The invention relates to methods of identifying, detecting, and locating a tissue(s), nodule(s) or mass(es) and its draining lymph nodes that is/are suspected to be abnormal, typically a neoplasm (i.e., cancer, malignancy, premalignancy) in an individual undergoing an invasive procedure (i.e., surgery or endoscopy) or a non-invasive procedure (ie. radiology). The method involves the use of, for example, indocyanine green (ICG). The uptake of this dye is different by diseased tissues and lymph nodes compared to non-diseased tissues when administered at the appropriate combination of dose and time and monitored with an appropriate device that can excite and capture the signal.