Current Approach in Radiochemical Quality Control of the 99mTc-Radiopharmaceuticals: a mini-review

Abstract To present optimized chromatographic systems for radiochemical purity (RCP) evaluation of 99mTc-eluate and 99mTc-radiopharmaceuticals, as well as to assess doses calibrator reliability for routine purposes in hospital radiopharmacies. RCP was determined by different systems and radioactivity was quantified by TLC-scanner, doses calibrator and gamma-counter. Suitable and optimized systems were presented for RCP analyses. No significant differences were observed between radioactivity counting devices and, thus, doses calibrator showed reliability for RCP determination in hospital radiopharmacies.

Preparation, quality control and thyroid molecule imaging of solid-target based radionuclide ioine-124 / 北京大学学报(医学版)

OBJECTIVE@#To provide useful information for the further production and application of this novel radio-nuclide for potential clinical application.@*METHODS@#124Te (p,n) 124I nuclide reaction was used for the 124I production. Firstly, the target material, 124TeO2 (200 mg) and Al2O3 (30 mg) mixture, were compressed into the round platinum based solid target by tablet device. HM-20 medical cyclotron was applied to irradiate the solid target slice for 6-10 h with helium and water cooling. Then, the radiated solid target was placed for 12 h (overnight) to decay the radioactive impurity; finally, 124I was be purified by dry distillation using 1 mL/min nitrogen for about 6 hours and radiochemical separation methods. Micro-PET imaging studies were performed to investigate the metabolism properties and thyroid imaging ability of 124I.After 740 kBq 124I was injected intravenously into the tail vein of the normal mice, the animals were imaged with micro-PET and infused with CT. The micro-PET/CT infusion imaging revealed actual state 124I's metabolism in the mice.@*RESULTS@#It was been successfully applied for 200 mg 124TeO2 plating by the tablet device on the surface of platinum. It showed smooth, dense surface and without obviously pits and cracks. The enriched 124Te target was irradiated for 6 to 10 hours at about 12.0 MeV with 20 μA current on HM-20 cyclotron. Then 370-1 110 MBq 124I could be produced on the solid target after irradiation and 370-740 MBq high specific activity could be collected afterdry distillation separation and radio-chemical purification.124I product was finally dissolved in 0.01 mol/L NaOH for the future distribution. The gamma spectrum of the produced 124I-solution showed that radionuclide purity was over 80.0%. The micro-PET imaging of 124I in the normal mice exhibited the thyroid and stomach accumulations and kidney metabolism, the bladder could also be clearly visible, which was in accordance with what was previously reported. To the best of our knowledge, it was the first production of 124I report in China.@*CONCLUSION@#In this study, the preparation of 124TeO2 solid target was successfully carried out by using the tablet device. After irradiation of the 124TeO2 solid target and radio-chemical purification, we successfully produced 370-740 MBq high specific activity 124I by a cyclotron for biomedical application, and micro-PET imaging of 124I in normal mice exhibited the thyroid accumulations. Also, slight uptake in stomach were also monitored with almost nonuptake in other organs in the micro-PET imaging. The production of 124I is expected to provide a new solid target radionuclide for the scientific research and potential clinical application of our country.

Determination of chemical and radiochemical purity of [14C] clozapine by high performance liquid chromatography and liquid scintillation

