RESUMEN
The goal of this study was to apply the principles of analytical quality by design (AQbD) to the analytical method for determining the radiochemical purity (PQR) of the radiopharmaceutical sodium iodide 131I oral solution, utilizing thin-layer chromatography (TLC) with a radio-TLC scanner, which also enables the evaluation of product quality. For AQbD, the analytical target profile (ATP), critical quality attributes (CQA), risk management, and the method operable design region (MODR) were defined through response surface methodology to optimize the method using MINITAB® 19 software. This study encompassed the establishment of a control strategy and the validation of the method, including the assessment of selectivity, linearity, precision, robustness, detection limit, quantification limit, range, and the stability of the sample solution. Under the experimental conditions, the method parameters of the TLC scanner were experimentally demonstrated and optimized with an injection volume of 3 µL, a radioactive concentration of 10 mCi/mL, and a carrier volume of 40 µL. Statistical analysis confirmed the method's selectivity for the 131I iodide band Rf of 0.8, a radiochemical impurity IO3- Rf of 0.6, a linearity from 6.0 to 22.0 mCi/mL, and an intermediate precision with a global relative standard deviation (RSD) of 0.624%. The method also exhibited robustness, with a global RSD of 0.101%, a detection limit of 0.09 mCi/mL, and a quantification limit of 0.53 Ci/mL, meeting the prescribed range and displaying stability over time (at 0, 2, and 20 h) with a global RSD of 0.362%, resulting in consistent outcomes. The development of a method based on AQbD facilitated the creation of a design space and an operational space, with comprehensive knowledge of the method's characteristics and limitations. Additionally, throughout all operations, compliance with the acceptance criteria was verified. The method's validity was confirmed under the established conditions, making it suitable for use in the manufacturing process of sodium iodide 131I and application in nuclear medicine services.
Asunto(s)
Radioisótopos de Yodo , Radiofármacos , Yoduro de Sodio , Cromatografía en Capa Delgada/métodos , Radiofármacos/química , Radiofármacos/análisis , Radioisótopos de Yodo/análisis , Yoduro de Sodio/química , Administración Oral , Reproducibilidad de los ResultadosRESUMEN
Radiopharmaceuticals are radioactive compounds that can be used for diagnostic and therapeutic purposes. Technetium (99mTc) Sestamibi is the most commercialized radiopharmaceutical in the world. It includes a coordination complex consisting of the radioisotope 99 m technetium bound to six copper tetramibi tetrafluorborate ligands, and is mainly used to image the myocardium via scintigraphy. As radiopharmaceuticals are regarded as drugs, they are subject to the same regulations; therefore, the objective of this study was to develop a quantification method for the active pharmaceutical ingredient before their complexation with the radioisotope by employing high-performance liquid chromatography (HPLC) methodology. A simple and efficient method (retention time = 2.5 min) was developed and validated for copper tetramibi tetrafluorborate in the final product using a buffer and organic solvent mixtures (ACN-methanol-ammonium sulfate buffer) and a C18 column. The analytical protocol was fast, taking around 30 min until evaluation of results. The validation parameters were evaluated with satisfactory results: in terms of linearity r > 0.99 (160-240 µg/mL) and no deviation was observed. The RSD of precision was <5%, and an average recovery of 99% was observed for accuracy. The proposed method was thus considered adequate for routine analysis in the pharmaceutical industries.
Asunto(s)
Boratos/análisis , Cromatografía Líquida de Alta Presión/métodos , Cobre/análisis , Radiofármacos/análisis , Tecnecio Tc 99m Sestamibi/análisis , Tecnecio Tc 99m Sestamibi/química , Modelos Lineales , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Traceability in Nuclear Medicine Service (NMS) measurements was checked by the Institute of Radioprotection and Dosimetry (IRD) through the Institute of Energy and Nuclear Research (IPEN). In 2016, IRD ran an intercomparison program and invited Brazilian NMS authorized to administer 131I to patients. Sources of 131I were distributed to 33 NMSs. Three other sources from the same solution were sent to IRD, after measurement at IPEN. These sources were calibrated in the IRD reference system. A correction factor of 1.013 was obtained. Ninety percent of the NMS comparisons results are within ±10% of the National Laboratory of Metrology of Ionizing Radiation (LNMRI) value, the Brazilian legal requirement.
