A control circuit optimizes a radiation-treatment plan to provide an initially-optimized radiation-treatment plan and then modifies that initially-optimized radiation-treatment plan to reduce corresponding monitor units (MUs) to provide a radiation-treatment plan that is further optimized for monitor units. This modification can comprise, at least in part, imposing a stronger smoothing constraint with respect to fluence. Optimizing a radiation-treatment plan to provide an initially-optimized radiation-treatment plan can comprise identifying at least one particular leaf pair for a multi-leaf collimator that requires a longest amount of time to move into a position that achieves a particular desired fluence and then selectively smoothing position requirements of that particular leaf pair to reduce the amount of time associated with that particular leaf pair while not also smoothing position requirements for all leaf pairs as comprise that multi-leaf collimator.