The mechanism of action and metabolism of clozapine, a complex drug used in psychopharmacology, is not completely understood. The effects of this compound in human body are related to some interactions with serotonin and dopamine neurotransmitter receptors. To further elucidate the mechanism of action and to support ongoing drug metabolism studies, [14C] clozapine with suitable radiochemical purity was synthesized in nuclear research center of AEOI. In this report radiochemical and chemical purity of [14C] clozapine were determined by liquid scintillation and reversed phase-HPLC respectively. Separation of [14C] clozapine and its synthesized interface products was carried on C8 optimal column and UV detector at 254nm.The mobile phase consisted of acetonitril-buffered aqueous solution of sodium phosphate with a flow rate of 1ml/min. Detection limit and analytical precision of RP-HPLC method were 0.01micro g/ml and 1-3.4% respectively. The chemical purity of synthesized clozapine was >99%. For determination of activity and radiochemical purity, liquid scintillation spectrometer was used and counting was done by direct addition of samples to ACS [Amersham] solution. Specific activity of synthesized clozapine was 10 micro Ci/mg and radiochemical purity of >99.% was achieved. By separation of [14C] clozapine and its synthesized intermediate products the represented methods, in addition to determination of total yield of reaction, it was possible to determine every step of reaction therefore; it was not nessaseray to use classical methods such as: distillation, liquid-liquid extraction, etc. If the HPLC instrument is equipped with radiochemical detector, simultaneous determination of radiochemical as well as chemical yields of products are possible

[Evaluation and comparison of different quality control methods in radiochemical purity determination of new peptide kits 99mTc-EDDA-Tricine-HYNIC-Tyr3-Octreotide and 99mTc-EDDA-Tricine-HYNIC-Tyr3-octreotate for imaging somatostatin receptor positive tumors]

Using labeled peptides enjoys high importance in nuclear medicine. Somatostatin analogs labeled with different radionuclide are vastly investigated for diagnosis or treatment of somatostatin receptor positive tumors. Labeling somatostatin analogs with 99mTc as alternative of 111In needs doing different quality control method for determination of labeling yield and complex stability for clinic applications. For determining radiochemical purity, three different methods were compared and evaluated including HPLC, TLC and Sep-Pak. All the three methods were suitable for determining of radiochemical purity in peptide kits, although using HPLC was more effective rather than the others. HPLC was the best method for determination of radiochemical purity of the peptide kits. TLC or Sep-Pak method should only be employed if HPLC is not available in nuclear medicine clinics, and after training and gaining sufficient operational experience. In this research, a new monoclonal antibody against colon cancer cells was prepared and antigen concentration in different cells determined by a radioimmunoassay method using iodine [I-125] labeled protein G. 125I-labeled protein G percent binding to white blood cell, HT29, LS180 and MCF7 cell lines were 7.1%, 91.2%, 75.8% and 40.2%, respectively. Regarding importance of monoclonal antibody applications, it is necessary to find an efficient method for their evaluation in cancer therapy. In this method, a radioactive agent with no count restriction was used. Also by this method, amount of the antigen can be easily quantified

Lanreotide and octreotide complexed with technetium-99m: labeling, stability and biodistribution studies

Lanreotide and Octreotide are cyclic octapeptide analogues of somatostatin that were labeled with the radioisotope Technetium-99m for use in diagnostic nuclear medicine. The peptides were processed in a tartrate/phthalate buffer solution containing reducing agent. The purpose of this investigation was to optimize direct labeling by varying some parameters, and to evaluate radiochemical stability and biodistribution in animals. The marked peptides were obtained with high labeling efficiency and no need for subsequent purification. best radiolabeling results corresponded to a molar ratio of SnCl2.H2O/peptide of 4.5. `ANTPOT. 99mTc'-peptides were radiochemically stable for 6 hours...

Guia para aplicaciones industriales de radiaccion trazadores y fuentes selladas de radiación

La referencia del uso de trazadores data del primer siglo de la era Cristiana, se utilizaba perfectamente en hidrologia, es por eso fueron las primeras aplicaciones industriales, hidrologicos y biologicos, se vio la posibilidad de prodicir radioisotopos; por ser una herremienta en la utiización de radio trazadores para las aplicaciones industriales de la tecnologia, Nuclear, como las industrias papeleras, quimicas, metalurgicas, cementeras, petroleros petroquimicas e ingenieria Sanitaria y del medio ambiente son algunos ambitos de aplicacción

Salvamento de extremidades en niños con tumores óseos malignos. Diferentes métodos / Different procedures for limb salvage in children who have malignant bone tumors

