Peptides containing the Arg-Gly-Asp (RGD) sequence have high affinity for α v β 3 integrin receptors overexpressed in tumor cells. The objective of this research was to determine the biodistribution and estimate the radiation dose from 68 Ga-DOTA-E-[c(RGDfK)] 2 using whole-body PET scans in humans. Methods: Five healthy volunteers (2 women, 3 men; mean age ± SD, 37.2 ± 15.6 y; range, 28-65 y; mean weight, 79.2 ± 21.0 kg; range, 64-115 kg) were included. After intravenous injection of the tracer (198.3 ± 3.3 MBq), 3 successive whole-body (vertex to mid thigh) PET/CT scans at 3 time points (30, 60, and 120 min) were obtained on a 16-slice PET/CT scanner. The subjects did not void the bladder until the entire series of images was completed. Low-dose CT without contrast agent was used for anatomic localization and attenuation correction. OLINDA/ EXM software was applied 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 the urinary bladder wall. The mean effective doses (all subjects, men and women) were 34.1 ± 4.9, 31.0 ± 2.4, and 20.9 ± 5.2 μSv/MBq for the no-voiding, 2.5-h-voiding, and 1-h-voiding models, respectively. Conclusion: Of particular interest in this research was the visualization of the choroid plexus and ventricular system, which seems to be a characteristic of RGD-dimeric peptides. Measured absorbed doses and effective doses are comparable to other previously reported RGD-based radiopharmaceuticals labeled with 68 Ga and 18 F. Therefore, 68 Ga-DOTA-E-[c(RGDfK)] 2 can safely be used for imaging integrin α V β 3 expression. The last few years have witnessed the development of a virtual revolution in PET molecular imaging, and radiolabeled receptor-binding peptides are emerging as powerful tools for imaging and therapy applications of tumors expressing peptide binding receptors (1-3). Somatostatin analogs have been in use the longest, have led to the accumulation of a vast amount of data, and have proven useful for the management of patients with neuroendocrine tumors (4-8). Several other peptide receptorbinding compounds have been synthesized within the past few years and are currently in various research stages-in vitro, in vivo, and preclinical studies-but have not yet been approved for clinical use (9-11). These new and rapidly expanding peptide-based radiopharmaceuticals deserve close attention.It has been shown that peptides based on the RGD amino acid sequence have a high affinity and selectivity for a V b 3 integrin receptors (12). The a V b 3 integrins are transmembrane proteins that are preferentially expressed on proliferating endothelial cells but absent from quiescent endothelial cells (13). Integrins are overexpressed on newly formed blood vessels of actively growing tumors and are therefore potential targets for receptor-mediated tumor imaging and therapy when labeled with the proper radionuclide. Angiogenesis, the formation of n...

El complejo de esclerosis tuberosa, también llamado enfermedad de Bourneville, es una facomatosis caracterizada por alteraciones neurológicas con diferentes grados de discapacidad intelectual y epilepsia, así como la formación de múltiples hamartomas en diferentes órganos y sistemas. Tiene criterios de diagnóstico genético y clínicos, los cuales requieren estudios de imagen para un adecuado diagnóstico, vigilancia y toma de decisiones. Presentamos cuatro casos con diagnóstico final de complejo esclerosis tuberosa de nuestro centro, enviados por sospecha clínica de este, los cuales consideramos que muestran las lesiones más comunes en sistema nervioso central y abdomen, principalmente tuberosidades corticales, nódulos subependimarios, astrocitoma subependimario de células gigantes y angiomiolipomas.

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