1. An apparatus for maintaining alignment of: (1) a tumor imaging beam, traveling along a tumor imaging beam path, with (2) a tumor treatment beam, traveling along a tumor treatment beam path, the tumor treatment beam comprising positively charged particles for treatment of a tumor of a patient, the apparatus comprising: a charged particle delivery system, comprising: a movable magnet configured to guide the positively charged particles in said tumor treatment beam path to the tumor; an imaging system, comprising: an imaging source element, said imaging source element configured to deliver the tumor imaging beam along said tumor imaging beam path during use; a rigid mechanical link linking said imaging source element to said movable magnet; and means for co-moving said imaging source element and said movable magnet using said rigid mechanical link.