Radiation Exposure Levels Research Articles

Analysis of space radiation exposure levels at different shielding configurations by ray-tracing dose estimation method

A ray-tracing method to calculate radiation exposure levels of astronauts at different spacecraft shielding configurations has been developed. The method uses simplified shielding geometry models of the spacecraft compartments together with depth-dose curves. The depth-dose curves can be obtained with different space radiation environment models and radiation transport codes. The spacecraft shielding configurations are described by a set of geometry objects. To calculate the shielding probability functions for each object its surface is composed from a set of the disjoint adjacent triangles that fully cover the surface. Such description can be applied for any complex shape objects.The method is applied to the space experiment MATROSHKA-R modeling conditions. The experiment has been carried out onboard the ISS from 2004 to 2016. Dose measurements were realized in the ISS compartments with anthropomorphic and spherical phantoms, and the protective curtain facility that provides an additional shielding on the crew cabin wall. The space ionizing radiation dose distributions in tissue-equivalent spherical and anthropomorphic phantoms and for an additional shielding installed in the compartment are calculated. There is agreement within accuracy of about 15% between the data obtained in the experiment and calculated ones. Thus the calculation method used has been successfully verified with the MATROSHKA-R experiment data.The ray-tracing radiation dose calculation method can be recommended for estimation of dose distribution in astronaut body in different space station compartments and for estimation of the additional shielding efficiency, especially when exact compartment shielding geometry and the radiation environment for the planned mission are not known.

The Potential Role of Grid-Like Software in Bedside Chest Radiography in Improving Image Quality and Dose Reduction: An Observer Preference Study.

ObjectiveTo compare the observer preference of image quality and radiation dose between non-grid, grid-like, and grid images.Materials and MethodsEach of the 38 patients underwent bedside chest radiography with and without a grid. A grid-like image was generated from a non-grid image using SimGrid software (Samsung Electronics Co. Ltd.) employing deep-learning-based scatter correction technology. Two readers recorded the preference for 10 anatomic landmarks and the overall appearance on a five-point scale for a pair of non-grid and grid-like images, and a pair of grid-like and grid images, respectively, which were randomly presented. The dose area product (DAP) was also recorded. Wilcoxon's rank sum test was used to assess the significance of preference.ResultsBoth readers preferred grid-like images to non-grid images significantly (p < 0.001); with a significant difference in terms of the preference for grid images to grid-like images (p = 0.317, 0.034, respectively). In terms of anatomic landmarks, both readers preferred grid-like images to non-grid images (p < 0.05). No significant differences existed between grid-like and grid images except for the preference for grid images in proximal airways by two readers, and in retrocardiac lung and thoracic spine by one reader. The median DAP were 1.48 (range, 1.37–2.17) dGy*cm2 in grid images and 1.22 (range, 1.11–1.78) dGy*cm2 in grid-like images with a significant difference (p < 0.001).ConclusionThe SimGrid software significantly improved the image quality of non-grid images to a level comparable to that of grid images with a relatively lower level of radiation exposure.

Residential exposure from extremely low frequency electromagnetic field (ELF EMF) radiation

ELF EMF radiation have received considerable attention as a potential threat to the safety and health of people living in the vicinity of high voltage transmission lines, electric distribution substations, power stations and even in close proximity to electronics and electrical household appliances. The paper highlights the study on the ELF EMF safety assessment performed at residences comprising of an owner-occupied house, a completed vacant house and an under construction condominium. The objectives of this study were to determine the ELF EMF radiation exposure level from the high voltage transmission line, electric distribution substation, power station and electrical household appliances in the residences, and to assess the potential exposure received by the occupants at the assessed locations. The results were logged in the electric and magnetic field strength with the units of volt per meter (V/m) and miliGauss (mG) respectively. The instrument setup and measurement protocols during the assessment were adopted from standard measurement method and procedures stipulated under the Institute of Electrical and Electronics Engineers (IEEE) Standard. The results were compared with the standards recommended in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines.

Assessment of quantification accuracy and image quality of a full-body dual-layer spectral CT system.

