ABSTRACT
BACKGROUND: Data on the current situation of nuclear medicine practices in cardiology in Brazil are scarce. The International Atomic Energy Agency (IAEA) has recommended eight "good practices" to minimize patients' ionizing radiation exposure during myocardial perfusion scintigraphy (MPS). OBJECTIVES: To assess the adoption of the eight good practices in MPS in Brazil. METHODS: Cross-sectional study with data obtained by use of a questionnaire. All hypothesis tests performed considered a significance level of 5%. RESULTS: We observed that 100% of the nuclear medicine services (NMS) assessed do not use thallium-201 as the preferred protocol. Regarding the use of technetium-99m, 57% of the NMS administer activities above the threshold recommended by the IAEA (36 mCi) or achieve an effective dose greater than 15 millisievert (mSv). The abbreviated stress-only myocardial perfusion imaging is not employed by 94% of the NMS; thus, only 19% count on strategies to reduce the radioactive doses. Approximately 52% of the NMS reported always performing dose adjustment for patient's weight, while 35% administer poorly calculated doses in the one-day protocol. CONCLUSION: A considerable number of NMS in Brazil have not adopted at least six practices recommended by the IAEA. Despite the difficulties found in nuclear practice in some Brazilian regions, almost all obstacles observed can be overcome with no cost increase, emphasizing the importance of developing strategies for adopting "good practices" when performing MPS.
Subject(s)
Myocardial Ischemia/diagnostic imaging , Myocardial Perfusion Imaging/standards , Nuclear Medicine/standards , Practice Guidelines as Topic , Radiation Exposure/standards , Brazil , Cardiology/standards , Cross-Sectional Studies , Humans , Myocardial Perfusion Imaging/methodsABSTRACT
Abstract Background: Data on the current situation of nuclear medicine practices in cardiology in Brazil are scarce. The International Atomic Energy Agency (IAEA) has recommended eight "good practices" to minimize patients' ionizing radiation exposure during myocardial perfusion scintigraphy (MPS). Objectives: To assess the adoption of the eight good practices in MPS in Brazil. Methods: Cross-sectional study with data obtained by use of a questionnaire. All hypothesis tests performed considered a significance level of 5%. Results: We observed that 100% of the nuclear medicine services (NMS) assessed do not use thallium-201 as the preferred protocol. Regarding the use of technetium-99m, 57% of the NMS administer activities above the threshold recommended by the IAEA (36 mCi) or achieve an effective dose greater than 15 millisievert (mSv). The abbreviated stress-only myocardial perfusion imaging is not employed by 94% of the NMS; thus, only 19% count on strategies to reduce the radioactive doses. Approximately 52% of the NMS reported always performing dose adjustment for patient's weight, while 35% administer poorly calculated doses in the one-day protocol. Conclusion: A considerable number of NMS in Brazil have not adopted at least six practices recommended by the IAEA. Despite the difficulties found in nuclear practice in some Brazilian regions, almost all obstacles observed can be overcome with no cost increase, emphasizing the importance of developing strategies for adopting "good practices" when performing MPS.
Resumo Fundamento: A situação atual das práticas da medicina nuclear em cardiologia no Brasil ainda é pouco conhecida. A Agência Internacional de Energia Atômica (AIEA) recomendou oito "boas práticas" para minimizar a exposição dos pacientes à radiação ionizante durante a Cintilografia de Perfusão Miocárdica (CPM). Objetivo: Analisar a adoção das oito boas práticas na CPM no Brasil. Métodos: Estudo transversal com dados obtidos através de questionário. Todos os testes de hipóteses desenvolvidos consideraram uma significância de 5%. Resultados: Observamos que 100% dos Serviços de Medicina Nuclear (SMN) não utilizam Tálio-201 como protocolo preferencial. Sobre a utilização do Tecnécio-99m, notamos que 57% administram atividades acima do limiar recomendado pela AIEA (36 mCi) ou resultam em uma dose efetiva maior que 15 milisievert (mSv). A fase única de estresse não é praticada por 94% dos SMN; portanto, somente 19% contam com estratégias de redução das doses radioativas. Cerca de 52% dos SMN afirmam que sempre realizam o ajuste da dose por peso e 35% administram doses mal calculadas no protocolo de um dia. Conclusão: Observamos que um número considerável de SMN no Brasil ainda não seguem seis ou mais das práticas recomendadas pela AIEA. Apesar das dificuldades enfrentadas na prática nuclear em algumas regiões do Brasil, quase todos os déficits observados podem ser resolvidos sem aumento de custos, ressaltando a importância do desenvolvimento de estratégias para aderência às "boas práticas" na realização da CPM.
Subject(s)
Humans , Practice Guidelines as Topic , Myocardial Ischemia/diagnostic imaging , Radiation Exposure/standards , Myocardial Perfusion Imaging/standards , Nuclear Medicine/standards , Brazil , Cardiology/standards , Cross-Sectional Studies , Myocardial Perfusion Imaging/methodsABSTRACT
Reactive oxygen species (ROS) modulate a variety of intracellular events, but their role in osteoblast adhesion and spreading remains unclear. ROS is a very-known physiological modulators of Protein Tyrosine Phosphatases activities, mainly to low molecular weight protein tyrosine phosphatase (LMW-PTP) activity. As this biological mechanism is not clear in osteoblast adhesion, we decided to investigate ROS levels and phosphorylations of FAK and Src, identifying these proteins as potential substrates to LMW-PTP activity. Our results showed that during osteoblast adhesion/spreading (30 min and 2 h of seeding) the intracellular ROS content (hydrogen peroxide) is finely regulated by an effective anti-oxidant system [catalase and Superoxide Dismutase (SOD) activities were evaluated]. During the first 30 min of adhesion, there was an increase in ROS production and a concomitant increase in focal adhesion kinase (FAK) activity after its phosphorylation at Tyrosine 397 (Y397 ). Moreover, after 2 h there was a decrease in ROS content and FAK phosphorylation. There was no significant change in LMW-PTP expression at 30 min or 2 h. In order to validate our hypothesis that LMW-PTP is able to control FAK activity by modulating its phosphorylation status, we decided to overexpress and silence LMW-PTP in this context. Our results showed that FAK phosphorylation at Y397 was increased and decreased in osteoblasts with silenced or overexpressed LMW-PTP, respectively. Together, these data show that ROS modulate FAK phosphorylation by an indirect way, suggesting that a LMW-PTP/FAK supra-molecular complex is involved in transient responses during osteoblast adhesion and spreading.
