Body Dose Research Articles

Radioprotective Effect of Beta D-Glucan and Vitamin E on Gamma Irradiated Mouse.

It is shown that beta-D-glucan is an immunologic system booster with radioprotectory effects. Radioprotectors are chemical components that can alleviate biological damage produced by ionizing radiation. This study was designed to investigate the synergistic radioprotectory effects of beta-D-glucan and vitamin E on irradiated mice with 60Co source. A total of 240 female mice were arranged in four, equal population groups of control group (C), treated group with beta D-glucan (G), treated group with vitamin E (E), and treated group with both beta D-glucan and vitamin E (G+E). Each group was divided into three equal population groups of D6, D7 and D8 exposed to 60Co radiation with prescribed total body dose of 6, 7 and 8 Gray (Gy), respectively. After the exposure, the number of survived animals was counted by time, then Lethal Dose50/30 (LD50/30), Lethal Dose50/60 (LD50/60) and Dose Reduction Factor (DRF) were calculated in all groups and corresponding groups. Based on the results of current study, treatment of the animals with vitamin E did not change values of LD50/30 and LD50/60, in comparison to control group. LD50/30 and LD50/60 of treated groups with beta D-glucan and beta D-glucan + vitamin E showed significant difference with those of control group (p<0.01). The DRF values in groups E, G and G + E, were calculated respectively as 1, 1.25 and 1.375 based on LD50/30, and respectively as 1, 1.17 and 1.33 based on LD50/60. While values of DRF in groups G and G + E showed significant difference in comparison to that of control group (p<0.01), but the difference between DRF of groups G and G + E was not significant (p=0.395). The findings of study obviously showed that, presence of beta D-glucan in the body of mice, during exposure to ionizing radiation, leads to DRF of higher than one, proving the radioprotectory effect of this agent. Also, we demonstrated that, while vitamin E had no radioprotectory effect on irradiated mice, beta D-glucan in combination with vitamin E increased resistance of mice against ionizing radiation.

Preliminary Monte Carlo Investigation of Using Ir-192 as the Source for Real Time Imaging Purpose.

The purpose of this study is to investigate the potential use of Ir-192 as the source for real time imaging during HDR (High Dose Rate) brachytherapy treatment. Phantom measurement was performed to determine outside of the body dose. Monte Carlo code, EGSnrcMP egs_inprz, was used for the simulation to calculate the outside of the body x-ray signal for CT reconstruction. Matlab code was developed to reconstruct the Ir-192 source and for 3D visualization in order to assess reconstructed CT resolution, signal-to-noise ratio, and imaging dose information. The measured dose was 0.67 ± 0.04 cGy, which was comparable to the Monte Carlo simulation result 0.71 ± 0.20 cGy. The reconstructed source diameter dimension was 1.3 mm compared with 1.1 mm for the real source dimension. The signal-to-noise ratio was 19.91 db following de-noising. Source position was within a 1 mm difference between programmed and simulated results. Although the Ir-192 signal is weak for CT imaging, it is possible to use it as a CT imaging x-ray source for HDR treatment localization, verification and dosimetry purposes. Further study is needed for the detailed design of an outside of the body CT-like device for use in brachytherapy imaging.

Personnel dose reduction in 90Y microspheres liver-directed radioembolization: from interventional radiology suite to patient ward.