The performance of a recently introduced spectral computed tomography system based on a dual‐layer detector has been investigated. A semi‐anthropomorphic abdomen phantom for CT performance evaluation was imaged on the dual‐layer spectral CT at different radiation exposure levels (CTDI vol of 10 mGy, 20 mGy and 30 mGy). The phantom was equipped with specific low‐contrast and tissue‐equivalent inserts including water‐, adipose‐, muscle‐, liver‐, bone‐like materials and a variation in iodine concentrations. Additionally, the phantom size was varied using different extension rings to simulate different patient sizes. Contrast‐to‐noise (CNR) ratio over the range of available virtual mono‐energetic images (VMI) and the quantitative accuracy of VMI Hounsfield Units (HU), effective‐Z maps and iodine concentrations have been evaluated. Central and peripheral locations in the field‐of‐view have been examined. For all evaluated imaging tasks the results are within the calculated theoretical range of the tissue‐equivalent inserts. Especially at low energies, the CNR in VMIs could be boosted by up to 330% with respect to conventional images using iDose/spectral reconstructions at level 0. The mean bias found in effective‐Z maps and iodine concentrations averaged over all exposure levels and phantom sizes was 1.9% (eff. Z) and 3.4% (iodine). Only small variations were observed with increasing phantom size (+3%) while the bias was nearly independent of the exposure level (±0.2%). Therefore, dual‐layer detector based CT offers high quantitative accuracy of spectral images over the complete field‐of‐view without any compromise in radiation dose or diagnostic image quality.

Radiation-Induced DNA Damage in Operators Performing Endovascular Aortic Repair.

Radiation exposure during fluoroscopically guided interventions such as endovascular aortic repair (EVAR) is a growing concern for operators. This study aimed to measure DNA damage/repair markers in operators perfoming EVAR. Expression of the DNA damage/repair marker, γ-H2AX and DNA damage response marker, phosphorylated ataxia telangiectasia mutated (pATM), were quantified in circulating lymphocytes in operators during the peri-operative period of endovascular (infrarenal, branched, and fenestrated) and open aortic repair using flow cytometry. These markers were separately measured in the same operators but this time wearing leg lead shielding in addition to upper body protection and compared with those operating with unprotected legs. Susceptibility to radiation damage was determined by irradiating operators' blood in vitro. γ-H2AX and pATM levels increased significantly in operators immediately after branched endovascular aortic repair/fenestrated endovascular aortic repair (P<0.0003 for both). Only pATM levels increased after infrarenal endovascular aortic repair (P<0.04). Expression of both markers fell to baseline in operators after 24 hours (P<0.003 for both). There was no change in γ-H2AX or pATM expression after open repair. Leg protection abrogated γ-H2AX and pATM response after branched endovascular aortic repair/fenestrated endovascular aortic repair. The expression of γ-H2AX varied significantly when operators' blood was exposed to the same radiation dose in vitro (P<0.0001). This is the first study to detect an acute DNA damage response in operators performing fluoroscopically guided aortic procedures and highlights the protective effect of leg shielding. Defining the relationship between this response and cancer risk may better inform safe levels of chronic low-dose radiation exposure.

Self-Shielding Analysis of the Zap-X System.

The Zap-X is a self-contained and first-of-its-kind self-shielded therapeutic radiation device dedicated to brain as well as head and neck stereotactic radiosurgery (SRS). By utilizing an S-band linear accelerator (linac) with a 2.7 megavolt (MV) accelerating potential and incorporating radiation-shielded mechanical structures, the Zap-X does not typically require a radiation bunker, thereby saving SRS facilities considerable cost. At the same time, the self-shielded features of the Zap-X are designed for more consistency of radiation protection, reducing the risk to radiation workers and others potentially exposed from a poorly designed or constructed radiotherapy vault. The hypothesis of the present study is that a radiosurgical system can be self-shielded such that it produces radiation exposure levels deemed safe to the public while operating under a full clinical workload. This study summarizes the Zap-X system shielding and found that the overall system radiation leakage values are reduced by a factor of 50 compared to the occupational radiation limit stipulated by the Nuclear Regulatory Commission (NRC) or agreement states. The goal of self-shielding is achieved under all but the most exceptional conditions for which additional room shielding or a larger restricted area in the vicinity of the Zap-X system would be required.

