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1.
Radiat Environ Biophys ; 60(2): 389-394, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33751179

RESUMO

This paper presents results of measurements of 99mTc activity concentration in air and nuclear medical personnel blood during ventilation-perfusion SPECT lung scans. 99mTc activity measurements were conducted at the Nuclear Medicine Department, John Paul II Hospital, Krakow. Technicians and nurses who perform examinations were equipped with personal aspirators enabling air sampling to determine the radiation exposure at their workplaces. Measurements allowed to evaluate the concentration of 99mTc in 14 air samples and it ranged from 7800 ± 600 to 10,000 ± 1000 Bq m-3 for air samples collected by technicians and from 390 ± 30 to 600 ± 40 Bq m-3 for air samples collected by nurses. In addition 99mTc concentrations in blood of medical personnel were determined in 24 samples. For technicians the maximum 99mTc blood concentration levels reached 920 ± 70 Bq L-1 and 1300 ± 100 Bq L-1. In the case of nurses, the maximum estimated activity concentrations were about ten times lower, namely 71 ± 7 Bq L-1 and 39 ± 3 Bq L-1. Although the intakes appear to be relatively high, the resulting annual effective doses are about 34 µSv for technicians and only 2 µSv for nurses.


Assuntos
Exposição Ocupacional/análise , Exposição à Radiação/análise , Tecnécio/análise , Pessoal de Saúde , Humanos , Pulmão/diagnóstico por imagem , Medicina Nuclear , Doses de Radiação , Monitoramento de Radiação , Tecnécio/sangue , Tomografia Computadorizada de Emissão de Fóton Único , Cintilografia de Ventilação/Perfusão
2.
Anal Chem ; 91(7): 4585-4591, 2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-30843388

RESUMO

In the frame of studies on the safe disposal of nuclear waste, there is a great interest for understanding the migration behavior of 99Tc. 99Tc originating from nuclear energy production and global fallout shows environmental levels down to 107 atoms/g of soil (∼2 fg/g). Extremely low concentrations are also expected in groundwater after diffusion of 99Tc through the bentonite constituting the technical barrier for nuclear waste disposal. The main limitation to the sensitivity of the mass spectrometric analysis of 99Tc is the background of its stable isobar 99Ru. For ultratrace analysis, the Accelerator Mass Spectrometry (AMS) setup of the Technical University of Munich using a Gas-Filled Analyzing Magnet System (GAMS) and a 14 MV Tandem accelerator is greatly effective in suppressing this interference. In the present study, the GAMS setup is used for the analysis of 99Tc in samples of the seawater reference material IAEA-443, a peat bog lake, and groundwater from an experiment of in situ diffusion through bentonite in the controlled zone of the Grimsel Test Site (GTS) within the Colloid Formation and Migration (CFM) project. With an adapted chemical preparation procedure, measurements of 99Tc concentrations at the fg/g levels with a sensitivity down to 0.5 fg are accomplished in notably small natural water samples. The access to these low concentration levels allows for the long-term monitoring of in situ tracer tests over several years and for the determination of environmental levels of 99Tc in small samples.


Assuntos
Magnetismo , Espectrometria de Massas/métodos , Tecnécio/análise , Água Subterrânea/análise , Lagos/química , Resíduos Radioativos/análise , Poluentes Radioativos da Água/análise
3.
Radiat Environ Biophys ; 58(3): 469-475, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30997611

RESUMO

This paper presents the results of measurements of 99mTc activity concentrations in indoor air in a nuclear medicine department and resulting estimated 99mTc intake by medical personnel. 99mTc air activity measurements were conducted at the Nuclear Medicine Department, John Paul II Hospital, Krakow, Poland, during ventilation-perfusion SPECT lung scans. Technetium from the air was collected by means of a mobile aerosol sampler with a Petryanov filter operating at an average flow rate of 10 dm3 min-1. Measured activities ranged from 99 ± 11 to 6.1 ± 0.5 kBq m-3. The resulting daily average intake of 99mTc by medical staff was estimated to be 5.4 kBq, 4.4 kBq, 3.0 kBq and 2.5 kBq, respectively, for male technicians, female technicians, male nurses and female nurses. Corresponding annual effective doses were 1.6 µSv for technicians and 1 µSv for nurses. The highest equivalent dose values were determined for extrathoracic (ET) airways: 5 µSv and 10 µSv for nurses and technicians, respectively. It is concluded that estimated annual absorbed doses are over three orders of magnitude lower than the dose limit established in the Polish Atomic Law Act and in recommendations of the International Commission on Radiological Protection for medical staff.


