Determination of the radiochemical purity of 99mTc-Tetrofosmin: comparision between five methods

GOAL: The manufacturing and distribution of strips of instant thin - layer chromatography with silica gel (ITLC - SG) (reference method) is currently discontinued so there is a need for an alternative method f or the determination of radiochemical purity (RCP) of 99m Tc - tetrofosmin. This study aims to compare five alternative methods proposed by the producer to determine the RCP of 99m Tc - tetrofosmin. METHODS: Nineteen vials of tetrofosmin were radiolabelled with 99m Tc and the percentages of the RCP were determined. Five different methods were compared with the standard RCP testing method (ITLC - SG, 2x20 cm): Whatman 3MM (1x10 cm) with acetone and dichloro - methane (method 1); Whatman 3MM (1x1 0 cm) with ethyl acetate (method 2); aluminum oxide - coated plastic thin - layer chromatography (TLC) plate (1x10 cm) and ethanol (method 3); Whatman 3MM (2x20 cm) with acetone and dichloro - methane (method 4); solid - phase extraction method C18 cartridge (meth od 5). RESULTS: The average values of RCP were 95,30% ± 1,28% (method 1), 93,95 ± 0,61% (method 2), 96,85% ± 0,93% (method 3), 92,94% ± 0,99% (method 4) and 96,25% ± 2,57% (method 5) (n=12 each), and 93,15% ± 1,13% for the standard method (n=19). There we re statistical significant differences in the values obtained for methods 1 (P=0,001), 3 (P=0,000) and 5 (P=0,004), and there were no statistical significant differences in the values obtained for methods 2 (P=0,113) and 4 (P=0,327). CONCLUSION: From the results obtained, methods 2 and 4 showed a higher correlation with the standard method. Unlike method 4, method 2 is less time - consuming than the reference method and can overcome the problems associated with the solvent toxicity. The remaining methods (1, 3 and 5) tended to overestimate RCP value compared to the standard method.

CYCLOTech - an innovative approach for the reliable production of 99mTc - technetium

CYCLOTech is a high-tech Project, related with an innovative method for direct production of a radioactive pharmaceutical, used in excess of 85% of 35 Million Nuclear Medicine procedures done yearly, worldwide, representing globally more than 3 Billion Euros. The CYCLOTech team has developed an innovative proprietary methodology based on the use of Cyclotron Centers, formally identified as the Clients (actually, there are around 450 of this Centers in function worldwide), to directly produce and deliver the radiopharmaceutical to the final users, at the Hospitals and other Health Institutions (estimating at around 25.000, worldwide). The investment still need to finish Research and Technological Development (RTD), Industrial, Regulatory and Intellectual Property Rights (IPR) issues and allow the introduction in the Market is 4,35 M€, with a Payback of 3 years, with an Investment Return Rate (IRR) of 81,7% and a Net Present Value (NPV) of 60.620.525€ (in 2020).

Estudo comparativo entre os efeitos terapêuticos da revascularização cirúrgica do miocárdio e angioplastia coronária em situações isquêmicas equivalentes: análise através da cintilografia do miocárdio com 99mTc-Sestamibi

OBJETIVO: Avaliar a carga isquêmica do miocárdio prévia e ulterior à revascularização do miocárdio. MÉTODOS: Foram avaliados 96 pacientes randomizados, portadores de doença arterial coronariana multivascular, angina estável, função do ventrículo esquerdo preservada e isquemia miocárdica esforço-induzida tratados com revascularização cirúrgica (RCM) ou angioplastia coronariana (ATC). Cintilografia do miocárdio com 99mTc-Sestamibi foi realizada antes e 6 meses após a revascularização do miocárdio. RESULTADOS: A RCM determinou índice significantemente maior de revascularização completa (p=0,001), aumento no número de testes ergométricos máximos (p=0,001) e redução no número de testes ergométricos positivos com angina de esforço (p=0,018). Ambos os procedimentos ofereceram melhora importante na classe funcional da angina (p=0,001), aumento no valor médio do duplo produto de pico (p=0,009), e do tempo de tolerância ao esforço (p<0,001), além de redução no valor médio da somatória do escore do esforço (p<0,001) e da diferença da somatória dos escores (p<0,001) nos dois grupos. CONCLUSÃO: ATC e RCM não diferiram significantemente quanto à redução da carga isquêmica do miocárdio 6 meses após o procedimento. A revascularização do miocárdio foi mais completa com a RCM do que com a ATC, mas não representou fator significante para redução da carga isquêmica do miocárdio.