The state Office of Health Strategy is holding a public hearing on Thursday about a proposed cancer treatment center in Danbury.  The $80 million facility seeks to use a novel type of radiation to kill more tumor cells and less healthy tissue.  The hearing is to determine whether the proposal from Danbury Proton is needed in Connecticut.  Spokesman Drew Crandall says similar centers in Boston and New York City are turning patients away because they can't handle the caseload.  This facility would be located on Wooster Heights Road.  The state Office of Health Strategy deemed the application complete.  Once the hearing is complete, the OHS will make a decision.  Danbury's land use commissions would next consider the application.  Another proton therapy center has been proposed in Wallingford, a partnership between Hartford HealthCare and the Yale New Haven Health System.