494 / 1544
ESTRO IMRT course 2015
IMRT optimization: algorithms&cost functions
Brussels October 5th, 2015
-17-
The minimum sits in a flat-pan
valley, the search direction is
well defined in few (ca. 100),
but vague in most dimensions
(ca. 10000),
a multiplicity of optimum
solutions exists.
Problems for the optimization algorithm:
convergence
in end game is very
slow –
terminate long before convergence
same
solution
may
not be reached
twice, although the cost functions
have identical values
no local minima, but still difficulties to find the optimum!
Fluence profile optimization (No MLC)