February 21, 2007

Precision Targeting Lowers Risk While Directing Higher Dose Of Radiation At Tumors

A new radiation treatment system at Rush University Medical Center addresses two important aspects of cancer treatment simultaneously with one device: confirming the exact location of a tumor during each treatment session and then delivering treatment. This approach is known as image guide radiation therapy (IGRT).

The TomoTherapy Hi-Art System combines 3-D imaging from computerized tomography (CT scanning) with precisely targeted radiation beams. Because of the remarkable accuracy of the system it is possible to direct a higher dose of radiation at a tumor with a lower risk of affecting surrounding tissues and organs.

Precise patient positioning is crucial for effective radiation treatment. With the TomoTherapy system, CT scan slices are taken through the area being treated as the patient lies on the treatment table. These slices are used to image the location of the tumor and to make immediate adjustments, if needed, to make sure the radiation is directed exactly to where it should be.

"This is extremely useful since a patient's tumor position may change slightly from session to session," said Dr. Ross Abrams, chairman, department of Radiation Oncology at Rush.

Immediately after determining the correct position, the TomoTherapy system delivers a very sophisticated form of intensity modulated radiation therapy (IMRT). As the patient slowly moves continuously through a rotating ring, the radiation beam makes a spiral pattern around the patient. Each time the linear accelerator, the mechanism that creates the radiation beam, comes around it is directing the beam at a slightly different plane targeting the tumor with optimal levels of radiation while minimizing the dose to healthy areas.

"It is an advantage to have a radiation treatment beam projected into the tumor continuously as it rotates, rather than having a limited number of fixed beams," said Abrams. "We can adjust the size, shape, and intensity of the radiation beam to target the radiation to the size, shape, and location of the patient's tumor," said Abrams.

According to Dr. Adam Dickler, a radiation oncologist at Rush who specializes in the treatment of prostate cancer, TomoTherapy provides the versatility he needs to optimally treat patients. "During a course of radiation treatment, a patient's prostate may move significantly due to changes in the amount of urine in the bladder or stool in the rectum. This technology allows us to adjust to the daily movement of the prostate."

Initially, the TomoTherapy System is being used on prostate cancer, head and neck cancer, brain cancer, and sarcomas. These are areas where precise radiation delivery is especially important. However, eventually it will be used to treat other cancers, including breast cancer.

The Department of Radiation Oncology at Rush is in the midst of a multimillion dollar renovation, improving the appearance of the treatment area and waiting areas and bringing in new, state-of-the art equipment. The department offers advanced radiation therapies including three-dimensional conformal radiotherapy, intensity-modulated radiation therapy, stereotactic radiosurgery, total skin electron irradiation and total body irradiation.

Rush University Medical Center, Chicago, Illinois

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