OBJECTIVE: The present study evaluated the doses received by companions who had shared therapeutic rooms with patients undergoing treatment with 131-iodine (131I). The results were compared with the limits established by the Brazilian radiation protection regulatory standard. MATERIALS AND METHODS: Six pairs of persons (a patient and a companion sharing a same therapeutic room) were evaluated. Still, other 23 experiments were accomplished with a phantom replacing the companion. The therapeutic 131I activities given to the patients corresponded to 3700 MBq or 5550 MBq. Powdered lithium fluoride thermoluminescent dosimeters doped with magnesium, titanium and sodium were utilized for evaluating the doses. RESULTS: The results demonstrate that a person sharing a same therapeutic room, for two days, with a patient who had been given 3700 MBq or 5550 MBq of 131I, according to radioprotection recommendations, is exposed to a mean dose of (0.51 ± 0.02) mSv for a 99% confidence level. CONCLUSION: According to the Brazilian radiation protection standards there is no impediment for a person to accompany a nuclear medicine patient who has been given 3700 MBq or 5550 MBq of 131I during the patient stay in the therapeutic room.

Keywords: Nuclear medicine, Companion, Therapeutic room, Thermoluminescent dosimeter

OBJECTIVE: To perform a survey on routine quality control tests of dose calibrators at nuclear medicine units in the city of São Paulo, SP, Brazil. To evaluate the accuracy of measurements of seven dose calibrators activities, utilizing sources of clinically significant radionuclides at the calibration laboratory of Instituto de Pesquisas Energéticas e Nucleares. MATERIALS AND METHODS: The survey on quality control of dose calibrators has been based on questionnaires answered by the nuclear medicine units. Seven dose calibrators, Ga-67, Tc-99m and Tl-201 sources and a secondary standard instrument have been utilized in the accuracy study. RESULTS: The survey results on the quality control tests of the dose calibrators showed some inappropriateness, for example, the absence of daily reproducibility tests in all of the units. The accuracy tests for the seven dose calibrators showed results within the acceptable limit in compliance with the national regulations (±10%). CONCLUSION: According to the few nuclear medicine units participating in the survey, the dose calibrators quality control is unsatisfactory. The accuracy study of seven dose calibrators has not demonstrated any performance faults, and has established the calibration of these instruments for the utilized sources.

Keywords: Nuclear medicine, Dose calibrators, Calibration, Quality control

The main objective of this study is to implement an impartial and efficient inspection method for a correct and secure use of ionizing radiation in nuclear medicine. The radiological protection model was tested in 113 nuclear medicine services (NMS) all over Brazil, following a biannual analysis schedule (1996, 1998, 2000 and 2002). In the analytical process, we adopted the methodology of assigning different importance levels to each of 82 features, based on the risk factors established by the "Comissão Nacional de Energia Nuclear" (CNEN) and on the International Atomic Energy Agency (IAEA) recommendations. A feature was considered a radioprotection fault when in nonconformity with the rules mentioned above, and was imparted a grade. The sum of those grades, classified the NMS in one of the three different ranges, as follows: operating without restriction - 100 points and below; operating with restriction - between 100 and 300 points; temporary shutdown - above 300 points. Permission for the second group to carry on operation should be attached to a defined and restricted period of time (6 to 12 months), considered enough for the NMS to solve the problems and submit to a new evaluation. The NMS's classified in the third group are supposed to go back into operation only after compliance with all the pending radioprotection requirements. Until the next regular evaluation, a multiplication factor 2n was applied to the recalcitrant NMS's, where n is the number of unwilling occurrences. The previous establishment of those items of radioprotection, with their respective grades, excluded subjective and personal values in the judgement and technical evaluation of the institutions.