Morphometric Indices of Scots Pine Needle under Chronic Radiation Exposure

We have studied the morphometric indices of needles in Scots pine populations that grow in Bryansk oblast in sites with radioactive contamination long after the Chernobyl accident. The variability in needle weight and length, as well as the fluctuating asymmetry indices and occurrence of necroses and morphoses, were studied in four contaminated and two reference populations of Scots pine in 2011, 2013, and 2014. The exposure of needles in radioactively contaminated sites varied from 7 to 130 mGy/yr. We found brachyblasts with three needles in contaminated Scots pine populations; this morphosis was absent in the reference populations. A dependence of the occurrence of needles damaged by necrosis on the levels of radiation exposure in 2011 was found. However, it was statistically insignificant in other years. The length and weight of needles in contaminated populations differed from the control values; however, the dependence of these indices on the level of radiation exposure was not revealed in the studied range of doses. In 2011 and 2013, the index of fluctuating asymmetry in needle length exceeded the control levels in sites where the absorbed doses were 90 and 130 mGy; this index also tended to grow (statistically significantly in 2011) with an increase in the characteristics of radioactive contamination of the studied plots: the exposure dose rate and the specific activity of 90Sr and 137Cs in cones and of 137Cs in the soil. Therefore, one can observe the consequences of chronic radiation exposure at the organismic level in populations of Scots pine (one of the most radiosensitive plant species) even 25 years after the accident. The data that we obtained in natural habitats confirm the international estimates, according to which the annual chronic radiation exposure of 100 mGy can be considered the limit of safe radiation exposure of natural populations according to morphological and ontogenetic parameters.

Biodosimetry: A Future Tool for Medical Management of Radiological Emergencies.

With the threat of future radiological or nuclear events, there is a need to model and develop new medical countermeasures for managing large-scale population exposures to radiation. The field of radiation biodosimetry has advanced far beyond its original objectives to identify new methodologies to quantitate unknown levels of radiation exposure that may be applied in a mass screening setting. New research in the areas of genomics, proteomics, metabolomics, transcriptomics, and electron paramagnetic resonance (EPR) applications have identified novel biological indicators of radiation injury from a diverse array of biological sample materials, and studies continue to develop more advanced models of radiation exposure and injury. In this article, we identify the urgent need for new biodosimetry assessment technologies, describe how biodosimetry diagnostics work in the context of a broad range of radiation exposure types and scenarios, review the current state of the science, and assess how well integrated biodosimetry resources are in the national radiological emergency response framework.

Radiation exposure levels according to vascular access sites during PCI : Aprospective controlled study.

We previously showed that using the radial artery access site as opposed to the femoral artery site decreases the radiation exposure of patients during coronary artery interventions. The objective of this study was to compare radiation exposure levels of the operating physician during coronary interventions when incorporating both radial and femoral artery approaches. The study assessed all coronary angioplasties performed in amajor metropolitan general hospital. The study design was prospective and observational, in which we measured the radiation exposure of the patient and the operator. Measurements of radiation levels were made using an electronic personal dosimeter (Diamentor® E2-DAP) at the radial and at the femoral artery access sites. Aninterventional cardiologist operator performed all the percutaneous coronary interventions (PCI) using asingle-plane angiography unit via both femoral and radial artery approaches. Data from 252 PCIs were recorded. The mean physician radiation exposure levels from the femoral access site and the right radial access site were 40.5± 20.2 µSv and 47.5± 26.5 µSv, respectively (p< 0.02). There was astrong correlation between physician and patient radiation exposure levels. However, there was no correlation between patient body mass index and radiation exposure levels. We found significantly higher physician radiation exposure levels with the radial artery than with the femoral artery access site.

