Oncologists take care of patients who have cancer by treating the cancer itself, as well as the symptoms caused by the disease. Often, oncologists take part in clinical trials, using new and experimental treatments for cancers that are otherwise incurable. 

Anesthesiologists are trained to manage patient pain and vital signs during surgery.  They also often manage medical emergencies in the hospital, such as cardiac arrest and sudden breathing problems. 

A radiologist is a physician who is trained in looking at and interpreting diagnostic tests. Often, the treating physician must look at the test as well, but the radiologist's interpretation and report can offer additional information or advice for further testing.

Neurologists are doctors who take care of patients with medical conditions that affect the brain, spine, or nerves.  Neurologists see patients who have complex medical disorders, such as Parkinson's disease, multiple sclerosis, and neuropathy. They also take care of patients who have common problems such as migraine headaches and dizziness.

Pulmonologists treat the cardio-pulmonary system, which consists of the organs that work together to help a person breathe, such as the lungs and heart. Their training is often critical care medicine in conjunction with pulmonary disease. As a result, they may work as intensivists (physicians who cover the intensive care unit) in addition to seeing patients in an office setting to treat breathing disorders, severe allergies, lung problems, and other respiratory diseases.

Otolaryngologists, also known as otorhinolaryngologists, are more commonly referred to as ENTs, which stands for "ear, nose, and throat." Otolaryngology is another field that entails a combination of surgical skills and office-based medicine and treatment. ENTs cover a lot of issues including sinus problems, allergies, head and neck cancers, and more. As a result, many physicians sub-specialize in a specific area of otolaryngology.