The Value Of ^99mTc-SC Lymphoscintigraphy Combined With 3D Fusion Mode In Sentinel Lymph Node Biopsy Of Breast Cancer

ObjectiveTo analyze the related factors of positive results of^99mTc-SC SPECT/CT sentinel lymph node（SLN）lymphoscintigraphy,to explore the value of ^99mTc-SC SPECT/CT lymphoscintigraphy in preoperative assessment of SLNs metastasis risk,and to locate SLNs combined with 3D fusion mode to explore the distribution of SLNs,so as to provide a basis for clinical precision medicine.MethodsA total of 288 patients who underwent^99mTc-SC SPECT/CT SLN lymphoscintigraphy in the Department of Nuclear Medicine,Affiliated Hospital of Inner Mongolia Medical University from January 1,2020 to December 31,2022 were selected.According to the results of lymphoscintigraphy,the patients were divided into positive lymphoscintigraphy group and negative lymphoscintigraphy group,and according to whether SLNs had metastasized,the patients were divided into positive SLN group and negative SLN group.Using 3D fusion reconstruction technology to reconstruct the patient’s skin and bones.The contents of this study include:1.The related factors of positive results of ^99mTc-SC SPECT/CT lymphoscintigraphy;2.The relationship between SLNs metastasis and^99mTc-SC SPECT/CT lymphoscintigraphy and clinicopathological features.3.To locate the SLNs by the axillary surface markings and intercostal space,and to explore the distribution of SLNs.Results1.Among the 288 patients with breast cancer,204 patients showed positive results of lymphoscintigraphy,the positive rate was 70.83%（204/288）,84 patients showed negative results of lymphoscintigraphy,the negative rate was 29.17%（84/288）.Univariate analysis showed that age（P=0.035）,injection method（P=0.046）and imaging time（P<0.001）were associated with positive results of lymphoscintigraphy.Multivariate analysis showed that imaging time（OR=4.220,95%CI 1.899～9.378,P<0.001）was an independent risk factor for positive results of lymphoscintigraphy.When the imaging time was 30min,the positive rate was 89.47%（68/76）.When the imaging time was 20min,the positive rate was 64.15%（136/212）.2.Among the 288 patients with breast cancer,65（22.57%）patients’axillary lymph nodes had metastasis;Among them,59（20.49%）patients’SLNs had metastasis;Although SLNs did not metastasize in the other 6 patients,pathological examination of the para-SLNs（pa SLNs）showed metastasis,with a false negative rate of 9.23%（6/65）for sentinel lymph node biopsy（SLNB）.Univariate analysis showed that age（P=0.038）,menstrual status（P=0.004）and number of SLNs on the SPECT/CT images（P=0.018）were associated with SLNs metastasis.Multivariate analysis showed that the number of SLNs on the SPECT/CT images（OR=2.379,95%CI 1.133～4.999,P=0.022）was an independent risk factor for SLNs metastasis.When the number of SLNs on the SPECT/CT images was less than or equal to 1,the SLNs metastasis rate was 24.14%（49/203）.When the number of SLNs on the SPECT/CT images was more than 1,the SLNs metastasis rate was 11.76%（10/85）.The sensitivity and specificity of SPECT/CT lymphoscintigraphy in the diagnosis of SLNs metastasis were83.05%（49/59）and 32.75%（75/229）,respectively.3.30.88%（63/204）,67.65%（138/204）and 1.47%（3/204）of the"hottest"SLNs were distributed near the anterior axillary line,the midaxillary line and the posterior axillary line respectively.37.25%（76/204）of the"hottest"SLNs were distributed in the first intercostal space,48.53%（99/204）in the second intercostal space,10.29%（21/204）in the third intercostal space,3.43%（7/204）in the fourth intercostal space,and 0.49%（1/204）in the fifth intercostal space.95.10%（194/204）of the"hottest"SLNs were distributed in the quadrilateral area bounded by the anterior axillary line,the midaxillary line and the first to third intercostal spaces.Conclusions1.Prolonging the imaging time appropriately can increase the positive rate of ^99mTc-SC SPECT/CT lymphoscintigraphy.2.^99mTc-SC SPECT/CT lymphoscintigraphy has certain value in preoperative assessment of the risk of SLNs metastasis,and its sensitivity in diagnosis of SLNs metastasis is high;3.^99mTc-SC SPECT/CT lymphoscintigraphy combined with 3D fusion mode can be used to locate SLNs.Most SLNs are distributed in the quadrilateral area bounded by the anterior axillary line,the midaxillary line and the first to third intercostal spaces.