Positron emission tomography imaging of vascular endothelial growth factor with 64Cu-labeled bevacizumab for non-invasive diagnosis of endometriosis

Introduction: Non-invasive diagnosis of endometriosis remains challenging. A promising approach for diagnosing endometriosis is the molecular imaging of vascular endothelial growth factor because angiogenesis plays a role in the establishment of endometriosis. This study aimed to evaluate the potential of copper-64-labeled bevacizumab, an anti-vascular endothelial growth factor antibody, for endometriosis imaging. Methods: Mouse endometriosis model was prepared by autologous transplantation. The vascular endothelial growth factor expression was evaluated by immunohistochemical staining. Biodistribution study and positron emission tomography imaging were performed at 1, 24, and 48 h after the injection of radiolabeled bevacizumab. Results: The immunohistochemical staining revealed that vascular endothelial growth factor is expressed around the stroma and glandular epithelial cells in the endometriosis lesion. The biodistribution study showed a high uptake of indium-111 bevacizumab in the endometriosis lesion. Positron emission tomography imaging with copper-64-labeled bevacizumab clearly visualized the endometriosis lesions at 24 and 48 h after injection. Conclusion: These results indicate the potential usefulness of copper-64-labeled bevacizumab for endometriosis imaging.