Radiation Exposure Levels Research Articles

Animal Lymphocyte Metaphase Chromosome Preparation.

Metaphase chromosome analysis of lymphocytes is the gold standard for biodosimetry to estimate the levels of radiation exposure in various animals as well as humans. Animals, including experimental, companion, and wild animals, are powerful and indispensable models for researching radiation injury, safety, and therapy. Moreover, biodosimetry of animal models can be used to support human biodosimetry data and may be useful for estimating environmental contamination by radioactive materials. The basic restraint procedure and venipuncture technique are different depending on each animal type. The general procedure evaluating metaphase chromosomes is similar to the human blood technique except for a minor modification in the initial culture. This chapter will introduce basic mouse, rat, rabbit, dog, cat, cow, horse, goat, pig, and wild boar venipuncture and blood sampling techniques for metaphase chromosome preparation and analysis.

Environmental Pollution of Cellular Mobile Base Station in Populated Areas

Cellular mobile communication technology has grown exponentially in the last decade resulting in large number of base stations in areas at which people are living or working. All over the world, the electromagnetic pollution produced from cellular base stations erected in residential areas and its effect on the environment and human body is a problem that has been concerning the society for many years. This paper, introduces the effects of electromagnetic energy emitted cellular base stations on the biological systems of the human body. The induced electromagnetic fields (EMF), and specific absorption rate (SAR) were calculated in close proximity to cellular mobile base stations. The calculated values of SAR were compared with the most commonly used international limits. The results show that the electromagnetic radiation (EMR) exposure levels at a distance of several meters from the base station towers can cause hazardous effects to the public

Radiation exposure during image-guided endoscopic procedures: The next quality indicator for endoscopic retrograde cholangiopancreatography.

Endoscopic retrograde cholangiopancreatography (ERCP) is one of the most frequently used image-guided procedures in gastrointestinal endoscopy. Post-ERCP pancreatitis is an important concern, and prophylaxis, cannulation and other related technical procedures have been well documented by endoscopists. In addition, medical radiation exposure is of great concern in the general population because of its rapidly increasing frequency and its potential carcinogenic effects. International organizations and radiological societies have established diagnostic reference levels, which guide proper radiation use and serve as global standards for all procedures that use ionizing radiation. However, data on gastrointestinal fluoroscopic procedures are still lacking because the demand for these procedures has recently increased. In this review, we present the current status of quality indicators for ERCP and the methods for measuring radiation exposure in the clinical setting as the next quality indicator for ERCP. To reduce radiation exposure, knowledge of its adverse effects and the procedures for proper measurement and protection are essential. Additionally, further studies on the factors that affect radiation exposure, exposure management and diagnostic reference levels are necessary. Then, we can discuss how to manage medical radiation use in these complex fluoroscopic procedures. This knowledge will help us to protect not only patients but also endoscopists and medical staff in the fluoroscopy unit.

New Comparative Metric for Evaluating Spacecraft Radiation Shielding

Given the lack of human medical data available to calibrate and tie the sophisticated model calculations of various space radiation exposure metrics, such as “dose equivalent,” to the actual biological harm expected from long-term exposure to galactic cosmic ray (GCR) radiation in the region of cislunar space [nominally at 1 astronomical unit (AU) from the sun], a new spacecraft shielding evaluation metric is proposed that empirically links to the available medical data collected from International Space Station (ISS) operations, and thereby improves shielding material assessment. Adequate protection from radiation is one of the most important unknowns regarding the contemplated long-term spaceflights beyond the Earth’s protective zone afforded by its magnetosphere. This new radiation shielding evaluation metric relies on a comparison of the relative shielding effectiveness of a particular material or shielding design in the cislunar space radiation environment to the verified radiation exposure environment inside the ISS, where hundreds of astronauts have flown and spent considerable time, and for which there is voluminous medical data and continuing medical observation. Thus, the new metric is a measure of how well a proposed shielding protocol operating in the 1 AU cislunar radiation environment replicates the ISS radiation exposure levels. And, because it is calculated on a strict comparable basis, it mitigates the unavoidable errors introduced in the shielding evaluation process inherent in using different GCR models and radiation transport codes, as well as the various versions of radiation quality or weighting factors.

