Abstract
Peptides containing the RGD sequence have high affinity for αvβ3 integrin receptors overexpressed in tumor cells. The objective of this research was to determine the biodistribution and estimate the radiation dose from 68Ga-DOTA-E-[c(RGDfK)]2 using whole-body (WB) PET scans in humans. Methods: Five healthy volunteers (2 women, 3 men, 37.2±15.6 y, 28-65 y, 79.2±21.0 Kg, 64-115 Kg) were included. After I.V. injection of the tracer (198.3 ± 3.3 MBq), 3 successive WB (vertex to mid-thigh) PET/CT scans at 3 time points (30, 60 and 120 min) were obtained on a Siemens Biograph 16 PET/CT. Subjects did not void the bladder until the entire series of images was completed. Low-dose CT scan without contrast was used for anatomic localization and attenuation correction. OLINDA/EXM software was used to calculate human radiation doses using the reference adult model. Results: The highest uptake was in the urinary bladder, followed by the liver, kidneys, and spleen, in descending order. The critical organ was urinary bladder wall. The mean effective doses (all subjects, men and women) were 34.1±4.9 μSv/MBq, 31.0±2.4 μSv/MBq, and 20.9±5.2 μSv/MBq for the no bladder voiding, 2.5- and 1-h bladder-voiding models, respectively. Conclusion: Of particular interest in this research was the visualization of the choroid plexus and ventricular system, not previously reported in humans for any RGD radiopeptide. Measured absorbed doses and effective doses are comparable to other previously reported RGD-based radiopharmaceuticals labeled with 68Ga and 18F. Therefore, 68Ga-DOTA-E-[c(RGDfK)]2 can safely be used for imaging integrin αvβ3 expression.
- PET/CT
- Radiobiology/Dosimetry
- Radiopharmaceuticals
- alpha(V)beta(3) integrin receptors
- angiogenesis
- dimeric RGD peptide
- gallium-68
- human dosimetry
- Copyright © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.