RADIO SURGERY TECHNOLOGY TREATMENT MORE COMFORT
A new stereotactic
radiosurgery system provides the same or a higher level of accuracy in
targeting cancer tumors -- but offers greater comfort to patients and the
ability to treat multiple tumors at once -- when compared to other radiation
therapy stereotactic systems, according to researchers at Henry Ford Hospital
in Detroit.
Radiosurgery is just
one shot of precision radiation with a very high dose to treat tumors,"
says study lead author Ning Wen, Ph.D., a physicist with the Department of
Radiation Oncology at Henry Ford.
"The key is
targeting the tumor and delivering the dose that we want while protecting
surrounding normal tissue, which is why it is so important to regularly
evaluate the systematic accuracy of such systems."
The study will
presented Sept. 16 at the 56th annual American Society for Radiation Oncology
(ASTRO) meeting in San Francisco.
Stereotactic
radiation is a procedure that precisely delivers intense radiation doses to
tumor targets in one to five treatments. The goal of this non-invasive
procedure is to destroy, or make inactive, the tumor while minimizing dose
exposure to the surrounding healthy tissue.
The Edge, created by
Varian Medical Systems, is the latest advancement in stereotactic radiosurgery.
It offers treatment in about 20 minutes and uses new real-time tumor tracking
technology to help compensate for tumor motion during treatment. Its six
degrees of freedom treatment couch provides flexibility needed to optimally
position and adjust patients, allowing them to be comfortable and breathe
freely during treatment.
Henry Ford was the
first in North America and it is the only hospital in Michigan to have the
Edge.
"The Edge truly
represents a novel platform in radiosurgery, offering a system that provides a
fully-integrated solution for planning and administering radiosurgery
treatments," notes Benjamin Movsas, M.D., Chair of the Department of
Radiation Oncology at Henry Ford and a co-author of the study.
For its study, Henry
Ford sought to evaluate the accuracy of the Edge by comparing it to existing
robot- or frame-based radiosurgery systems.
To do so,
researchers took a novel approach using -- for the first time -- a phantom
prototype cube to determine treatment precision.
The phantom includes
implanted inserts and has four different densities for cone beam computed
tomography, three Calypso beacons, 5 mm diameter steel BBs in the center for
localization accuracy testing, 16 ceramic BBs for radiographic imaging, and
simultaneous dual orthogonal film planes insert for dosimetric verification.
With the phantom
prototype, targets were localized using all components of the Edge system,
including optical surface monitoring system, electromagnetic beacon-based
tracking, cone-beam CT, "snap-shot" planar x-ray imaging during
treatment and a "robotic" six degree of freedom couch.
Ten plans were
created to study various treatment sites including brain, spine, lung and
pancreas.
Overall, the study
demonstrated that the "end-to-end" locational accuracy of the Edge
was within 0.9 mm for single target treatment and 1.2 mm for single isocenter
multi-targets treatment, making it highly accurate when compared to robot- or
frame-based radiosurgery systems.
"With our
radiosurgery team, everything we do is continuously under study," says Dr.
Wen. "As pioneers in the field, we want to show we have done due diligence
with this new system to ensure we're providing the best care to our
patients."
Dr. Wen and his
colleagues plan to continue to study the Edge, expanding their research to
evaluation how tumors interact with treatment.
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