We performed the first multi-bed-position dynamic PET acquisition using 68Ga-PRGD2 to study its pharmacokinetics in various organs and access the potential value of whole-body parametric imaging in lung cancer patients.
Sixteen lung cancer patients underwent 60-min four-bed-position dynamic PET scans. In each time frame of dynamic imaging, bed was shuttling between different bed-positions to cover the whole body. Dynamic image series were then acquired for not only primary lesion in lung but also multiple metastasis lesions all over the body. Time-activity curves (TACs) of major organs were consequently acquired after image reconstruction and used to compute the volume of distribution (VD). Parametric maps of binding potential (BpND) which indicating the integrin expression level were estimated using Logan graphical analysis. Static 18F-FDG PET/CT scans were performed on each individual within 3 days after the dynamic RGD scans.
Relative high VD was observed in the kidneys, liver, stomach and small intestine; VD of the tumor was more than 6 fold higher than that of muscle. Comparing with static images, parametric maps showed substantial increase of tumor-background ratio and pixel-wise quantification of integrin expression in primary and metastatic lesions all over the body. BpND varied among primary lesions and metastatic lesions in different organs. Little difference of SUVs was observed among primary and metastasis lesions in either RGD or FDG static images.
Multi-bed-position dynamic imaging of 68Ga-PRGD2 was successfully performed on lung cancer patients. Whole-body dynamic imaging and parametric map showed potentials to quantitatively access the integrin expression level in cancer patients for whole-body range. It also brings unique benefits for the diagnosis and treatment management of patients with multiple metastases.
This study is highlighted by SNMMI press release (read more).