To describe a method to reduce the external radiation exposure emitted from the patient after liver-directed radioembolization using 90Y glass microspheres, to quantitatively estimate the occupational dose of medical personnel providing patient care to the patient radioembolized with the use of the method and to discuss radiation exposure to patients who are adjacent if the patient radioembolized needs hospitalization. A lead-lined blanket of lead equivalence of 0.5 mm was used to cover the patient abdomen immediately after the 90Y radioembolization procedure, in order to reduce the radiation emitted from the patient. The interventional radiologist used a rod-type puncture site compressor for haemostasis to avoid direct contact with possible residual radioactivity at the puncture site. Dose rates were measured at the interventional radiologist chest and hand positions during puncture site pressing for haemostasis with and without the use of the blanket. The measurement results were applied to estimate the occupational dose of colleagues performing patient care to the patient radioembolized. The exposure to patients adjacent in the ward was estimated if the patient radioembolized was hospitalized. The radiation exposures measured at the radiologist chest and hand positions have been significantly reduced with the lead-lined blanket in place. The radiologist, performing puncture site pressing at the end of radioembolization procedure, would receive an average hand dose of 1.95 μSv and body dose under his own lead apron of 0.30 μSv for an average 90Y microsphere radioactivity of 2.54 GBq. Other medical personnel, nurses and porters, would receive occupational doses corresponding to an hour of background radiation. If the patient radioembolized using 90Y needs hospitalization in a common ward, using the lead-lined blanket to cover the abdomen of the patient and keeping a distance of 2 m from the patient who is adjacent would reduce the exposure by 0.42% of dose limit for the general public. By placing a lead-lined blanket on the patient abdominal region after 90Y radioembolization, hospital staff receive minimal radiation exposure in order to comply with the radiation protection "as low as reasonably achievable" principle. There will be no increase in radiation level in ward if the patient radioembolized using 90Y needs to be hospitalized. Therefore, the patient radioembolized can be accommodated alternatively at a corner bed of a common ward if an isolation room with private toilet facility is not available. Advances in knowledge: To reduce exposure to personnel providing patient care to patients radioembolized using 90Y.

Initial evaluations of the effectiveness of spinetoram as a long-acting, oral systemic pulicide for controlling cat flea (Ctenocephalides felis) infestations on dogs

Spinetoram is a semi-synthetic, spinosyn class natural product derived from fermentation by the actinomycete, Saccharopolyspora spinosa. Based on LD50 (50% lethal dose) values against adult cat fleas (Ctenocephalides felis) using an in vitro contact assay, spinetoram was approximately 4-fold more potent than spinosad. Subsequently, two parallel-arm, randomized block design laboratory studies were conducted to evaluate the effectiveness of orally administered spinetoram against experimental C. felis infestations on dogs, when administered as a single dose or multiple doses over a 6–12h interval. In the first study, 16 mixed-breed dogs were allocated to two treatment groups of eight dogs each, based on pre-treatment flea retention rates: negative (placebo) control; and a single dose of spinetoram at 30mg/kg. In the second study, 32 mixed- and pure-breed dogs were allocated to four treatments groups of eight dogs each, based on pre-treatment flea retention rates: negative (placebo) control; a single dose of 60mg/kg; three sequential 20mg/kg oral doses evenly administered over a 6h period; and three sequential 20mg/kg oral doses evenly administered over a 12h period. In both studies, treatments were administered to dogs in a fed state in order to enhance absorption of spinetoram. Therapeutic efficacy was assessed 24h after treatment and persistent efficacy was assessed 48h after each subsequent flea infestation. The duration of effectiveness was assessed at approximate weekly intervals beginning on Day 5 through Day 56 in the first study, or through Day 105 in the second study. In both studies, treatment efficacy was ≥99% (geometric means) through 44 d, with ≥99% efficacy continuing through 72 d for all three treatments in the second study. Efficacy remained ≥90% for at least 8 weeks with a single 30mg/kg dose; through 13 weeks with three sequential 20mg/kg doses; and through 15 weeks with a single 60mg/kg dose. For all time points and in both studies, spinetoram-treated groups had significantly fewer live fleas relative to their respective negative control group (p<0.05). The pharmacokinetic profile in dogs revealed that the mean plasma concentration of spinetoram required for effectiveness against fleas was maintained for at least 3 months regardless of whether the 60mg/kg total body dose was administered as a single bolus or in three sequential 20mg/kg doses administered over a 6–12h period of time. The results of preliminary in vitro and in vivo studies demonstrate that orally administered spinetoram was well tolerated, and provides long lasting effectiveness against C. felis infestations on dogs.

