An outline of at least a patient on a patient support is determined. Based on at least one image of the patient, a plurality of orientations of the patient support and of at least one device are determined. The at least one device is capable of delivering a radiation treatment to the patient or of performing imaging associated with the radiation treatment. Based on the outline and the plurality of orientations of the patient support and of the at least one device, a clearance zone that no portion of the at least one device will occupy when the at least one device or the patient supported by the patient support is in motion is calculated.