Tumor localization using radio-frequency identification clip marker: experimental results of an ex vivo porcine model.

PURPOSE: With the widespread use of minimally invasive surgery, tumor detection is becoming more difficult. We present the experimental results of a radio-frequency identification (RFID) lesion detection system in an ex vivo porcine model.

METHODS: The efficacy and feasibility of a newly developed RFID lesion detection system were examined. It was applied to the stomach and colon of pigs weighing 40 kg. The RFID clip was attached to the upper and lower mucosal sides of the stomach. Colon specimens with thin and thick walls were used. The clipped sites were marked on the serosa by a pin. The longest distance from the pin the RFID tag could be detected was measured 25 times in each direction.

RESULTS: In the upper gastric wall, the RFID tag detection distance was 4.5 ± 0.9 mm, 5.6 ± 0.7 mm, 12.5 ± 0.7 mm, and 5.3 ± 0.5 mm in the four directions, respectively (right, left, upper, and lower). In the antrum, the RFID tag detection distance was 5.8 ± 0.7 mm, 6.9 ± 0.5 mm, 5.6 ± 0.5 mm, and 3.7 ± 0.5 mm in the four directions. In the thin colon, the RFID tag detection distance was 6.3 ± 0.5 mm, 5.0 ± 0.5 mm, 9.7 ± 0.7 mm, and 6.4 ± 0.4 mm in the four directions. In the thick colon, the RFID tag detection distance was 3.5 ± 0.8 mm, 6.6 ± 0.5 mm, 8.4 ± 0.6 mm, and 9.8 ± 0.5 mm in the four directions. The area of detection was smallest for the antrum (83.7 mm2 ) and similar for the other sites (150.6, 154.7 and 157.7 mm2 for the upper body, thin colon, and thick colon, respectively).

CONCLUSIONS: The distance at which the RFID tag was detected was usually within 10 mm. These results indicate the feasibility of the clinical application of the add-on clip and RFID tag as a marker for identifying the location of various gastrointestinal tumors.