RESUMO
Purpose: Mapping the distribution of internal mammary sentinel lymph nodes (IM-SLNs) presented on single photon emission computed tomography in conjunction with computed tomography (SPECT/CT) images to explore the value of IM-SLN to guide tailored clinical target volume (CTV) delineation of postoperative prophylactic IMNI. Materials and methods: Ninety-seven patients who underwent preoperative lymphoscintigraphy by SPECT/CT and had imaging of IM-SLN were selected in this study. The imaging IM-SLNs on SPECT/CT of eligible patients were projected onto corresponding anatomical positions of a representative axial CT image. The IMN CTVs were delineated on the representative axial CT images according to the Radiation Therapy Oncology Group (RTOG) and Danish Breast Cancer Cooperative Group (DBCG) guideline, and defined as CTVRTOG and CTVDBCG. The location of the IM-SLNs was compared with the RTOG and DBCG guidelines of IMN target volume delineations, respectively. The intercostal space distribution of IM-SLNs was recorded. The distances from the CTVRTOG and CTVDBCG to the IM-SLNs were measured, respectively. Results: The total number of imaging IM-SLNs was 136. IM-SLNs were mostly found in the first intercostal space (40.4%), with 30.2, 24.3, 4.4, and 0.7% of IM-SLNs in the second, third, fourth, and fifth intercostal space, respectively. The average distance from the edge of the CTVRTOG and the edge of CTVDBCG to the central points of the IM-SLNs was 4.10 mm (SD, 3.3 mm) and 1.60 mm (SD, 2.6 mm), respectively (t = 16.640, P = 0.000). The average distance from the edge of CTVRTOG and the edge of CTVDBCG to the lateral border IM-SLN was 6.40 mm (SD, 3.5 mm) and 3.34 mm (SD, 3.3 mm), respectively (t = 19.815, P = 0.000). Only 18.4% of IM-SLN central points were included in the CTVRTOG, and 60.3% of IM-SLN central points were included in the CTVDBCG. When covering 90 and 100% of the IM-SLN center points, the CTVRTOG needs to expand 8 and 15 mm, respectively, and the CTVDBCG needs to expand 5 and 13 mm, respectively. Conclusion: Neither the RTOG nor DBCG consensus guideline about the delineation of IMN CTV was sufficient to cover 90% of IM-SLNs. For 90% coverage of IM-SLN central points, CTVRTOG needed to be expanded by 8 mm, and CTVDBCG needed to be expanded by 5 mm.
RESUMO
PURPOSE: To evaluate the diagnostic value of 18F-FDG PET/CT for detection of bone metastasis in comparison with the efficacies of 18F-FDG PET/CT, CT, 18F-FDG PET and conventional planar bone scintigraphy in a series of cancer patients. METHODS: Five hundred and thirty patients who underwent both 18F-FDG PET/CT and bone scintigraphy within 1 month were retrospectively analyzed. The skeletal system was classified into 10 anatomic segments and interpreted blindly and separately. For each modality, the sensitivity, specificity, accuracy, PPV and NPV were calculated and the results were statistically analyzed. RESULTS: Bone metastases were confirmed in 117 patients with 459 positive segments. On patient-based analysis, the sensitivity, specificity, accuracy, PPV and NPV of 18F-FDG PET/CT were significantly higher than bone scintigraphy, CT and 18F-FDG PET (P<0.05). On segment-based analysis, the sensitivity of CT, bone scintigraphy, 18F-FDG PET and 18F-FDG PET/CT were 70.4%, 89.5%, 89.1% and 97.8%, respectively (P<0.05, compared with 18F-FDG PET/CT). The overall specificity and accuracy of the four modalities were 89.1%, 91.8%, 90.3%, 98.2% and 90.3%, 90.9%, 89.8%, 98.0%, respectively (P<0.05, compared with 18F-FDG PET/CT). The PPV and NPV were 89.8%, 87.6%, 85.6%, 97.2% and 85.6%, 93.2%, 92.8%, 98.6%, respectively. Three hundred and twelve lesions or segments were presented as lytic or sclerotic changes on CT images at the corresponding sites of increased 18F-FDG uptake. In lytic or mixed lesions, the sensitivity of 18F-FDG PET/CT and 18F-FDG PET were better than bone scintigraphy, while in osteoblastic lesions bone scintigraphy had a similar performance with 18F-FDG PET/CT but better than 18F-FDG PET alone. CONCLUSION: Our data allow the conclusion that 18F-FDG PET/CT is superior to planar bone scintigraphy, CT or 18F-FDG PET in detecting bone metastasis. 18F-FDG PET/CT may enhance our diagnosis of tumor bone metastasis and provide more information for cancer treatment.
