Practical considerations for implementing an adaptive or non-adaptive direct-to-unit radiotherapy programme

Introduction: Direct-to-unit (DTU) radiotherapy is an increasingly popular treatment paradigm in which a traditional computed tomography simulation (CT-sim) is foregone, and a patient’s diagnostic imaging (DI) is used for treatment planning. DTU can be delivered with (ART-DTU) or without online adaptation (non-ART-DTU). Herein, we describe considerations for the implementation of both non-ART and ART DTU. Innovation: DI selection criteria are dependent on the technique in use, as ART DTU image criteria may be less strict due to the capability to adapt to the anatomy of the day. Patient-related selection criteria for DTU include the ability to tolerate increased time on the table as well as the target location. Clinic needs and billing considerations must be addressed prior to formally installing a DTU programme. Discussion: DTU workflows will increase in complexity with the advent of new and intriguing technology. It is also anticipated that DTU will increase in popularity as efficient workflows for oligometastatic patients become more in vogue. Evaluation of this technique in prospective clinical trials is critical. Recommendations: DTU can be beneficial to patients, but great care must be taken when installing these workflows into the clinic. Close coordination between physicians and physicists and careful assessment of clinic demands are essential to success.