Cardiologists and radiologists are physician specialists. Cardiologists specialize in medical care of the heart and blood vessels. Radiologists specialize in using medical imagery to diagnose various health conditions and to determine the best ways to manage them. Both cardiologists and radiologists work in a mix of medical settings, including hospitals, physician offices and health clinics.

Cardiologist Basics

Through examinations, interviews and tests, cardiologists work with patients to determine their heart health. They consider such aspects of a patient's condition as blood pressure and weight and the condition of the heart, lungs and blood vessels, according to the American College of Cardiology. Cardiologists do not perform surgery, though they may perform a cardiac catheterization to examine the heart and perhaps relieve a blockage. Cardiologists collaborate with other physicians, including surgeons, to provide care for patients. Cardiologists may prescribe medicine or lifestyle adjustments, such as a change in diet or exercise regimen, to improve a patient's condition.

Radiologist Basics

Radiologists have access to a number of different imaging tools to examine a patient. These include X-ray, ionizing radiation, radionuclides, ultrasound, electromagnetic radiation and image-guided intervention, according to the Association of American Medical Colleges. Radiologists are trained to read the images these tools produce to determine patients' illnesses and injuries and to work with other physicians on the most effective treatment options. Radiologists may specialize in radiation oncology, neuroradiology, nuclear radiology, pediatric radiology or vascular and interventional radiology.

Education and Training

Both cardiologists and radiologists must first earn their undergraduate and medical degrees. Cardiologists subsequently serve a three-year residency in internal medicine and then a minimum of three more years in training related to cardiology and possibly a chosen subspecialty, according to the American College of Cardiology. Radiologists must complete a five-year residency that includes at least four years of diagnostic radiology, according to the Association of American Medical Colleges. Radiologists who want to be certified in a subspecialty must spend an another year training in that area.

Pay

Cardiologists and radiologists both are among the most highly paid physician specialties. Radiologists earned an average income of $439,384 in 2011, according to a Modern Healthcare survey. Invasive cardiologists, who perform procedures such as cardiac catheterization, tend to make more than noninvasive cardiologists. In 2011, invasive cardiologists earned $479,275, while noninvasive cardiologists earned an average wage of $424,359. Invasive cardiologists were the second highest-paid specialty in the survey, surpassed only by orthopedic surgeons.