Prostate cancer occurs when certain cells within the prostate gland grow in an uncontrolled, abnormal, manner. The prostate gland is the male organ located next to the bladder that contributes to the production of semen.
The American Cancer Society estimated more than 240,000 new cases of prostate cancer will be diagnosed in the United States and nearly 40,000 men will die from the disease in 2011. Prostate cancer is the second leading cause of cancer death in American men, behind only lung cancer.
When detected early, prostate cancer has more than a 90 percent cure rate. Because treatment is highly individualized, molecular imaging technologies are dramatically improving the ways in which prostate cancer is diagnosed and treated.
Treatment options include surgery to remove the prostate, radiation therapy and chemotherapy. Determining whether the prostate cancer has spread to the lymph nodes or other parts of the body is critical for making accurate decisions on whether and how to treat prostate cancer. In addition to improving the accuracy of prostate cancer diagnosis, molecular imaging tools can provide detailed information about the cancer that help patients and their physicians choose the best treatment option.
Molecular imaging technologies most commonly used to diagnose and guide the treatment of prostate cancer include a bone scan, the prostate-specific membrane antigen (PSMA) study and positron emission tomography (PET) scanning and PET in conjunction with computer-aided tomography (CT).
A bone scan is a diagnostic imaging test used to determine whether cancer has spread beyond the prostate to the skeleton. A tiny amount of radiotracer is injected into the patient’s bloodstream and accumulates predominantly in the bones where it can be detected by a specialized imaging device called a gamma camera. The resulting two-dimensional or three-dimensional images can reveal various processes such as bony fractures, infection, inflammation or the presence of prostate cancer cells.
A PSMA study, also called a ProstaScint® scan, is an imaging test to locate and determine the extent of prostate cancer. PSMA studies are performed on newly diagnosed prostate cancer patients to determine if the disease has spread to pelviclymph nodes. The study is also performed on patients who have had their prostate gland removed (prostatectomy) and have an increase in prostate-specific antigen (PSA) blood levels.
The study involves a special molecule called a monoclonal antibody developed in a laboratory and designed to bind to the prostate-specific membrane antigen on cancer cells. This antibody is paired with a radioactive material called Indium-111 that can be detected by a gamma camera. When injected into the patient’s bloodstream, the radioactive antibody travels and attaches to cancer cells. The gamma camera then produces three-dimensional images of the tumor and its location inside the body.
This study is performed over as many as three days. On the first day, the patient first receives an intravenous (IV) injection of the radioactive antibody. Imaging is performed in two sessions, separated by 24 or more hours. Each imaging session will last between two and four hours. The camera rotates around the patient, who remains still.
Physicians use molecular imaging to:
Scientists are working on new molecular imaging techniques that will: