Waiting rooms are often full at community health centers, which operate on limited budgets and provide care even when patients can't pay. Private-practice doctors from the region who would be willing to donate services to help ease the burden on centers' staffs are stymied by a federal law. But members of Congress, including Rep. Tim Murphy, R-Upper St. Clair, are trying to change that. The Federal Court Claims Act provides malpractice protection for physicians employed by the health centers but doesn't cover physicians who want to volunteer. Mr. Murphy wants to extend to volunteer medical professionals the same malpractice protections given to paid clinic employees.