Determination of Ionizing Radiation Exposure Levels within Four Local Mining Sites Selected from Sardauna Local Government Area of Taraba State - Nigeria

Miners and the people living close to mining sites are exposed to elevated levels of ionizing radiation with or without their consent. This study determined the background ionizing radiation of four mining sites from Sardauna local government area of Taraba state using an inspector alert nuclear radiation meter manufactured by S.E. International, Inc USA with serial number 35440. The meter has a halogen- quenched Geiger Muller tube with a ± 45 mm effective diameter and mica window density of 1.5- 2.0 mg/cm3. The Geiger tube in the meter generates a pulse of electrical current each time radiation is incident on the tube and causes ionization. The measured values ranged from 0.19 - 0.40 mSv/yr across all the mining sites and 500 m away from the sites. These results were found to be far less than the standard of 1.0 mSv/yr set by International Commission on Radiological Protection (ICRP) for the general public and 20.0 mSv/yr set by the Nigeria Basic Ionization Radiation Regulation (NiBIRR) for the whole body of adult radiation protection workers which means that the miners and inhabitants of this areas are safe. Nevertheless, there could be long term variations in the consequences arising from the effects of ionizing radiation among the miners and even the inhabitants. Strong correlations were found between the equivalent doses at the excavating and the processing points of the sites which mean that the miners and people living close to these mining sites are subjected to uniform distribution of consequences arising from ionizing radiation. We do recommend that policy makers and regulatory bodies should apply mitigation measures to the effects by means of creating awareness to the miners at various mining sites and the use of modern mining strategies to protect other natural resources especially water.

CHROMOSOMAL ABERRATIONS AND HEMATOLOGICAL ALTERATIONS AMONG RADIATION-EXPOSED HEALTH CARE WORKERS IN MANSOURA UNIVERSITY HOSPITALS, EGYPT.

Introduction: The relationship between ionizing radiation (IR) exposure levels and the elevation of frequencies of different types of structural chromosomal aberrations (CA) is not yet completely clarified specifically at presumably chronic low-dose cumulative exposures. Aim of work: measurement of frequency of chromosomal aberrations (CA) and hematologic alterations in different radiation exposed occupational groups, verification of the presence of relevant health effects and measurement of accuracy of White Blood Cells (WBCs) count compared to chromosomal gene culture as biomarkersof exposure to IR. Materials and methods: A comparative cross-sectional study was carried out over a period of one calendar year in 2016 upon 97 Health Care Workers (HCWs) occupationally exposed to radiation in Diagnostic Radiology, Intervention Cardiology and Radiotherapy departments of Mansoura University Hospitals (MUHs) and a reference age- matched group of 50 HCWs unexposed to IR. They were subjected to interview-based semi-structured questionnaire including enquiries on sociodemographic data, full occupational history and clinical history and to blood samplingfor both chromosomal culture and complete blood count analysis. Results: Significant reduction in the count of WBCs and lymphocytes among the exposed groups was found compared to reference group (p<0.001). This reduction was not revealed in MRI operators. Frequency of chromosomal aberrations increased significantly among radiologists, radiotherapists, interventional cardiologists (P<0.001, <0.001, 0.04; respectively). Significant positive correlation between frequency of aberrations and lifetime exposure score was found. The accuracy of WBCs count Area Under Curve (AUC=0.69) was estimated to be less than Chromosomal Culture (AUC=0.71). Conclusion: HCWs in Radiology Departments of MUHs may be considered to be exposed to higher-than-guidelines doses of IR. Chromosomal aberrations analysis can be used as a sensitive biomarker for IR exposure added to regular CBC done periodically in classified high-risk groups.

