def variable_axis(self):
"""The axis that is varying.
There are five types of images:
* Reference : All axes are at 0.
* Gantry: All axes but gantry at 0.
* Collimator : All axes but collimator at 0.
* Couch : All axes but couch at 0.
* Combo : More than one axis is not at 0.
"""
G0 = is_close(self.gantry_angle, [0, 360])
B0 = is_close(self.collimator_angle, [0, 360])
P0 = is_close(self.couch_angle, [0, 360])
if G0 and B0 and not P0:
return COUCH
elif G0 and P0 and not B0:
return COLLIMATOR
elif P0 and B0 and not G0:
return GANTRY
elif P0 and B0 and G0:
return REFERENCE
else:
return COMBO
def z_offset(self):
"""The offset or distance between the field CAX and BB in z-direction (SI)."""
if is_close(self.couch_angle, [0, 360], delta=2):
return self.cax2bb_vector.y