Asunto(s)
Instituciones de Atención Ambulatoria , Radioisótopos de Yodo/análisis , Servicio de Medicina Nuclear en Hospital , Radiofármacos/análisis , Brasil , Calibración , Competencia Profesional , Control de Calidad , Reproducibilidad de los Resultados , Factores de Tiempo , IncertidumbreRESUMEN
ABSTRACT Cleaning validation, a requirement of the current Good Manufacturing Practices (cGMP) for Drugs, consists of documented evidence that cleaning procedures are capable of removing residues to predetermined acceptance levels. This report describes a strategy for the selection of the worst case product for the production of lyophilized reagents (LRs) for labeling with 99mTc from the Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/São Paulo). The strategy is based on the calculation of a "worst case index" that incorporates information about drug solubility, cleaning difficulty, and occupancy rate in the production line. It allowed a reduction in the required number of validations considering the possible manufacturing flow of a given product and the subsequent flow, thus facilitating the process by reducing operation time and cost. The products identified as "worst case" were LRs PUL-TEC and MIBI-TEC.
RESUMO A validação de limpeza é uma exigência dos atuais regulamentos de Boas Práticas de Fabricação de Medicamentos (BPF) e consiste na evidência documentada, que demonstra que os procedimentos de limpeza removem os resíduos em níveis de aceitação pré-determinados. Este estudo apresenta uma estratégia para escolha do produto "pior caso" da linha de produção de reagentes liofilizados para marcação com 99mTc do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/São Paulo). A estratégia baseia-se no cálculo de um índice denominado "índice para pior caso," que utiliza informações de solubilidade dos fármacos, dificuldade de limpeza dos equipamentos e ocupação dos produtos na linha de produção. A estratégia adotada proporcionou a diminuição no número de validações necessárias, considerando-se as possibilidades de sequências de fabricação de um determinado produto e do produto subsequente, possibilitando a simplificação do processo e redução no tempo e nos custos das atividades envolvidas. Os produtos indicados como pior caso foram os reagentes liofilizados (RL) PUL-TEC e MIBI-TEC.
Asunto(s)
Radiofármacos/análisis , Estudios de Validación como Asunto , Liofilización , Tareas del Hogar/métodosRESUMEN
Knowledge of the radiochemical purity of radiopharmaceuticals is mandatory and can be evaluated by several methods and techniques. Planar chromatography is the technique normally employed in nuclear medicine since it is simple, rapid and usually of low cost. There is no standard system for the chromatographic technique, but price, separation efficiency and short time for execution must be considered. We have studied an alternative system using common chromatographic stationary phase and alcohol or alcohol:chloroform mixtures as the mobile phase, using the lipophilic radiopharmaceutical [(99m)Tc(MIBI)6]⺠as a model. Whatman 1 modified phase paper and absolute ethanol, Whatman 1 paper and methanol:chloroform (25:75), Whatman 3MM paper and ethanol:chloroform (25:75), and the more expensive ITLC-SG and 1-propanol:chloroform (10:90) were suitable systems for the direct determination of radiochemical purity of [(99m)Tc(MIBI)6]⺠since impurities such as (99m)Tc-reduced-hydrolyzed (RH), (99m)TcO(4)(-) and [(99m)Tc(cysteine)2]⻠complex were completely separated from the radiopharmaceutical, which moved toward the front of chromatographic systems while impurities were retained at the origin. The time required for analysis was 4 to 15 min, which is appropriate for nuclear medicine routines.
Asunto(s)
Cromatografía en Papel/métodos , Cromatografía en Capa Delgada/métodos , Radiofármacos/análisis , Pertecnetato de Sodio Tc 99m/análisis , Alcoholes , Cloroformo , Cromatografía/economía , Cromatografía/métodos , Cromatografía en Papel/economía , Cromatografía en Capa Delgada/economía , Control de Calidad , Radiofármacos/clasificaciónRESUMEN
Knowledge of the radiochemical purity of radiopharmaceuticals is mandatory and can be evaluated by several methods and techniques. Planar chromatography is the technique normally employed in nuclear medicine since it is simple, rapid and usually of low cost. There is no standard system for the chromatographic technique, but price, separation efficiency and short time for execution must be considered. We have studied an alternative system using common chromatographic stationary phase and alcohol or alcohol:chloroform mixtures as the mobile phase, using the lipophilic radiopharmaceutical [99mTc(MIBI)6]+ as a model. Whatman 1 modified phase paper and absolute ethanol, Whatman 1 paper and methanol:chloroform (25:75), Whatman 3MM paper and ethanol:chloroform (25:75), and the more expensive ITLC-SG and 1-propanol:chloroform (10:90) were suitable systems for the direct determination of radiochemical purity of [99mTc(MIBI)6]+ since impurities such as99mTc-reduced-hydrolyzed (RH),99mTcO4- and [99mTc(cysteine)2]-complex were completely separated from the radiopharmaceutical, which moved toward the front of chromatographic systems while impurities were retained at the origin. The time required for analysis was 4 to 15 min, which is appropriate for nuclear medicine routines.
