RT Journal Article SR Electronic T1 The Evolution of Positron Emission Tomography JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 15N OP 26N VO 32 IS 4 A1 Sarah M. Tilyou YR 1991 UL http://jnm.snmjournals.org/content/32/4/15N.abstract AB