Keywords: Nuclear medicine, Radiation protection, Rules, Inspection

OBJECTIVE: The aim of this work was to establish a working standard for intercomparison and calibration of dose calibrators used in most of nuclear medicine facilities for the determination of the activity of radionuclides administered to patients in specific examinations or therapeutic procedures. MATERIALS AND METHODS: A commercial dose calibrator, a set of standard radioactive sources, and syringes, vials and ampoules with radionuclide solutions used in nuclear medicine were utilized in this work. RESULTS: The commercial dose calibrator was calibrated for radionuclide solutions used in nuclear medicine. Simple instrument tests, such as linearity response and variation response with the source volume at a constant source activity concentration were performed. CONCLUSION: This instrument may be used as a reference system for intercomparison and calibration of other activity meters, as a method of quality control of dose calibrators utilized in nuclear medicine facilities.

Keywords: Nuclear medicine, Dose calibrator, Working standard, Intercomparison, Calibration, Quality control

Clinical examination alone is not sufficient to precisely evaluate lymph node involvement in head and neck cancer. The results of computed tomography of the neck and lymphoscintigraphy were evaluated in 21 patients with carcinoma of the mouth and oropharynx staged N0. Nine patients were treated by homolateral and 12 by bilateral neck dissection. Sensitivity and specificity of computed tomography were 16% and 73% for homolateral side and 0% and 90% for contralateral side, respectively. Lymphatic drainage was observed in 76.2% of the cases. No-migration was associated with cases involving the retromolar region and tonsillar fossa, where injection of the 99mTc-Dextran 500 is more difficult. Bilateral migration occurred only in carcinomas of the floor of the mouth, with involvement of the midline. From these results it was concluded that computed tomography was less efficient than clinical examination. Nevertheless, it must be considered that conventional computed tomography was used. We are currently undertaking similar studies with helical computed tomography. Lymphoscintigraphy showed promising results, and the same method to evaluate sentinel lymph nodes in patients with carcinoma of the mouth is being used.

Keywords: Scintigraphy, Nuclear medicine, Computed tomography

Objective: To establish the costs for quality control of [^99mTc]technetium radiopharmaceuticals in Brazilian nuclear medicine centers, in compliance with Agência Nacional de Vigilância Sanitária (National Health Surveillance Agency) resolutions RDC No. 38/2008 and No. 63/2009. Materials and Methods: Prices for consumables, equipment and labor involved in quality control procedures were calculated and the values were converted into units of volume, time or other appropriate units for use in mathematical formulas for determining unit prices. Results: Estimated investment for acquisition of consumables and equipment was R$ 35,500.00. The final unit cost for quality control of a [^99mTc]technetium radiopharmaceutical kit ranged from R$ 6.44 to R$ 7.80 per kit, depending on the product under analysis, on the methodology applied and on the qualification of the professional involved in the process. Such values may correspond to 0.5% to 10% of the amount received by the institution per diagnostic procedure. In practice the effective cost might be lower, considering that a single labeled kit can be fractionated into several doses. Conclusion: Considering the gains in quality and patients’ safety, the authors conclude that costs for implementing a quality control program for radiopharmaceuticals can be absorbed in the financial planning of nuclear medicine centers.

Keywords: Technetium; Radiopharmaceuticals; Quality control; Cost analysis; Nuclear medicine; National Health Surveillance Agency; Anvisa.

Objective: The present study was aimed at determining the acceptability of a national or regional phantoms bank to be deployed in Brazil for shared use in quality control activities by nuclear medicine centers. Materials and Methods: The authors analyzed the answers to a questionnaire applied to medical physicists and radioprotection supervisors in Brazilian nuclear medicine centers. Initially, the questionnaire was validated by professionals in the city of Aracaju, SE, which is located in the Northeast region. The present study sample was geographically distributed as follows: the Northeast region, with answers from 13 professionals of nuclear medicine centers; the North region, with 2 professionals; the South region, with 7 professionals; the Southeast region, with 43 professionals; and the Midwest region, with 2 professionals. Results: According to the data analyzed, 82% of the respondents consider that the implementation of a phantoms bank would be a suitable alternative for improving nuclear medicine quality control. The interest in sharing the bank was reported by 87% of the respondents. Conclusion: The present study demonstrated the motivation for a shared use of a future phantoms bank.

Keywords: Nuclear medicine; Quality control; Phantom.