Assuntos
Poluentes Ocupacionais do Ar/análise , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Exposição Ocupacional/estatística & dados numéricos , Tecnécio/análise , Feminino , Pessoal de Saúde , Humanos , Masculino , Corpo Clínico , Polônia , Doses de Radiação , Monitoramento de Radiação , Proteção Radiológica
4.
Med Mycol ; 56(4): 479-484, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28992125

RESUMO

Cryptococcus gattii is one of the etiologic agents of cryptococcosis, a systemic mycosis that occurs in healthy and immunosuppressed humans and animals worldwide. Primary pulmonary infection caused by C. gattii is usually followed by fungal dissemination to the central nervous system, resulting in high mortality rates. In this context, animal models of cryptococcosis are useful in the study of fungal pathogenesis and host response against the pathogen, and for testing novel therapeutic options. The most frequently applied method to study fungal dissemination from the lungs to other organs is by culturing tissues, which is not accurate for the detection and quantification of fungal load at early stages of the infection. To overcome this problem, the purpose of this study was to develop a new method for the quantification of Cryptococcus dissemination. One C. gattii strain was efficiently radiolabeled with technetium-99m (99mTc), without affecting viability of the cells. Further, the 99mTc-C. gattii (111 MBq) strain was used to infect mice by intratracheal and intravenous route for biodistribution studies. 99mTc-C. gattii was successfully used in detection of the yeast in the brain of mice 6 hours postinoculation, while the detection using colony forming units was possible only 24 hours postinfection. Our results provided an alternative method that could be applied in further investigations regarding the efficacy of antifungals, fungal virulence, and host-pathogen interactions.


Assuntos
Criptococose/microbiologia , Cryptococcus gattii/fisiologia , Tecnécio , Animais , Contagem de Colônia Microbiana , Cryptococcus gattii/metabolismo , Modelos Animais de Doenças , Humanos , Marcação por Isótopo , Pulmão/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tecnécio/análise , Tecnécio/metabolismo , Distribuição Tecidual
5.
Cutan Ocul Toxicol ; 37(1): 1-8, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28372461

RESUMO

Radioactive skin contamination is one of the most likely risks which occurs after accidental or occupational radiological accidents apart from internal contamination. In such cases where the radioactive contamination has occurred, the person who is contaminated should be decontaminated as early as possible to reduce the damaging health effects of radiation. In the present study, the decontamination efficiency of a developed skin decontamination kit "dermadecon" has been evaluated in animal models and human subjects using gamma scintigraphy. Decontamination efficiency (percentage of the radioactive contaminant removed) was calculated for each radioactive isotope of the study and compared with control where general washing procedure was followed using liquid and soap. The effectiveness of the kit was calculated in animal model with respect to 99mTc-sodium-pertechnetate (99mTcO4-), 201TlCl and 131I and was found 92.84 ± 4.9%, 91.18 ± 3.23% and 94.67 ± 2.92%, respectively. Whereas, in case of human skin, the decontamination efficiency for 99mTcO4- was observed to be 95.00 ± 3.21%. On the basis of findings from the study, it can be concluded that the decontamination agents of the used skin decontamination kit are effective for removal of localized radioactive contaminants from skin, as compared with normal decontamination using soap and water.