Asunto(s)
Cromatografía en Papel/métodos , Cromatografía en Capa Delgada/métodos , Radiofármacos/análisis , /análisis , Alcoholes , Cloroformo , Cromatografía en Papel/economía , Cromatografía en Capa Delgada/economía , Cromatografía/economía , Cromatografía/métodos , Control de Calidad , Radiofármacos/clasificaciónRESUMEN
To evaluate the effect of hydroalcoholic extract of A. muricata on biodistribution of two radiopharmaceuticals: sodium phytate and dimercaptosuccinic acid (DMSA), both labeled with 99mtechnetium. METHODS: Twenty four Wistar rats were divided into two treated groups and two controls groups. The controls received water and the treated received 25mg/kg/day of A. muricata by gavage for ten days. One hour after the last dose, the first treated group received 99mTc-DMSA and the second sodium 99mTc-phytate (0.66MBq each group), both via orbital plexus. Controls followed the same protocol. Forty min later, all groups were sacrificed and the blood, kidney and bladder were isolated from the first treated group and the blood, spleen and liver isolated from the second treated group. The percentage of radioactivity per gram of tissue (%ATI/g) was calculated using a gamma counter. RESULTS: The statistical analysis showed that there was a statistically significant decrease (p<0.05) in the uptake of %ATI/g in bladder (0.11±0.01and1.60±0.08), kidney (3.52±0.51and11.84±1.57) and blood (0.15±0.01and 0.54±0.05) between the treated group and control group, respectively. CONCLUSION: The A. muricata hydroalcoholic extract negatively influenced the uptake of 99mTc-DMSA in bladder, kidney and blood of rats.
Asunto(s)
Animales , Ratas , Annona , Radiofármacos/análisis , Solución Hidroalcohólica , Ratas/clasificaciónRESUMEN
To evaluate the effect of hydroalcoholic extract of A. muricata on biodistribution of two radiopharmaceuticals: sodium phytate and dimercaptosuccinic acid (DMSA), both labeled with 99mtechnetium. METHODS: Twenty four Wistar rats were divided into two treated groups and two controls groups. The controls received water and the treated received 25mg/kg/day of A. muricata by gavage for ten days. One hour after the last dose, the first treated group received 99mTc-DMSA and the second sodium 99mTc-phytate (0.66MBq each group), both via orbital plexus. Controls followed the same protocol. Forty min later, all groups were sacrificed and the blood, kidney and bladder were isolated from the first treated group and the blood, spleen and liver isolated from the second treated group. The percentage of radioactivity per gram of tissue (%ATI/g) was calculated using a gamma counter. RESULTS: The statistical analysis showed that there was a statistically significant decrease (p<0.05) in the uptake of %ATI/g in bladder (0.11±0.01and1.60±0.08), kidney (3.52±0.51and11.84±1.57) and blood (0.15±0.01and 0.54±0.05) between the treated group and control group, respectively. CONCLUSION: The A. muricata hydroalcoholic extract negatively influenced the uptake of 99mTc-DMSA in bladder, kidney and blood of rats.(AU)
Asunto(s)
Animales , Ratas , Radiofármacos/análisis , Annona , Solución Hidroalcohólica , Ratas/clasificaciónRESUMEN
The Northeastern Regional Centre for Nuclear Sciences (CRCN-NE), National Nuclear Energy Commission, has organized for the first time in nuclear medicine services (NMSs) in the Brazilian northeast region a comparison of activity measurements for (99m)Tc, (131)I, (67)Ga, (201)Tl and (57)Co. This tool is widely utilized to evaluate not only the accuracy of radionuclide calibrators, but also the competence of NMSs to measure the activity of the radiopharmaceuticals and the performance of the personnel involved in these measurements. The comparison results showed that 90% of the results received from participants are within the ±10% limit established by the Brazilian Norm.
