Research Description

Virtual Patient Phantoms for Radionuclide Therapy Treatment of Non-Hodgkin's Lymphoma

Non-Hodgkin’s Lymphoma (NHL) is the fifth leading cause of cancer death in the United States, with approximately 56,930 new cases and 19,200 deaths in 2005. Typical treatments of NHL are dependent on both classification and staging of the disease and include chemotherapy, radiotherapy, immunotherapy or a combination of the three. Patients who have relapsed following these initial treatments now have the option of undergoing radioimmunotherapy with either 90Y-ibritumomab tiuxetan (ZevalinTM) or 131I-tositumomab (BexxarTM) that may provide a viable means of accomplishing improved response rates. One of the key problems in radioimmunotherapy of NHL is the lack of patient-specific dosimetry models needed to properly assess radiation doses received by individual patients being treated with these radiopharmaceuticals. I am using the new generation of hybrid patient phantom models created by UF as virtual models of patients with NHL who are being treated with either Bexxar or Zevalin radionuclide therapies. I am first implementing lymphatic node models in the adult UF hybrid phantom. I will use these phantoms to create a library of tissue doses for radionuclide sources located in each of the 9 lymph nodal regions including extrathoracic (head), cervical (neck), thoracic, breast (female only), mesentery (abdomen), axillary (armpit), cubital (elbow), inguinal (groin), and popliteal (knee). Specific absorbed fractions for I-131 and Y-90 will be generated for each lymphatic node region. Finally, I will look at a selected set of real patient data and use the phantom to model these patients and assess Bexxar dosimetry. Through the use of Monte Radiation transport studies, the radiopharmaceuticals’ effectiveness to target diseased lymphatic nodes will be characterized.