radiologist
A medical doctor who specializes in diagnosing and treating diseases using medical imaging (X-rays, CT, MRI, etc.).
He works at a hospital as a radiologist.
放射線技師 is a radiological technologist who operates imaging equipment, while 放射線科医 is a physician who interprets images and makes diagnoses.
Compound of 放射線 (radiation) + 科 (department) + 医 (doctor).