Imaging Technologies Combine To Better Target Tumors

Seven years after successful treatment for breast cancer, Janet Freeman learned another tumor appeared in her chest near nerves that led to her arm.

Her radiation oncologist carefully planned where to aim the radiation beam.

"So if it were not pinpointed very precisely, I guess my nerves could be damaged," she said.

Poorly-targeted radiation can also damage other vital tissues.

In the past, using fuzzy X-ray images, aiming the radiation beam could be hit or miss. Now with IGRT, or Image Guided Radiation Therapy, there is no guesswork.

Combined images from CT and PET scans guide the beam to the target.

Dr. Pete Hoffman, a radiation oncologist at Rex Hospital, uses new computer software to fuse the two scans. A mild radioactive tracer is injected into the blood stream. The tumor absorbs the tracer and shows up clearly on the PET scan.

"The activity is very bright, so it helps you determine where the cancer is and the extent of involvement in the tissues," Hoffman said. "It helps us to better focus our treatment so that we minimize the side effects of therapy and maximize our control of the cancer."

The tumor caused Freeman to lose sensation and movement in her arm and hand, but the image-guided treatments are helping.

"Within two weeks, I could feel a difference in the motion of my arm and in the strength of my arm," Freeman said.

The IGRT has proven itself useful in treating several types of cancerous tumors including lymphomas, and cancer in the colon, lung and breast.