RESUMO
The aim of the present study is to analyse quantitatively the potential reduction of doses to the eye lens and the hands of an operator and a nurse by the use of a pelvic lead blanket during coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) procedures. Thermoluminescent dosimeters were used to assess dose levels to the left eye lens and fingers on both hands of both physician and nurses during single procedures performed with or without the lead blanket. The measurements were carried out at one medical centre and include dosimetric data from 100 procedures. Additional measurements including physician's and patient's doses were made on phantoms in the laboratory. In order to determine the reduction potential of the lead blanket, the doses normalized to DAP (Dose-Area Product) corresponding to the same position of dosimeter were compared against each other for both procedure categories (with and without protection). There was no statistically significant decrease observed in physicians' and nurses' eye lens doses, nor in doses normalized to DAP due to the use of the lead pelvic shield in clinic. However, some trend in reducing the eye lens doses by this shield can be observed. Regarding finger doses, the differences are statistically significant but only for physicians. The mean DAP-normalised doses to the eye lens and left and right finger of physicians, in the presence of a ceiling-suspended transparent lead shield, were 2.24e-5 ± 1.41e-5 mSv/µGym2, 2.31e-4 ± 1.21e-4 mSv/µGym2, and 2.60e-5 ± 1.57e-5 mSv/µGym2 for standard procedures performed without the lead blanket, and 1.77e-5 ± 1.17e-5 mSv/µGym2, 1.70e-4 ± 1.01e-4 mSv/µGym2, and 1.86e-5 ± 1.13e-5 mSv/µGym2 for procedures performed with it. A comparison of the results from the laboratory and the clinic shows that they are consistent regarding the eye lens, while for fingers it suggests that the dose reduction properties of the lead shield are related to the physician's work technique and both patient and lead blanket sizes or its positioning. The highest degree of reduction is observed for cranial and caudal projections together with the use of a patient-adjustable lead blanket; about a 2-fold decrease in finger doses is expected for optimum conditions. However, the laboratory measurements suggest that the use of lead blanket might slightly increase the patient dose, but only when specific projections are constantly used. This limitation should be considered by cardiologists during clinical work if this protection is used. In the light of the presented results, the ceiling-suspended transparent lead shield and the lead glasses seem to be the preferred way to reduce the doses to the eye lens, compared to the lead blanket.
Assuntos
Cardiologistas , Mãos/efeitos da radiação , Chumbo , Cristalino/efeitos da radiação , Enfermeiras e Enfermeiros , Exposição Ocupacional/prevenção & controle , Lesões por Radiação/prevenção & controle , Proteção Radiológica/instrumentação , Angioplastia , Angiografia Coronária , Dispositivos de Proteção dos Olhos , Humanos , Pelve , Dosimetria TermoluminescenteRESUMO
The aim of the study was to check, in clinical practice, the potential for the dose reduction of lead eyewear and a ceiling-suspended shield used to protect the eye lens of physicians working in interventional cardiology. To this end, for the lead eyewear, the dose reduction factors were derived to correct the readings from a dosimeter used routinely outside the glasses. Four types of lead eyewear with attached loose thermoluminescent dosimeters and EYE-D dosimeters were worn by physicians in two clinical centres, for two-month periods, during coronary angiography (CA), percutaneous coronary intervention (PCI), and pacemaker procedures. In order to analyse, separately, how a ceiling-suspended lead screen absorbs the scattered radiation, a series of measurements was carried out during single CA/PCI procedures performed with and without the protection. The lead eyewear may reduce the doses to the eye closest to the x-ray tube by a factor between 1.1 and 3.4, depending on its model and the physician's position. The effectiveness of the eyewear may, however, vary-even for the same model and physician-almost twofold between different working periods. The ceiling-suspended shield decreases the doses in clinical practice by a factor of 2.3. The annual eye lens doses without the eyewear estimated from routine measurements are high-above or close to the new eye lens dose limit established by the recent EU Basic Safety Standards, even though the ceiling-suspended shield was used. Therefore, to comply with the new dose limit that is set in the Directive, protection of the eyes of physicians with high workloads might require the use of both the eyewear and the ceiling-suspended shield.
Assuntos
Cardiologia , Dispositivos de Proteção dos Olhos , Cristalino/efeitos da radiação , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/prevenção & controle , Lesões por Radiação/prevenção & controle , Proteção Radiológica/métodos , Radiografia Intervencionista , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Doses de Radiação , Radiometria/métodos , Dosimetria TermoluminescenteRESUMO
α-Amanitin, the main toxic substance from mushroom species (Amanita genus), blocks the activity of RNA polymerase II (Pol II) in mammalian cells causing inhibition of transcription and subsequent synthesis of structural and enzymatic proteins. It has been postulated that α-amanitin generates the increase of reactive oxygen species (ROS) concentration. The micronucleus (MN) test was used on an animal experimental model to evaluate possible potential genotoxic effect of α-amanitin on mice bone marrow cells. At the same time the activity of antioxidant enzymes: superoxide dismutase (SOD) and catalase (CAT) as well as concentration of thiobarbituric acid reactive substance (TBARS) were investigated in the lysate of mice erythrocytes. α-Amanitin was administered intraperitoneally at the doses: 0.1, 0.15, and 0.25 mg/kg bw (LD(50) for mice) 48 h prior to sacrification. A statistically significant increase of SOD activity was observed in the hemolysate for all the investigated α-amanitin doses as compared to the negative control (p < 0.05). CAT activity for α-amanitin doses 0.1 and 0.15 mg/kg was higher in comparison to the negative control but the differences were not statistically significant (p > 0.05). However, for the dose 0.25 mg/kg the activity of CAT was statistically significantly higher (p < 0.001). All the tested α-amanitin doses decreased TBARS concentration in the hemolysate as compared to the negative control but the differences were not statistically significant (p > 0.05). A statistically significant increase of mean values of MN percent was found in polychromatic erythrocytes (PCEs) as compared to the negative control for α-amanitin dose 0.1 and 0.25 mg/kg (p < 0.05). For the dose 0.15 mg/kg the mean value of MN percent was higher but it did not demonstrate statistical significance (p > 0.1). The observed disturbances in the activity of the examined antioxidant enzymes in cells exposed in vivo to α-amanitin suggest indirect genotoxic effect of α-amanitin through ROS generation.