A case of azoospermia in a non-destructive testing\xa0worker exposed to radiation

BackgroundInterest in radiation-related health problems has been growing with the increase in the number of workers in radiation-related jobs. Although an occupational level of radiation exposure would not likely cause azoospermia, several studies have reported the relation between radiation exposure and azoospermia after accidental or therapeutic radiation exposure. We describe a case of azoospermia in a non-destructive testing (NDT) worker exposed to radiation and discuss the problems of the related monitoring system.Case presentationA 39-year-old man who was childless after 8 years of marriage was diagnosed with azoospermia through medical evaluations, including testicular biopsy. He did not have any abnormal findings on biochemical evaluations, other risk factors, or evidence of congenital azoospermia. He had been working in an NDT facility from 2005 to 2013, attaching and arranging gamma-ray films on the structures and inner spaces of ships. The patient’s thermoluminescent dosimeter (TLD) badge recorded an exposure level of 0.01781 Gy for 80 months, whereas results of his florescence in situ hybridization (FISH) translocation assay showed an exposure level of up to 1.926 Gy of cumulative radiation, which was sufficient to cause azoospermia. Thus, we concluded that his azoospermia was caused by occupational radiation exposure.ConclusionThe difference between the exposure dose records measured through TLD badge and the actual exposure dose implies that the monitor used by the NDT worker did not work properly, and such a difference could threaten the health and safety of workers. Thus, to protect the safety and health of NDT workers, education of workers and strengthening of law enforcement are required to ensure that regulations are strictly followed, and if necessary, random sampling of NDT workers using a cytogenetic dosimeter, such as FISH, should be considered.

69-Year-Old Man With Abdominal Pain and Obstipation

69-Year-Old Man With Abdominal Pain and Obstipation

Relationship between radiologist training level and radiation exposure for therapeutic hip injections

ObjectiveThe aim of this study was to determine the relationship between the level of training of the performing radiologist and patient radiation exposure, as measured by fluoroscopy time (FT) and dose area product (DAP), during fluoroscopic guided hip injections. Materials and methodsThis IRB-approved retrospective review of our institutional radiology report database identified all fluoroscopic guided hip injections performed between August 1st, 2012 and May 30th, 2015. Performing radiologists were divided into groups based on their level of training at the time of the procedure: first-year residents (R1), second-year residents (R2), third-year residents (R3), fourth-year residents (R4), staff fellowship trained musculoskeletal radiologists, and non-musculoskeletal radiologists. A mixed effects model was applied, using level of training as an independent predictor to model FT and DAP separately. ResultsThere were 20, 19, 18 and 20 residents in the R1, R2, R3 and R4 groups, respectively. There were 5 performers in the non-MSK radiologist group, and 7 in the MSK radiologist group. A total of 1362 hip injection procedures met the inclusion criteria and were included in the analysis. The overall average FT was 26s (±17SD) and overall average DAP was 20.4uGy*m2 (±22.3SD). The mixed effects model showed no statistically significant difference between the groups, for FT (p=0.31) and for DAP (p=0.82). ConclusionThere is no association between radiologist level of training and patient radiation exposure for fluoroscopic hip injections. Resident trainees maintain radiation exposure to patients at levels comparable to their more experienced colleagues.

Radiation reduction during percutaneous coronary intervention

The percutaneous coronary intervention (PCI) procedure is associated with potentially high levels of radiation exposure and therefore increased risk of adverse radiation-induced outcomes, ranging from cataract to malignancy. Frame rate reduction and selective fluoroscopy storage may help reduce radiation exposure. In this study, we evaluated the efficacy of a radiation reduction protocol that uses a lower frame rate and selective storage of fluoroscopic images in terms of its effect on reducing the radiation dose during PCI.The new protocol incorporated a lower frame rate as compared with the conventional protocol, and used selective storage of fluoroscopic images. We reviewed the medical records of patients who underwent PCI under the conventional protocol from January 2013 to December 2013, and compared them with those who underwent PCI with the new protocol from January 2015 to December 2015. The primary endpoint was radiation dose reduction expressed as cumulative air kerma and dose-area product (DAP). The image quality was assessed by 3 independent well-trained cardiologists.One hundred fifty-five patients were enrolled in the conventional protocol group, and 152 were enrolled in the radiation reduction protocol group (total, n = 307). There was no statistical significance in terms of the baseline characteristics, including body mass index. Overall, the radiation reduction protocol group showed a significant reduction in both cumulative air kerma (1634.39 ± 717.95 vs 2074.75 ± 1003.72 mGy, P < .001) and DAP (12344.86 ± 5371.75 vs 15312.19 ± 7136.58 μGy m2, P < .001). Image quality was acceptable in both groups.The radiation reduction protocol, which uses a lower frame rate and selective storage of fluoroscopic images, may be an alternative approach to reducing PCI radiation dose.

