Technological breakthroughs improve patient care at Travis AFB

Published Feb. 1, 2012
By Nick DeCicco
60th Air Mobility Wing Public Affairs

TRAVIS AIR FORCE BASE, Calif. -- From the time the stethoscope was introduced in 1816, innovation has played a role in improving medical practices.

While technology has improved many processes and departments at Travis' David Grant USAF Medical Center, one in particular is the Joint Radiation Oncology Center.

"We are tech dependent," said Dr. (Col.) Roland Engel, 60th Diagnostics and Therapeutics Squadron joint radiation oncology center staff physician. "Our technology has radically changed in my time at Travis and throughout my career."

A major change occurred in the last two years with the arrival of linear accelerators-- devices which deliver doses to patients in a precision measured to fractions of a millimeter.

Staff members use a network of computers and programs to administer doses of radiation and operate the devices.

"The goal is to maximize the dose to the tumor and minimize the side effects," said Charles Hersey, a medical dosimetrist who works in the center.

The accelerators improve not just the accuracy of the doses, but have decreased treatment time, Engel said.

For Dave DeMauro, 65, a prostate cancer patient, the treatment is not invasive.

"There's nothing to it," said DeMauro, who served 18 months in the Army in Berchtesgaden, Germany, after being drafted in 1966.

On a recent visit to the JROC, DeMauro laid down inside the arm of the accelerator, which rotates around a patient to deliver the treatment. Metal markers injected into DeMauro help staff members align him so he matches images taken of his body such as X-rays and computed tomography scans. This assures the treatment is delivered accurately down to the sub-millimeter.

In order to apply the proper doses, dosimetrists such as Hersey discern boundaries within a patient's body tissues on a computer screen, marking off which areas will require different levels of radiation. Staff members refer to this as "dose painting."

"We give prescription like other doctors give meds," Engel said. "We determine how much and how often. The computer won't exceed the limit or prescription."

Hersey said part of the radiation is even delivered into the healthy tissue surrounding the tumor to prevent cancer from recurring.

In the accelerators, 120 metallic leaves, each driven by their own motor, separate the blasts of radiation each time its arm rotates. Because the arms of the accelerators move around a person's body, doses can be disseminated differently depending upon the angle.

"We can tailor high doses so they fit even oddly shaped regions," Engel said. "The dose for a lump is higher than for microscopic, but with this system they can get both at the same time It's a very tailored, very dynamic thing."

For prostate cancer patients such as DeMauro, computerization has brought the percentage of recurrence down from 15 percent to 5 percent.

The department introduced the accelerators in 2010, but Engel said the progress already is measurable.

Before the machines' introduction, physicans and dosimetrists imaged patients once a week and relied on what Engel called the boney anatomy seen in a Computed Tomography scan.

As a tumor shrinks, the department is able to rescan a patient's body and replan treatment on a daily basis, a process also unavailable to members of the center in the past.

Successful early stage lung cancer treatment has risen from 80 percent to 20 percent for appropriate patients.

Also, patients were previously referred to DGMC's hyperbaric chamber to deal with the side effects, but Engel said they are now sent intermittently.

The overall quality of the care the center can provide has improved, Engel said.

"The point is to make sure we get the dosage right so we avoid doing it ever again," Engel said. "Radiation therapy nowadays is considerably better than 10 years ago."