Trends in stereotactic body radiation therapy for stage I small cell lung cancer

ObjectivesWe aimed to report trends in stereotactic body radiation therapy (SBRT) utilization, dose prescriptions, and chemotherapy administration for stage I small cell lung cancer (SCLC) in the United States. Materials and methodsThe National Cancer Data Base (NCDB) was used to identify patients with cT1-2 N0 SCLC treated with SBRT between 2004 and 2013. Trends in SBRT use and dose prescription were analyzed over time. Multivariable logistic regression was used to determine factors associated with the administration of chemotherapy with SBRT. The Kaplan-Meier method was used to estimate overall survival. ResultsOf 9265 patients with clinical stage I SCLC who were examined for initial treatment allocation, 285 were treated with SBRT and represented the subject of the primary analysis. SBRT utilization increased from 2004 (0.4% of all stage I patients diagnosed that year) to 2013 (6.4%). During this same time period, definitive surgical management also increased from 14.9% of all patients in 2004 to 28.5% in 2013. The median SBRT biologically effective dose (BED10) was 112.5Gy (range, 72–290) and only 33 out of 285 (11.6%) received a BED10<100Gy. Nearly half of all patients (130/285, 45.6%) received chemotherapy, with 42.7% of those patients receiving their chemotherapy prior to SBRT. On multivariable logistic regression, only age<75 (the median) vs. ≥75years (OR 4.97, 95% CI 2.96–8.35, p<0.001) and year of diagnosis 2004–2008 vs. 2009–2013 (OR 2.58, 95% CI 1.27–5.26, p=0.009) were predictive of chemotherapy use with SBRT. After median follow up of 45 months, the median survival was 23.5 months. ConclusionsOur findings suggest that SBRT utilization for stage I SCLC has increased between 2004 and 2013, highlighting the need for additional research to validate the feasibility of this management approach for inoperable patients.

Source Term Analysis of Long-Life 620 MWt BWR During Loss of Coolant Accident (LOCA)

Source term analysis on a long-life 620 MWt BWR has been performed. The study includes fuel cell calculations, multi-groups diffusion equation calculation with 8 groups of energy, source term calculation and dose calculation. The scope of the source term analysis includes fission product inventories calculation in core, their activity and their toxicity during the Loss of Coolant Accident (LOCA). The calculation based on the assumption that the reactor has been operating for 10950 days or 30 years with full power of 620 MWt. The total activity of the core is 1,12x109 Ci, and the higher inventory of the core is dominated by the trans-uranium elements. The release of fission product activity to the atmosphere is 1,11x107 Ci. And the toxicity analysis shows that noble gas has the higher toxicity degree. Whole body dose calculation result in exclusion zone is 7.17x10-04 rem and the thyroid dose calculation result in this zone is 7.21x10-02 rem. And for the whole body dose calculation result in low population zone is 2.69x10-05 rem and the thyroid dose calculation result in this zone resulted 1.80x10-03 rem.

Associated particle neutron elemental imaging in vivo: A feasibility study.

