Diagnostic and Therapeutic Modalities Practice Test 2026 – Complete Exam Prep

Teletherapy means delivering radiation therapy from outside the body, using external beams aimed at the tumor. That’s exactly external beam irradiation, the general method used in most conventional radiotherapy sessions with a machine like a linear accelerator. Brachytherapy, by contrast, places radioactive sources inside or very close to the tumor, so it isn’t teletherapy. Proton therapy is a type of external beam radiotherapy that uses protons, and stereotactic radiosurgery is a highly precise external beam technique for specific targets. But the fundamental idea of teletherapy is external beam irradiation.