Unity mr linac

This study was comprised of six steps (Figure 1). First, T2* image sets were acquired before and after the IV SPION-CA injection (Figure 1a) using a 1.5T Elekta Unity MR-Linac (Elekta; Stockholm, Sweden). The two sets of pre- and post-SPION T2* image sets were transferred to MiM software (v7.0.6, MIM Software Inc, Cleveland, OH, USA). The liver and tumor contours, manually delineated by a physician for radiation treatment planning, were then copied to both pre- and post-SPION T2* image sets (Figure 1b) in the MiM. Then, both liver contours of the pre- and post-SPION T2* image sets were extracted by binary masking for the voxel-wise 3D liver volumes (Figure 1c). Next, we calculated R2* relaxation rates [27 (link)] for R2* liver maps (Figure 1d) and auto-contoured FLPV (see Figure 1e). Finally, the FLPV was overlaid on the liver image. This allowed us to evaluate the efficiency of an in-house auto-contouring tool (Figure 1f) to improve conformal avoidance for further uses of FLPV during radiation treatment planning.

Twelve patients (aged 53–86 years) with primary (n = 8) and metastatic liver tumors (n = 4) were enrolled in an Intuitional Review Board (IRB)-approved study at Allegheny Health Network Cancer Institute (AHN-CI), Pittsburgh, PA, USA as part of a registered clinical trial study (NCT04682847). All patients underwent two MRI sessions using a 1.5T Philips MR scanner hybrid with Elekta Unity MR-Linac (Elekta; Stockholm, Sweden) before and after the IV injection of the SPION-CA Ferumoxytol^® (Feraheme, AMAG Pharmaceuticals, Waltham, MA, USA).

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.