[Clinical practice of 99mTc-peplimycin imaging and radio guided surgery for lung neoplasms]

Intraoperatively,the routine method to differentiate malignant lung neoplasms from benign lesions is by the judgment of naked eye or frozen section. It is not accurate to judge by naked eye and will take long time by frozen section. Using a gamma-detecting probe (GDP) to accurately detect the tumors and the metastases, the operators could decide the resection range and the treatment plan. This study was preliminary clinical practice of tumor imaging and radioimmunoguided surgery (RGS) using (99m)Tc-PPM (peplomycin) as a tumor tracer.

Thirty-seven patients were administered with injection of (99m)Tc-PPM. The images were taken preoperatively. Region of interest (ROI) method was performed and tumor-to- normal-tissue (T/NT) ratio was calculated on the image. The radioactivity of the specimens resected from the patients was detected using GDP at the time of surgery. T/NT ratio was obtained by comparing the radioactivity of the tumor tissue with the normal lung tissue.

The uptake ratios (T/NT) of (99m)Tc-PPM were different between malignant and benign lesion (P< 0.01). The ratio (T/NT, x+/-2s) was regarded as the threshold for differentiation of malignant and benign lesions. The sensitivity, specificity, and accuracy of identifying malignant lesion were 90%, 87.5%, and 89.3%, respectively; GDP could be used to accurately detect the invasive range of the tumors, with the sensitivity, specificity, and accuracy of identifying lymph node metastases of 91%, 88%, and 90%, respectively.

(99m)Tc-PPM is a useful agent in differentiating malignant lung neoplasm from benign lesions, and as a tumor tracer can be used in detecting tumor by GDP intraoperatively. The RGS is a simple method that can help the surgeon in the intraoperative assessment of the tumor and the lymph node metastases.