Reference level of the occupational radiation exposure in a deep geological disposal facility for high-level nuclear waste: A Monte Carlo study

In deep geological repositories for high-level nuclear waste, radiation field around the disposed nuclear waste package is characterized by highly scattered radiations due to the surrounding host rock layers or cement liner. Calculation of the reference level of the occupational radiation exposure in such a facility is hence of interest, since geometrical conditions of the occupational exposure in the facility cannot be readily represented by the standard irradiation geometries considered by ICRP. In this study, a horizontal emplacement drift inside rock salt was modeled to represent a deep geological disposal facility. A nuclear waste package, simulated with a shielding cask loaded with spent nuclear fuel, was placed on the ground of the rock salt drift. A “reference worker” inside the drift was represented by the ICRP/ICRU reference adult voxel phantom. The reference level of the occupational radiation exposure was then calculated with a Monte Carlo code in terms of the effective dose based on the ICRP 2007 recommendation. In order to investigate the occupational exposure of a worker during different working scenarios in the drift, the effective dose was calculated with the voxel phantom placed at various distances and different body orientations with respect to the shielding cask. Furthermore, the effective dose obtained with voxel phantom was compared with that obtained with the fluence-to-effective-dose conversion coefficients for the standard irradiation geometries provided by ICRP. It was found out that (1) usage of the dose conversion coefficients for the isotropic (ISO) geometry, which is recommended by ICRP for highly scattered radiation fields, generally underestimates the effective dose in the rock salt emplacement drift; (2) depending on the orientation of the worker in the drift, the dose conversion coefficients for the anterior-to-posterior (AP) or the rotational (ROT) geometry should be used, in order to obtain an adequate estimation of the effective dose in the rock salt drift.

Changes of the genetic structure in chronically irradiated scots pine populations

Summary: Background. The vast forest areas were affected by radioactive fallout of the Chernobyl accident. Data about the long-term effects of chronic radiation exposure are insufficient, as well as knowledge about its influence on the genetic structure of populations. Study of isozyme polymorphism allows us to identify how chronic low-dose radiation exposure affects the genetic structure of plant populations and to develop new methods for assessing the biological effects of anthropogenic impact on terrestrial ecosystems.&#x0D; Materials and methods. The study was conducted in six sites in the Bryansk region (4 radioactively contaminated and 2 reference ones). The method of vertical electrophoresis in PAAG was used for estimation of polymorphism of three enzymes involved in metabolic pathways. Activity of enzymes in seeds of Scots pine was assessed by spectrophotometry.&#x0D; Results. The frequency of mutations in isozymes loci increased along the level of radiation exposure (7-130 mGy/year), as well as some characteristics of the genetic structure of populations. Biochemical activity of studied enzymes does not depend on the level of dose absorbed in the generative organs of pine.&#x0D; Conclusions. It was found that the frequency of mutational events in loci of catabolic/anabolic enzymes and in the loci of previously studied antioxidant enzymes increases along the level of radiation exposure. The degree of the biological effect of chronic exposure was different in groups of catabolic/anabolic enzymes and antioxidant enzymes. Radiation exposure contributes to changes in the genetic structure of Scots pine populations.