Assuntos
Descontaminação/métodos , Radioisótopos do Iodo/análise , Tecnécio/análise , Radioisótopos de Tálio/análise , Ácido Acético/química , Adulto , Animais , Cetrimônio , Compostos de Cetrimônio/química , Quelantes/química , Ácido Edético/química , Humanos , Ácido Hipocloroso/química , Radioisótopos do Iodo/química , Masculino , Pessoa de Meia-Idade , Oxidantes/química , Cintilografia , Ratos Sprague-Dawley , Substâncias Redutoras/química , Pele , Bicarbonato de Sódio/química , Tecnécio/química , Radioisótopos de Tálio/química , Tiossulfatos/química , Adulto Jovem
6.
Mol Imaging ; 16: 1536012116689001, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28654377

RESUMO

The aim of this study is to evaluate the localization of 99mTc-labeled dextran-coated superparamagnetic iron oxide (SPIO) nanoparticles to the liver tumor using image-based analysis. We delivered 99mTc-SPIO intravenously or intra-arterially (IA) with/without Lipiodol to compare the tumor localization by gamma scintigraphy, single-photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) in a rabbit liver tumor. The gamma and SPECT image-based analysis shows that the uptake ratio of the tumor to the normal liver parenchyma is highest after delivery of 99mTc-SPIO with Lipiodol IA and that well correlates with the trend of the signal decrease in the liver MRIs. Intra-arterial delivery of SPIO with Lipiodol might be a good drug delivery system targeting the hepatic tumors, as confirmed by image-based analysis.


Assuntos
Infusões Intra-Arteriais/métodos , Imageamento por Ressonância Magnética/métodos , Tecnécio/análise , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Animais , Meios de Contraste , Coelhos
7.
Anal Chem ; 89(11): 5857-5863, 2017 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-28478682

RESUMO

99Tc is an artificial beta emitter widely used in nuclear medicine for diagnostic tests. A fully automated and rapid system for 99Tc monitoring is introduced with the aim to improve hospital residues management. This system can also be helpful for controlling urban wastewater. Figures of merit similar to those obtained with liquid scintillation counting were achieved by exploiting a simple, economic, and portable system with spectrophotometric detection. The combination of flow analysis techniques, i.e., lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), with a selective resin ((weak base extraction chromatographic (WBEC) resin) enables the analysis to be performed in a short time, achieving high selectivity and sensitivity levels. After elution with NH4OH (3 mol·L-1), 99Tc is derivatized with 1,5-diphenylcarbohydrazide (DPC) and finally detected by a miniaturized fiber optic CCD spectrophotometer at 520 nm, exploiting a long path-length liquid waveguide capillary cell (LWCC) of 100 cm path length. The proposed method was optimized by experimental design, achieving a limit of detection (LOD) of 4 ng of 99Tc (2.5 Bq), a reproducibility of 6%, and a resin durability of 78 injections. The microcolumn allows one to preconcentrate up to 100 mL of sample without deterioration of the analytical signal. The automated system was successfully applied to hospital residues and urban wastewater, and the attained recoveries were between 90% and 110%.


Assuntos
Monitoramento Ambiental/métodos , Tecnécio/análise , Gerenciamento de Resíduos/métodos , Águas Residuárias/análise , Automação/métodos , Hospitais , Limite de Detecção , Urbanização
8.
Anal Chem ; 89(2): 1260-1266, 2017 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-27981843