The purpose of this study is to develop a Monte Carlo simulation model for in vivo associated particle neutron elemental imaging (APNEI) and to study the feasibility of using APNEI to determine the iron distribution in a human liver with the defined model. The model presented in this study was defined in mcnp by the basic geometry of the human body, the use of D + D source neutrons, iron as the element of interest, an iron-containing voxel in the liver as the target region, and 2 large germanium detectors anterior and posterior to the trunk of the body. The f8 pulse height tally was employed in mcnp to determine the signal acquired from iron inelastic scatter gamma rays at various iron concentrations in the target liver voxel. Correspondingly, the f4 average flux tally in mcnp was modified by a dose function such that the equivalent dose to the whole liver and the effective dose to the whole body could be estimated and used as the basis for a limiting number of neutron histories which could feasibly allow for the collection of a sufficient volume of data to construct a 2D image of iron distribution in the liver voxel. Assuming an allowable equivalent dose to the liver of 5 mSv, 143 inelastic scatter iron gamma ray counts (at ∼847 keV) would ideally be registered at the germanium detectors for a 1 cm3 cube-shaped liver voxel with an iron concentration of 1000 ppm. According to the simulation model, an image of iron distribution in the liver can be constructed with a 1 cm resolution at the level of 1000 ppm iron. Collecting such an image would yield an estimated whole body dose of 0.82 mSv. The mathematical introduction of image uncertainty resulting from source spot diameter and detector timing resolution more closely approximates the result of real world application. APNEI of certain elements in vivo appears feasible given several timing, sensitivity, and resolution caveats. However, further study is required to determine what the detection limit of iron would be and what image resolution would be in an experimental setup as the present model contains idealized assumptions which overestimate the signal attributable to iron inelastic scatter gamma rays.

ITPase activity modulates the severity of anaemia in HCV-related cirrhosis treated with ribavirin-containing interferon-free regimens.

To investigate the association between inosine triphosphatase (ITPase) activity and the degree of anaemia occurring during direct-acting antiviral (DAA)/ribavirin (RBV)-based therapy in patients with cirrhosis. In a multicentre, prospective study 227 patients with HCV-related cirrhosis treated with DAA and RBV were enrolled. All patients were screened for the rs1127354 and rs7270101 ITPA single nucleotide polymorphisms using direct sequencing. 150 (66.1%) patients had normal (100%) ITPase activity, 48 (21.1%) had moderate (60%) activity and 29 (12.8%) minimal (≤30%) activity. The ITPase activity significantly influenced the haemoglobin concentration: at day 15 it was -1.248 (sd ±0.978) in the 150 patients with an ITPase activity of 100% and -0.616 (±0.862) in the 77 patients with an ITPase activity less than 100% (P<0.000), and at day 30 it was -1.941 ±1.218 versus -1.11 ±1.218 (P<0.000). The 63 patients with a severe (at least 3/dl) haemoglobin decline, compared to those without, more frequently had an ITPase activity of 100% (82.1% versus 62.8%; P=0.021), were older (mean age ±sd: 66.7 ±8.2 versus 61.4 ±9.7 years; P=0.004) and were treated with a higher ribavirin dose (13.7 ±2.1 versus 12.8 ±2.5 mg/kg/day; P=0.008). At multivariate logistic regression analysis, the ITPase activity of 100% (OR: 2.83; 95% CI: 1.12, 7.10), male gender (OR: 3.22; 95% CI: 1.35, 7.66), body mass index (OR: 1.17; 95% CI: 1.03, 1.34) and dose of ribavirin (OR: 1.22; 95% CI: 1.06, 1.47) were independent predictors of a severe decline in haemoglobin (P<0.0001). This study suggests that the polymorphisms in the ITPA gene influence the severity of anaemia during the first month of a DAA/RBV-based treatment in HCV-related cirrhosis.

Mobile phone use, behavioural problems and concentration capacity in adolescents: A prospective study.

The aim of this study is to prospectively investigate whether exposure to radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phones and other wireless communication devices is related to behavioural problems or concentration capacity in adolescents. The HERMES (Health Effects Related to Mobile phonE use in adolescentS) study sample consisted of 439 Swiss adolescents aged 12-17 years. Behavioural problems were assessed using the Strengths and Difficulties Questionnaire (SDQ), concentration capacity of the adolescents was measured by means of a standardized computerized cognitive test named FAKT. Cross-sectional and longitudinal (1year of follow-up) analyses were performed to investigate possible associations between behavioural problems and concentration capacity and different exposure measures: self-reported and operator-recorded wireless communication device use, cumulative RF-EMF brain and whole body dose and measured personal RF-EMF exposure. In the cross-sectional analyses behavioural problems were associated with several self-reported wireless device use measures but not operator-recorded mobile phone use measures, concentration capacity was associated with several self-reported and operator-recorded exposures. The longitudinal analyses point towards absence of associations. The lack of consistent exposure-response patterns in the longitudinal analyses suggests that behavioural problems and concentration capacity are not affected by the use of wireless communication devices or RF-EMF exposure. Information bias and reverse causality are likely explanations for the observed cross-sectional findings.