Objetivo: A principal utilidade da tomografia por emissão de pósitrons com 18-fluordeoxiglicose (FDG-PET) está no estadiamento do câncer de pulmão. Porém, ela também pode ser utilizada para diferenciar lesões pulmonares indeterminadas, mas seu impacto na ressecção cirúrgica de lesões benignas é desconhecido. O objetivo deste estudo foi comparar a prevalência de lesões benignas em toracotomias feitas por suspeição de câncer de pulmão, antes e após a introdução do FDG-PET, em um centro de referência de cirurgia torácica. Materiais e Métodos: Os autores analisaram, prospectivamente, uma base de dados cirúrgicos de todos os pacientes consecutivos submetidos a toracotomia por câncer de pulmão suspeito ou comprovado e compararam a prevalência de lesões benignas em dois grupos ao longo de dois anos consecutivos, respectivamente antes (grupo I) e depois (grupo II) da introdução da FDG-PET. Resultados: Ressecção cirúrgica foi feita em 1.233 pacientes durante o período do estudo. A prevalência de lesões benignas na cirurgia nos grupos I e II foi similar (44/626 e 41/607, ambas correspondendo a 7%), e também no grupo II, entre aqueles submetidos a FDG-PET e os restantes (21/301 e 20/306 respectivamente, ambos correspondendo a 7%). No grupo II, dos 21 pacientes com lesões benignas submetidos a FDG-PET, 19 tiveram um estudo falso-positivo (valor médio padrão de captação 5.3 [faixa 2.6–12.7]). Desses, respectivamente 13 e 4 pacientes tiveram broncoscopia não diagnóstica e biópsia transtorácica percutânea de pulmão antes da toracotomia. Não houve diferença na proporção de lesões benignas diferentes ressecadas entre o grupo I e aqueles submetidos a FDG-PET no grupo II. Conclusão: A introdução da FDG-PET não alterou a proporção de pacientes submetidos a toracotomia por lesões benignas, principalmente devido à avidez pelo isótopo de algumas lesões não malignas. Tais resultados falsos-positivos devem ser considerados nos casos em que se contempla a possibilidade de ressecção cirúrgica em pacientes com câncer de pulmão não confirmado.

Keywords: Tomografia por emissão de pósitrons; Tomografia computadorizada; Pulmão – lesões benignas ou congênitas; Câncer de pulmão – diagnóstico e estadiamento; Câncer de pulmão – cirurgia.

Objetivo: Avaliar a percepção de médicos residentes em radiologia de 4º ano sobre as melhores modalidades de imagem na investigação de neoplasias e trauma. Materiais e Métodos: Vinte e sete médicos residentes de 4º ano de quatro programas de residência em radiologia americanos participaram do estudo. Aos participantes foi perguntado sobre a melhor modalidade de imagem para se avaliar o cérebro e a coluna vertebral, pulmões, abdome e o sistema musculoesquelético. As modalidades de imagem disponíveis foram: RM, TC, ultrassonografia, PET e radiografia simples. Todos os achados foram comparados com os Critérios de Adequação de Exames de Imagem e Radioterapia do ACR. Resultados: A RM foi escolhida como melhor modalidade de imagem para se avaliar neoplasias encefálicas, espinhais, abdominais e musculoesqueléticas por 96,3%, 100%, 70,4% e 63% dos residentes, respectivamente. A TC foi escolhida por 88,9% dos residentes para avaliar neoplasias pulmonares. A modalidade de imagem ótima para se avaliar trauma foi a TC para lesões encefálicas (100%), espinhais (92,6%), pulmonares (96,3%), abdominais (92,6%) e grandes lesões traumáticas musculoesqueléticas (74,1%); a RM foi escolhida para lesões esportivas (96,3%). Observou-se concordância com os critérios de adequação do ACR. Conclusão: Houve concordância entre a percepção dos residentes sobre as melhores modalidades de imagem para avaliação de neoplasias e trauma e os critérios de adequação do ACR.

Keywords: Formação de residentes; Educação médica; Modalidades de imagem.

