ABSTRACT
The purpose of radiotherapy is to eradicate a tumor with high-energy X-rays while sparing the surrounding organ-at-risks (OAR) as much as possible. Typically, there will always be some discrepancy between the planning situation and treatment. Coinciding with the initiation of the electronic portal imaging devices (EPID) development, a number of workshops were held that eventually evolved into the recurring Electronic Portal Imaging (EPI) conferences. This meeting series is still continuing to date-every other year, mostly in Europe, United States, or Australia. Over the years, the meetings changed focus from detector development to image analysis, clinical application, setup error correction protocols, treatment margins, etc. The most obvious design for an EPID is to combine a fluorescent screen with a video camera similar to the devices used for low-energy X-rays. The field of EPI initially focused on detector development, but eventually covered all aspects of image-guided radiotherapy such as image processing, decision protocols, and treatment margins.
