RT Journal Article SR Electronic T1 The Difference between t̄ and t½—Reply JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 760 OP 760 VO 17 IS 8 A1 Alpert, Nathaniel A1 Correia, John YR 1976 UL http://jnm.snmjournals.org/content/17/8/760.abstract AB