Long-Term Consequences of the Chernobyl Radioactive Fallout: An Exploration of the Aggregate Data.

This study investigates the association between the radioactive 137 Cesium fallout originated by the 1986 Chernobyl nuclear accident and dispersed over Western Europe, as a result of a combination of radioactive cloud passage days and rainy days over a 10-day period, and long-term health patterns and related costs. Since the half-life of 137 Cesium is 30.17 years, part of the radioactivity in the affected regions is still present today, and it is usually still detected in the food chain, although at lower concentration levels. We match longitudinal data on neoplasm incidence over the time span 2000-2013 in a number of European regions not immediately adjacent to Chernobyl with the randomly distributed levels of cesium deposition after the nuclear disaster in order to assess whether we can detect an association with the long-term health effects on the European population through a random effects model. Considering 3 levels of fallout deposition-low, medium, and high-hospital discharges after treatment for neoplasms are, respectively, 0.36, 0.44, and 0.98 discharges over 100 inhabitants higher compared to regions with no fallout, with the population average being around 1.7 hospital discharges by neoplasms over 100 inhabitants. We checked the robustness of our findings to a number of tests including a placebo simulation and different model specifications. Radioactive fallout is positively associated with a higher incidence of hospital discharges after treatment for neoplasms almost 30 years after its release, with larger effects in regions where the radioactivity was more intense. Our estimates are comparable to the findings of the largest-scale study on the long-term health effects of continuous low levels of radiation exposure among workers in the nuclear industry and suggest that more research is needed on this topic, given its enormous importance for public health and safety.

Pediatric Considerations Before, During, and After Radiological or Nuclear Emergencies

Infants, children, and adolescents can be exposed unexpectedly to ionizing radiation from nuclear power plant events, improvised nuclear or radiologic dispersal device explosions, or inappropriate disposal of radiotherapy equipment. Children are likely to experience higher external and internal radiation exposure levels than adults because of their smaller body and organ size and other physiologic characteristics, by picking up contaminated items, and through consumption of contaminated milk or foodstuffs. This policy statement and accompanying technical report update the 2003 American Academy of Pediatrics policy statement on pediatric radiation emergencies by summarizing newer scientific knowledge from studies of the Chernobyl and Fukushima Daiichi nuclear power plant events, use of improvised radiologic dispersal devices, exposures from inappropriate disposal of radiotherapy equipment, and potential health effects from residential proximity to nuclear plants. Policy recommendations are made for providers and governments to improve future responses to these types of events.

A Mobile Technology Intervention With Ultraviolet Radiation Dosimeters and Smartphone Apps for Skin Cancer Prevention in Young Adults: Randomized Controlled Trial

BackgroundSkin cancer is the most prevalent and most preventable cancer in Australia. Despite Australia’s long-running public health campaigns, young Australian adults continue to report high levels of ultraviolet radiation (UVR) exposure and frequent sunburns. Young people are now increasingly turning away from traditional media, such as newspapers and TV, favoring Web-based streaming, which is challenging the health care sector to develop new ways to reach this group with targeted, personalized health promotion messages. Advances in technology have enabled delivery of time- and context-relevant health interventions.ObjectiveThe primary aim of this randomized controlled trial was to test the effect of UVR feedback from a smartphone app or a UVR dosimeter feedback device on sun protection habits, sun exposure behaviors, sunburn, and physical activity levels in young adults.MethodsYoung adults aged 18-35 years (n=124) were recruited from Queensland, Australia, between September 2015 and April 2016, via social or traditional media campaigns and outreach activities in the local community. Participants were randomized into 3 groups for a 4-week intervention: (1) no intervention control group; (2) UVR monitor group, who were asked to wear a UVR dosimeter feedback device set to their skin type; and (3) a SunSmart app group, who were asked to download and use the SunSmart phone app. Data were self-assessed through Web-based surveys at baseline and 1 week and 3 months postintervention.ResultsComplete data were available for 86.2% (107/124) of participants (control group, n=36; UVR monitor group, n=36; and SunSmart app group, n=35). Intervention uptake in the UVR monitor group was high, with 94% (34/36) of participants using the device all or some of the time when outdoors. All SunSmart app group participants downloaded the app on their smartphone. There was no significant difference in the change in the sun protection habits (SPH) index (main outcome measure) across the 3 groups. However, compared with the control group, a significantly greater proportion of the participants in the UVR monitor group reduced their time unprotected and exposed to UVR on weekends during the intervention compared with the baseline (odds ratio [OR]: 2.706, 95% CI 1.047-6.992, P=.04). This significant effect was sustained with greater reductions observed up to 3 months postintervention (OR: 3.130, 95% CI 1.196-8.190, P=.02). There were no significant differences between the groups in weekday sun exposure, sunscreen use, sunburn, suntan, or physical activity.ConclusionsUsing technology such as apps and personal UVR monitoring devices may improve some sun exposure behaviors among young adults, but as the SPH index did not increase in this study, further research is required to achieve consistent uptake of sun protection in young people.Trial RegistrationThe Australian and New Zealand Clinical Trials register ACTRN12615001296527; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=368458 (Archived by WebCite at http://www.webcitation.org/731somROx)

