Efectos biológicos y aspectos de seguridad de las radiaciones no ionizantes en la resonancia magnética / Non-Ionizing Biological Effects and Security Issues in Magnetic Resonance

Objetivo: Hacer una revisión, en español, de los efectos biológicos determinísticos de los campos magnéticos estáticos, dinámicos y de radiofrecuencia, propios de los exámenes de resonancia magnética (RM) en hospitales. Metodología: Se hace referencia a los límites definidos dependiendo de los distintos usos de la radiofrecuencia en un examen de RM y sus posibles efectos biológicos. Además, se muestran los aspectos de seguridad que deben tenerse en cuenta cuando se diseñan zonas que incluyan esta técnica diagnóstica. Finalmente, se hace una breve revisión de los temas que deben tener en cuenta los entes reguladores ante este tipo de exámenes con radiaciones no ionizantes. Conclusiones: A pesar de no ser determinantes los estudios sobre riesgo biológico, sí hay riesgos, principalmente por la existencia de altos campos magnéticos, que aconsejan tener ciertas precauciones en cuanto a instalaciones y personal calificado, así como una legislación acorde, de la que, por otra parte, carece Colombia.

Objective: To review the deterministic biological effects of static, dynamic and dependent magnetic fields used in clinical magnetic resonance imaging (MRI). Methods: The suggested limits are referenced depending on the different MRI applications, as well as their possible biological effects. In addition, safety aspects which must be taken into account when areas that include this diagnostic technique are shown. Lastly, a short description of the important items for the regulatory authorities to consider when facing these types of test with non-ionizing radiation is discussed. Conclusions: Even though there is no agreement in the literature about the biological risks, risks do exist due to the presence of high magnetic fields. Specific precautions should be taken in terms of proper facilities and qualified personnel, as well as an appropriate legislation which does not exist in Colombia.

Tratamento da retinopatia por radiação com injeção intravítrea de bevacizumab (Avastin®): relato de caso / Treatment of radiation retinopathy with intravitreal injection of bevacizumab (Avastin®): case report

OBJETIVO: Relatar tratamento de retinopatia por radiação em paciente submetido à radioterapia por linfoma em órbita direita com injeção intravítrea de bevacizumab (Avastin®). Paciente de 55 anos, diabético, com diagnóstico de linfoma MALT orbitário há três anos, tratado com radioterapia local (dose: 35Gy) há dois anos, com queixa de redução da acuidade visual do olho direito há quatro meses. Ao exame oftalmológico, apresentava alterações sugestivas de retinopatia por radiação, bem como espessura macular à tomografia de coerência óptica de 480 µm. Paciente foi submetido à injeção intravítrea (0,05 ml) de bevacizumab (Avastin®) no olho direito, apresentando redução do edema macular, bem como melhora discreta da acuidade visual. Neste caso, o tratamento da retinopatia por radiação com injeção intravítrea de bevacizumab (Avastin®) foi relativamente útil, com melhora discreta da acuidade visual, devido à regressão do edema macular.

PURPOSE: To report a case of radiation retinopathy treatment with intravitreal injection of bevacizumab (Avastin®) in a patient undergoing radiotherapy for lymphoma in the right orbit. Patient of 55 years-old male, diabetic, diagnosed with an orbital MALT lymphoma three years ago, treated with local radiotherapy (dose: 35Gy) two years ago, complaining of reduced visual acuity of the right eye for about four months. During the ophthalmologic evaluation, he had an exam suggestive of radiation retinopathy. Macular thickness at the optical coherence tomography was 480 µm. Patient was referred to intravitreal injection (0.05 ml) of bevacizumab (Avastin®) in the right eye, showing reduction of macular edema and mild improvement of visual acuity. In this case, the treatment of radiation retinopathy with intravitreal injection of bevacizumab (Avastin®) was relatively useful, with mild improvement of visual acuity due to the regression of macular edema.

Non-cancer Diseases of Korean Atomic Bomb Survivors in Residence at Hapcheon, Republic of Korea

Many Koreans, in addition to Japanese, were killed or injured by the atomic bombs detonated over Hiroshima and Nagasaki, Japan, in 1945. Our study examined noncancer diseases of Korean A-bomb survivors in residence at Hapcheon, Republic of Korea and evaluated whether they had significantly higher prevalence of noncancer diseases than non-exposed people. We evaluated a number of tests, including anthropometric measurements, blood pressure, blood chemistry, hepatitis B surface antigen, and urinalysis, of survivors (n=223) and controls (n=372). Univariate analysis revealed significantly lower fasting glucose and creatinine, and higher diastolic blood pressure, aspartate aminotransferase, alanine aminotransferase, and blood urea nitrogen levels in the survivors than in the controls. The calculation of crude prevalence ratios (PRs) revealed that A-bomb survivors had a significantly higher prevalence of hypertension (PR, 1.16; 95% CI, 1.00-1.35) and chronic liver disease (2.20; 1.59-3.06) than controls. After adjusting for covariates (age, sex, body mass index, marital status, education, alcohol consumption, and smoking), A-bomb survivors had a significantly higher prevalence of hypertension (1.24; 1.06-1.44), chronic liver disease (2.07; 1.51-2.84), and hypercholesterolemia (1.79; 1.11-2.90) than controls. This study suggests that A-bomb exposure is associated with a higher prevalence of non-cancer diseases in Korean survivors.