Heuristic optimization relies on features such as the lung, heart,
breast/chest wall, and seroma cavity (provided it is delineated) to
place treatment beams. The method generates robust treatment
plans with simple modulation by minimizing the number of segments
for modulation and by automatically producing large segments
that
cover the entire breast/chest wall volume and include “flash” that is
prospectively optimized. Accordingly, the methodology forces large,
highly weighted segments to be generated and prospectively optimized
thus eliminating any manual manipulation once the optimization
is complete. Total calculation time for all planning steps is in the
order of minutes.
The module allows the user to specify clinical objectives instead
of technical or dose-volume goals. Since the beam geometry and
modulation are the most important consideration in tangential breast
plans, the user can tailor how the automated algorithm prioritizes
competing clinical objectives. Default settings provide the user with
a fully automated solution that will apply for the majority
of patients.
However,
advanced settings are available for the user to specify how
the automated algorithm prioritizes the clinical objectives.
For example, the user can:
• Specify the acceptable amount of lung volume in the
treatment beams
• Specify the margin between the beam and seroma cavity
• Specify the beam shielding for normal tissues
• Constrain the limits in which beams are angled
• Apply geometric beam adjustments depending on breast
size/chest wall and seroma cavity location.