Measurement of Background Ionizing Radiation Exposure Levels in Selected Farms in Communities of Ishielu LGA, Ebonyi State, Nigeria

The perceived implication of increase background radiation levels of farm lands due to inputs of fertilizers and agrochemicals has suggested the need to investigate the background ionization radiation (BIR) levels and associated radiation health parameters in farmlands located in communities of Ishielu LGA of Ebonyi State, Nigeria. An in-situ method of BIR measurement in five farmlands each located in Nkalagu, Ezillo, Okpoto and Nteze communities was carried out using portable GQ GMC-320 Plus radiation meter at an elevation of 1.0 m above ground level with a GPS for geographical location. The BIR levels observed in Nkalagu and Ezillo farmlands are high ranging with same mean values of 0.016±0.002mR/h which is higher than 0.013 mR/h ICRP recommendations for normal environment. The BIR measured at Okpoto and Nteze farmlands are low ranging with mean values of 0.013±0.001 mR/h which is in tandem with ICRP recommendation. The corresponding absorbed doses in all the farmlands and associated excess lifetime cancer risks are far higher than their recommended safe limit of 84.0 ηGy/h and 0.29×10 -3 respectively. The values for the annual effective dose for all the farm lands are lower than the permissible limits of 1.00 mSv/yr for the general public. The study shows that the radiation levels and the doses observed in the farmlands do not constitute any immediate negative radiological health effect on the farmers and general public. However, there exists the possibility of cancer development due to accumulated doses as suggested by the excess lifetime cancer risk values. Keywords : Background radiation levels, absorbed doses, farm lands, Ishielu communities

Pediatric Considerations Before, During, and After Radiological or Nuclear Emergencies.

Infants, children, and adolescents can be exposed unexpectedly to ionizing radiation from nuclear power plant events, improvised nuclear or radiologic dispersal device explosions, or inappropriate disposal of radiotherapy equipment. Children are likely to experience higher external and internal radiation exposure levels than adults because of their smaller body and organ size and other physiologic characteristics as well as their tendency to pick up contaminated items and consume contaminated milk or foodstuffs. This technical report accompanies the revision of the 2003 American Academy of Pediatrics policy statement on pediatric radiation emergencies by summarizing newer scientific data from studies of the Chernobyl and the Fukushima Daiichi nuclear power plant events, use of improvised radiologic dispersal devices, exposures from inappropriate disposal of radiotherapy equipment, and potential health effects from residential proximity to nuclear plants. Also included are recommendations from epidemiological studies and biokinetic models to address mitigation efforts. The report includes major emphases on acute radiation syndrome, acute and long-term psychological effects, cancer risks, and other late tissue reactions after low-to-high levels of radiation exposure. Results, along with public health and clinical implications, are described from studies of the Japanese atomic bomb survivors, nuclear plant accidents (eg, Three Mile Island, Chernobyl, and Fukushima), improper disposal of radiotherapy equipment in Goiania, Brazil, and residence in proximity to nuclear plants. Measures to reduce radiation exposure in the immediate aftermath of a radiologic or nuclear disaster are described, including the diagnosis and management of external and internal contamination, use of potassium iodide, and actions in relation to breastfeeding.

