Radiosynthesis of [191]Os-2-acetylpyridine thiosemicarbazone complex, as an in vivo therapeutic radionuclide generator

Due to the anti-proliferative properties of platinum group-thiosemicarbazone complexes, the production of [191]Os-labeled 2-acetyl pyridine 4-N-methylthiosemicarbazone [[191]Os-APMTS] was investigated. [[191]Osmium [T[1/2]= 15.4d] was produced via the [190]Os[n,gamma][191]Os nuclear reaction using enriched target irradiated with thermal neutrons. Reaction of in-house synthesized 2-acetylpyridine thiosemicarbazone [APMTS] with [191]Os yielded [[191]Os]APMTS checked by ITLC followed by stability, partition co-efficient and biodistribution determination. Following synthesis and spectroscopic determination of the ligand [>99% chemical purity], the complex was prepared with a radiochemical purity of more than 95% [RTLC] and specific activity of 21.5 GB/mM and was stable in the formulation and presence of human serum at 37[degree sign]C for up to 48h. The partition coefficient was determined [log P. 1.23]. The biodistribution study up to 4 days demonstrated significant tissue uptake differences in the bone, blood, heart and thyroid. This is the first Os-191 labeled thiosemicarbazone designed as an in-vivo therapeutic radionuclide generator. Further investigation is ongoing on the evaluation of the complex in tumor bearing animals

Determination of [99]Mo contamination in [99m]Tc elute obtained from [99]Mo / [99m]Tc- generator

[99m]Tc is a widely used radioisotope in nuclear medicine centers which is obtained by elution from Mo-[99]/Tc-[99m] generators. Usually the generators are either supplied by the Iran Atomic Energy Agency or by private companies from foreign countries. In this study we have measured [99]Mo contamination in [99m]Tc elute from different generators in a period of one year. The radionuclide impurity of the [99m]Tc elute were studied in two types of radionuclide generators [A: produced in Iran and B: imported from other country]. In-vitro measurements were performed using dose calibrator. Direct measurements were made, using a standard canister at the time of milking of the generators and also in subsequent hours after milking. The results showed a mean of [99]Mo impurity in generators A and B to be 0.00932 +/- 0.0043 and 0.0170 +/- 0.0127 respectively. Although the results showed that the [99]Mo contamination in [99m]Tc elute was lesser than the maximum accepted activity limit of 0.015%, the difference in these two types may reflect different methods of productions of generator, as well as the quality control procedures. The mean of [99]Mo contamination in generators produced in Iran Atomic Energy Organization was lesser than generators imported from foreign origin

Gallium-68 (68Ga); the revival of an old positron emission tomography (PET) agent: the leading experience in Chile

In January 2008, we set up a 68Ge/ 68Ga generator able to produce enough quantities of 68Ga to label the same polypeptides, somatostatin analogos, used to treat patients suffering from neuroendocrine tumors. As far as we know, this is the first time that such a device is installed in Latin-America for specific PET/CT imaging different from 18F. During the last three months we have studied 30 patients for staging, re-staging and treatment control of neuroendocrine tumors using PET/CT images with 68Ga-DOTATATE. In all cases the image quality was excellent, providing clinically useful information in most of them. 68Ga is a very promising positron emitter radionuclide, cyclotron-independent, to label peptides and other molecules that open a wide window for Molecular Imaging.

En Enero de 2008 instalamos un generador de 68Ge/ 68Ga capaz de producir cantidades suficientes de 68Ga para marcar los mismos péptidos, análogos de la somatostatina, utilizados para el tratamiento de pacientes con tumores neuroendocrinos. De acuerdo con nuestro conocimiento, esta es la primera vez que se utilizada este aparato en Latinoamérica para obtener imágenes PET/CT específicas con un agente diferente al 18F. Durante los últimos tres meses hemos estudiado 30 pacientes con tumores neuroendocrinos con 68Ga-DOTATATE para etapificación, re-etapificación y control de tratamiento mediante imágenes PET/CT. En todos los casos la calidad de la imagen fue excelente proporcionando información clínicamente útil en la mayoría de ellos. 68Ga es un promisorio radionucleido emisor de positrones, independiente de un ciclotrón, para marcar péptidos y otras moléculas abriendo una amplia ventana para las Imágenes Moleculares.

Proyecto de fabricación de generadores de tecnecio - 99m / A project to manufacture technetium-99m generators

Introducción. El Tecnecio-99m (99mTc) es el radioisótopo más utilizado en medicina nuclear. Su uso en diagnóstico permite visualizar imágenes de estructuras anatómicas y brindar información sobre distintas funciones orgánicas. La gran demanda de este radionucleído se debe a sus favorables propiedades nucleares, a la gran cantidad de compuestos que se pueden marcar con él y al hecho de poder contar con generadores de 99mTc, lo que posibilita su obtención en lugares alejados de los centros de producción. Un generador de radioisótopos es un sistema mediante el cual un radionucleído padre genera por decaimiento radiactivo un radionucleído hijo de vida media más corta que la del padre. En el caso del generador de 99mTc, el radionucleído padre es el Molibdeno-99 (99Mo) cuya vida media es de 66 horas, mientras el radionucleído hijo, el 99mTc, tiene una vida media de 6 horas. Objetivo. La Comisión Chilena de Energía Nuclear (CCHEN) a través del Laboratorio de Producción de Radioisótopos realiza diariamente una producción de 99mTc, la cual entrega a Centros de Medicina Nuclear de la Región Metropolitana. Siin embargo, debido al método por el cual se obtiene, no es posible abastecer a los Centros de Medicina Nuclear de provincias. Conciente de esta necesidad, la CCHEN ha decidido poner en marcha el proyecto de fabricación de generadores de 99Mo - 99mTc, con lo cual nos situaremos en un breve plazo dentro del contexto de países que ya poseen esta tecnología. Materiales y Método. El método de fabricación se basa en la adsorción selectiva del 99Mo en óxido de aluminio (Al2O3 ), mientras el 99mTc que se genera por decaimiento radiactivo del 99Mo y que está débilmente unido a la alúmina, se puede eluir diariamente. Este tipo de generador es simple de operar y está diseñado en un sistema cerrado que permite mantener la esterilidad y proporcionar un producto de alta pureza. Resultados y Conclusión. La preparación de la alúmina, el acondicionamiento del Mo y las característica...

Quality control of 188W/188re generators

Quality control of 188W/188Re generators from two different manufacturers and two levels of activity each, was carried out.Elution yields, chemical as well as radionuclidic and radiochemical purities, elution profiles along six months, were evaluated.Broad elution profile, high efficiency, with tandem alumina column added, ionic exchange column needed for increase of radionuclidic concentration were characteristics of type I generators.Easy handling with slightly lower yields and high concentrations of activity were observed in type II generators. Similar radionuclidic impurities namely 192Ir, 191Os, 188W, 110mAg, 54Mn, 134Cs and 60Co as well as similar radiochemical yields obtained in the labelling of 188 Re-HEDP were observed with eluates of both generator types.Absorbed doses to radiopharmacy staff were less important in type II generators.