RESUMO

A rapid and accurate identification of necrotic myocardium is of great importance for diagnosis, risk stratification, clinical decision-making, and prognosis evaluation of myocardial infarction. Here, we explored technetium-99m labeled rhein derivatives for rapid imaging of the necrotic myocardium. Three hydrazinonicotinic acid-linker-rhein (HYNIC-linker-rhein) derivatives were synthesized, and then, these synthetic compounds were labeled with technetium-99m using ethylenediaminediacetic acid (EDDA) and tricine as coligands [99mTc(EDDA)-HYNIC-linker-rhein]. The necrosis avidity of the three 99mTc-labeled rhein derivatives was tested in a mouse model of ethanol-induced muscular necrosis by gamma counting, histochemical staining, and autoradiography. A lead tracer for visualization of necrotic myocardium was assessed by single photon emission computed tomography/computed tomography (SPECT/CT) imaging in a rat model with reperfused myocardial infarction. The necrosis avidity mechanism of the tracer was explored by DNA binding studies in vitro and blocking experiments in vivo. Results showed that the uptake in necrotic muscles of the three 99mTc-compounds was higher than that in viable muscles (P < 0.001). Autoradiography and histochemical staining results were consistent with selective uptake of the radiotracer in the necrotic regions. Among the these tracers, 99mTc(EDDA)-HYNIC-ethylenediamine-rhein [99mTc(EDDA)-HYNIC-2C-rhein] displayed the best distribution profiles for imaging. The necrotic myocardium lesions were clearly visualized by SPECT/CT using 99mTc(EDDA)-HYNIC-2C-rhein at 1 h after injection. The necrotic-to-viable myocardium and necrotic myocardium-to-blood uptake ratios of 99mTc(EDDA)-HYNIC-2C-rhein were 4.79 and 3.02 at 1 h after injection. DNA binding studies suggested HYNIC-linker-rhein bound to DNA through intercalation. The uptake of 99mTc(EDDA)-HYNIC-2C-rhein in necrotic muscle was significantly blocked by excessive unlabeled rhein, with 77.61% decline at 1 h after coinjection. These findings suggested 99mTc(EDDA)-HYNIC-2C-rhein emerged as a "hot spot" imaging probe that has a potential for rapid imaging of necrotic myocardium. The necrosis avidity mechanism of 99mTc(EDDA)-HYNIC-linker-rhein may be due to its interaction with exposed DNA in necrotic tissues.


Assuntos
Antraquinonas/análise , Coração/diagnóstico por imagem , Infarto do Miocárdio/diagnóstico por imagem , Miocárdio/patologia , Necrose/diagnóstico por imagem , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tecnécio/análise , Animais , Camundongos , Ratos
9.
Anal Chem ; 88(23): 11931-11937, 2016 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-27813399

RESUMO

An extremely high accumulation and retention of technetium in marine plants, especially brown seaweed, makes it a unique bioindicator of technetium. In the present work, a novel approach was developed for the speciation analysis of technetium in seaweed, wherein a series of biochemical separations was exploited to isolate different species of technetium. Inductively coupled plasma mass spectrometry (ICP-MS) was applied for the measurement of 99Tc after thorough radiochemical preconcentration and purification. The results show that the distribution of technetium species in seaweed is relatively dispersive. Besides the inorganic species of TcO4-, most of technetium (>75%) combined with organic components of seaweed such as algin, cellulose, and pigment. This investigation could provide important fundamental knowledge for studying the processes and mechanisms of 99Tc accumulation in the natural seaweed.


Assuntos
Alga Marinha/química , Tecnécio/análise , Espectrometria de Massas , Radioquímica
10.
Anal Chem ; 87(17): 9054-60, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26270580

RESUMO

This paper presents a new approach for liquid scintillation counting (LSC) analysis of single-radionuclide samples containing appreciable organic or inorganic quench. This work offers better analytical results than existing LSC methods for technetium-99 ((99g)Tc) analysis with significant savings in analysis cost and time. The method was developed to quantify (99g)Tc in environmental liquid and urine samples using LSC. Method efficiency was measured in the presence of 1.9 to 11 900 ppm total dissolved solids. The resultant quench curve proved to be effective for quantifying spiked (99g)Tc activity in deionized water, tap water, groundwater, seawater, and urine samples. Counting efficiency was found to be 91.66% for Ultima Gold LLT (ULG-LLT) and Ultima Gold (ULG). Relative error in spiked (99g)Tc samples was ±3.98% in ULG and ULG-LLT cocktails. Minimum detectable activity was determined to be 25.3 and 22.7 mBq for ULG-LLT and ULG cocktails, respectively. A preconcentration factor of 1000 was achieved at 100 °C for 100% chemical recovery.


