The Evaluation Of The Chemotherapy In SCLC With ^99mTc-octreotide SPECT/CT Receptor Scintigraphy

Objective To observe the primary tumor and its metastases in small cell lung cancer with 99 m Tc-octreotide SPECT/CT receptor scintigraphy and to evaluate the clinical value of the early chemotherapy of the small cell lung cancer.Methods 22 patients with a histological diagnosis of SCLC without surgical treatment were performed with 99 m Tc-octreotide SPECT/CT imaging before the chemotherapy and after the 2 cycles of chemotherapy, respectively. CT examination was performed during this period, within the interval of 1 weeks. Primary tumors and metastasis were detected with 99 m Tc-octreotide SPECT/CT imaging before therapy.The uptake of 99 m Tc-octreotide of primary tumors, metastasis lymph nodes and distant metastases in 22 cases of SCLC were observed before and after chemotherapy. The primary tumors were divided into high uptake group, moderate uptake group, and mild uptake group with 99 m Tc-octreotide imaging, and narrow diameter > 2 cm group,narrow diameter < 2 cm group, diameter increase group and no change group with CT.Tumor to normal tissues ratios(T/N) were observed using ROI(region of interest), and the T/N ratio was compared with CT size before and after chemotherapy of primary tumor in 22 cases of SCLC.Results 28 primary tumors, 27 metastasis lymph nodes and 7 distant metastases were detected in 22 SCLC with 99 m Tc-octreotide SPECT/CT imaging before chemotherapy, and the sensitivity of them were 93.33%, 60.00%, and 77.77%respectively. The uptake level of 99 m Tc-octreotide in primary tumors and metastasis lymph nodes were mainly moderate, while distant metastases were mild before chemotherapy; after therapy, the former turned into mild intake, while no obvious change was found in distant metastases. There was significant statistical difference between high uptake group and moderate uptake of the T/N ratios of 28 positive imaging in primary tumors before and after treatment. Compared with CT, the T/N ratios were 2.58±0.44vs1.42±0.43(diameter sinking > 2 cm),2.61±0.52vs1.69±0.40( diameter sinking < 2 cm),and 1.99±0.25vs2.68±0.48(diameter increase) before and after treatment in patients with primary tumors. There were significant difference between the 3 groups. There was also statistical significance of the T/N ratios in 3 groups Before chemotherapy(F=3.378, P = 0.035 < 0.05). There was also significant difference between effective group and non-effective group of the T/N ratios.Conclusion 99 m Tc-octreotide SPECT/CT receptor scintigraphy for SCLC primary tumors and distant metastases shows a higher detection rate. SCLC tumors with high uptake of imaging agent are more likely to achieve clinical remission after chemotherapy. TC/NC ratio is a more accurate, economic and effective index for SCLC patients to evaluate the chemotherapy.