No firefighter shall receive disability benefits under this chapter until he or she has been examined by a duly qualified physician or surgeon, selected by the firefighter or, if not selected by the firefighter, selected by the Commissioner for that purpose. If the firefighter is found to be permanently disabled, he or she shall be entitled to present a claim to the Commissioner. The examining doctor shall prepare a written report which shall be submitted to the Commissioner and shall be part of the records. Any firefighter receiving benefits under this chapter shall be examined periodically by a duly qualified physician or surgeon as required by the Commissioner to determine if such disability has ceased to exist.