To continue the support for the growing trend of chemistry involvement in nuclear medicine, the Division of Nuclear Chemistry and Technology (DNCT) of the American Chemical Society (ACS) planned for a symposium to cover this aspect. This was expressed in arequest to me, as a member of the Program Committee, to organize a symposium on topics related to nuclear and radiochemistry applications to nuclear medicine. Realizing the growing interest in imaging, specially with positron emitting radioisotopes, I invited several colleagues to study with me the idea of imaging centers and the involvement of chemists in their structure and function. The formulated Organizing Committee supported this idea which evolved in proposing an extended international symposium to be held in conjunction with the 206th ACS National meeting in Chicago, Illinois, U. S. A. on August 22-27, 1993. The following are the members of the Organizing Committee: Jorge R. Barrio, Ph. D. Thomas E. Boothe, Ph. D. J. Robert Dahl, Ph. D. Robert F. Dannals, Ph. D. Bruce R. Erdal, Ph. D. Mark M. Goodman, Ph. D. George W. Kabalka, Ph. D. James F. Lamb, Ph. D. Ronald G. Manning, Ph. D. Henry C. Padgett, Ph. D. Roy S. Tilbury, Ph. D. Steven W. Yates, Ph. D. and Ali M. Emran, Ph. D.