[en] Progress is reported in the following areas: (1) preliminary evaluation of tumor localization of N-13 labeled L-amino acids; (2) evaluation of N-13 labeled amino acids and ammonia for physiological studies in patients undergoing chemotherapy for colorectal hepatic metastases; (3) evaluation of C-11 labeled alpha-aminoisobutyric acid (AIB) in patients with prostate cancer; (4) biological studies with N-13 labeled metabolites; (5) amino acid transport studies with synthetic C-11 labeled amino acids; (6) development of an imaging technique for measurement of regional perfusion; (7) carbon-11 labeled thymidine for tumor imaging and metabolic studies; (8) enzymatic synthesis of metabolites labeled with N-13 and C-11; (9) organic synthesis of C-11 labeled amino acids; (10) the preparation of F-18 fluorinating agents; and (11) remotely controlled, semi-automatic preparation of N-13 ammonia