Validation of ELDO approaches for retrospective assessment of cumulative eye lens doses of interventional cardiologists—results from DoReMi project

The first validation results of the two approaches developed in the ELDO project for retrospective assessment of eye lens doses for interventional cardiologists (ICs) are presented in this paper. The first approach (a) is based on both the readings from the routine whole body dosimeter worn above the lead apron and procedure-dependent conversion coefficients, while the second approach (b) is based on detailed information related to the occupational exposure history of the ICs declared in a questionnaire and eye lens dose records obtained from the relevant literature. The latter approach makes use of various published eye lens doses per procedure as well as the appropriate correction factors which account for the use of radiation protective tools designed to protect the eye lens. To validate both methodologies, comprehensive measurements were performed in several Polish clinics among recruited physicians. Two dosimeters measuring whole body and eye lens doses were worn by every physician for at least two months. The estimated cumulative eye lens doses, calculated from both approaches, were then compared against the measured eye lens dose value for every physician separately.Both approaches results in comparable estimates of eye lens doses and tend to overestimate rather than underestimate the eye lens doses. The measured and estimated doses do not differ, on average, by a factor higher than 2.0 in 85% and 62% of the cases used to validate approach (a) and (b), respectively. In specific cases, however, the estimated doses differ from the measured ones by as much as a factor of 2.7 and 5.1 for method (a) and (b), respectively. As such, the two approaches can be considered accurate when retrospectively estimating the eye lens doses for ICs and will be of great benefit for ongoing epidemiological studies.

O40. The cytogenetic response of human T-lymphocytes to low doses of p(66)/Be neutrons and heterogeneous exposures to 60Co [formula omitted]-rays

Introduction Radiological health concerns for individuals exposed to ionizing radiation are governed by both the extent of exposure, as well as the microscopic dose distribution of the radiation modality. Several quantitative biological endpoints have been developed for radiation dose estimation and are employed worldwide. For real world biodosimetry applications, qualitative aspects such as the radiation type and homogeneity of exposure are vital in the decision making process with respect to suitable medical interventions. Materials and methods Whole blood samples collected from two consenting adults were exposed to 60 Co γ -rays to doses ranging from 1–6 Gy and 0–2 Gy p(66)/Be neutrons. The samples exposed to 60 Co γ -rays were subsequently diluted with un-irradiated blood to yield a series of equivalent total body doses (ETBD) from 0 up to 4 Gy. Dicentric formation frequencies in T-lymphocyte metaphase spreads were enumerated with the aid of a semi-automated image analysis microscopy system. Results Dicentric formation induction frequencies were used to estimate whole body doses for each sample respectively. Estimated whole body doses where compared to the equivalent total body dose (ETBD) and found to be in agreement (Pearson’s ρ 0.97 p ( σ 2 / y ¯ ≥ 1.2 ) and high LET neutron samples ( σ 2 / y ¯ ≈ 1.2 ) were found to be over-dispersed assuming a Poisson distribution applies to the induction of dicentric formations in cells. Conclusion The dispersion parameter proves to be a useful addition to the dicentric chromosome assay to ascertain qualitative aspects of the exposure conditions required for effective population triage for samples analysed with the high throughput automated image analysis system.

