Avaliação de meios de contraste submetidos à radiação ionizante

Abstract

OBJECTIVE: The purpose of the present study was to investigate the influence of ionizing radiation from x-rays and gamma rays on the molecular structure stability of several radiologic contrast media employed in diagnostic imaging by means of 1 H and 13 C nuclear magnetic resonance spectroscopy. MATERIALS AND METHODS: Eight different types of iodinated contrast media (three ionic and five non-ionic) were exposed to x-rays and gamma rays irradiation. Subsequently, the H} nuclear magnetic resonance spectra of both ionic and non-ionic contrast media irradiated by x-rays or gamma rays demonstrated the absence of any alteration of the contrast media chemical composition. CONCLUSION: There is no problem in keeping contrast media inside examination rooms or close to radiological equipment. It is important to mention that, during the tests, the samples were directly irradiated, while in a radiology examination room, the irradiation is not direct and, therefore, radiation levels in these cases are much lower than those employed in the present study. Keywords: Imaging diagnosis; Contrast media; Ionizing radiation; Nuclear magnetic resonance spectroscopy; X-rays; Gamma rays.OBJETIVO: O presente estudo consistiu em investigar a influência da radiação ionizante por raios X e raios gama sobre a estabilidade molecular de diversos meios de contraste radiológicos utilizados em exames de diagnóstico por imagem, por meio da espectroscopia de ressonância magnética nuclear de H} de ambos os meios de contraste iônicos e não iônicos irradiados por raios X ou raios gama mostraram que não houve alterações na composição química desses contrastes. CONCLUSÃO: Não há problemas em armazenar as amostras nas salas, ou próximo aos equipamentos em que são realizados os exames. Enfatiza-se que a radiação recebida pelas amostras durante os ensaios foi direta, enquanto em uma sala de exames de radiodiagnóstico a radiação é indireta e, portanto, os níveis de radiações nestes casos são bastante inferiores àqueles empregados neste estudo. Unitermos: Diagnóstico por imagem; Meios de contraste; Radiação ionizante; Espectroscopia de ressonân-cia magnética nuclear; Raios X; Raios gama. AbstractResumo * Study developed at Universidade Tecnológica Federal do Paraná (UTFPR), in a partnership with the

Contrast-enhanced Computed Tomography Examinations: Discussion of Hydration Protocols for Patients with Altered Creatinine Levels

“…The use of substances to enhance the visualization of internal structures in the body through radiological images has a long history, dating back approximately half a century (PINHO et al, 2009).…”

Eventos adversos a meios de contraste iodados em angioplastias coronárias

“…It is estimated that more than 80 million per year of diagnostic or therapeutic interventions using iodinated contrast media. [5][6][7] It is shown that ICM, by increasing the visibility of all surfaces of organs and tissues to be studied, may help the interventional cardiologist to determine the presence and extent of coronary artery disease or injury during the procedure of cardiac catheterization and during PCI.…”

“…Barium Sulphate, Fluorescein, Gadolinium and iodinated contrast media (ICM) are included in the contrast media available on the market, the latter being the focus of the work. [5][6][7] The ICMs are classified according to their basic properties, which are: osmolality in relation to plasma (number of free particles), so called high-ICM(600 to 2100 mOsm/kg H2O), low osmolality (290 and 860mOsm/Kg H2O) or isosmolar (290mOsm/kg H2O) and according to their ionicity, chemical structure and viscosity. 2,4 It is reported that osmolality is the number of free particles in relation to one Kg of H2O, with the mean osmolality of the solutions and organic cells being about 290 mOsm/kg H2O, ie the closer the osmolality of the medium of iodinated contrast of the osmolality of the organic solutions, the better will be its tolerance in the human organism.…”

“…Thus, adverse events to ICM are common, which can be divided into three different types: toxic reactions; allergic and non-allergic hypersensitivity reactions, which may occur less than one hour after the infusion of ICM (immediate reactions), triggered by unknown mechanism or immunoglobulin E (IgE) mediated as anaphylactic symptoms, or one to ten days after the infusion of ICM (non-immediate reactions), triggered by unknown mechanism or by cells, such as the appearance of erythematous rashes, in addition to unrelated events that may appear as nonspecific symptoms. [5][6][7] Adverse events that may be related to the use of ICMs due to their severity are differentiated between: mild (signs and symptoms are selflimiting, with no evidence of progression); signs and symptoms are more pronounced and commonly require medical treatment, where some of these events have the potential to become serious if left untreated) and severe (signs and symptoms are often life-threatening and may result in permanent morbidity and death if not properly managed). 4,11,12 Immediate hypersensitivity reactions are reported to occur in 0.7% to 3% of the population exposed to iodinated (nonionic) contrast medium and, from these reactions, 0.02% to 0.04% are severe and 0.00001 % to 0.00003% are fatal; in non-immediate reactions, the incidence is 0.5% to 3%, being more associated with the use of nonionic dimer contrast.…”

Análise de propriedades dosimétricas de materiais quanto à dependência energética usando simulação de Monte Carlo

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