Asunto(s)
Radioisótopos/análisis , Radiometría/normas , Radiofármacos/análisis , Brasil , Calibración , Humanos , Medicina Nuclear/normas , Control de Calidad , Radiometría/instrumentaciónRESUMEN
(18)FDG, an analogue of glucose labelled with the radionuclide (18)F, is the most widely used radiopharmaceutical in positron emission tomography/computed tomography technique. In Brazil, there are currently eight (18)FDG plants in operation and other facilities are expected to start their production in the near future. The growth in the production and clinical use of (18)FDG represents an increasing risk of worker exposures. According to national regulations and international recommendations, internal exposures should be effectively controlled in order to keep doses as low as possible. The implementation of a routine monitoring programme towards the estimation of internal doses related to the incorporation of (18)F is difficult, mainly due to its short physical half-life, the cost of a bioassay laboratory and the need of a monitoring service promptly available near the production plant. This paper describes the implementation and evaluation of a methodology for in vivo brain monitoring of (18)F to be applied in cases of suspected incorporation of (18)FDG. The technique presented a minimum detectable effective dose in the order of nanoSieverts, which allows its application for occupational monitoring purposes.
Asunto(s)
Encéfalo/efectos de la radiación , Fluorodesoxiglucosa F18/análisis , Exposición Profesional/prevención & control , Monitoreo de Radiación/métodos , Protección Radiológica , Radiofármacos/análisis , Bioensayo , Brasil , Humanos , Laboratorios , Fantasmas de Imagen , Tomografía de Emisión de PositronesRESUMEN
The presence of caretakers/comforters during nuclear medicine examinations is relatively common. These caretakers receive higher doses than the general public, who receive only environmental/background exposure. The aim of this research was to know about the doses received by two significant groups of caretakers: comforters of cancer patients (Group I) and mothers of small children (Group II). The patients were scheduled to undergo two different diagnostic studies: Inmuno-Scintigraphy using a monoclonal antibody bound to (99m)Tc (for adults) and Renal Scintigraphy using (99m)Tc-dimercaptosuccinic acid (for children). The average effective doses were 0.27 and 0.29 mSv for Groups I and II, respectively. Additionally, environmental monitoring was performed in the waiting room for injected patients (Room I) and inside the procedure room (Room II). Equivalent environmental doses of 0.28 and 0.24 mSv for Rooms 1 and II, respectively, were found, which are similar to values reported by other authors.
Asunto(s)
Cuidadores/estadística & datos numéricos , Exposición a Riesgos Ambientales/estadística & datos numéricos , Madres/estadística & datos numéricos , Neoplasias/diagnóstico por imagen , Dosis de Radiación , Radiofármacos/análisis , Dosimetría Termoluminiscente/métodos , Adolescente , Adulto , Niño , Exposición a Riesgos Ambientales/análisis , Femenino , Humanos , Masculino , Protección Radiológica/métodos , Cintigrafía , Adulto JovenRESUMEN
The national traceability chain for (131)I activity measurements performed in nuclear medicine in Cuba is described. At the highest (primary) level, liquid scintillation counting employing the CIEMAT/NIST method is used; at the secondary level, a secondary standard radionuclide calibrator is utilized that allows for a quick and simple transference of the measurement unit to the tertiary level of end-users' instruments. The equivalence of Cuban standards and the assessment of measurement uncertainties at the end-user level are determined through the results of measurement comparisons.
Asunto(s)
Radioisótopos de Yodo/análisis , Radioisótopos de Yodo/normas , Medicina Nuclear/normas , Radiometría/normas , Radiofármacos/análisis , Radiofármacos/normas , Cuba , Estándares de Referencia , Valores de ReferenciaRESUMEN
Micelles composed of amphiphilic copolymers linked to a radioactive element are used in nuclear medicine predominantly as a diagnostic application. A relevant advantage of polymeric micelles in aqueous solution is their resulting particle size, which can vary from 10 to 100 nm in diameter. In this review, polymeric micelles labeled with radioisotopes including technetium (99mTc) and indium (111In), and their clinical applications for several diagnostic techniques, such as single photon emission computed tomography (SPECT), gamma-scintigraphy, and nuclear magnetic resonance (NMR), were discussed. Also, micelle use primarily for the diagnosis of lymphatic ducts and sentinel lymph nodes received special attention. Notably, the employment of these diagnostic techniques can be considered a significant tool for functionally exploring body systems as well as investigating molecular pathways involved in the disease process. The use of molecular modeling methodologies and computer-aided drug design strategies can also yield valuable information for the rational design and development of novel radiopharmaceuticals.
