Intra-Cavity Astigmatic Mode Converting VECSEL

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Comparative biodistribution profile of [131I]VIP and [131I]VIP10-28

Various tumor cells express significantly higher amounts of VIP receptors (VIPR) that provided the basis for the clinical use of radiolabeled VIP for the in vivo localization of tumors. This work studied the labeling of VIP and VIP10-28 with iodine-131 to compare the biological distribution of the labeled compounds in Nuce mice and the affinity for tumor cells. Both VIP and VIP10-28 peptides contain two tyrosine residues, in positions 10 and 22, that are theoretically equally susceptible to radioiodination employing oxidative electrophilic substitution using oxidizing agents like Chloramine T. Radiochemical purity of the reaction mixture was determined by electrophoresis and HPLC. The VIP peptide and the fragment were labeled with radioiodine with good radiochemical yield (above 96%). Suitable, but important differences can be observed in biological distribution studies. Comparatively, blood clearance was faster for labeled VIP and perhaps because of this, the uptake in tumor was lower, especially during the first hour. These differences observed in the biological distribution of the compounds can be related to the lipophilicity of the labeled compounds.<br>Várias células tumorais expressam significantemente uma alta quantidade de receptores VIP (VIPR) que determinam a base para o uso clínico de VIP radiomarcado para localização de tumores in vivo. Foi estudado neste trabalho a marcação do VIP e do fragmento VIP10-28 com iodo-131 comparando a distribuição biológica dos compostos marcados em camundongos Nude e sua afinidade pelas células tumorais. Ambos os peptídeos, VIP e VIP10-28. contém dois resíduos de tirosina nas posições 10 e 22, que teoricamente são igualmente susceptíveis pela substituição eletrofílica oxidativa do radioiodo utilizando Cloramina T como agente oxidante. A pureza radioquímica da mistura de reação foi determinada por eletroforese e cromatografia líquida de alta eficiência (CLAE). O VIP e fragmento foram marcados com radioiodo com bom rendimento radioquímico (superior a 96%). Importantes diferenças foram observadas nos estudos de distribuição biológica. Comparativamente, o clareamento sanguíneo foi mais rápido para VIP marcado e por esta razão, a captação no tumor foi inferior, especialmente na primeira hora. Estas diferenças observadas na distribuição biológica dos compostos podem estar relacionadas com a lipofilicidade dos compostos marcados

Improved tumour detection by gastrin receptor scintigraphy in patients with metastasised medullary thyroid carcinoma.

Contains fulltext : 49478.pdf (publisher's version ) (Closed access)PURPOSE: Radiopeptide imaging is a valuable imaging method in the management of patients with neuroendocrine tumours (NET). To determine the clinical performance of gastrin receptor scintigraphy (GRS), it was compared with somatostatin receptor scintigraphy (SRS), computed tomography (CT) and (18)F-FDG positron emission tomography (PET) in patients with metastasised/recurrent medullary thyroid carcinoma (MTC). METHODS: Twenty-seven consecutive patients underwent imaging with GRS, SRS (19 patients), CT and PET (26 patients). GRS and SRS were compared with respect to tumour detection and uptake. CT, PET, magnetic resonance imaging (MRI), ultrasound (US) and follow-up were used for verification of findings. In addition, GRS, CT and PET were directly compared with each other to determine which method performs best. RESULTS: Nineteen patients underwent both GRS and SRS. Among these, GRS showed a tumour detection rate of 94.2% as compared to 40.7% for SRS [mean number of tumour sites (+/-SD) and 95% confidence intervals (CI): GRS 4.3+/-3.1/2.8-5.7, SRS 1.8+/-1.6/1.1-2.6]. In 26 patients, GRS, CT and PET were compared. Here, GRS showed a tumour detection rate of 87.3% (CT 76.1%, PET 67.2%; mean number of tumour sites and 95% CI: GRS 4.5+/-4.0/2.9-6.1, CT 3.9+/-3.5/2.5-5.3, PET 3.5+/-3.3/2.1-4.8). If GRS and CT were combined, they were able to detect 96.7% of areas of tumour involvement. CONCLUSION: GRS had a higher tumour detection rate than SRS and PET in our study. GRS in combination with CT was most effective in the detection of metastatic MTC