Biodistribution and Pharmacokinetics of the αvβ3-Selective Tracer 18F-Galacto-RGD in Cancer Patients

Journal of Nuclear Medicine

Ambros J. Beer¹  Markus Schwaiger¹  Stephan Luderschmidt¹  Roland Haubner¹  Wolfgang A. Weber¹  Hans-Jürgen Wester¹  Michael Goebel¹  Mary E. Spilker¹ 

关键词: ¹⁸F-Galacto-RGD;    α_vβ₃ expression;    PET;    whole-body biodistribution;    kinetic modeling;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

18F-Galacto-RGD has been developed for PET of αvβ3 integrin expression, a receptor involved in, for example, angiogenesis and metastasis. Our aim was to study the kinetics and biodistribution of 18F-Galacto-RGD in cancer patients. Methods: Nineteen patients with metastases of malignant melanoma (n = 7), sarcomas (n = 10), or osseous metastases (n = 2) were examined. After injection of 133–200 MBq 18F-Galacto-RGD, 3 consecutive emission scans from the pelvis to the thorax or dynamic emission scans of the tumor over 60 min, followed by 1 static emission scan of the body, were acquired. Time–activity curves and standardized uptake values (SUVs) were derived by image region-of-interest analysis with image-based arterial input functions. Compartmental modeling was used to derive the distribution volume for muscle tissue and tumors. Results: 18F-Galacto-RGD showed rapid blood clearance and primarily renal excretion. SUVs in tumors ranged from 1.2 to 9.0. Tumor-to-blood and tumor-to-muscle ratios increased over time, with peak ratios of 3.1 ± 2.0 and 7.7 ± 4.3, respectively, at 72 min. The tumor kinetics were consistent with a 2-tissue compartment model with reversible specific binding. Distribution volume values were, on average, 4 times higher for tumor tissue (1.5 ± 0.8) than those for muscle tissue (0.4 ± 0.1). The data suggest that there was only minimal free and bound (specific or nonspecific) tracer in muscle tissue. Conclusion: 18F-Galacto-RGD demonstrates a highly favorable biodistribution in humans with specific receptor binding. Most important, this study shows that 18F-Galacto-RGD allows visualization of αvβ3 expression in tumors with high contrast. Consequently, this tracer offers a new strategy for noninvasive monitoring of molecular processes and may supply helpful information for planning and controlling of therapeutic approaches targeting the αvβ3 integrin.

【 授权许可】

Unknown