Assuntos
Compostos Radiofarmacêuticos/análise , Contagem de Cintilação , Tecnécio/análise , Poluentes Radioativos da Água/análise , Rios/química
11.
Anal Bioanal Chem ; 407(19): 5571-8, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26007698

RESUMO

A new approach exploiting in-syringe dispersive liquid-liquid microextraction (DLLME) for (99)Tc extraction and preconcentration from biological samples, i.e., urine and saliva, and liquid residues from treated patients is presented. (99)Tc is a beta emitter with a long half-life (2.111 × 10(5) years) and mobility in the different environmental compartments. One of the sources of this radionuclide is through the use of its father (99m)Tc in medical diagnosis. For the first time a critical comparison between extractants and disperser solvents for (99)Tc DLLME is presented, e.g., tributyl phosphate (TBP), trioctylmethylammonium chloride (Aliquat®336), triisooctylamine (TiOA), as extractants in apolar solvents such as xylene and dodecane, and disperser solvents such as acetone, acetonitrile, ethanol, methanol, 1-propanol, and 2-propanol. The system was optimized by experimental design, and 22.5% of Aliquat®336 in acetone was selected as extractant and disperser, respectively. Off-line detection was performed using a liquid scintillation counter. The present method has a (99)Tc minimum detectable activity (MDA) of 0.075 Bq with a high extraction/preconcentration frequency (8 h(-1)). Urine, saliva, and hospital residues were satisfactorily analyzed with recoveries of 82-119%. Thus, the proposed system is an automatic powerful tool to monitor the entry of (99)Tc into the environment. Graphical Abstract (99m)Tc is widely used in Nuclear Medicine for diagnosis. Its daugther (99)Tc is automatically monitored in biological samples from treated patients by in-syringe dispersive liquid-liquid microextraction.


Assuntos
Automação , Microextração em Fase Líquida/instrumentação , Contagem de Cintilação , Tecnécio/análise , Humanos , Recursos Humanos em Hospital , Tecnécio/sangue , Tecnécio/urina
12.
Environ Sci Technol ; 48(7): 3935-42, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24617716

RESUMO

An automated multisample processing flow injection (FI) system was developed for simultaneous determination of technetium, neptunium, plutonium, and uranium in large volume (200 L) seawater. Ferrous hydroxide coprecipitation was used for the preliminary sample treatment providing the merit of simultaneous preconcentration of all target radionuclides. Technetium was separated from the actinides via valence control of technetium (as Tc(VII)) in a ferric hydroxide coprecipitation. A novel preseparation protocol between uranium and neptunium/plutonium fractions was developed based on the observation of nearly quantitative dissolution of uranium in 6 mol/L sodium hydroxide solution. Automated extraction (TEVA for technetium and UTEVA for uranium) and anion exchange (AGMP-1 M for plutonium and neptunium) chromatographic separations were performed for further purification of each analyte within the FI system where four samples were processed in parallel. Analytical results indicate that the proposed method is robust and straightforward, providing chemical yields of 50-70% and improved sample throughput (3-4 d/sample). Detection limits were 8 mBq/m(3) (0.013 pg/L), 0.26 µBq/m(3) (0.010 fg/L), 23 µBq/m(3) (0.010 fg/L), 84 µBq/m(3) (0.010 fg/L) and 0.6 mBq/m(3) (0.048 ng/L) for (99)Tc, (237)Np, (239)Pu, (240)Pu and (238)U for 200 L seawater, respectively. The unique feature of multiradionuclide and multisample simultaneous processing vitalizes the developed method as a powerful tool in obtaining reliable data with reduced analytical cost in both radioecology studies and nuclear emergency preparedness.


Assuntos
Atividades Humanas , Monitoramento de Radiação/métodos , Radioisótopos/análise , Água do Mar/química , Poluentes Radioativos da Água/análise , Compostos Férricos/química , Análise de Injeção de Fluxo , Humanos , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Netúnio/análise , Oxirredução , Plutônio/análise , Hidróxido de Sódio/química , Soluções , Tecnécio/análise , Urânio/análise
14.
Pharm Dev Technol ; 19(2): 189-93, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23369008

RESUMO

The application of combined diagnosis and therapy through nanotechnology applications is attracting increasing attention worldwide. Polymeric self-assembled nanoparticles (NPs) have been studied for this purpose. Micelles and vesicles with or without a magnetic core can efficiently carry diagnostic and/or therapeutic agents to a desired target. The biological behavior of these NPs has been evaluated in this study, after radiolabeling with (99m)Tc. In vitro stability, in media that mimic the environment of the living body, was better for vesicles than for micelles at 1 h and decreased for both as time passed. After administration to healthy animals, all NPs presented major uptake at liver and spleen as expected. Biodistribution and imaging studies confirmed the higher uptake in these organs for the hybrid NPs and at higher extent for the ones with larger size, indicating that the magnetic load and size play an important role on in vivo distribution.


