A control circuit identifies (prior to optimizing a radiation-treatment plan) at least one angle (such as one or more gantry angles as correspond to an arc-therapy treatment platform) to provide one or more identified angles. The control circuit then optimizes a radiation-treatment plan with respect to a particular patient target volume by using the identified angle(s) as preferred angles as regards irradiating the patient target volume. Being “preferred,” the radiation-treatment plan is thereby influenced (without being required) towards changing a rate of moving the gantry when traversing the preferred angle(s). For example, the plan can be biased towards slowing down movement of the gantry at such angles to thereby deliver a relatively greater amount of radiation to the patient target volume at the preferred angle.
