The remedy against the United States provided by sections
1346
(b) and
2672 of title
28, or by alternative benefits provided by the United States where the availability of such benefits precludes a remedy under section
1346
(b) of title
28, for damage for personal injury, including death, resulting from the performance of medical, surgical, dental, or related functions, including the conduct of clinical studies or investigation, by any commissioned officer or employee of the Public Health Service while acting within the scope of his office or employment, shall be exclusive of any other civil action or proceeding by reason of the same subject-matter against the officer or employee (or his estate) whose act or omission gave rise to the claim.