Advancements in Radiation Therapy Treatment Workflows for Precision Medicine: A Review and Forward Looking

The conventional radiation therapy (RT) workflow, standardized over the past 3 decades, comprises 4 key phases: computed tomography (CT) simulation, treatment planning, quality assurance, and treatment delivery. This workflow relies heavily on the acquisition of planning CT scans for accurate 3-dimensional planning and patient positioning. Advancements in on-board 3-dimensional imaging, such as fan-beam or cone-beam CT and magnetic resonance imaging, now offer improved dosimetric accuracy directly or through synthetic CT generation, image deformation, and bulk density override techniques. These developments enable margin reduction, dose escalation, and online adaptive therapy, optimizing clinical outcomes. Additionally, various workflows integrating diagnostic CT and daily on-board 3-dimensional imaging, omitting the need for the planning CT acquisition, have shown feasibility, efficiency, and treatment accuracy. This article reviews simulation-omitted RT workflows, evaluating their procedures, dosimetric advantages, staffing requirements, billing challenges, and limitations. The convergence of improved imaging capabilities and adaptive strategies marks a significant opportunity for clinical innovation, offering pathways to refine RT workflows and enhance patient outcomes.