Radiation exposure comparison nuclear medicine vs PET/CT

Purpose Personnel monitoring results provide information on routine radiation exposure, assist in work planning and allow control of the workplace. The aim of this study was to compare the gamma dose received by dedicated medical workers operating in the first PET/CT department in Greece and also by dedicated medical workers operating in conventional Nuclear Medicine procedures in the same center. PET/CT studies are restricted to the use of 18 F fluorodeoxyglucose (FDG). In addition Tc-99m, Tl-201, Ga-67 and I-131 are the radiotracers mostly used in our Nuclear Medicine department. Method To estimate the effective dose from external exposure, all 9 members of the staff (2 nurses, 2 medical physicists, 5 technologists) had TLD badges worn at the upper pocket of their overall and digital dosimeters worn at the side pocket. Nurses and Medical Physicists also had TLD rings. The nurses and technologists 1,2 are working only in the PET/CT department, while technologists 3,4,5 are operating only in the Nuclear Medicine department covering the most common procedures. Medical Physicists 1,2 are operating in both departments. Results In the period of January 2015 to December 2015 a total of 977 PET/CT studies and 2322conventional Nuclear Medicine procedures were performed. The collective effective and finger doses received by all 4 members of the PET/CT staff were the following: Nurse 1 received 4.98 mSv as a whole body dose and 44.3 mSv as a hand dose and Nurse 2 received 5.01 mSv whole body dose and 46.7 mSv hand dose respectively. Technologists 1 and 2 received 1,95 mSv and 1,56 mSv as the whole body dose respectively. Medical Physicist 1 received 1,75 mSv whole body dose and 65.3 mSv hand dose and Medical Physicist received 2 2,17 mSv and 66.1 mSv respectively. Technologists 3,4 and 5 received 1,85 mSv, 1,76 mSv and 1,82 mSv as whole body doses respectively Conclusion The personnel dose results are significantly lower than the recommended annual dose by International Commission for Radiological Protection. The higher value of gamma dose for PET/CT workers by comparison with the staff operating conventional Nuclear Medicine procedures is attributable to the higher specific gamma constant of 18 F, as well as the longer exposure time required for accurate positioning.

Staff dose at different body regions and at different stages of 18F-FDG PET/CT procedures

Purpose Personnel monitoring results provide information on routine radiation exposure, assist in work planning and allow control of the workplace. The FDG PET/CT applications have been continuously increasing for diagnostic procedures. Although such an increase is a positive trend for the benefit of patients, the associated risk of radiation exposure of staff needs to be properly evaluated. The aims of this study were to estimate the effective dose for the staff at different body regions and at different stages of the PET/CT procedure. Method To estimate the effective dose from external exposure, all 6 members of the staff (2 nurses, 2 medical physicists, 2 technologists) had TLD badges worn at the upper pocket of their overall and digital dosimeters worn at the side pocket. High sensitivity thermolumiscent dosimeters were used. The measurements that were made include 5 different body regions: eye, thyroid, gonads, fingers and body at all stages of the PET/CT procedure: dose segmentation, injection of the radiopharmaceutical, handling the patient and positioning the patient. Results Results show that the mean effective dose received by each member of the staff was approximately 12.32 μSv and the mean daily dose/MBq was about 0.03 μSv. All statistical tests show no significant differences between the results for eye, thyroid and body. The staff dose received in at gonads is found to be statistical significant lower when compared to the body dose. About 57% of the staff dose resulted from patient interaction. The maximum doses to fingers were during the segmentation of radiopharmaceutical and the maximum whole body dose was during the injection of the FDG. Conclusion The personnel dose results are significantly lower than the recommended annual dose by International Commission for Radiological Protection. However a greater effort should be made to reduce the doses further in line with the ALARA principle.

