Mass. Gen. Laws ch. 152 § 9A
Whenever a medical question is in dispute in any case, and an impartial physician has not, prior to seven days before the date assigned for each hearing thereof, been appointed by the administrative judge, the employee may engage his own physician, and one additional physician if the administrative judge finds that justice and equity require the same, to appear and testify or be deposed, in his behalf, and, if the decision of the administrative judge or reviewing board is in favor of the employee, a reasonable fee shall be allowed by the administrative judge or reviewing board for the services of each such physician and shall be added to the amount so awarded and be paid by the insurer under the provisions of this chapter; provided, that, notwithstanding the foregoing, in every case wherein the decision of the administrative judge or reviewing board is in favor of the employee, if more than one physician appeared and testified in behalf of the insurer a reasonable fee shall be allowed for the services of each of the physicians, up to a like number, who appeared and testified or were deposed in behalf of the employee, which fees shall be added to the amount so awarded and be paid by the insurer under the provisions of this chapter.
Mass. Gen. Laws ch. 152, § 9A