Diagnostic imaging methods using rhenium and technetium complexes containing a hypoxia-localizing moiety

A method for the diagnostic imaging of hypoxic tissue in a mammalian species comprising the steps of:

• administering a pharmaceutical formulation comprising a metal complex, said metal complex comprising a radionuclide of technetium and a ligand of either formula Ia or Ib:
• ##STR46## wherein at least one R' is --(A).sub.p --R.sub.2 where (A).sub.p is a linking group and R.sub.2 is a nitro-heterocyclic hypoxia localizing moiety;
• and wherein the other R' groups, that are not --(A).sub.p --R.sup.2, and the R groups are the same, or different and are independently selected from hydrogen, halogen, hydroxy, alkyl, alkonyl, alkynyl, alkoxy, aryl, --COOR.sub.3, ##STR47## --NH.sub.2, hydroxyalkyl, alkoxyalkyl, hydroxyaryl, haloalkyl, arylalkyl, alkyl--COOR.sub.3, --alkyl--CON(R.sub.3).sub.2, --alkyl--N(R.sub.3).sub.2, --aryl--COOR.sub.3, --aryl--CON(R.sub.3).sub.2, --aryl--N(R.sub.3).sub.2, 5- or 6-membered nitrogen- or oxygen-containing heterocycle;
• or two groups taken together with the one or more atoms to which they are attached form a carbocyclic or heterocyclic, saturated or unsaturated spiro or fused ring which may be substituted with R groups;
• R.sub.1 is hydrogen, a thiol protecting group or --(A).sub.p --R.sub.2 ;
• R.sub.3 is hydrogen, alkyl or aryl;
• m=2 t5;
• p=0 t20;
• and where the term aryl denotes phenyl or substituted phenyl, and
• obtaining a diagnostic image of said hypoxic tissue.