Application of dielectric properties for identification of normal and malignant gastrointestinal tumors and lymph nodes ex vivo.

A need exists for a quick, simple method to accurately assess resection margins and lymph node metastases in gastrointestinal cancer surgeries. We aimed to develop a real-time, non-destructive technique to differentiate between normal and cancerous tissues using dielectric properties. Dielectric properties of tissues from 50 gastric and 120 colorectal cancer patients were measured during surgery using an open-ended coaxial probe, spanning frequencies from 10 MHz to 4 GHz. Lymph nodes were classified based on pathology into metastatic and non-metastatic, and tissues were divided into cancerous and normal, the latter being 3 cm from the cancer edge. Statistically significant differences in dielectric properties were found between metastatic and non-metastatic lymph nodes (P < 0.05), and between normal and malignant tissues. Metastatic lymph nodes showed higher dielectric permittivity and conductivity across the frequency range, with no significant difference between gastric and colorectal cancers. The coaxial probe method distinguishes between metastatic and non-metastatic lymph nodes by their dielectric properties within 10-4000 MHz, offering a potential tool for real-time identification of malignant tissues during surgery, despite not identifying the cancer type.