Risk of radiation-induced lens opacities among surgeons and interventional medical staff.

The main effect of ionizing radiation on the eyes is the onset of posterior cortical and subcapsular cataracts. Recent studies have raised questions about the mechanism of ocular damage and the threshold dose for the onset of such effects. Currently, operators may be exposed to ionizing radiation during surgical procedures. It has been estimated that urologists can be exposed to an annual dose close to or above 20mSv/year. The aim of our study was to evaluate the frequency of cataracts in a group of professional radiological operators to verify their possible association with the radiation dose to the crystalline lens and the tasks performed. The records of 73 health workers exposed to ionizing radiation were reviewed. The average annual dose to the crystalline lens, the number of years of exposure, and the presence of radiation-compatible opacities were assessed for all operators. Lenticular opacities were observed in 16.4% of subjects. The presence of alterations was associated with exposure doses below 10mSv and > 10 years' experience in fluoroscopically guided procedures. Based on our results, protection of the crystalline lens against exposure to ionizing radiation by means of goggles is recommended. In addition, examination of the lens via slit lamp examination is recommended for all operators involved in interventional procedures with the current levels of radiation exposure.

Radiation exposure during C-arm-guided (fluoroscopy) small animal orthopaedic surgery

The purpose of the current study was to investigate the radiation exposure level of surgeons performing C-arm guided small animal orthopaedic surgery using thermoluminescent dosimeters located inside and outside personnel shielding devices at major body parts. A prospective study was conducted to measure the radiation exposure dose of individuals in three positions (first assistant, operating surgeon and anaesthesiologist) using thermoluminescent dosimeters placed inside and outside protective devices. The lead equivalent protective devices included panorama mask, thyroid shield, apron and arm shield placed at five anatomic sites (eye, thyroid, breast, gonad and hand). Radiation exposure was measured during 12 surgical procedures with mean kVp of 51 and mean mAs of 1.6. The equivalent doses for thyroid, breast and gonad (outside/inside in mSv) were 1.75/0.58, 2.01/0.13 and 3.03/0.11, respectively, for the first assistant and 1.69/1.46, 4.82/0.35 and 5.25/0.22 for the operating surgeon. The dose of eye, thyroid, breast, gonad and arm for the anaesthesiologist were 0.61/0.51, 0.35/0.3, 0.67/0.34, 0.72/0.29 and 0.62/0.35, respectively. The exposure dose to gonads outside the lead protection showed the highest values in all participants. With lead protection, there was a significant reduction in the exposure dose to the gonads (first assistant, 96%; operating surgeon, 96%; anaesthesiologist, 60%). These results suggest that a radiation shield is essential in veterinary surgery with C-arms, particularly for gonad protection. In addition, these results demonstrate that exposure dose decreases with increasing distance from the C-arm machine.

Assessment of a novel radiation reduction protocol for pediatric and adult congenital device implantation.

Device implantation requires fluoroscopic guidance, which carries inherent risks of ionizing radiation. We evaluated the impact of a low-dose fluoroscopic protocol on radiation exposure during device implantation. All patients who underwent pacemaker or ICD implantation with new transvenous leads from July 2011 to January 2018 were included. A novel ALARA protocol consisting of ultra-low frame rates (2-3 frames/s), low dose/frame (6-18mGy/frame), and use of the "air-gap" technique in patients < 20kg was employed. Demographics, procedural data, and radiation exposure levels were collected and analyzed. Thirty patients underwent device implantation without additional catheterization, electrophysiology study, or ablation procedure (median age 15years; range 5-50) with a total of 43 leads placed. Forty-seven percent of patients had a primary rhythm disturbance, 33% had cardiomyopathy, and 20% had congenital heart disease. Fifty percent were pacemakers (53% dual-chamber, 27% ventricle, 20% atrial) and 50% of devices implanted were ICDs (87% single-chamber). All implants were acutely successful with acceptable atrial and ventricular sensing and capture thresholds. The median fluoroscopy time was 11.5min (inter-quartile range (IQR) 8.0-18.2), median air kerma dose 4.0mGy (IQR 2.5-19.5), and median dose-area product 27.8μGy/m2 (IQR 17.1-106.5). Median implant procedure time was 133min. One patient required revision secondary to device migration without lead derangement 2days post-procedure. Use of a novel fluoroscopic protocol may help decrease radiation exposure to patients and staff without affecting efficacy or risk. These data may represent benchmarks against which future device implantation procedures can be compared.

