Angiogenesis-Targeted 68Ga-DOTA-RGD2 PET/CT Imaging: a Potential Theranostic Application in the Case of Chondrosarcoma.

Chondrosarcoma is a cartilaginous tumor of mesenchymal origin. The histology and grade of the tumor determine the chances of relapse and survival. These tumors usually respond poorly to chemo-radiotherapy in cases of non-resectable and recurrent disease. 18F-FDG PET/CT has been used in evaluation of recurrence. However, these tumors show only mild to moderate FDG avidity due to their lower mitotic activity and large acellular matrix. These tumors are known to have a high degree of angiogenesis, especially in those of higher grade. We present a case of a 53-year-old man with grade II chondrosarcoma of the left femur showing only mild avidity on 18F-FDG PET/CT but showing moderate to intense tracer avidity on 68Ga-DOTA-RGD2 PET/CT. This may enable the use of angiogenesis-targeted positron and beta-emitting radiopharmaceuticals as a potentially new theranostic alternative treatment in cases of refractory metastatic chondrosarcoma.