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‘Virtual Patient’ Software Unveiled

USC/Norris physician Oscar Streeter Jr.

Photo by Irene Fertik

THANKS TO A NEW software program created by USC/Norris Comprehensive Cancer Center radiation oncologists, cancer patients everywhere may soon have access to state-of-the-art radiation treatment that has been available almost exclusively at major medical centers.

Medical physicist Melvin Astrahan, associate professor of radiation oncology, first created the software to help Norris staff physicians plan and deliver high-tech radiation treatments to patients with greater ease and efficiency. Over the last five years, Astrahan has continued to develop and test the software in collaboration with USC/Norris physician Oscar Streeter Jr., associate professor of clinical radiation oncology.

The program was licensed to SSGI/Prowess Systems, a Chico-based company that makes software for radiation therapy treatment planning. Pro-Sim VPS (virtual patient simulator), a simplified program based largely on the USC/Norris software, was sent out this month to selected users for testing and is awaiting approval from the U.S. Food and Drug Administration.

SSGI spokesman Lee Potts said they expect Pro-Sim VPS to be officially released in May. Later this year, they will release a second program, 3D Treatment Planning, also based on Astrahan’s original design.

The software allows physicians to create a computer simulation of a real patient and a proposed treatment protocol. The “virtual patient” lets doctors more easily plan three-dimensional conformal radiation treatment, in which therapists manipulate radiotherapy beams to precisely fit the shape of each patient’s tumor.

By delivering many beams from different angles, doctors maximize the radiation reaching the tumor, while minimizing the exposure of the surrounding healthy tissue. As a result, patients treated with the conformal therapy suffer much fewer side effects than they would with traditional radiotherapy.

With the new software, doctors like Streeter first visualize a tumor in three-dimensional space, working with a digital image of a patient from a computed tomography (CT) scan. The CT images are electronically transferred to the radiation oncology computer network, so that physicians can view the “virtual” patient’s tumor in 3-D. Then, they plan to use simulations to optimize the paths of the radiation beams. On the computer, a radiation oncologist can view not only a virtual patient during the planning stages, but also a virtual treatment machine and couch as if the patient were actually inside the linear accelerator, the machine that delivers the high-energy beams.

THE OLD STYLE of radiation treatment requires patients to wait for hours while radiation oncologists interpret CT scans and then laboriously plan the placement of beams. The planning has to take place with the patient in the treatment room, lying stock-still on a hard table. “Now the patient can go home and come back when we’ve finished the plan,” Streeter said. “Using the virtual patient makes a huge difference in how physicians work and how patients experience the treatment.”

Working with Streeter, Astrahan designed the Norris program to be easy to use and learn. “We have a collaboration of ideas here,” Astrahan said. “I do the development and create the software. Oscar uses the program to actually plan treatment of patients, so he brings ideas about features that physicians would like to see, about what the program should be.”

“With this program,” Streeter said, “we’ve reduced the time spent from four to five hours per patient to 10 to 15 minutes per patient. With multiple computers, we can provide it to every radiation oncologist on staff, and thus to all patients. No other place that we know of offers this to all of their patients.”

And distribution of the new software program may help smaller hospitals gain greater access to this quality of care, since it will make 3-D treatment planning more convenient and cost-effective for more patients, the USC/Norris team says. Existing programs for conformal radiotherapy planning require using a work station and working on just one case at a time. Astrahan’s program enables radiation oncologists to plan treatment at their own desktop computers.

The programs and case files can even be loaded onto laptop computers, which means that physicians can see their virtual patients whenever they have time – even at home or waiting for a meeting. “I can have dinner with my family and not have to come back to the hospital to finish up a treatment plan,” Streeter said.

‘Virtual Patient’ Software Unveiled

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