A control apparatus for a radiotherapy irradiation system in which a calculation
time required for calculation to be performed after restrictions are modified is
shortened. The control apparatus includes a unit for setting an initial solution
indicating an initial irradiated beam weight, a unit for inputting restrictions
according to a prescription, and a unit for setting an evaluation function under
the restrictions. The control apparatus further includes a unit for iteratively
calculating the evaluation function until the evaluation function is minimized
and determining an irradiated beam weight optimizing irradiation, and unit for
outputting an optimal solution indicating an optimal irradiated beam weight to
the irradiation system. After restrictions are modified, a new evaluation function
is set under the modified restrictions. An irradiated beam weight is then determined
for optimizing irradiation. At this time, the initial solution setting unit adopts
the previous optimal solution indicating an optimal irradiated beam weight, which
is obtained before the restrictions are modified, as the initial solution indicating
the initial irradiated beam weight.
