1. The composition of the visualization agent containing an isolated polypeptide comprising SEQ ID NO: 1, SEQ ID NO: 2 or a conservative version of these sequences conjugated with AlF-NOTA chelator (2.2 ′, 2 ′ ′ - (1,4,7 triazonan-1,4,7-triyl) triacetic acid) to form a polypeptide conjugated to an AlF-NOTA chelator, where an isolated polypeptide conjugated to an AlF-NOTA chelator specifically binds to the HER2 protein (human epidermal growth factor receptor type 2) or its variants. 2. The method for preparing a visualization agent composition according to claim 1, comprising: (1) obtaining an isolated polypeptide comprising SEQ ID NO: 1, SEQ ID NO: 2 or a conservative version of these sequences； (2) the interaction of a polypeptide with a NOTA chelator to form a polypeptide conjugated with a NOTA chelator； and (3) the interaction of a polypeptide conjugated with a NOTA chelator with an AlF moiety to form a polypeptide conjugated with an AlF-NOTA chelator. 3. A method for producing an F-NOTA chelator, comprising reacting a NOTA chelator with an AlF source. 4. The method of claim 3, wherein the NOTA chelator comprises a NOTA chelating moiety and a linker. The method for preparing a visualization agent composition according to claim 1, comprising: (1) obtaining an isolated polypeptide comprising SEQ ID NO: 1, SEQ ID NO: 2 or a conservative version of these sequences； (2) the interaction of the polypeptide with a NOTA chelator comprising the NOTA chelating group and a linker to form a polypeptide conjugated with a NOTA chelator； and (3) the interaction of the polypeptide conjugated with a NOTA chelator with the F group or source F. 6. A pharmaceutical composition comprising an imaging agent composition according to claim 1 and a pharmaceutically acceptable1. Композиция агента визуализации, содержащая изолированный полипептид, включающий SEQ ID NO: 1, SEQ ID NO: 2 или консервативный вариант этих последовательностей, конъюгированный с хелатором AlF-NOTA (2,2′,2′′-(1,4,7-т
