A field effect transistor is provided. Using the target metallic solutions results in damage free use to surrounding optical components since no debris are formed. The bed status system is coupled to the patient bed and is configured to monitor at least one condition of the bed, and to generate a bed message indicating the status of the monitored condition. Each of the heat transfer fins includes a plurality of sets of cut-and-raised parts with each set being straightly aligned from the upstream side toward the downstream side.