The invention belongs to the technical field of
medical imaging, and discloses a
gallium-based radioactive contrast agent with
glycosylation-modified
maltotriose covalently linked with a chelating group as well as a preparation method and application of the
gallium-based radioactive contrast agent. The preparation method comprises the following steps: firstly, modifying a cyclic polydentate ligand, carrying out
nucleophilic substitution, then connecting an upper half flexible chain or loop chain, and then carrying out
glycosylation on acetyl protected
maltotriose to connect a
sugar part half flexible chain or loop chain; the preparation method comprises the following steps: preparing a polydentate ligand, carrying out
reductive amination or
urea condensation connection on
aldehyde groups or
aldehyde groups on half-chain end groups on two sides to form a whole, adding
methanol and a
sodium methoxide solution, removing acetyl of
sugar, adding
trifluoroacetic acid to remove protective groups on the polydentate ligand, and finally adding 68Ga for
chelation to obtain a final product. And
maltotriose is adopted as a guiding group, so that higher bacterial specificity and permeability are achieved, and the distinguishing degree in diagnosis of bacterial infection is higher.