Gamma Probe Assisted Ex Vivo Detection of Small Lymph Node Metastases Following the Administration of Indium-111-Labeled Monoclonal Antibodies to Colorectal Cancers

This study evaluated the ability of ex vivo gamma-probe scanning to detect lymph node metastases in resected surgical specimens from primary colorectal carcinoma patients undergoing external scintigraphy following intravenous administration of 4.1-5.3 mCi of 111 ln-labeled anti CEA monoclonal antibodies. The ex vivo probe counting technique led to a twofold to fourfold increase in the number of detectable lymph nodes with the majority measuring 2-5 mm in diameter. Results indicate a potentially useful role for ex vivo probe counting in detection and mapping small (2-5 mm) lymph nodes metastases