Micelas poliméricas compostas de copolímeros ligadas a um elemento radioativo são utilizadas em Medicina Nuclear com aplicação predominantemente diagnóstica. A vantagem relevante da utilização de micelas poliméricas em solução aquosa é o tamanho de suas partículas, as quais podem variar de 10 a 100 nm de diâmetro. Neste trabalho de revisão são apresentadas micelas poliméricas marcadas com radioisotopos, como tecnécio-99m (99mTc) e índio-111 (111In), assim como suas aplicações clínicas em técnicas de diagnóstico como Tomografia por emissão de Fóton Único (Single photon Emission Computed Tomography - SPECT), cintilografia, e Ressonância Magnética Nuclear (RMN). Neste contexto, sua aplicação em diagnóstico de sistema linfático e linfonodo sentinela recebe atenção especial. O emprego de técnicas de diagnóstico pode ser considerado uma ferramenta importante para a exploração de sistemas no organismo humano assim como para a investigação de caminhos moleculares envolvidos nos processos de diversas doenças. O uso de metodologias de modelagem molecular e estratégias de desenvolvimento de fármacos assistidas computacionalmente também pode fornecer informações valiosas para o planejamento e o desenvolvimento racional de novos radiofármacos.
Asunto(s)
Radiofármacos/análisis , Micelas , Radioisótopos/análisis , Diagnóstico por Imagen/clasificación , Técnicas de Diagnóstico por Radioisótopo/clasificaciónRESUMEN
La Medicina Nuclear es una de las áreas de la Radiología que estudia al organismo dinámicamente, emplea radiofármacos y detectores externos para la obtención de la imagen, su eficacia diagnóstica depende en gran medida de la precisión con la que el Activímetro mide la actividad de un radiofármaco, lo cual está garantizado por el control de calidad diario, particularmente, mediante el cálculo de la exactitud. Por lo anterior, el objetivo general de la presente investigación es determinar el nivel de coincidencia del cálculo de exactitud teórica y práctica del Activímetro marca CAPINTEC modelo CRC-15 del centro diagnóstico PET SCAN PERU. Para el presente estudio, se recopilaron un total de 306 datos, obtenidos mediante cuadros de trabajo virtuales redactados en formatos Word y Excel para recolectar los datos de exactitud teórica y práctica del Cesio137 y Cobalto57 por cada mes a partir de Mayo de 2010 a diciembre de 2011, los cuales cumplieron con los criterios de inclusión y exclusión establecidos. De éstos, 153 (50 por ciento) fueron de Cesio137 y 153 (50 por ciento) fueron de Cobalto57. El 100 por ciento de los datos de radiación de fondo estuvieron dentro de los valores normales. Mediante la prueba estadística T de Student se demostró que existe semejanza entre los datos de exactitud teórica y práctica. Con la prueba Correlación de Pearson (R) se demostró que el nivel de coincidencia del cálculo de la exactitud teórica y práctica fue alto (95 por ciento). Sin embargo, para el Cobalto57 en el mes de agosto 2010 (0.0632) y para el Cesio137 el mes de junio de 2011 (0.158), hubo un bajo nivel de coincidencia (5 por ciento)
Nuclear medicine is one of the areas of radiology that studies the body dynamically, radiopharmaceuticals and external detectors used to obtain the image; its diagnostic efficacy depends largely on the exactness which the Activimeter measures the radiopharmaceutical activity. This is guaranteed by the daily quality control, exactly by calculating accuracy. Therefore, the overall objective of this research is to determine the level of matching accuracy of the calculation of theoretical and practical Activimeter CAPINTEC CRC-15, in the Diagnostic Center PET SCAN PERU. For the present study were collected a total of 306 data, obtained by virtual work tables written in Word and Excel to collect data on theoretical and practical accuracy of Cesio137 and Cobalto57 per month from May 2010 to December 2011, which met the inclusion criteria and exclusion set. Of these, 153 (50 per cent) were Cesio137 and 153 (50 per cent) were Cobalto57. 100 per cent of the background radiation data were within normal values. By means of the statistical test T de Student demonstrated that similarity exists between the information of theoretical and practical accuracy. With the test Pearson's Correlation (R) demonstrated that the level of coincidence of the calculation of the theoretical and practical accuracy was high (95 per cent). Nevertheless, for the Cobalto57 in August, 2010 (0.0632) and for the Cesio137 June, 2011 (0.158), there was a low level of coincidence (5 per cent)
Asunto(s)