Evaluation of Radiation Exposure From Computed Tomography of the Head

In an effort to reduce radiation exposure from computed tomography (CT), practitioners and facilities need to monitor radiation exposure while delivering high-quality diagnostic examinations. One way to minimize a patient's exposure to radiation from CT is the use of an automatic exposure control device. Current research is focusing on these devices and their actual benefits to patients. To assess the effectiveness of such a device, analysis of radiation doses per CT examination must occur. Machine-specific dose-length product and/or CT dose index are the only indicators of specific dose levels. This project compares current levels of radiation exposure to patients undergoing CT scans of the head versus the national levels as evaluated by the Nationwide Evaluation of X-ray Trends program.

Assessment of iterative image reconstruction on kidney and liver donors: Potential role of adaptive iterative dose reduction 3D (AIDR 3D) technology

ObjectiveThe aim of this study was to evaluate the radiation exposure levels in two different types of subjects including liver and kidney donors in diagnostic assessment of transplant operation and also the significance of dose reduction on total effective dose. Materials and methodsA number of Sixty subjects (40 males and 20 females, average age of 35 ± 10 years) were randomly prospectively recruited and equally divided into two distinct groups namely kidney donors (KD, 24 M and 6 F) and liver donors (LD, 21 M and 9 female). Kidney donors were divided into full dose (KFD, n = 20) group and low dose (KLD, n = 10) group. They had undergone dynamic renal scan using Tc99 m-DTPA, CT renal angiography and x-ray plain radiograph. Liver donors were divided into full dose (LFD, n = 20) and low dose (LLD, n = 10) groups and performed CT liver volumetry. The CT dose index (CTDIvol), dose length product (DLP), total milli-ampere product time mAs, effective dose and image noise index were measured in all subjects of kidney and liver donors comparing full dose and low dose protocols. ResultsIn comparison of all subjects of kidney donor groups (KFD vs KLD), the parameters (mAs = 16386.8 ± 3140.7 vs 2830.286 ± 831.676), (CTDIvol = 183.19 ± 32.58 mGy vs. 45.5 ± 13.3 mGy), DLP = 2884 ± 859.0 mGy.cm vs. 1437.5 ± 399 mGy.cm) and (effective dose = 49.0 ± 9.0 mSv vs. 18.9 mSv±5.7 mSv) were significant, p < 0.0005. Statistical evaluation of liver donors groups (LFD vs LLD) showed that (mAs = 14348.8 ± 4571.8 vs 3123.357 ± 794.5), (CTDIvol = 333.6 ± 59.5 mGy vs. 51.4 ± 13 mGy), (DLP = 3268.3 ± 604.3 mGy.cm vs 1260.5 ± 404.6 mGy.cm) and (effective dose = 43.3 mSv±12.9 mSv vs. 21.6 ± 5.9 mSv) are statistically significant, p < 0.0005. Nevertheless, the comparative evaluation of the image quality noise index of KFD vs KLD groups and LFD vs LLD showed a no statistical significance p > 0.05. ConclusionRenal and liver donors bear a relatively significant radiation dose due to diagnostic evaluation and patient management. The CT iterative reconstruction using AIDR3D proved very valuable tool in dose reduction such that it can reduce 37% in kidney donors and 48% in liver donors while able to maintain an acceptable image quality. Monitoring of those subjects on the clinical and radiobiological levels are recommended.