Los tumores óseos en niños han sido causa de controversia en cuanto a tratamiento médico y quirúrgico a través de los años. El presente trabajo tiene como objetivo el salvamento de extremidades en niños con tumores óseos, conservar la vida como objetivo principal y conservar la fundación de las extremidades mediante tratamiento médico y la colocación de injerto e implante diferentes. El presente trabajo se realizó en el Instituto Nacional de Pediatría en el Departamento y Ortopedia de 1991 a 1997 en el cual se seleccionaron a 30 pacientes, los cuales cumplieron con los criterios de selección del estudio con edad promedio de 14 años, todos con cáncer óseo. Predominó en un 95 por ciento el osteosarcoma (28/30), más un condroblastoma y un quiste óseo aneurismático. Se realizó resección ósea más injerto autólogo de peroné, resección ósea más colocación de clavo Colchero, clavo Küntscher, autoinjerto y yeso, y endoprótesis no convencional. Los pacientes han tenido un seguimiento de 4 a 50 meses; 22 pacientes están vivos y sin datos de actividad tumoral, 8 pacientes han fallecido secundario a sepsis, segunda neoplasia y por recaída del tumor. El promedio de la función articular es de 78 por ciento, y la complicación posoperatoria más frecuente, fue de origen infeccioso y en la endoprótesis. La curva de sobrevida de los pacientes libres de patología fue del 71 por ciento. A todos los pacientes con osteosarcoma se les realizaron 8 ciclos de quimioterapia

Technetium-99m-alendronate: a new radiopharmaceutical for bone scanning

The purpose of this paper is to report the preparation of a new technetium-99m-radiopharmaceutical for bone scanning. The chelating agent for99mTc is a new bisphosphonate, alendronate, 4-amino-1-hydroxy-butylidene-1,1-bisphosphonate (ABP) used as a treatment for osteoporosis. ABP, because of its amino group, seems to be better suited to form a strong and stable complex with technetium-99m and therefore might be better than 99mTc-etidronate (HEDP) or 99mTc-medronate (MDP) for bone scanning. A sterile dry kit containing APB, a reducing agent and a stabilizer was prepared. The parameters studied were molar concentrations, pH, shelf life, labeling efficiency and radiochemical purity. the oven dried sterile kit was formulated with 5 mg ABP, 0.25 mg stannous fluoride and 0.025 mg gentisic acid at pH2.5-3.5. The labeling efficiency with 20 - 1500 MBq of pertechnetate (99mTcO4-) was over 95 percent at room temperature and was stable for 5 h. Technetium-99m-alendronate was tested in two rabbits and it proved to be a promising new radiopharmaceutical for bone scanning. Work is underway to study underway to study 99m-Tc-ABP biodistribution in a statistically significant number of laboratory animals and, later on, to determine radiopharmacokinetic parameters in normal volunteers

Noçöes de química da radiaçäo em sistemas biológicos / Notions of chemistry radiation in biological systems

A presente publicaçäo examina alguns aspectos dos efeitos biológicos diretos e indiretos da radiaçäo: formaçäo de pares, radicais livres, ion superóxido de hidrogênio, radical hidroxila, oxigênio singleto junto aos mecanismos radioprotetores endógenos dos organismos e os meios em que pode ser incrementada a radiorresistência de sistemas bioquímicos

Controle radioquimico e biológico da metaiodobenzil-Guanidina (MIBG) marcado com 131I / Radiochemical and biological control of metaiodobenzyl-Guanidine(MIBG) labeled with 131I

aeste trabalho apresentam-se a padronizaçäo do Controle de Radioquímico da MIBG- 131I, por meio de eletroforese em tampäo acetato pH 4,5 à 300V, durante 40 minutos e da distribuiçäo biológica em rato Wistar por um tempo näo superior a 60 minutos, após a administraçäo do traçador

Nuevos avances en radiofarmacia, su aplicación en medicina nuclear / New progress in radiophomacy, its aplication in nuclear medicine

Se describen nuevos radiofármacos de aplicación en gastroenterología, huesos, sistema cardiovascular, cerebro y riñones, en medicina nuclear