Non-Hodgkin's lymphoma (NHL), a cancer affecting the lymphatic system, is the second-fastest-rising cancer in the United States. Incidence rates have nearly doubled over the past 30 years. It is estimated that 360,000 Americans are currently living with NHL, and about 58,000 new cases are expected to occur in the United States this year. NHL is difficult to target and treat, as the disease can be found throughout the body in any blood-filtering tissue such as bone marrow. Patients typically have multiple relapses, meaning the cancer returns multiple times. This makes it very important for patients, their caretakers and their loved ones to talk to a physician about all available treatment options and to get access to the latest therapies. NHL patients are traditionally treated with chemotherapy and/or radiation therapy. While these treatments destroy cancer cells, they also destroy surrounding healthy cells. Additionally, chemotherapy and radiation therapy can take up to five months to complete and may require patients to stay in the hospital. An innovative class of drugs is harnessing the immune system to fight NHL. Radioimmunotherapy (RIT) is a promising area of cancer treatment that combines the specificity of monoclonal antibodies (similar to other antibodies the immune system makes to fight infection) with the cell-killing ability of radiation. When injected into a patient, these radiation-carrying antibodies seek out and bind to specific tumor cells, and then deliver radiation directly to those and surrounding cells. Two RIT products have been approved by the U.S. Food and Drug Administration (FDA). These products are completed in just one treatment regimen, lasting 1-2 weeks, so patients don't need to frequently return to their doctor's office for treatment on a weekly or semiweekly basis. Coupled with the fact that RIT can be administered on an outpatient basis, these therapies provide more convenience for patients and their families. Recent studies have shown that NHL patients may benefit most from these therapies when they are used early in the treatment of NHL, prior to multiple courses of chemotherapy. RIT delivers radiation to B-cells by recognizing and attaching to the CD20 antigen.