Section 47T. (a) For the purposes of this section, the following words shall have the following meanings:

''Prosthesis'', an artificial appliance used to replace a lost natural structure; provided, however, that prosthesis shall include, but not be limited to, artificial arms, legs, breasts, scalp hair or glass eyes.

''Scalp hair prosthesis'', an artificial substitute for scalp hair.

(b) Any blanket or general policy of insurance described in subdivision (A), (C) or (D) of section 110 which provides hospital expense and surgical expense insurance, which is delivered or issued for delivery or subsequently renewed by agreement between the insurer and the policyholder, within or without the commonwealth, or any policy of accident and sickness insurance as described in section 108 which provides hospital expense and surgical expense insurance, which is delivered or issued for delivery or subsequently renewed by agreement between the insurer and the policyholder in the commonwealth, or any employees' health and welfare fund which provides hospital expense and surgical expense benefits and which is issued or renewed to any person or group of persons in the commonwealth, if such policy or fund provides coverage for any other prosthesis, shall provide coverage for expenses for scalp hair prostheses worn for hair loss suffered as a result of the treatment of any form of cancer or leukemia; provided, however, that such coverage shall be subject to a written statement by the treating physician that the scalp hair prosthesis is medically necessary; and provided, further, that such coverage shall be subject to the same limitations and guidelines as other prostheses. Scalp hair prosthesis coverage pursuant to this section shall not exceed an amount of $350 per year.