While 3DCRT developed, radiotherapy for prostate cancer gained widespread attention, as the technology and methods for interstitial brachytherapy became well-developed. Implantation of radioactive sources was performed under ultrasound (US) guidance, which provided good so tissue contrast and realtime feedback. Radiation oncologists and medical physicists were integrally involved in these procedures and gained a high level of skill and comfort with US imaging.2 It was in this context that US imaging for external beam radiation therapy (EBRT) was introduced.