AbstractID: 6897 Title: An automatic intra-operative HDR brachytherapy planning system
A treatment decision in intraoperative HDR brachytherapy requires quick source
localization, accurate dose and volume calculation, and optimal dwell-time configuration.
Model-based treatment plan and flat surface approximation may introduce significant
geometry and dosimetry error. This is critical for the single fraction and large dose
treatment. An automatic intraoperative HDR planning system is introduced in the
research effort. The system consists of a rapid-source-localization method using 3D
surface imaging technique (Rainbow Camera, Genetex Inc, MD, USA), a simple and
accurate dose calculation and evaluation tool – dose-texture plot (Li, Med. Phys, 28(1),
2001), and an iteration optimization. The accuracy of the source localization has been
measured using a pelvis-wall-shape phantom. In comparison with current biplane
radiograph-based source localization, the 3D optical image-based source localization
provided seed positions within experiment errors (3-mm). The source localization time is
accomplished within a few minutes. The home-developed dose calculation and treatment
optimization takes only two minutes and provides optimal dose distribution to the
treatment volume (doses in the treatment depth). Based on the feasibility tests, users can
tape or place the catheters on the thin sheet overlapped on the treatment surface. The
catheters can be arranged pre-operation or during operation. A thin sheet (< 2-mm) is
more flexible and will take the curvature of the treatment surface. The benefit of the
design is not only the accurate geometry to the treatment surface but also reduce the dose
delivery time.