Radiologists do far more than read X-rays. They perform dozens of distinct procedures spanning diagnostic imaging, minimally invasive surgeries, cancer treatments, pain management injections, and emergency assessments. A radiologist is a physician with roughly 10 years of training, including medical school, residency, and often a fellowship. This distinguishes them from radiologic technologists, who operate the imaging equipment but do not interpret results or perform procedures.
Diagnostic Imaging Interpretation
The most common thing radiologists do is interpret medical images. Every time you get a CT scan, MRI, X-ray, ultrasound, or mammogram, a radiologist reviews those images and writes a report for the doctor who ordered the test. The technologist positions you and runs the machine, but the radiologist is the one who reads the results and identifies what’s normal, what’s abnormal, and what needs further investigation.
The main imaging types radiologists interpret include:
- X-rays: invisible energy beams that produce images of bones, joints, and internal organs on film or digital screens
- CT scans: specialized X-ray equipment paired with computers to produce detailed cross-sectional images of the body
- MRI scans: large magnets and radio waves that create highly detailed pictures of soft tissues, the brain, and joints without radiation
- Ultrasound: high-frequency sound waves that create real-time images of blood vessels, organs, and tissues
- Mammography: low-dose X-ray imaging specifically designed to examine breast tissue, now recommended by the USPSTF as biennial screening starting at age 40 through age 74
Radiologists also interpret nuclear medicine scans, including PET and SPECT imaging. PET scans use injected radioactive tracers to detect cancer, monitor its progression, and evaluate treatment response. SPECT scans are primarily used to diagnose and track heart disease, such as blocked coronary arteries, but they can also identify bone disorders and gastrointestinal bleeding.
Image-Guided Biopsies
When a scan reveals something suspicious, radiologists often perform the biopsy themselves. Rather than sending you to a surgeon, the radiologist inserts a needle through your skin and uses live imaging to guide it precisely to the target. This is called a percutaneous biopsy, and it avoids the need for open surgery in many cases.
CT-guided biopsies are common for lung lesions. The radiologist identifies the lesion on a scan, marks the shortest path on your chest, and inserts a needle along that route while watching its progress on the CT screen. Ultrasound-guided biopsies provide real-time imaging and work especially well for superficial, accessible lesions like thyroid nodules or breast masses. Core needle biopsies, which extract a small cylinder of tissue rather than just loose cells, are frequently performed under ultrasound guidance.
For prostate cancer, radiologists use a technique that fuses MRI and ultrasound images together. They first create a 3D model of the prostate from MRI data, pinpointing the suspected tumor’s location, then overlay that model onto live ultrasound during the biopsy. This fusion approach lets them target the exact spot rather than sampling the prostate randomly.
Interventional Vascular Procedures
Interventional radiology is a subspecialty where radiologists perform minimally invasive, catheter-based procedures that replace traditional surgery for many conditions. These physicians thread thin tubes through blood vessels, using live imaging to navigate inside the body.
Angiography is one of the foundational procedures. The radiologist injects contrast dye through a catheter and takes X-ray images of arteries and veins to find blockages, narrowing, or other vascular problems. When a blockage is found, they can treat it on the spot with angioplasty, inflating a small balloon inside the vessel to open it up. If the vessel needs structural support to stay open, they place a stent, a tiny mesh coil that expands against the vessel wall.
Radiologists also dissolve blood clots by injecting clot-busting medications directly to the site through a catheter, restoring blood flow to arms, legs, or organs. They can place filters inside large veins to catch blood clots before they travel to the lungs. And they remove foreign bodies from blood vessels using catheter-based retrieval techniques.
Embolization for Bleeding and Other Conditions
Embolization is a procedure where a radiologist deliberately blocks a blood vessel by delivering tiny particles, coils, or other materials through a catheter. This has a surprisingly wide range of uses.
In trauma situations, embolization is now a standard option for controlling active arterial bleeding from pelvic fractures or organ injuries. Rather than emergency open surgery, the interventional radiologist can thread a catheter to the bleeding vessel and seal it off, stabilizing the patient. For aneurysms or pseudoaneurysms, they pack the abnormal sac with coils until it’s excluded from circulation, sometimes using a “sandwich technique” that blocks flow both above and below the aneurysm to prevent blood from feeding back in through side branches.
Embolization also treats uterine fibroids. By cutting off the blood supply to the fibroid, the radiologist causes it to shrink without surgery. The same principle applies to vascular malformations, whether congenital or acquired.
