Search results for "Radiation Protection"
showing 10 items of 72 documents
Biologically based models of cancer risk in radiation research
2020
PURPOSE: In radiation risk analysis the state-of-the-art approach is based on descriptive models which link excess rates of cancer incidence and mortality to radiation exposure by statistical association. To estimate the number of sporadic and radiation-induced cases descriptive models apply parametric dose response function which directly determine the radiation risk. In biologically-based models of cancer risk (BBCR models) dose responses are implemented for key events on the biological level such as early mutations or clonal expansion of initiated cells. Influenced by radiation these events then shape the risk response on the epidemiological level. Although BBCR models facilitate a more …
Comparison of the Ultraviolet Light Filtering across Different Intraocular Lenses.
2018
SIGNIFICANCE We have analyzed the ultraviolet transmittance of some commercial intraocular lenses (IOLs). The results show differences of wavelength cutoff among them. PURPOSE The purpose of this study was to measure and compare the ultraviolet light transmittance of different IOLs made out of acrylic hydrophobic, hydrophilic, and hydrophilic with hydrophobic surface materials from different manufacturers. METHODS The spectral transmission curves of eight monofocal IOLs with the same dioptric power of +20.0 diopters were measured using a PerkinElmer Lambda 35 ultraviolet/visible spectrometer. Two IOLs of each type were tested three times. The ultraviolet cutoff wavelength at 10% transmissio…
Photoprotection and photoreception of intraocular lenses under xenon and white LED illumination.
2016
Objective. To analyze the photoprotection and phototransmission that various intraocular lenses (10Ls) provide under the illumination of a xenon (Xe) lamp and white LEDs (light emitting diode). Methods. The spectral transmission curves of six representative 10Ls were measured using a Perkin-Elmer Lambda 35 UV/VIS spectrometer. Various filtering simulations were performed using a Xe lamp and white LEDs. The spectral emissions of these lamps were measured with an ILT-950 spectroradiometer. Results. The 10Ls analyzed primarily show transmission of nearly 100% in the visible spectrum. In the ultraviolet (UV) region, the filters incorporated in the various 10Ls did not filter equally, and some o…
Radiation protection in paediatrics age
2014
Radiological protection in paediatric population from medical imaging is a subject promoted by various international associations and it is becoming a main field of interest. Paediatric patients have a significant risk from ionizing radiation (IR) following X-ray examination (chest, abdomen and skeletal segments), multidetector CT (MDCT) and PET imaging [1]. Their greater damage’s risk is due to: growing tissues with elevated turnover and high radio sensitivity cellular, the high water content which amplifies the damage, the small body size that involves the exposure of large areas associated with the expectation of long- life makes possible the development of diseases resulting from geneti…
Brachytherapy structural shielding calculations using Monte Carlo generated, monoenergetic data
2014
Purpose: To provide a method for calculating the transmission of any broad photon beam with a known energy spectrum in the range of 20–1090 keV, through concrete and lead, based on the superposition of corresponding monoenergetic data obtained from Monte Carlo simulation. Methods: MCNP5 was used to calculate broad photon beam transmission data through varying thickness of lead and concrete, for monoenergetic point sources of energy in the range pertinent to brachytherapy (20–1090 keV, in 10 keV intervals). The three parameter empirical model introduced byArcher et al. [“Diagnostic x-ray shielding design based on an empirical model of photon attenuation,” Health Phys. 44, 507–517 (1983)] was…
Radiation dose distribution around a mobile linear accelerator Mobetron using Monte Carlo simulation
2016
The aim of this work is to analyze the scattered radiation produced by the mobile accelerator Mobetron. To do so detailed Monte Carlo simulation using two different codes, Penelope2011 and Geant4, were performed. Experimental measurements were also done to validate them. To quantify the attenuation of the internal structures present in the accelerator head on the scattered radiation produced, some of the main structural shielding in the Mobetron has been incorporated into the simulation. Results are compared with experimental measurements. Some discrepancies between the calculated and measured dose values were found. These differences can be traced back to the importance of the radiation co…
Radiation Shielding Study of Advanced Data and Power Management Systems (ADPMS) Housing Using Geant4
2008
The tendency to reduce the spacecraft mass covers nowadays all components of the spacecraft. One potential target is to reduce the mass of electronics and its housings. The use of composite materials, especially CFRP is a well known and vastly used approach to mass reduction. In cost reduction the use of standard (non-space qualified) electronics has increased. These commercial circuits and other components cannot tolerate as high radiation levels as space qualified components. Therefore the use of standard electronics components poses challenge in terms of the radiation protection capability of the ADPMS housings. The main goal of this study is to give an insight on the radiation shielding…
The appropriate and justified use of medical radiation in cardiovascular imaging: a position document of the ESC Associations of Cardiovascular Imagi…
2014
The benefits of cardiac imaging are immense, and modern medicine requires the extensive and versatile use of a variety of cardiac imaging techniques. Cardiologists are responsible for a large part of the radiation exposures every person gets per year from all medical sources. Therefore, they have a particular responsibility to avoid unjustified and non-optimized use of radiation, but sometimes are imperfectly aware of the radiological dose of the examination they prescribe or practice. This position paper aims to summarize the current knowledge on radiation effective doses (and risks) related to cardiac imaging procedures. We have reviewed the literature on radiation doses, which can range …
Nordic Cooperation in the Nuclear Safety Sector: High, Low, or Differentiated Integration?
2020
Nordic cooperation has been depicted as eroding due to the increased importance of EU-related cooperation and integration. However, scholars propose that longstanding Nordic networks, grounded in professions and located in the state administration, may prove to be more robust toward external changes. This article discusses this proposal by looking at Nordic cooperation between the national radiation protection and nuclear safety authorities in Iceland, Denmark, Norway, Sweden, and Finland. The article maps behavioural perceptions of agency staff based on a dataset of 37 interviews to illustrate if the cooperation between the Nordic authorities is characterized by high integration, low integ…
Changes in radiological protection and quality control in Spanish dental installations: 1996-2003.
2008
Introduction: The European Union has established specific directives concerning radiological protection which are obligatory for member States. In addition, all Spanish dental clinics with radiological equipment are required to have an annual quality control check. Objective: To analyze the effect of new European legislation on dental radiological practice in Spain and to determine whether it has resulted in lower doses being administered to patients. Material and Methods: A total of 10,171 official radiological quality control reports on Spanish dental clinics, covering 16 autonomous regions, were studied following the passing of Royal Decree 2071/1995 on quality criteria in radiodiagnosti…