The inventive alignment frame simplifies the task of attaching a fixation frame to a patient's skull prior to radiotherapy treatments. The frame is adjustably attachable to the fixation frame and is equipped with a bite plate that allows a patient to bite down on the bite plate to immobile the alignment-calibration frame and the attached fixation frame. The positional relationships are adjusted to bring the fixation screws into optimal locations on the patient's skull. Needle calibration assemblies placed into the fixation screw holders include clear needle guides through which a hypodermic needle is inserted to inject anesthetic into the future fixation screw location. The needle calibration assemblies are removed and the optimal length fixation screw is tightened into the anesthetized location. After all the fixation screws are in place, the patient releases the bite plate and the entire alignment-calibration frame is removed from the fixation frame.