Assuntos
Micelas , Nanopartículas/análise , Polímeros/farmacocinética , Animais , Feminino , Camundongos , Polímeros/análise , Tecnécio/análise , Distribuição Tecidual
15.
Artigo em Inglês | MEDLINE | ID: mdl-38626842

RESUMO

BACKGROUND AND OBJECTIVES: In a hospital radiopharmacy with 2a operational level, including the preparation of radiopharmaceuticals from prepared and approved reagent kits, it is common to have a single activimeter or dose calibrator for labeling and fractionation, and to perform the quality controls of the 99mTc-radiopharmaceuticals. In certain cases, the accumulation of radioactive material or accidental contamination of the work area causes the background to exceed the limits to carry out the radiochemical purity analyses and it is necessary to look for viable alternatives. In this work, a Geiger Müller detector (equipped with a probe for measuring surface contamination) frequently used for radioprotection purposes, was validated as an alternative and its performance was compared against the activimeter for 99mTc-radiopharmaceuticals. MATERIALS AND METHODS: Using [99mTc]pertechnetate, systematic studies of error analyses and detector response to activity concentration, activity and measurement time were carried out in liquid matrices and in paper. The results were compared against an activimeter calibrated for [99mTc]Tc. RESULTS: The developed method was used to determine the radiochemical purity of the compounds [99mTc]Tc-MDP and [99mTc]Tc-MIBI by ascending paper chromatography tests, obtaining comparable values to those measured with an activimeter in the same system (within 1% uncertainty) and using the method of vial partitioning in a dedicated equipment. CONCLUSIONS: This work demonstrates that a Geiger Müller detector with a probe for measuring surface contamination can be adequately used to replace other equipment in the control of radiochemical purity in the hospital radiopharmacy.


Assuntos
Controle de Qualidade , Compostos Radiofarmacêuticos , Compostos Radiofarmacêuticos/análise , Tecnécio/análise , Calibragem , Pertecnetato Tc 99m de Sódio/análise
16.
J Pharm Biomed Anal ; 246: 116224, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38759321

RESUMO

Cardiovascular diseases, including fatal myocardial infarctions from atheromatous plaques, are the primary global mortality cause. Detecting stenotic atheromatous plaques is possible through coronary angiography, but vulnerable plaques with eccentric remodeling are undetectable with current diagnostic methods. Addressing this challenge, our group developed a radiopharmaceutical drug targeting vascular cell adhesion molecule 1 (VCAM-1), radiolabeled with technetium-99m. Given the absence of a monograph in the European Pharmacopoeia, and in order to draft the investigational medicinal product documentation, analytical methods had to be validated by high performance liquid chromatography (HPLC) and thin layer chromatography (TLC) to determine the radiochemical purity (RCP) of 99mTc-cAbVCAM1-5. This study therefore presents the results of the validation of analytical methods obtained in this context. The method validation followed the European Association of Nuclear Medicine (EANM) recommendations adapted from ICH Q2(R1), ensuring conformity with specificity, accuracy, repeatability and intermediate precision, linearity, robustness, quantification limit (LoQ), and range criteria. Regarding the results of specificity, both HPLC and TLC methods demonstrated excellent separation of 99mTc-cAbVCAM1-5 from impurities 99mTcO4-. Accuracy results indicated recovery percentages within the range of 99.52-101.40% for the HPLC and 99.51-101.97% for TLC, ensuring reliable measurements for each concentration of 99mTcO4-. Precision of the methods was validated by assessing repeatability and intermediate precision. Linearity was determined over the usual concentrations range and the correlation coefficient was greater than 0.99 for both methods. The limit of quantification was measured by diluting the 99mTcO4- to obtain a signal-to-noise ratio of around 10:1. Under these conditions, we obtained an LOQ of 2.10 MBq/mL for HPLC and 2Mbq/mL for TLC. In conclusion, the analytical methods developed in this study comply with EANM recommendations. This therefore allows us to correctly assess the radiochemical purity of 99mTc-cAbVCAM1-5, a new radiotracer targeting inflammation in vulnerable plaques.


