Technical recommendations for implementation of Volumetric Modulated Arc Therapy and Helical Tomotherapy Total Body Irradiation

•Conformal multi-isocenter Total Body Irradiation is being introduced in an increasing number of radiotherapy departments.•Due to its complexity, implementation and setup techniques are heterogeneous and consensus guidelines would help to standardize practices.•Consensus recommendations increase collaboration, avoid individual implementation errors, and make evaluation within research possible.•Early adopters joined to form consensus regarding technical recommendations for Volumetric Modulated Arc Therapy and Helical Tomotherapy TBI. As a component of myeloablative conditioning before allogeneic hematopoietic stem cell transplantation (HSCT), Total Body Irradiation (TBI) is employed in radiotherapy centers all over the world. In recent and coming years, many centers are changing their technical setup from a conventional TBI technique to multi-isocenter conformal arc therapy techniques such as Volumetric Modulated Arc Therapy (VMAT) or Helical Tomotherapy (HT). These techniques allow better homogeneity and control of the target prescription dose, and provide more freedom for individualized organ-at-risk sparing. The technical design of multi-isocenter/multi-plan conformal TBI is complex and should be developed carefully. A group of early adopters with conformal TBI experience using different treatment machines and treatment planning systems came together to develop technical recommendations and share experiences, in order to assist departments wishing to implement conformal TBI, and to provide ideas for standardization of practices.