OBJECTIVE: To determine correction factors for the variation in volume of radiopharmaceuticals in containers of different geometries, comparing the influence of such factors on the determination of ^99mTc and ¹²³I activity with two types of calibrators – one with ionization chamber and another with Geiger-Müller (G-M) detector –; and to evaluate calibrators performance in the measurement of ^99mTc and ¹²³I activities. MATERIALS AND METHODS: Eight calibrators, 10R glass vials, 3 and 5 mL plastic syringes and ^99mTc and ¹²³I solutions were utilized. The correction factors were determined with basis on practical measurements of the variation in the calibrators' response according to the volume of radionuclide solution in the glass vials. The performance was evaluated according to the acceptance criterion of ±10% accuracy required by the Brazilian standard. RESULTS: The variation of the calibrators' response according to the variation in radionuclide volume was reasonably greater in the calibrator with G-M detector. It was also greater for ¹²³I than for ^99mTc. CONCLUSION: The results confirm that the calibrators' response depends on the radionuclide volume contained in the vials. Such dependence is more critical for the calibrators equipped with G-M detector and for ¹²³I as compared with ^99mTc.

Keywords: Radionuclides calibrator; Nuclear medicine; Activity; Tc-99m; I-123.

OBJETIVO: Este estudo teve por finalidade avaliar a perfusão miocárdica de pacientes com diabetes mellitus tipo 1 (DM1) e tipo 2 (DM2) assintomáticos, sem diagnóstico prévio de doença arterial coronariana (DAC) ou acidente vascular cerebral. MATERIAIS E MÉTODOS: Cinquenta e nove pacientes consecutivos (16 DM1, 43 DM2) foram submetidos a cintilografia de perfusão miocárdica com sestamibi-^99mTc (CPM). Foram avaliados quanto ao índice de massa corpórea, controle metabólico do diabetes, dislipidemia, terapia para o diabetes, hipertensão arterial sistêmica, nefropatia, retinopatia, neuropatia periférica, tabagismo e história familiar de DAC. RESULTADOS: CPM foi anormal em 25,4%: 12 (20,3%) com alterações de perfusão e 3 com disfunção ventricular esquerda isolada. Os mais fortes preditores de perfusão miocárdica anormal foram: idade igual ou maior a 60 anos (p = 0,017, odds ratio [OR] = 6,0), neuropatia periférica (p = 0,028, OR = 6,1), nefropatia (p = 0,031, OR = 5,6) e ECG de esforço positivo para isquemia (p = 0,049, OR = 4,08). CONCLUSÃO: A isquemia miocárdica silenciosa ocorre em mais de um em cada cinco diabéticos assintomáticos. Os mais fortes preditores de isquemia foram: idade avançada, neuropatia periférica, nefropatia, retinopatia e ECG de esforço positivo para isquemia.

Keywords: Diabetes mellitus; Cintilografia de perfusão miocárdica; Isquemia miocárdica silenciosa; Doença arterial coronariana.

OBJETIVO: Avaliar a completude das fissuras, resposta radiológica ao tratamento e análise quantitativa por TC (AQTC) em população de pacientes com enfisema grave submetidos ao implante de valvas endobrônquicas (VEB). MATERIAIS E MÉTODOS: Foram estudados exames de TC multidetectores de 29 pacientes, realizados com protocolo de baixo dose, cortes finos, sem contraste. Dois radiologistas revisaram, retrospectivamente, os exames em consenso. A completude das fissuras foi estimada em escala de 5% e a resposta radiológica (atelectasia/perda volumétrica do lobo alvo) foi avaliada. AQTC foi realizada nos exames pré e pós-tratamento utilizando programa completamente automático. RESULTADOS: Resposta radiológica positiva foi vista em 16/29 pacientes. Os 13 pacientes sem resposta à TC apresentavam fissuras incompletas e completude média das fissuras obliquas de 72,8%, contra 88,3% no outro grupo. Os resultados mais significativos da AQTC mostraram redução do volume pulmonar (VP) total (média de 542 ml), VP tratado (700 ml) e volume de enfisema (331,4 ml) no grupo com resposta positiva, que também apresentou melhora nos testes funcionais. CONCLUSÃO: O benefício das VEB é maior em pacientes com fissuras completas e que desenvolvem atelectasia lobar. Nos pacientes sem resposta radiológica encontramos maior prevalência de fissuras incompletas e grau de incompletude das fissuras. Nossa AQTC automática detectou as alterações pós-tratamento, principalmente considerado a análise do pulmão tratado.

