Fig. 1: Stereotactic body radiotherapy (SBRT) procedure for pulmonary artery denervation.

A Bama miniature swine undergo sequential chest computed tomography (CT) scans including a respiration gated 4-dimensional CT scan by using the Real-time Position Management Respiratory Gating System and a contrast-enhanced CT. B The target volume showing the pulmonary artery bifurcation area is depicted in red on five respirational phases (30-70%) of 4-dimensional CT, and the internal target volume is then created on the phase-averaged CT image for motion compensation. Contours of organs at risk include heart (blue), lungs (yellow), trachea (purple), esophagus (brown), aorta (cyan) and spinal cord (green). C In this treatment plan, the planning target volume (orange boundary), a 5 mm expansion on internal target volume (red boundary), is delivered with a dose of 20 Gy. The color scale shows the prescribed dosage encompasses the target while minimizing radiation to surrounding tissues with a rapid dose falloff. D At the time of treatment, the swine is positioned using lasers and skin markers. E Before radiation delivery, a cone-beam CT is acquired for image alignment with the planning CT. F Respiration gated SBRT is then performed by means of an image-guided linear accelerator.