Cancer Treatment Procedures
Interventional oncology has become a major part of what radiologists do. Two categories dominate: ablation and transarterial embolization.
Thermal ablation destroys tumors by inserting a needle-like probe directly through the skin into the tumor and applying energy. The three main types are radiofrequency ablation (RFA), microwave ablation, and cryoablation, which freezes the tumor instead of heating it. For small liver cancers (three or fewer tumors, each under 3 cm), RFA has shown results comparable to surgical removal. One major trial found five-year survival rates of about 70% for RFA versus roughly 75% for surgery, with virtually identical recurrence-free survival rates near 43% for both approaches.
Transarterial chemoembolization, or TACE, delivers chemotherapy drugs loaded onto tiny beads directly to a tumor through its blood supply, concentrating the treatment at the cancer site while minimizing side effects throughout the rest of your body. A related technique, radioembolization, delivers radioactive microspheres instead of chemotherapy. For liver cancer patients, radioembolization has achieved response rates above 80%. These procedures serve patients who aren’t candidates for surgery, transplant, or ablation, and they’re also used to shrink tumors before transplant.
Cryoablation has applications beyond liver cancer. Radiologists have used it for recurrent and metastatic soft tissue sarcomas in hundreds of cases, treating tumors percutaneously without the need for open surgical access.
Joint Injections and Pain Management
Radiologists perform therapeutic injections for joints throughout the body, using imaging guidance to place the needle precisely inside the joint space. These injections treat inflammatory conditions like rheumatoid arthritis, osteoarthritis, gout, tendonitis, and bursitis.
The medications injected typically include corticosteroids to reduce inflammation, local anesthetics for short-term pain relief, or hyaluronic acid to supplement the joint’s natural lubrication. Hyaluronic acid injections are particularly used for knee osteoarthritis and thumb-base arthritis when conservative treatments like physical therapy haven’t worked and surgery isn’t appropriate.
Shoulder injections target several specific conditions. Injections into the main shoulder joint treat osteoarthritis, frozen shoulder, and rheumatoid arthritis. Subacromial injections, placed in the space above the rotator cuff, address bursitis, impingement syndrome, and rotator cuff tendon inflammation. Elbow injections treat arthritis and persistent pain from inflammatory conditions, and can also provide relief after radial head fractures by draining fluid and delivering anesthetic.
Emergency and Trauma Imaging
In emergency settings, radiologists interpret critical imaging that guides immediate treatment decisions. One of the most time-sensitive procedures is the FAST exam (Focused Assessment with Sonography for Trauma), an ultrasound protocol used on trauma patients to rapidly detect internal bleeding or fluid around the heart.
The traditional FAST exam checks four regions in a specific order: the space around the heart (looking for cardiac tamponade), the right upper abdomen, the left upper abdomen, and the pelvis. All four areas are assessed for free fluid, which signals internal bleeding. The extended version, called e-FAST, adds evaluation of the spaces around the lungs to check for blood or air in the chest cavity. The entire exam takes only minutes and uses a standard low-frequency ultrasound probe, making it one of the fastest ways to determine whether a trauma patient needs emergency surgery.
Catheter and Access Procedures
Radiologists place various types of long-term catheters and access devices that other specialists then use for treatment. Central venous catheters inserted into large veins allow delivery of chemotherapy drugs, intravenous nutrition, or hemodialysis access. These are placed using image guidance to ensure the catheter tip sits in exactly the right position.
Gastrostomy tubes, which provide a feeding route directly into the stomach for patients who can’t eat by mouth, are another procedure radiologists perform. Rather than placing these surgically, the radiologist uses imaging to guide the tube through the abdominal wall and into the stomach. Drainage catheters for abscesses, fluid collections, or blocked bile ducts follow the same principle: image guidance replaces open surgery with a small puncture through the skin.
Nuclear Medicine Therapy
Beyond diagnostic scans, radiologists in nuclear medicine also deliver targeted radiation treatments. The approach works like a two-step process. First, a very small diagnostic dose of a radioactive tracer is injected and imaged to confirm the tracer concentrates in the right place. If the uptake looks appropriate, a much larger therapeutic dose of the same or a paired radioactive compound is given, delivering radiation directly to diseased tissue.
This theranostic approach, where the same molecule is used first for diagnosis and then for treatment, has expanded significantly in recent years. It’s used across a range of conditions from thyroid disease to certain advanced cancers, offering a way to deliver radiation with precision that external beam radiation can’t always match.