Computer Science Colloquium

The number of new cancer cases is expected to approach 1.2 million in the US this year. Approximately half of those patients will receive some form of radiation therapy (RT). The proportion of patients responding favorably to radiation therapy varies widely depending upon the type and advancement of the cancer. While the basic mechanism of radiation damage is well-known, there is still much work to be done in elucidating the steps to achieve maximum tumor response while sparing normal tissue. Many factors affect cell survival after radiation exposure. Densely and sparsely ionizing radiation have different effects upon irradiated tissue, and the dosage schedule can affect the ultimate response of tumors to RT. In addition, variations in the cellular environment, such as oxygenation, stage in the cell cycle and the presence of certain growth factors, can greatly affect the survival of individual cells to RT.

The unique cellular environment of tumors poses many hurdles to effective treatment of cancer. It has been demonstrated, in many transplanted and spontaneous tumors, that tumors exhibit an elevated interstitial fluid pressure. This hypertension restricts blood flow, and hence, delivery of oxygen and therapeutic agents. Radiation has been shown to affect the interstitial fluid pressure by changing the vascular and interstitial transport. This overview of radiation effects will briefly cover the fundamentals of radiation biology, tumor biology, and biological transport and will introduce some current research trends and topics in radiation oncology.

Dr. Znati received her B.S. in Chemical Engineering from the University of Illinois at Urbana-Champaign in 1987. She received her M.S. in Chemical Engineering in 1991 from Michigan State University where she designed and evaluated a rapid, industrially suitable enzyme-based biosensor. Dr. Znati received her Ph.D. in 1995, also in Chemical Engineering, from Carnegie Mellon University. For her dissertation, she examined the effect of radiation on the transport in tumors under the direction of Rakesh K. Jain. Dr. Znati furthered her investigations into the effects of radiation on tumors at the Allegheny Singer Research Institute in Pittsburgh. While at ASRI, she explored the combined effect of radiation and cryotherapy (exposure to extreme freezing conditions) on the survival of prostate tumor cells. Currently, Dr. Znati is working for a research and development firm near Pittsburgh refining magnetic separation techniques.