December 7, 2001

Radiation Oncology department expanding

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Linda Norman submitted a grant proposal to develop a program aimed at promoting cultural and intercultural competence in nurses worldwide. (photo by Dana Johnson)

Radiation Oncology department expanding

Vanderbilt’s Department of Radiation Oncology is expanding its ability to serve patients in more ways than one.

New computerized “radiation-sculpting” technology is now being used at the Vanderbilt-Ingram Cancer Center to provide the most sophisticated therapy available, particularly for tumors that are difficult to treat because of nearby vital structures.

Construction is well under way on the Vanderbilt-Ingram Cancer Center at Franklin, Williamson County’s first radiation oncology facility, and Radiation Oncology recently started providing radiation therapy services at Gateway Health Systems in Clarksville.

And, at Vanderbilt, an expansion project nearing completion will significantly increase the size of the clinic and will reorient the space to improve patient flow and make patients’ visits more convenient.

“All of these things will position us to fulfill our obligation to provide the very best treatment possible, at the greatest convenience possible to patients and their families,” said Dr. Dennis Hallahan, professor and chairman of Radiation Oncology.

Features of the expanded Radiation Oncology clinic include:

• an additional 9,000 square feet, increasing the clinic area by about 50 percent.

• a reorientation of the entire clinic, with a larger, new reception area. Instead of entering Radiation Oncology from The Vanderbilt Clinic, patients will get to the clinic from the Frances Williams Preston Building Lobby. The elevators to the right of the lobby as patients enter from Capers Garage will lead directly to the waiting area.

• a total of 11 examination rooms, up from the current six.

• strategically placed waiting areas near the four treatment rooms, which will improve patient flow.

• a larger nursing station, with direct view of examination rooms, including rooms with glass doors where patients will await stereotactic radiosurgery. These patients require continuous monitoring and require a nurse to be with them at all times in the current clinic because the examination rooms are not in view of the nursing station.

• a separate physician workroom providing more privacy for dictation and other tasks.

• new offices for the Radiation Oncology faculty, freeing up office space in the current clinic area for computerized dosimetry, post-docs, residents, fellows and new faculty.

Radiation is a commonly used cancer therapy, whether alone or in combination with surgery and/or chemotherapy. The major challenge for radiation oncologists is to deliver the highest possible dose to the tumor while protecting the surrounding normal tissue, especially critical structures such as the heart, lungs or spinal cord.

With more traditional systems, the target area must include some surrounding normal tissue to ensure that the entire tumor is included. That, in turn, limits the dose that can be delivered to the tumor.

The new technology being used at Vanderbilt, called Intensity Modulated Radiation Therapy (IMRT), uses three basic components to improve delivery of radiation and enable physicians to push the dose to the tumor higher.

First, complex computerized treatment planning software is used to determine more precisely the number and angles of radiation beams to deliver the maximum cancer-killing dose throughout the tumor but spare adjacent healthy tissue.

With traditional systems, various images are combined by a computer to determine the volume of tumor to be treated, but the medical physicist has to figure out the combination of beams that will provide the dose of radiation that has been prescribed.

The IMRT software, which has been used at Vanderbilt-Ingram since October, enables the radiation oncologist to program the treatment volume and the desired dosage of radiation. Typically, this process results in a great number of treatment fields, allowing more precise delivery of the maximum dosage.

The second essential component is a linear accelerator (the machine that generates and delivers the radiation beam) that can conform the X-ray to the shape of the tumor. Vanderbilt-Ingram has had this equipment, called a “multi-leaf collimator,” for about two years. The collimator is a series of 120 metal fingers or leaves, about a quarter of an inch wide, which are individually controlled by a computer to move in and out of the field for specific periods of time, effectively filtering the beams of radiation in a precise pattern.

With traditional accelerators, specially made lead blocks are used to conform the X-ray beam to the shape of the tumor. Several blocks of different shapes may be used to treat a patient in order to tailor the dosage to the tumor during the total treatment, but while each block is in place, the dose of radiation is consistent all the way through the field. In order to shape the total dosage, the treatment must be periodically stopped to change the blocks.

With IMRT, the multi-leaf collimator allows shaping of the beam continuously throughout the procedure. The result is a varied dosage throughout the field, not only from side to side and top to bottom but also from front to back.

The third component is a strict quality control system, which includes imaging and measuring systems.

The same IMRT technology will also be available in the Vanderbilt-Ingram Cancer Center at Franklin, which is scheduled to open in February.