General principles for prescribing, recording and reporting a therapeutic irradiation

Exchange of clinical information is essential for the development and progress in radiation oncology. This goal can be achieved only through a general harmonization on methods of reporting. The ICRU has been involved for several decades in a continuous effort to harmonize reporting of dose and to standardize methods used to determine the doses and points or volumes where these doses are delivered. Requirements for reporting proton and ion beam therapy should, in principle, be as similar as possible to reporting the current radiation therapy modalities. However, proton and ion therapy have their own clinical and technical uniqueness: in particular, they require definition of new clinical, radiobiological and technical concepts, and strict quality assurance programmes for efficient and safe clinical application. The current ICRU definitions of volumes are reviewed: Gross Tumour Volume (GTV), Clinical Target Volume (CTV), Planning Target Volume (PTV), Organs At Risk (OAR), Planning organ at Risk Volume (PRV), treated volume and reference volume. The irradiation conditions and the absorbed dose should always be reported together with the point(s) and/or volume(s) where the dose is delivered. In addition, the weighting factor W(RBE) introduced to take into account the RBE, and the related weighted dose D(RBE) have to be reported.