Provided are methods of determining the quantity and location of &bgr;III-tubulin expression in a subject, which may be used to determine the location and/or extent of excessive or uncontrolled growth of cells such as tumors. Such methods may include administering at least one compound to a patient and determining the quantity and location of &bgr;III tubulin expression within the patient by visualizing the compound within the patient. Visualization of the compound may be indicative of the binding of the compound to cells that are actively expressing &bgr;III tubulin.