Radiofármacos/análisis , Control de Calidad , Medicina Nuclear/instrumentación , Medición de Radiación , Estudios Observacionales como Asunto , Estudios Retrospectivos , Estudios TransversalesRESUMEN
Brazil has about 300 nuclear medicine services (NMS), 44 of them located in the state of Rio de Janeiro (RJ). Most nuclear medicine staff are routinely monitored for external dose. This paper makes a statistical analysis of all the RJ NMS annual external occupational doses in year 2005. Around 100 professionals of RJ NMS received annual doses >4.0 mSv, considering only external doses, but no one receives doses higher than the mean annual dose limit of 20 mSv. Extremities dosemeters are used by about 10 % of the staff. In some cases, these doses are more than 10 times higher than the dose in thorax. The maximum ratio of extremity dose/thorax dose, in 2005, was 72. This study shows the importance to improve radiation protection procedures in nuclear medicine, mainly because the number of occupational individuals in nuclear medicine and their external doses are increasing.
Asunto(s)
Medicina Nuclear , Exposición Profesional/prevención & control , Medicina del Trabajo/normas , Monitoreo de Radiación/métodos , Radiometría/métodos , Brasil , Humanos , Medicina Nuclear/métodos , Medicina del Trabajo/métodos , Fotones , Tomografía de Emisión de Positrones/métodos , Dosis de Radiación , Protección Radiológica/métodos , Radiofármacos/análisis , Tórax/efectos de la radiación , Tomografía Computarizada de Emisión de Fotón Único/métodos , Recursos HumanosRESUMEN
Use of radionuclides in medical practice has grown steadily in recent years due to the introduction of new radiopharmaceuticals and new equipments. This paper presents a survey of nuclear medicine procedures performed in Alagoas, State of Brazil, in order to help establish reference levels for nuclear medicine patients. Data were gathered on the type of radiopharmaceuticals used and administered activity of each kind of examination, and the age and sex of the patients involved over the period 2002-2005. Based on ICRP-60, the effective dose (E) and collective effective dose (Ecol) have been calculated. The results showed an annual increase in the nuclear medicine examinations during the period of study and cardiac scintigraphy are the most common procedure. The results also indicated that the activities administered to patients are higher than the guidance levels of the Basic Safety Standards (BSS) in most of the kind of examinations. The differences found in the administered activities may reflect the differences in the quality assurance programs implemented. It was observed that the Ecol and E/inhabitant are higher than other countries. Therefore, it is suggested that the protocols have been revised in order to reduce the patient dose without reduce the image quality.
Asunto(s)
Medicina Nuclear/tendencias , Radiofármacos/análisis , Adolescente , Adulto , Brasil , Niño , Preescolar , Diagnóstico por Imagen , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Medicina Nuclear/normas , Garantía de la Calidad de Atención de Salud , Dosis de Radiación , Radioisótopos/análisis , Adulto JovenRESUMEN
In Brazil, the radionuclides used for therapy are: (131)I, (153)Sm, (90)Y and (177)Lu, both for routine or research protocols. The radionuclide activity excreted by patients may be quantified by bioassay analysis and constitutes a powerful tool for individual treatment planning. The Bioassay Laboratory (LBIOVT) of the Institute of Radiation Protection and Dosimetry (IRD) has equipments for gamma and beta spectroscopy. These systems are calibrated in energy and efficiency using reference sources supplied by the National Laboratory of Radiation Metrology (LMNRI/IRD). The LBIOVT has operational procedures according ISO-ABNT-17025 recommendations and participates of international and national intercomparisons. The patient samples are collected immediately after radiopharmaceutical administrations, at the hospital or at the patient residence, and are handled, stored and transported according national radiation protection regulations. The radionuclide specific activity (Bq/L) is referenced to date and time of excretion, for the estimation of the individual biological half-live. The volume of excreta may carefully manipulated in order to avoid losses and misinterpretation in the activity quantification. The process of the LBIOVT accreditation and its participation in intercomparisons may guarantee the confidence of the results, allowing the minimization of the uncertainties in the individual monitoring.
