Mass. Gen. Laws ch. 112, § 12B

No physician duly registered under the provisions of section two, two A, nine, nine A or nine B, no physician assistant duly registered under the provisions of section nine I or his employing or supervising physician, and no nurse duly registered or licensed under the provisions of section seventy-four, seventy-four A or seventy-six, or resident in another state, in the District of Columbia or in a province of Canada, and duly registered therein, who, in good faith, as a volunteer and without fee, renders emergency care or treatment, other than in the ordinary course of his practice, shall be liable in a suit for damages as a result of his acts or omissions, nor shall he be liable to a hospital for its expenses if, under such emergency conditions, he orders a person hospitalized or causes his admission.