Until recently, a patient undergoing cancer surgery might have to be transported to a different area of the hospital to receive radiation treatment -- or Intraoperative Radiation Therapy -- at the time of surgery.

Intraoperative Radiation Therapy (IORT) is a technique that has been used for cancer patients since the mid-1980s. More than 11,000 patients have been treated with IORT, which has been effective in helping to contain the growth of cancer. The use of radiation therapy at the time of surgery, however, has also meant added time and inconvenience as patients are transported four floors from the operating room to the radiation facility and back again. In addition, scheduling in both the surgery and radiation departments becomes more complex when surgical cases require radiation.

Now an innovative mobile electron beam system called the Mobetron, the first of its type, is in use at UCSF Medical Center. The Mobetron allows cancer patients to receive radiation therapy without having to leave the surgery suite.

Developed by Intraop Medical Inc, in Santa Clara, the Mobetron is expected to cut the time, cost and complexity of transporting surgical patients to the radiation facility. In addition, it will provide a way for the oncology team to administer precision high dosages of radiation that potentially could be more effective than what a patient might receive during conventional radiation therapy.

"This is going to be a major tool in cancer surgery where you have tumors with a high risk of advancing," said Ted Phillips, chairman of the UCSF radiation oncology department, who noted that there is a high local recurrence rate for such tumors.

The Mobetron has been used in more than 15 procedures at UCSF to date, including on patients with head and neck cancer and mesotheliomas (chest or abdominal cavity cancers). Because it produces an electron beam -- rather than the photon beam in conventional x-ray methods -- the Mobetron allows physicians to deliver a large dose of radiation safely to the patient.

"This offers something to patients where conventional therapy hasn't worked. It offers them another chance to have their cancer controlled," said Richard Krieg, UCSF clinical professor of radiation oncology, who has used the Mobetron in several cases with head and neck cancer.

Phillips also noted that because of the precision of the beam and type of radiation, patients can be treated in an ordinary operating room without the expense of concrete shielding.

"It's much easier and less cumbersome than transporting patients to our radiation facility," said David Jablons, UCSF chief of general thoracic surgery, who has used the Mobetron in surgeries involving mesothelioma. "The high-energy electron beam is as good or better than the accelerator downstairs," he said referring to the conventional radiation treatment facility located on the ground floor of the UCSF Medical Center.

The Mobetron was developed by a team of engineers from Intraop with input from physicists, surgeons and radiation oncologists from throughout the world. Weighing 2,500 lbs. (about one-eighth the size of conventional radiation accelerators), the Mobetron is built to fit in most operating rooms, and can be moved from one operating room to another.

Funding for the development was obtained initially from a National Cancer Institute grant. Under terms of a recent agreement, Siemens Oncology Care Systems, a division of Siemens Medical Systems Inc, will begin manufacturing the Mobetron.

by Dale Martin

1st appeared 3/10/98

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