This study was approved by the Ethics Committee of Chiba University Hospital (HK202304-07). The study enrolled three patients who underwent MRgOART for pancreatic cancer using Elekta Unity MR-linac (Elekta, Stockholm, Sweden). The patient details are presented in Table 1. At our hospital, MRIs are performed using a T2 navigator echo sequence under abdominal compression to measure respiratory movement. Patients 2 and 3 (conditions 2 and 3) who could be treated with butylscopolamine bromide (Buscopan®Injection, Paris, France) were administered the drug to suppress intestinal peristalsis. Butylscopolamine was deemed contraindicated in Patient 1 (condition 1) owing to a history of valvular heart disease. Moreover, our hospital incorporates contour delineation on images captured in multiple sequences into the workflow using the treatment planning support device MIM Maestro (MIM Software, 7.1.5, Cleveland, OH, USA) (condition 3) (9 (link), 13 (link)). The imaging sequences provided by the vendor were used for MRI acquisition, except for one sequence, T1-eTHRIVE. Table 2 presents the parameters of the imaging sequence. Figure 1 shows an example of a treatment image captured using the T2 3D Tra Navi sequence and provides an overview of our delineation study.
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