Minimizing Ionizing Radiation Exposure in Invasive Cardiology Safety Training for Medical Doctors

Advanced imaging systems, such as C-Arm machines, greatly improve physicians' diagnostic abilities and provide greater precision. Yet, these benefits come with a price of ionizing radiation exposure to medical teams and patients. Supplying proper training and skill improvement to operators on how to use this technology safely can help minimize risk of exposure. Previous studies on radiation knowledge among physicians and radiologists presented disturbing results of underestimated risk of exposure. The following research is based on an innovation in simulation-based training (SBT), a simulator using the Wizard of Oz (WOZ) concept that incorporates an online human trainer and was used for training emergency room (ER) physicians and ultrasound medical personnel. This research integrated WOZ technology with a radiation exposure formula for training to minimize unnecessary radiation exposure. The exposure formula presents real-time and overall exposure levels to operators based on their technique. The simulator also incorporates 3D animation graphics, enabling trainees to simulate the control of various factors. Image quality and the operator's radiation exposure levels are also animated, assisting trainees to focus on their exposure based on their device settings. Contrary to most previous studies, we measured radiation dose to the operator and quantified image quality accordingly. Validation was done on different C-Arm machines. Validation of learning outcomes was done using knowledge exams. Results from our knowledge exams presented significant improvement. The average result of knowledge exams given prior to training was 54%, whereas the average result after training was 94% (p &lt; 0.001). Additionally, after a gap of 2–3 months, high retention was also found.

Radiation Dose and Procedure Time for 994 CT-guided Spine Pain Control Procedures

Background: Image guidance for spine pain control procedures, including epidural steroid injection, nerve root block, and facet block, can be performed with either computed tomography (CT) or conventional fluoroscopy. CT has the advantage of improved anatomic localization and use of air for contrast; however, there are concerns that CT leads to higher radiation dose and longer procedure time. Objective: To evaluate procedure time and radiation dose for multiple types of spine pain control procedures performed under CT guidance. Study Design: Retrospective evaluation. Setting: Department of radiology in single academic medical center. Methods: Institutional review board approval was obtained. We reviewed CT-guided spine procedures performed over a 12-month period from January 2012 to December 2012. Procedure type, procedure time, and dose-length product were recorded. Patient age and gender were recorded for each case; additionally, demographic and medical history data were obtained for a sub-group of patients. Results: Nine hundred ninety-four studies (performed in 699 patients) were reviewed, including 585 epidural steroid injections, 228 nerve root blocks, and 90 facet blocks. For all studies, procedure time averaged 7:34 ± 5:05, and dose-length product averaged 75 mGy·cm ± 61. Additional medical history (available for 483 patients) revealed high rate of obesity (body mass index [BMI] = 30 ± 6.8, with 76% of patients overweight [BMI &gt; 25] and 42% obese [BMI &gt; 30]), and frequent medical comorbidities (including hypertension [n = 179], diabetes [n = 101], renal failure [n = 30], and heart failure [n = 17]). Limitations: This study was performed retrospectively, and limited to a single institution. Conclusion: These findings add to the growing evidence that CT guidance is a safe and effective technique for epidural steroid injection. These results further demonstrate that other spine intervention procedures, including nerve root block and facet block, can also be performed under CT guidance with short procedure time and reasonable levels of radiation exposure. This approach can be effectively used in a patient population with a high rate of obesity and medical comorbidities. Key words: Epidural steroid injection, nerve root block, facet block, CT-guidance, spine intervention, radiation dose

Optical imaging of irradiated cyclotron target window foils using Cerenkov and radioluminescence imaging

Radioisotopes production for PET radiopharmaceuticals is performed using cyclotrons resulting in radio activation of different cyclotron components. It is thus necessary to measure the level of radiation exposure and, if possible, to image the areas where most of the radiations are emitted in particular during maintenance or decommissioning procedures. In this work we present a novel optical imaging approach using Cerenkov luminescence imaging (CLI) and radioluminescence imaging (RLI). CLI was performed by placing a glass Cerenkov radiator on a target window (Havar foils) and RLI data were obtained by covering the Havar foils with an intensifying screen. CLI or RLI were acquired using a small animal optical imaging system used in bioluminescence mode without the use of any optical filters. The analysis of the normalized radiance line profiles of both CLI and RLI images showed a similar pattern, however the absolute radiance of the RLI signal is several order of magnitude higher with respect to CLI. We conclude that optical imaging with CLI and RLI can be considered a novel method to detect and image activation areas in irradiated samples from a medical cyclotron.