Radiology is the branch of medicine that uses imaging to diagnose and treat disease. It covers X-ray, ultrasound, CT, MRI and nuclear medicine, and is practised by radiologists — specialist doctors who interpret the images. The word comes from 'radiation', but not all radiology uses it: ultrasound and MRI use none. Radiology has two broad arms: diagnostic (imaging to find out what's wrong) and interventional (using imaging to guide treatment).
Key takeaways
- Radiology is the medical field that uses imaging to diagnose and treat disease.
- It covers X-ray, ultrasound, CT, MRI and nuclear medicine.
- Radiologists — specialist doctors — interpret the images.
- Not all radiology uses radiation: ultrasound and MRI use none.
Radiology is the branch of medicine that uses imaging to diagnose and treat disease and injury.[1] If you’ve ever had an X-ray, ultrasound, CT, MRI or a nuclear medicine scan, you’ve used radiology.
The one-line definition
Radiology is the use of medical imaging — and image-guided procedures — to work out what’s happening inside the body and, increasingly, to treat it.
The word comes from “radiation,” because the field began with X-rays. But that’s a historical hangover: not all radiology uses radiation. Ultrasound (sound waves) and MRI (magnets) use none at all.[2]
What it covers
The main imaging tools are:[2]
- X-ray — quick pictures, best for bones and the chest;
- CT — detailed cross-sections built from X-rays;
- Ultrasound — real-time sound-wave images (no radiation);
- MRI — very detailed soft-tissue images with magnets (no radiation);
- Nuclear medicine (incl. PET) — a tracer showing how organs work.
Two arms: diagnostic and interventional
Radiology has two broad sides:[1]
- Diagnostic radiology — imaging to find out what’s wrong (the everyday scans).
- Interventional radiology — using imaging to guide treatment through tiny incisions (biopsies, drainages, stents, treating aneurysms).
A radiologist is the specialist doctor who interprets the images and, for interventional work, performs the procedures. For a fuller beginner’s tour of how each scan works and who’s who, see our introduction to radiology.
Frequently asked questions
What does “radiology” actually mean?
It’s the medical field that uses imaging to diagnose and treat disease. The name comes from “radiation” (X-rays), but modern radiology also includes radiation-free tools like ultrasound and MRI.[1]
Is radiology the same as medical imaging?
Almost — “medical imaging” usually refers to the scans themselves, while “radiology” is the medical specialty that performs and interprets them. In everyday use the terms overlap.[2]
Does all radiology involve radiation?
No. X-ray, CT and nuclear medicine use ionising radiation; ultrasound and MRI use none.[2]
Sources
- RadiologyInfo.org (RSNA & ACR) — What does a radiologist do? — www.radiologyinfo.org/en/info/article-your-radiologist
- healthdirect (Australia) — Diagnostic imaging — www.healthdirect.gov.au/diagnostic-imaging
