the patient so multiple beams converge on the tumor. This arrangement delivers precise, high-dose gamma radiation to the target while sparing surrounding tissue, which is ideal for treating brain tumors and other lesions. Other devices rely on electrons or X-rays produced by linear accelerators rather than cobalt-60 gamma rays, so they use different radiation types and delivery methods. Thus, the cobalt-60 unit is the one that uses gamma ray radiation from a cobalt-60 source.