Carbon-10: Example of cyclotron production of positron emitters as an open research field

This paper supports the thesis that significant improvement of PET output response to clinical questions can be achieved by innovation in radionuclide production. Moreover, that development can be performed with the resources available at a clinical centre. Carbon-10 production parameters studies are used as example. A technical methodology for measurement of excitation function of nuclear reactions yielding short-lived radionuclides, performed to measure cross section values of the 10B(p,n)10C reaction in a PET-devoted cyclotron, is presented.http://www.sciencedirect.com/science/article/B6TVT-4JVT1KS-D/1/27f31c7a6e33bde32315dd89804a773

Structural and in vivo studies of metal chelates of Ga(III) relevant to biomedical imaging

The solution chemistry and structure of the complex of the triazamacrocyclic ligand NOTP (1,4,7-triazacyclononane-1,4,7-tris(methylenephosphonate)) with Ga3+ in D2O have been investigated by 1H, 71Ga and 31P NMR spectroscopy. These NMR results show the presence of a 1:1 Ga(NOTP)3- complex, with a highly symmetrical, pseudo-octahedral geometry, possibly with a C3 axis. The 1H spectrum shows that the triazamacrocyclic chelate ring is very rigid, with all the ring protons non-equivalent. The complex is stable in aqueous solution in a wide pH range. Its high thermodynamic stability agrees well with previous results from biodistribution and [gamma] imaging studies in Wistar rats with 67Ga3+ chelates of triaza macrocyclic ligands, which showed that the neutral chelates 67Ga(NOTA) (where NOTA is 1,4,7-triazacyclononane-1,4,7-triacetate) and 67Ga(NOTPME) (where NOTPME is 1,4,7-triazacyclononane-1,4,7-tris(methylenephosphonate monoethylester)) have similar in vivo behaviour, with high stability and rapid renal excretion, but the high negatively charged 67Ga(NOTP)3- has a considerably slower kidney uptake and elimination.http://www.sciencedirect.com/science/article/B6TGG-40X8D8M-26/1/b0839261f5ddd424e05a2da9204295a

Visualização da Rede Linfática Pulmonar Profunda usando Radioliposomas

Resumo: A drenagem linfática profunda desempenha um papel importante no pulmão, uma vez que remove materiais estranhos depositados sobre a superfície das vias respiratórias, tais como microrganismos patogénicos. Esta drenagem está igualmente associada às vias de disseminação tumoral. Liposomas com uma membrana especificamente desenhada foram usados para simular partículas estranhas a ser removidas pelos linfáticos pulmonares. Pretendem obter-se imagens dos linfáticos profundos em babuínos usando liposomas que encapsulam 99mTc-HMPAO sob a forma de aerossol. Observaram-se gânglios linfáticos axilares 30 min pós-inalação, que se tornaram mais evidentes 1 hora após, quando os gânglios abdominais e aórticos também se tornaram visíveis. Imagens tardias não acrescentaram informação relevante. Foram desenhadas ROI's (regiões de interesse), bem como as correspondentes curvas de actividade-tempo para obter informação acerca da biocinética. Em conclusão, pode dizer-se que a técnica proposta torna possível a visualização da rede linfática profunda do pulmão e os gânglios linfáticos. Esta metodologia poderá vir a ser importante na libertação pulmonar controlada de fármacos citotóxicos. Abstract: Deep lymphatic drainage plays an important role in the lung, as it removes foreign materials laying on the airways surface, such as pathogenic microorganisms. This drainage is also associated with lung tumour dissemination route. Liposomes with a specially tailored membrane were used as foreign particles to be removed by the lung lymphatics. We aim to obtain images of deep lung lymphatics in baboons using liposomes encapsulating 99mTc-HMPAO, as aerosols. Axillary lymph nodes were visualized 30 min post-inhalation, becoming more evident 1 hour after, when abdominal aortic and inguinal lymph nodes were also observed. Late images added no additional information. ROI's and their time-activity curves were drawn to obtain biokinetic information. In conclusion, we can say that the proposed technique enables visualization of the deep lymphatic lung network and lymph nodes. This methodology may be an important tool for targeted lung delivery of cytotoxic drugs. Palavras-chave: Liposomas, Drenagem linfática, Cintigrafia, Libertação pulmonar controlada, Estudos in vivo, Keywords: Liposomes, Lymphatic drainage, Scintigraphy, Pulmonary delivery, In vivo studie

Characterization of 111In3+ complexes of DTPA amide derivatives: biodistribution and clearance studied by gamma imaging

A large series of structurally related diethylenetriaminepentaacetic acid amide derivatives with different structures and lipophilic properties were synthesized and radiolabeled with 111In3+. Two of the more hydrophobic compounds studied ([111In]L9 and [111In]L10) showed high affinity for human serum albumin (HSA). The biodistribution and clearance properties shown by all complexes upon injection in Wistar rats were followed by gamma imaging. The blood retention time of the chelates correlates better with their binding to HSA than with their hydrophilic/lipophilic ratio. Hydrophilic and negatively charged complexes undergo renal retention, while the majority of the lipophilic complexes are retained in the blood for a longer period of time and are cleared through the liver.http://www.sciencedirect.com/science/article/B6T9Y-43X3775-F/1/b025cc67d43a82f7dead68ec99e0f4b

153Sm3+ and 111In3+ DTPA derivatives with high hepatic specificity: in vivo and in vitro studies

Two DTPA derivatives, a mono-amide derivative containing an iodinated synthon, DTPA-IOPsp (L1) and the ligand DTPA(BOM)3 (BOM=benzyloxymethyl) (L2), radiolabelled with 153Sm3+ and 111In3+, were studied as potential hepatospecific gamma scintigraphic agents. In vivo studies with Wistar rats show that the main excretory pathway for all the chelates studied is the hepatobiliary system. The complexes of L2 show even greater hepatobiliary specificity than L1, perhaps as a consequence of longer blood circulation times due to their strong affinity towards HSA. The 153Sm3+ chelates are also more hepatospecific than the corresponding 111In3+ chelates. The La3+ and In3+ chelates of L1 and L2 show some structural and dynamic differences in aqueous solution, as studied by 1H NMR spectroscopy. While only two nona-coordinated isomers were observed for the La3+ complexes with both ligands, its number is much larger in the In3+ complexes, with both octa- and hepta-coordinated species (with unbound side arms), as well as structural isomers for each coordination number.http://www.sciencedirect.com/science/article/B6TGG-45HFJNC-1/1/26df0708dbb11a2e6f7218c1115fd80