AbstractID: 9872 Title: Patient and organ position verification using Electronic Portal Imaging
Devices
Patient and organ positioning have become increasingly important in modern
radiation therapy. Due to the advent and popularity of IMRT treatments
margins used for treatment are getting smaller and complication rates
are plummeting,
The use of smaller margins necessitates accurate positioning. One of the
tools to reach this objective, be it to correct for placement errors or
for organ motion are electronic portal imagers (EPIDs).
EPIDs can be used not only to image bony anatomy, but can be used
to visualize soft tissue positioning by using volume CT scans or
alternatively implanted markers.
The digital nature of EPIDs allows
different ways, yielding momentary
data. The information is available
to perform on--line corrections or
adaptive analysis.
to process the information in
snapshots, accumulated data, combined
in almost real--time and can be used
stored in a database for off--line
Finally, goal of the EPID--image can be to visualize, bony anatomy,
soft tissue or implanted fiducial markers, allowing to reduce setup
errors and organ motion.
Educational objectives:
1) Attain a basic understanding of adjustment and verification rationale
2) Understand how EPIDs can be used to obtain information on bony anatomy
position as well as soft tissues.
3) Learn how to compare the efficacy of two different positioning modalities.
Statement:
The author is partly sponsored by the Uniformed Services University
of the Health Sciences through Contract Number MDA905-92-C-0009 awarded to
the Henry M. Jackson Foundation for the Advancement of Military Medicine
as a subcontract to Varian Inc.
The content of the information does not necessarily reflect the position
or the policy of the Government, and no official endorsement should
be inferred.