Keywords: Enfisema; Terapia de colapso pulmonar; Tomografia computadorizada.

OBJECTIVE: To investigate the outpatient access to nuclear medicine procedures by means of the Brazilian Unified Health System (SUS), analyzing the correspondence between data provided by this system and those from Comissão Nacional de Energia Nuclear (CNEN) (National Commission of Nuclear Energy). MATERIALS AND METHODS: Data provided by Datasus regarding number of scintillation chambers, outpatient procedures performed from 2008 to 2012, administrative responsibility for such procedures, type of service providers and outsourced services were retrieved and evaluated. Also, such data were compared with those from institutions certified by CNEN. RESULTS: The present study demonstrated that the system still lacks maturity in terms of correct data input, particularly regarding equipment available. It was possible to list the most common procedures and check the growth of the specialty along the study period. Private centers are responsible for most of the procedures covered and reimbursed by SUS. However, many healthcare facilities are not certified by CNEN. CONCLUSION: Datasus provides relevant data for analysis as done in the present study, although some issues still require attention. The present study has quantitatively depicted the Brazilian reality regarding access to nuclear medicine procedures offered by/for SUS.

Keywords: SUS; Nuclear medicine; Gamma camera.

OBJECTIVE: The present study was aimed at evaluating the viability of replacing ¹⁸F with ^99mTc in dose calibrator linearity testing. MATERIALS AND METHODS: The test was performed with sources of ^99mTc (62 GBq) and ¹⁸F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical ^99mTc and ¹⁸F sources activities were calculated and subsequently compared. RESULTS: Mean deviations between experimental and theoretical ^99mTc and ¹⁸F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the ^99mTc source as measured with the equipment pre-calibrated to measure ^99mTc and ¹⁸F was 3.42 (± 0.06), and for the ¹⁸F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time. CONCLUSION: The results of the linearity test using ^99mTc were compatible with those obtained with the ¹⁸F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in ¹⁸F acquisition suggest ^99mTc as the element of choice to perform dose calibrator linearity tests in centers that use ¹⁸F, without any detriment to the procedure as well as to the quality of the nuclear medicine service.

Keywords: Nuclear medicine; Dose calibrator; Linearity test; Nuclear instrumentation.

OBJETIVO: Avaliar os padrões tomográficos relacionados aos agentes etiológicos da pneumonia em pacientes durante o primeiro ano após transplante renal. MATERIAIS E MÉTODOS: Foram analisados dados de prontuários de 956 pacientes submetidos a transplante renal, no período de 2013 a 2018, em um centro transplantador renal do nordeste do Brasil. Nos pacientes que desenvolveram pneumonia, os agentes etiológicos foram classificados em bactérias piogênicas, micobactérias, fungos, vírus e pneumonia polimicrobiana, enquanto os padrões tomográficos foram classificados em consolidação, broncopneumonia, pneumonia intersticial e nódulos e massas. Para verificar associação estatística entre micro-organismos e padrões tomográficos, foi utilizado o teste exato de Fisher, com p < 0,001. RESULTADOS: Foram encontrados 101 casos de pneumonia, dos quais 60 (59,4%) tiveram agente etiológico identificado, sendo as bactérias piogênicas as mais frequentes, detectadas em 22 (36,7%) dos casos. Entre os pacientes com agente causal identificado, o padrão tomográfico predominante foi o de nódulos e massas, identificado em 25 (41,7%) casos. Foi observada associação entre bactérias piogênicas e o padrão de consolidação, fungos com nódulos e massas, bem como entre agentes virais e padrão intersticial. CONCLUSÃO: Foi demonstrada associação estatística entre micro-organismos causadores de pneumonia e padrões tomográficos, informação que pode contribuir para o planejamento da terapia de pacientes transplantados renais.

Keywords: Pneumonia; Transplante de rim; Tomografia computadorizada.