Abstract: The invention provides compound which is an 18F-radiolabelled S-propylhomocysteine or a derivative thereof. The compound has an enantiomeric purity of at least about 90%. 18F-radiolabelled S-propylhomocysteine may be made by treating an N-protected ester of a substituted S-propylhomocysteine with a complexed F? salt in the presence of a base to form a protected product and then deprotecting the protected product to form the 18F-radiolabelled S-propylhomocysteine. In this method the N-protected ester has a leaving group on the S-propyl group and has an enantiomeric purity of at least about 90%. The base should be such that it does not cause racemisation of the protected product.

Abstract: A compound comprising a pyridine carboxamide structure, for use in imaging or treating melanoma, is described. An aromatic ring in the structure is substituted with a radiohalogen atom and the substitution on the amide nitrogen atom is such that the compound binds to melanin.

Abstract: The invention provides fluorinated compounds of formula (I): The compounds may be used in diagnosis or treatment of a disorder in a mammal characterised by an abnormal density of peripheral benzodiazepine receptors.

Abstract: The invention provides imidazo [1,2-a] pyridines of formula (1), wherein Y is selected from F, Cl, Br, I, OH, SH, NH2, CN and COOH; Z is selected from N(R3)C(O)R4 and C(O)NR3R4; R1, R2, R3, R4 can represent various radicals; m and n are independently 0, 1 or 2; and p is an integer from 1 to 4; radiolabelled derivatives and pharmaceutical compositions thereof. The compounds of the invention are useful for the diagnosis and treatment, including radiotherapy, of disorders that are characterized by an abnormal density of peripheral benzodiazepine receptors.