Clinical Value Of ⁹⁹Tc^m-octreotide Somatostatin Receptor Imaging In Staging And Target Volume Delineation Of Small Cell Lung Cancer

Objective Observe the application of 99Tcm-octreotide SPECT-CT in clinical staging of small cell lung cancer. To explore the 99Tcm-octreotide SPECT-CT scan effects in clinical staging and treatment strategies of small cell lung cancer.Methods 36 cases confirmed by histopathology with small cell lung cancer were included in this study, all patients come from Affiliated Hospital of Qingdao University, from August 2014 to November 2015, all patients underwent 99Tcm-octreotide SPECT-CT scan after the CT scan, radioactivity concentrated positive lesions were confirmed by histopathology, MRI or CT scan. Recording the number of lesions detected by two methods, divided into 4 groups according to the lesion sites, bone metastasis group, lymphatic metastasis group, lung lesions group, other metastasis group, the number of lesions was statistically analyzed. Clinical staging after 99Tcm-octreotide SPECT-CT scan was compared with CT-based, investigate the effect of 99Tcm-octreotide SPECT-CT in clinical staging and treatment strategy of small cell lung cancer.Results 99Tcm-octreotide SPECT-CT scan found 336 lesions, CT scan found 247 lesions, 99Tcm-octreotide SPECT-CT scan found 126 bone metastasis and CT scan found 65 (P<0.01); 99Tcm-octreotide SPECT-CT scan found 105 lymph node metastasis and CT scan found 57 (P<0.05); 99Tcm-octreotide SPECT-CT scan found 42 lung lesions, other metastatic lesions 63, CT group were 38 and 57, there were no significantly difference between two groups(P>0.05). 99Tcm-octreotide SPECT-CT changed clinical stage of 9 patients, because of found bone metastasis, cervical lymph nodes, adrenal gland and other distant metastasis, whereas CT failed to found, so that clinical staging upgrade; 2 patients ruled out the bone metastasis, the contralateral hilar lymphatic metastasis by 99Tcm-octreotide SPECT-CT, clinical staging degradation and the treatment strategies were changed.Conclusion 99Tcm-octreotide SPECT-CT changed the clinical staging and treatment strategies of partial small cell lung cancer patients. 99Tcm-octreotide SPECT-CT has important reference value for newly diagnosed small cell lung cancer patients in clinical staging and treatment strategies.Objective To explore value of 99Tcm-octreotide SPECT-CT in target volume delineation in limited small cell lung cancer by comparing with the target volume delineation based on CT scan.Methods 99Tcm-octreotide SPECT-CT scanning was performed for 32 patients with pathologically proved limited stage small cell lung cancer. The gross tumor volume (GTV) was delineated and three-dimensional conformal radiotherapy (3D-CRT) planning was established based on 99Tcm-octreotide SPECT-CT fused image and CT image according to 50 and 62 report of the International Commission on Radiation Units and Measurements. The indexes including volume of GTV (VGTV), percentage of the total lung volume which received more than 20 Gy (V2o), mean lung dose (MLD), and dose to spinal cord (Ds) were selected and evaluated. All patients were divided into three groups:lymphatic metastasis group (16 cases), atelectasis group (10cases), solitary focus group (6 cases). The gross target volumes delineation by 99Tcm-octreotide SPECT-CT and by CT were compared in the three groups, analyze the impact of 99Tcm-octreotide SPECT-CT on target delineation of limited small cell lung cancer.Results The gross tumor volume(GTV)was delineated on the CT image and "Tcm-octreotide SPECT-CT fused image respectively, The differences of indexes including VGTV (P=0.008), V20 (P=0.001) and MLD (P=0.006) between the two radiotherapy planning were statistically significant, whereas the Ds was not.Conclusion There are varying degrees of difference between GTVSPECT-α and GTVCT, Compared with CT, 99Tcm-octreotide SPECT-CT can reduce the VGTV in patients with atelectasis and obstructive pneunonitis when contouring the target volume, so can provide better protection for normal surrounding lung tissue. On the other hand, 99Tcm-octreotide SPECT-CT is more sensitive in detecting lymphatic metastasis than CT, and the VGTV can be more precise and guaranteed. Guaranteed Ds in the normal tolerance dose, Radiopneumonitis may be more effectively prevented because of significant decrease in V20 and MLD by more precise planning based on 99Tcm-octreotide SPECT-CT. Patients with atelectasis and obstructive pneunonitis benefit most from 99Tcm-octreotide SPECT-CT.