Successful radiation treatments of cancer depend critically on the knowledge of the precise amount and location of radiation given to a patient, and the opportunity for the radiation oncologists to exchange this information and disseminate the results achieved. As far as dose calculation is concerned, ICRU published several reports recommending dosimetry protocols for photon beams, i.e., Reports 17 (1970), 23 (1973), 24 (1976), 64 (2001), for electron-beams, i.e., Reports 29 (1978) and 71 (2004), for neutron beams, i.e., Report 45 (1989), for proton beams, i.e., Report 59 (1998) and more recently for light ion beams, i.e., Report 93 (2016).

In addition to accurate dosimetry protocols, an important aspect in radiation oncology is the necessity to communicate and understand each other to facilitate the exchange of information on patient treatment data among colleagues and peers. In this respect, ICRU has been pioneering in publishing reports on prescribing, recording and reporting therapy with photons, i.e., Reports 50 (1993), 62 (1999) including IMRT, i.e., Report 83 (2010) and stereotactic treatment, i.e., Report 91 (2014). Reports on different beam quality have also been published for electrons, i.e., Report 71 (2004), protons, i.e., Report 78 (2007), and light ions, i.e., Report 93 (2016). Last ICRU also covered interstitial therapy with Report 58 (1998), and brachytherapy for cervix tumors, i.e., Reports 38 (1985) and 89 (2016). In all these reports, special attention was brought to introduce and define the concept of target volume and organ-at-risk [e.g., Gross Tumor Volume (GTV), Clinical Target Volume (CTV), Planning Target Volume (PTV), Organ at Risk (OAR)], which are being used throughout the world in daily radiotherapy practice. The implementation of these concepts are being presently revisited to better integrate their probabilistic nature.

Last, progress in radiation therapy requires the ability to compare clinical results achieved in different centers using different radiation modalities and protocols. Thus, a common language for reporting fractionation schedules, doses, and techniques is required for optimal patient management. ICRU is devoting considerable effort in that direction with a report in preparation for 2021.