Relationship between Non-Ionizing Radiation (NIR) Exposure Level and the Base Station Tower Installation around Kuala Nerus

The rapid development of wireless technology nowadays has led to the increases of erection of base station telecommunication (BST). However, the exposure transmitted from BST generated the public concern on health problem because it is said can causes high risk to the human and surroundings. Therefore, this study will focused on the influence of selected BST installed around Kuala Nerus towards the ambient NIR exposure value at surroundings. By using spectrum analyzer connected to receiving omni-directional antenna, the NIR exposure level in terms of electric field (EF) strength is measured horizontally at 50 m until 500 m around the BSTs. The comparison between the measured values and the international reference levels of ICNIRP were done. Besides, the exposure values were compared among the BSTs area by considering the other influenced factors at surroundings. The result shows that the highest exposure level was recorded at BST located in sub-urban area and has the higher number of antennas installed on the top. It can be concluded that the number of BST nearby, the number of antennas, the direction of the antenna and the presence of other sources influenced the ambient NIR exposure at that area.

A Comparison of the Effects of Neutron and Gamma Radiation in Silicon Photomultipliers

The effects of radiation damage in silicon photomultipliers (SiPMs) from gamma rays have been measured and compared with the damage produced by neutrons. Several types of MPPCs from Hamamatsu were exposed to gamma rays and neutrons at the Solid State Gamma Ray Irradiation Facility (SSGRIF) at Brookhaven National Lab and the Institute for Nuclear Research (Atomki) in Debrecen, Hungary. The gamma ray exposures ranged from 1 krad to 1 Mrad and the neutron exposures ranged from 10$^8$ n/cm$^2$ to 10$^{12}$ n/cm$^2$. The main effect of gamma ray damage is an increase in the noise and leakage current in the irradiated devices, similar to what is seen from neutron damage, but the level of damage is considerably less at comparable high levels of exposure. In addition, the damage from gamma rays saturates after a few hundred krad, while the damage from neutrons shows no sign of saturation, suggestive of different damage mechanisms in the two cases. The change in optical absorption in the window material of the SiPMs due to radiation was also measured. This study was carried out in order to evaluate the use of SiPMs for particle physics applications with moderate levels of radiation exposures.

Quantitative accuracy of CT numbers: Theoretical analyses and experimental studies.

The CT number accuracy, that is, CT number bias, plays an important role in clinical diagnosis. When strategies to reduce radiation dose are discussed, it is important to make sure that the CT number bias is controlled within an acceptable range. The purpose of this paper was to investigate the dependence of CT number bias on radiation dose level and on image contrast (i.e., the difference in CT number between the ROI and the background) in Computed Tomography (CT). A lesion-background model was introduced to theoretically study how the CT number bias changes with radiation exposure level and with CT number contrast when a simple linear reconstruction algorithm such as filtered backprojection (FBP) is used. The theoretical results were validated with experimental studies using a benchtop CT system equipped with a photon-counting detector (XC-HYDRA FX50, XCounter AB, Sweden) and a clinical diagnostic MDCT scanner (Discovery CT750 HD, GE Healthcare, Waukesha, WI, USA) equipped with an energy-integrating detector. The Catphan phantom (Catphan 600, the Phantom Laboratory, Salem, NY, USA) was scanned at different mAs levels and 50 scans were performed for each mAs. The bias of CT number was evaluated for each combination of mAs and ROIs with different contrast levels. An anthropomorphic phantom (ATOM 10-year-old phantom, Model 706, CIRS Inc. Norfolk, VA, USA) with much more heterogeneous object content was used to test the applicability of the theory to the more general image object cases. Both theoretical and experimental studies showed that the CT number bias is inversely proportional to the radiation exposure level yet linearly dependent on the CT number contrast between the lesion and the background, that is, . The quantitative accuracy of CT numbers can be problematic and thus needs some extra attention when radiation dose is reduced. In this work, we showed that the bias of the FBP reconstruction increases as mAs is reduced; both positive and negative bias can be observed depending on the contrast difference between a targeted ROI and its surrounding background tissues.