Assuntos
Compostos Radiofarmacêuticos , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia em Camada Fina/métodos , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/análise , Reprodutibilidade dos Testes , Tecnécio/química , Tecnécio/análise , Compostos de Organotecnécio/química , Compostos de Organotecnécio/análise
17.
Environ Sci Technol ; 47(23): 13857-64, 2013 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-24147650

RESUMO

We present a novel methodology for determining the transport of technetium-99m, a γ-emitting metastable isomer of (99)Tc, through quartz sand and porous media relevant to the disposal of nuclear waste in a geological disposal facility (GDF). Quartz sand is utilized as a model medium, and the applicability of the methodology to determine radionuclide transport in engineered backfill cement is explored using the UK GDF candidate backfill cement, Nirex Reference Vault Backfill (NRVB), in a model system. Two-dimensional distributions in (99m)Tc activity were collected at millimeter-resolution using decay-corrected gamma camera images. Pulse-inputs of ~20 MBq (99m)Tc were introduced into short (<10 cm) water-saturated columns at a constant flow of 0.33 mL min(-1). Changes in calibrated mass distribution of (99m)Tc at 30 s intervals, over a period of several hours, were quantified by spatial moments analysis. Transport parameters were fitted to the experimental data using a one-dimensional convection-dispersion equation, yielding transport properties for this radionuclide in a model GDF environment. These data demonstrate that (99)Tc in the pertechnetate form (Tc(VII)O4(-)) does not sorb to cement backfill during transport under model conditions, resulting in closely conservative transport behavior. This methodology represents a quantitative development of radiotracer imaging and offers the opportunity to conveniently and rapidly characterize transport of gamma-emitting isotopes in opaque media, relevant to the geological disposal of nuclear waste and potentially to a wide variety of other subsurface environments.


Assuntos
Sistemas Computacionais , Câmaras gama , Resíduos Radioativos/análise , Eliminação de Resíduos , Tecnécio/análise , Adsorção , Calibragem , Análise Numérica Assistida por Computador , Porosidade , Quartzo/química
18.
Biomed Chromatogr ; 27(9): 1150-6, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23629925

RESUMO

Medications compounded with isoniazid (INH) are usually applied to surgical sites at the completion of surgery to locally kill postoperative residual tubercle bacilli. However, the distribution and elimination of INH in the vertebrae in vivo are not known. In this study, isotope tracing was used in conjunction with high-pressure liquid chromatography (HPLC) to address this. INH and technetium-99 m-labeled INH were applied to the vertebrae of rabbits. After 2 and 6 h, osseous tissues containing INH, as determined by radionuclide imaging, were collected for detection with HPLC. The results showed that INH mainly stayed around the vertebrae 6 h after its application and did not permeate widely into the blood or other organs, except for the kidneys. The standard deviations of INH concentrations in the technetium-99 m-INH group were approximately four-fold smaller than those in the INH group. This method of coupling isotope tracing and HPLC can effectively limit experimental error during sample collection, allowing accurate and reliable identification of the concentration levels of INH in osseous tissues in vivo.


Assuntos
Antituberculosos/análise , Cromatografia Líquida de Alta Pressão/métodos , Isoniazida/análise , Coluna Vertebral/diagnóstico por imagem , Tecnécio/análise , Animais , Antituberculosos/sangue , Antituberculosos/farmacocinética , Feminino , Isoniazida/sangue , Isoniazida/farmacocinética , Modelos Lineares , Masculino , Coelhos , Cintilografia , Coluna Vertebral/química , Tecnécio/sangue , Tecnécio/farmacocinética , Distribuição Tecidual , Imagem Corporal Total
19.
Med Pr ; 64(5): 625-30, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24502125

