The technique the doctors are most likley to use in this case would be "a magnetic resonance imaging (MRI) scan".
Magnetic resonance imaging (MRI) is a test that utilizes great magnets, radio waves, and a PC to make detailed pictures inside your body.
Your doctor can utilize this test to analyze you or to perceive how well you've reacted to treatment. Not at all like X-beams and CT scan, a MRI doesn't utilize radiation.
MRI enables a doctor to analyze a disease or damage, and it can screen how well you're doing with a treatment. X-rays should be possible on various parts of your body.