Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268

Thu., November 10, 2005, at 3:00 p.m. (refreshments at 2:40 p.m.)

186Re: An Isotope for Radioimmunotherapy in the Treatment of Cancer

Suzanne Lapi, Simon Fraser University, Vancouver, BC, Canada
Bldg. 6008 Conference Room

Radioimmunotherapy is already making an impact on the lives of many patients diagnosed with cancer. Two radiolabeled antibodies, which are marketed under the trade names Zevalin (90Y) and Bexxar (131I), are currently being used in the US to target non-Hodgkin's lymphoma. Research into new radioisotopes and the impact of specific activity on these preparations is key to the development of this promising type of cancer therapy.

186Re has been considered a good candidate for radiotherapy because it decays by beta-emission and has a half-life of 3.7 days. This isotope is also a good choice because it is chemically similar to 99mTc, which has already been extensively studied. 186Re is commonly produced in reactors via the 185Re(n,gamma) reaction. This results in a product with very low specific activity, which is not optimal for therapeutic applications.

The method of production of a high specific activity of 186Re using low energy protons or deuterons has not been used due to the low cross sections of the 186W(p,n) and 185W(d,n) reactions. It has been suggested that high specific activity 186Re could be obtained from a neutron irradiated target of 185Re by using a mass separator to extract radioactive 186Re free from stable 185Re.

This talk will begin with a brief overview of radioimmunotherapy and how it is used in the treatment of cancer. The importance of specific activity will be addressed and studies to determine the therapeutic efficacy of 186Re labeled antibodies of varying specific activity will be described. Finally, preliminary results from experiments with the OLTF into development of a Rhenium radioactive ion beam will be discussed.