Asunto(s)
Radioisótopos/análisis , Radiometría/instrumentación , Radiometría/normas , Radiofármacos/análisis , Bioensayo/métodos , Humanos , Dosis de Radiación , Radiometría/métodos , Reproducibilidad de los Resultados , Manejo de Especímenes , Espectrometría gamma , Factores de Tiempo , UrinálisisRESUMEN
Gamma and beta radiation emitting radiopharmaceuticals are handled in nuclear medicine services, and in many cases there is only individual monitoring of gamma radiation. In this paper, the results obtained using a wrist dosimeter prototype (CaSO(4):Dy+Teflon pellets) show that the doses for workers occupationally exposed to beta radiation from (153)Sm are not negligible. It is important that this dose is evaluated, and it has to be taken into consideration in the individual monitoring system.
Asunto(s)
Carga Corporal (Radioterapia) , Personal de Salud , Monitoreo Ambulatorio/instrumentación , Exposición Profesional/análisis , Monitoreo de Radiación/instrumentación , Radioisótopos/análisis , Samario/análisis , Diseño de Equipo , Análisis de Falla de Equipo , Rayos gamma , Humanos , Monitoreo Ambulatorio/métodos , Proyectos Piloto , Dosis de Radiación , Monitoreo de Radiación/métodos , Radioisótopos/uso terapéutico , Radiofármacos/análisis , Radiofármacos/uso terapéutico , Samario/uso terapéutico , MuñecaRESUMEN
Nuclear medicine procedures that use I activity represent significant sources of potential absorbed dose to medical staff, volunteers, and the general public. The potential exposures are due principally from exposures to excreted and retained activities in the patients' bodies. In general, exposure rate decreases in a simple exponential manner. The average effective half-life found for all patients in the study reported here is 11.41 +/- 0.02 h; this information may be used in guidelines on the management of patients in thyroid cancer therapy and for general radioprotection practice.
Asunto(s)
Radioisótopos de Yodo/farmacocinética , Radioisótopos de Yodo/uso terapéutico , Neoplasias de la Tiroides/metabolismo , Neoplasias de la Tiroides/radioterapia , Recuento Corporal Total/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Carga Corporal (Radioterapia) , Femenino , Semivida , Humanos , Radioisótopos de Yodo/análisis , Radioisótopos de Yodo/química , Masculino , Tasa de Depuración Metabólica , Persona de Mediana Edad , Radiofármacos/análisis , Radiofármacos/química , Radiofármacos/farmacocinética , Radiofármacos/uso terapéutico , Efectividad Biológica Relativa , Estudios RetrospectivosRESUMEN
The evaluation of the absorbed dose from radioactive patients during the treatment of thyroid disease is an important factor in establishing precautions in these procedures, and the I retention/excretion by patients' bodies provides additional information to medical and radioprotection service. In 94 patients, the measurement of exposure rates was performed over 7 d following NaI administration, and the rates permitted the study of the dynamics of excretion and the potential dose evaluation. The administered activities ranged from 3.7 GBq (100 mCi) to 16.65 GBq (450 mCi), and the results proved that the majority of the activity is excreted by patients in the first 3 d after NaI administration. The average (131)I activity excreted at 24, 48, 72, 96, and 120 h after oral administration was (72 +/- 10), (91 +/- 6), (97 +/- 3), (98.9 +/- 1.5), and (99.6 +/- 0.7)%, respectively. According to the administered activity, the evaluation of the accumulated absorbed dose from patients ranged from 3.0 +/- 0.7 to 8.4 +/- 1.1 mSv at 1 m and 1.2 +/- 0.4 to 3.2 +/- 0.4 mSv at 2 m. The data reported here are important to radioprotection policy and to add to and improve on the guidelines reported in U.S. NRC Regulatory Guide 8.39.