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| Breakthrough
technology that moves radiation beyond 3 D
conformal therapy, then past IMRT and IGRT to
achieve ART.
Once CT scans and
computers were used to identify targets for
radiation treatment in the 1990's, the beam
could be conformed (or modified) to better hit
the tumor and avoid normal structures in three
dimensions (called 3D conformal therapy.) Often
5 or 6 separate beams were used. |
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| Later in 1990's
and early 2000's the beams could be further
modified to even more accurately hit the target
using a technique called Intensity Modulated
Radiation Therapy (IMRT ). Then imaging devices
were attached to the linear acceleratory to
better ensure that that target was set up
accurately every day using a technique called
Image Guided Radiation Therapy (IGRT). Often as
many as 7 or 9 beams were used to provide even
more sophisticated targeting
Finally the
ultimate machine was designed and built using
technology similar to a CT scanner. Just as a
CT scan provides extremely precise and detailed
information about normal and abnormal anatomy,
the TomoTherapy treatment device is able to
deliver radiation extremely accurately to the
target area while delivering very little
radiation to normal tissues. It is able to do
this because instead of delivering the radiation
at only a few different directions, it delivers
the radiation during a complete 360 degree arc
while continuously modifying the shape and
intensity of the radiation beam. |
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| Since the device is designed around a CT
scanner, it is able to do a CT scan each day before treatment delivery
to verify that the target area is where it is expected to be. If it
isn't, the radiation treatment can be modified to adapt to changes in
the position of the tumor and changes in the patient's anatomy (like
weight loss) which is a technique called adaptive radiotherapy (ART).
More details on diseases treated go
here |
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The IMRT beam than travels
around in a circular or helical fashion and accurately hits the tumor |