Within the past few months there was a few SGRT short videos from the SGRT community meetings. In it Abdomen ROI was shown. It was basically an upside-down horseshoe. Make sure you do NOT include the stomach to account for breathing. The sides of the abdomen can be included. See attached pics. We reached out to Align Rt and got excellent response back that went from almost giving up on a Pancreases case to having almost no shifts after cbct. There is also a small spiral bound booklet that we had sitting near the Linac Console with similar images of recommended ROIs for the abdomen. See attached recommendations from Align Rt.
For cases in pelvis or lower abdomen, this is best:
No belly motion involved.
Still get enough AP and Lat information
If still have some belly movement, 2 options:
Take gated reference capture
Remove center area of the ROI; the ROI doesn’t need to connect in the middle
(between red dotted lines on the picture can be removed)
Keep in mind where the pillowcase is covering the patient. Should look like what’s green.
Remember, anything that shows up very green on the patient, is above where the surface should be. So if you see a lot of green within the ROI, your sheet is probably in the ROI.”