Basic Research And Clinical Application Of Sentinel Lymph Nodes Tracing In Penile Carcinoma Using Fusion Image Of Visible And Near-infrared Fluorescence

Objective:The basic theory and clinical application of detecting sentinel lymph nodes of penile carcinoma were studied by using in vitro visible light and near infrared fluorescence fusion images,adopting indocyanine green for injection.Methods:1.Concentration and standing time: 14 concentrations of indocyanine green solution were prepared(initial concentration was 1.3 mg / ml,then concentration was halved).Imaging was performed at 0 min、10 min、20 min、30 min、60 min、2 h、4 h、6 h、8 h、12 h、24 h.Then we analyze the gray value and signal-to-noise ratio(SNR)of indocyanine green at different times;2.Penetration depth of near-infrared light in 760nm: indocyanine green was dissolved in 1.5% agarose gel at 104.85 μmol / L,13.11 μmol / L,1.64 μmol /L,1.64 μ mol/L.The depth of penetration was observed under near infrared fluorescence irradiation;3.Metabolism in vivo and imaging in vitro of animal experiment: SD rats were injected with indocyanine green solution(2.5 mg /ml,4 mg/kg)through the caudal vein to observe the development of indocyanine green;4.Clinical experiment: 4 patients with penile carcinoma,aged 62-78 years,with tumor diameter of 1 ~ 3.5cm,were injected subcutaneously with 1ml(2.5 mg/ml)of indocyanine green solution around the tumor.The development of bilateral inguinal lymph nodes was observed in real time.Lymph node resection was performed under its guidance.Results:1.When the concentration was 13.11 μmol/L,the fluorescence gray value and the SNR of indocyanine green were the best,too low or too high concentration will affect the imaging;2.At room temperature,the fluorescence gray value and SNR decreased and disappeared in 24 hours;3.At 13.11 μmol/L,the maximum penetration depth was 9.0 mm;4.Indocyanine green firstly accumulates in the liver and then metabolizes through digestive tract metabolism;5.10 mins later after ICG(1ml,2.5mg/ml)was injected subcutaneously around the tumor,NIR fluorescence in vitro could accurately locate the sentinel lymph nodes and continue to guide the dissection and excision of lymph nodes during operation.Conclusion:The fluorescence intensity of indocyanine green is affected by concentration and standing time,so it’s best to use it immediately.The best imaging depth is 9mm.It mainly metabolism through the liver into the intestine.Visible light and near infrared fluorescence fusion images can effectively trace sentinel lymph nodes of penile carcinoma.