Assessing the feasibility of intranasal radiotracer administration for in brain PET imaging

IntroductionThe development of clinically useful tracers for PET imaging is enormously challenging and expensive. The intranasal (IN) route of administration is purported to be a viable route for delivering drugs to the brain but has, as yet, not been investigated for the delivery of PET tracers. If the intranasal (IN) pathway presents a viable option, it extends the PET imaging field by increasing the number of tracers available for human use.Here we report the results of a rodent study testing the feasibility of the IN route to administer radiotracers for brain PET imaging. MethodsWe used two different, well characterised, brain penetrant radiotracers, [18F]fluorodeoxyglucose ([18F]FDG) and [18F]fallypride, and aimed to evaluate the pharmacokinetics after administration of the tracers via the intranasal route, and contrast this to intravenous administration. Image acquisition was carried out after tracer administration and arterial blood samples were collected at different time intervals, centrifuged to extract plasma and gamma counted. We hypothesised that [brain region]:[plasma] ratios would be higher via the intranasal route as there are two inputs, one directly from the nose to the brain, and another from the peripheral circulation. To assess the feasibility of using this approach clinically, we used these data to estimate radiation dosimetry in humans. ResultsContrary to our hypothesis, in case of both radiotracers, we did not see a higher ratio in the expected brain regions, except in the olfactory bulb, that is closest to the nose. It appears that the radiotracers move into the olfactory bulb region, but then do not progress further into other brain regions. Moreover, as the nasal cavity has a small surface area, the extrapolated dosimetry estimations for intranasal human imaging showed an unacceptably high level (15 mSv/MBq) of cumulative skin radiation exposure. ConclusionsTherefore, although an attractive route for brain permeation, we conclude that the intranasal route would present difficulties due to non-specific signal and radiation dosimetry considerations for brain PET imaging.

Optimizing imaging and reducing radiation exposure during complex aortic endovascular procedures.

Improvements in endovascular technologies and development of custom-made fenestrated and branched endografts currently allow clinicians to treat complex aortic lesions such as thoraco-abdominal and aortic arch aneurysms once treatable with open repair only. These advances are leading to an increase in the complexity of endovascular procedures which can cause long operation times and high levels of radiation exposure. This in turn places pressure on the vascular surgery community to display more superior interventional skills and radiological practices. Advanced imaging technology in this context represents a strong pillar in the treatment toolbox for delivering the best care at the lowest risk level. Delivering the best patient care while managing the radiation and iodine contrast media risks, especially in frail and renal impaired populations, is the challenge aortic surgeons are facing. Modern hybrid rooms are equipped with a wide range of new imaging applications such as fusion imaging and cone-beam computed tomography (CBCT). If these technologies contribute to reducing radiation, they can be complex and intimidating to master. The aim of this review is to discuss the fundamentals of good radiological practices and to describe the various imaging tools available to the aortic surgeon, both those available today and those we anticipate will be available in the near future, from equipment to software, to perform safe and efficient complex endovascular procedures.

Evaluation the annual effective dose of the NORM decontamination workers during cleaning the oil and gas equipment

Oil and gas production processing operations have been known to produce a large amount of naturally occurring radioactive materials (NORMs) at elevated concentrations as by-product waste streams. This means that TE-NORM wastes from the oil & gas industry may generate radiation exposure levels, which require attention and continuous monitoring during NORM decontamination of oil and gas equipment. This exposure is mostly caused by external and internal radiation coming from the 226Ra &228Ra (U-238 and Th -232 series) radionuclide and their progenies. This study focuses on follow up the annual effective dose for workers during decontaminating naturally occurring radioactive materials (NORM) of oil and gas equipment. The external effective dose was evaluated using thermoluminescence detector (TLD). The obtained data showed that the range of the annual dose was from 1.07 to 1.78 mSv and the average dose of the ten workers under investigation was 1.4 ±0.24 mSv. The average dose is about 7 % of the occupational annual dose limit. We conclude that protective measures against external and internal contamination helped in the protection of the workers against NORM hazards)