Stopping ntm treatment

Son has ntm, we passed the year mark so team decided to try to stop treatment and see what happens to his cultures. I have asked when they are doing another ct scan and they said they don’t need one. It doesn’t make sense to me as guidelines specify ntm pulmonary disease must be assessed with ct scan and that xrays shouldn’t be used because don’t highlight ntm changes in the lungs? Thx Edited to add he has ntm abs/abs