Radiation therapy.

come to Yale Cancer Center Answers with Drs. Ed Chu and Ken Miller. I am Bruce Barber. Dr. Chu is Deputy Director and Chief of Medical Oncology at Yale Cancer Center and Dr. Miller is an oncologist specializing in pain and palliative care. If you would like to join the discussion, you can contact the doctors directly. The address is canceranswers@yale.edu and the phone number is 1-888-234-4YCC. This evening, Dr. Chu is joined by Dr. Lynn Wilson. Dr. Wilson is a Professor, Vice Chairman and Clinic Director of the Department of Therapeutic Radiology at Yale School of Medicine and is here to discuss the use of radiation therapy for cancer treatment.Chu Why don’t we start off by discussing what radiation therapy is.Wilson Radiation therapy is the medical usage of radiation to treat cancer patients. There are some nonmalignant or noncancerous indications that would require the use of radiation treatment, but greater than 95% of the patients we treat have cancer of some sort. There are three different ways we provide radiation to such patients, it can be a part of a definitive cure, and it can be given adjuvantly, meaning after the primary treatment for a patient who may have had surgery as their primary treatment; we often use radiation after the surgical procedure. It can also be used in the palliative setting where we are trying to help a patient get relief from symptoms, whether it is bleeding or pain.Chu Let’s hold off on that for a moment and start with the basics. When I think of radiation therapy, I think of some machine focusing x-rays at a particular spot. Is that correct, or are there other ways of giving radiation therapy?Wilson There are several ways. Thinking of the machine focusing on a particular spot is really the primary modality, and that machine is called a linear accelerator, which has been around for many years. Different generations of technology have improved our ability to focus, but these machines actually generate electrons that are accelerated several feet down a pathway at very-very high speeds. They impact a tungsten target usually, and that produces a photon, which is an x-ray that is aimed very precisely at the part of the body that we are interested in treating. A photon is really just a group of very energetic particles that can interact with cellular DNA to damage cancer cells. When the beam comes out of this linear accelerator device, it is highly focused and extremely precise. There are other ways of delivering radiation therapy though. Brachytherapy is a term that refers to the implantation of radioactive seeds, for example, to treat prostate cancer, cervical cancer and a variety of other tumors. There are some relatively new, systemically given agents, which have monoclonal antibodies that are targeted at certain types of cells. Those have radioactive molecules attached to them so that the radiation can be delivered very, very specifically.Chu Are there any instances in which you might think of combining the x-ray form of radiation therapy and the brachytherapy approach?3:24into mp3 file http://www.yalecancercenter.org/podcast/Answers_Feb-17-08.mp3Wilson Yeah. There are of a variety. That is sometimes done in prostate cancer. Here at Yale, we have extensive experience in brachytherapy and a variety of different organ systems, particularly for GYN cancers and for head and neck cancers, and quite often we combine brachytherapy, the implantation of radioactive