Ventilatory motion management strategies in conscious individuals for improved radiotherapy and diagnostic imaging: an evidence map

BACKGROUND: Respiration-induced motion hampers accurate radiotherapy, and diagnostic image quality. Ventilatory motion management strategies (VMMS, i.e. continuous positive airway pressure, jet ventilation, non-invasive mechanical ventilation, percussive ventilation and high-flow nasal oxygen) have emerged as novel respiratory motion management strategies. This evidence map aims to summarise these approaches of non-invasive respiratory motion-control to assess feasibility, comfort, potential benefits for radiotherapy and diagnostic imaging, and the identification of current research gaps. METHODS: Medline, Embase, and Web of Science were searched for publications evaluating VMMS in healthy volunteers or patients to reduce respiratory motion or alter organ positioning during radiotherapy or imaging, published in Dutch, English, or German until October 2024. RESULTS: We identified 114 studies, of which 55 were included for analysis. Ventilatory motion management strategies, ventilator settings, and patient groups appeared to be heterogenous. . Most (50/55) studies reported reduced motion, favourably changed organ shape/position and/or prolonged breath-hold durations, resulting in reduced organs-at-risk dose, improved time-efficiency or higher diagnostic image quality. In 17/55 studies, most subjects found ventilation comfortable. CONCLUSIONS: VMMS are feasible, versatile and highly beneficial in radiotherapy and diagnostic imaging, warranting further prospective comparative studies. Identified research gaps included lack of clinical outcomes and standardized reporting and terminology.