Linking ligands that have specific targets in common with a wide range of cancers to ultrasound CAs is necessary to make targeted ultrasound CAs that gather in tumor tissues and achieve USMI for a wide range of malignancies. Carbonic anhydrase IX (CAIX) is highly expressed on cell membranes of various malignant solid tumors, making it an ideal target for USMI [65–67]. Here, CA9 is linked to cancer.