RESUMO

BACKGROUND: Due to its use of ionising radiation, the field of nuclear medicine is a unique and significant part of medical diagnostics and patient treatment. The aim of this study was to assess the internal exposure of nuclear medicine employees to radioiodine 131I and technetium 99mTc as well as to assess the external exposure doses. MATERIAL AND METHODS: The radioiodine 131I and technetium 99mTc contents in the thyroid of staff members (about 100 persons) dealing with these radionuclides have been measured in four departments of nuclear medicine. The measurements were conducted with a portable detection unit for in situ measurements of radioiodine and technetium. High sensitivity environmental thermoluminescent dosimeters (TLD) were used to measure the external exposure dose. RESULTS: The average values and ranges of radioiodine 131I activity measured in the thyroids of all of the medical units' employees were: 83 Bq (range: 70-250 Bq), 280 Bq (range: 70-4000 Bq), 275 Bq (range: 70-1000 Bq) for technical staff, nuclear medicine staff and hospital services staff, respectively. The mean value of technetium 99mTc content in the thyroids of nuclear medicine staff was approximately 1500 Bq (range: 50--1800 Bq). External exposure dose rates were in the range of 0.5-10 microGy/h. CONCLUSIONS: The calculated average effective dose for particular person caused by the inhalation of radioiodine 131I is below 5% of 20 mSv/year (occupational exposure limit).


Assuntos
Radioisótopos do Iodo/análise , Medicina Nuclear , Exposição Ocupacional/análise , Radiação Ionizante , Tecnécio/análise , Glândula Tireoide/química , Adulto , Pessoal Técnico de Saúde , Feminino , Humanos , Exposição por Inalação , Masculino , Corpo Clínico Hospitalar , Doses de Radiação , Medição de Risco , Local de Trabalho
20.
Eur J Hosp Pharm ; 30(3): 167-171, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-34285112

RESUMO

OBJECTIVES: Technetium-99m mercapto-acetyl-triglycine ([99mTc]Tc-MAG3) is a radiopharmaceutical diagnostic agent used in nuclear medicine intended for the exploration of nephrological and urological disorders. Patient safety and reliability of this imaging procedure especially depend on the radiochemical purity (RCP) of the [99mTc]Tc-MAG3 preparation. Recently, the Summary of Product Characteristics (SPC) of NephroMAG, a kit dedicated to [99mTc]Tc-MAG3 preparation, proposed a two-strip thin layer chromatography (TLC) based quality control (QC) method. Also, Straub et al recently proposed another TLC based QC method. We sought to evaluate the transferability of these QC methods in our hospital radiopharmacy and compared them to our currently employed TLC method and radio-HPLC (high-pressure liquid chromatography) to select the most appropriate in the context of hospital radiopharmacy. METHODS: Ten consecutive [99mTc]Tc-MAG3 preparations were controlled using: HPLC combined with a radiodetector (radio-HPLC), a single strip TLC method (method 1) in current use in our centre, a two-strip TLC method described in the SPC (method SPC) and a two-strip TLC method (method 2) described by Straub et al. Quantitative results for the four tested QC methods were measured and compared in terms of RCP (%), sodium pertechnetate ([99mTc]TcO4 -) (%) and duration of analysis (min). RESULTS: RCP was significantly different between method SPC and radio-HPLC (p<0.001) and method 2 (p<0.001). Also, the percentage of [99mTc]TcO4 - was statistically different between the radio-HPLC and the method SPC (p<0.001), but not with the method 1 and method 2 group (p>0.05). The duration of analysis (min) was significantly different between the four QC procedures (p<0.001) with method 2 and method SPC being the quickest. CONCLUSIONS: Our study showed it is possible to transfer and select a quick and reliable QC method for the preparation of NephroMAG kits in our centre. We therefore advise the widespread use of the method from Straub et al in hospital radiopharmacies.


Assuntos
Tecnécio Tc 99m Mertiatida , Tecnécio , Humanos , Tecnécio/análise , Reprodutibilidade dos Testes , Compostos Radiofarmacêuticos/análise , Compostos Radiofarmacêuticos/química , Controle de Qualidade
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