Theranostics 2012; 2(6):577-588. doi:10.7150/thno.4443 This issue Cite
Research Paper
1. School of Health Sciences, Purdue University, IN 47907, USA.
2. Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China.
Purpose: The purpose of this study was to evaluate the capability of u-SPECT-II/CT to monitor the progression of breast cancer lung metastasis using 99mTc-3P-RGD2 as a radiotracer.
Methods: The breast cancer lung metastasis model was established by tail-vein injection of 2 x 105 - 1.5 x 106 MDA-MB-231 cells into each athymic nude mouse. SPECT/CT studies were performed at a specified time after inoculation of MDA-MB-231 cells. Histological staining was used to further confirm the presence of lung metastases.
Results: We found that both inoculation time and tumor cell load had significant influence on the extent of lung metastasis. For example, if animals were injected with 2 x 105 MDA-MB-231 cells, there were no detectable metastatic breast tumors in the lungs after 8 weeks. If animals were injected with 1 x 106 MDA-MB-231 cells, there were many tumors in both lungs at week 8. When 1.5 x 106 MDA-MB-231 cells were injected, the animal became very weak by week 7. We also found a rare example of breast cancer metastasis in the muscle and mediastinal lymph nodes. The tumor necrotic regions were clearly delineated by u-SPECT-II/CT.
Conclusion: This study clearly demonstrated that 99mTc-3P-RGD2 is an excellent radiotracer for noninvasive imaging of metastatic breast tumors in the lungs, mediastinal lymph nodes and muscles. 99mTc-3P-RGD2 SPECT/CT is an outstanding platform for monitoring the progression of breast cancer lung metastases, semi-quantification of breast tumor load in the lungs and delineation of tumor necrosis in small animals.
Keywords: Breast Cancer Lung Metastasis, 99mTc-3P-RGD2, u-SPECT-II/CT.