from pylinac import DRGS

# note the keys are the names of the ROIs and can be anything you like
custom_roi_config = {'200 MU/min': {'offset_mm': -20}, '300 MU/min': {'offset_mm': 20}}

my_drgs = DRGS.from_demo_images()
my_drgs.analyze(roi_config=custom_roi_config)
my_drgs.plot_analyzed_image()