Validation measurements for the retrospective calculation of eye lens doses of interventional cardiologists

Introduction The eye lens radiation-induced risk has been assessed for various population groups. In the framework of the European epidemiological study, EURALOC, an attempt is made to determine a possible dose-response relationship by targeting interventional cardiologists, a group of high exposure values. Purpose In the study, eye lens doses are assessed using two approaches: combining self-reported data on working practices and eye lens doses from literature (approach 1); and converting the whole-body dose values to eye lens doses (approach 2). Eye lens dose measurements are performed to validate both approaches and to determine their associated uncertainties. Materials and methods Eye lens dose measurements are performed on cardiologists in routine practice using commercially available dedicated eye lens dosemeters. Furthermore, whole-body dose values are obtained from whole-body dosemeters worn above the lead apron at the chest left position. Exposure information including tube orientation, operator position and orientation are collected. Results The first values of eye lens doses measured in routine clinical conditions are in good agreement with eye lens dose estimates obtained with the two approaches No systematic errors have been found which is encouraging in order to continue using either of the two approaches for the estimation of eye lens doses and the final benchmarking against lens opacities. Conclusion Preliminary measurements in clinical conditions validate the two suggested complementary dosimetric methodologies: the first, based on self-reported occupational history while the second, starts from personal whole body doses to determine the eye lens dose.

Radiation-epidemiological Study of Cerebrovascular Diseases in the Cohort of Russian Recovery Operation Workers of the Chernobyl Accident.

The paper presents an analysis of the incidence of cerebrovascular diseases (CeVD) in the cohort of Russian workers involved in recovery tasks after the Chernobyl accident. The studied cohort consists of 53,772 recovery operation workers (liquidators) who arrived in the zone of the Chernobyl accident within the first year after this accident (26 April 1986-26 April 1987). The mean external whole body dose in the cohort was 0.161 Gy, while individual doses varied from 0.0001 Gy to 1.42 Gy. During the follow-up period 1986-2012, a total of 23,264 cases of CeVD were diagnosed as a result of annual health examinations. A Poisson regression model was applied for estimation of radiation risks and for an assessment of other risk factors of CeVD. The following factors were considered as risk factors for CeVD: the dose, duration of the liquidators' work in the Chernobyl zone, and the concomitant diseases (hypertension, ischemic heart disease, atherosclerosis, and diabetes). The baseline incidence of CeVD is statistically significantly (p < 0.001) associated with all studied concomitant diseases. The incidence of CeVD has revealed a statistically significant dose response with the lack of a latent period and with the average ERR/Gy = 0.45, 95% CI: (0.28, 0.62), p < 0.001. Radiation risks of CeVD statistically significantly (p = 0.03) varied with the duration of liquidators' stay in the Chernobyl zone; for those who stayed in the Chernobyl zone less than 6 wk, ERR/Gy = 0.64, 95% CI = (0.38; 0.93), p < 0.001. Among studied concomitant diseases, diabetes mellitus statistically significantly (p = 0.002) increases the radiation risk of CeVD: for liquidators with diagnosed diabetes, ERR/Gy = 1.29.

Occupational radiation exposure in vascular interventional radiology: A complete evaluation of different body regions

PurposeTo perform a complete evaluation on radiation doses, received by primary and assistant medical staff, while performing different vascular interventional radiology procedures. Materials and methodsWe evaluated dose received in different body regions during three categories of vascular procedures: lower limb angiography (Angiography), lower limb percutaneous transluminal angioplasty (Angioplasty) and stent graft placement for abdominal aortic aneurysm treatment (A. A. A. Treatment). We positioned the dosimeters near the eye lens, thyroid, chest, abdomen, hands, and feet of the interventional physicians. Equivalent dose was compared with annual dose limits for workers in order to determine the maximum number of procedures per year that each physician could perform. We assessed 90 procedures. ResultsWe found the highest equivalent doses in the A. A. A. Treatment, in which 90% of the evaluations indicated at least one region receiving more than 1mSv per procedure. Angioplasty was the only procedural modality that provided statistically different doses for different professionals, which is an important aspect on regards to radiological protection strategies. In comparison with the dose limits, the most critical region in all procedures was the eye lens. ConclusionsSince each body region of the interventionist is exposed to different radiation levels, dose distribution measurements are essential for radiological protection strategies. These results indicate that dosimeters placed in abdomen instead of chest may represent more accurately the whole body doses received by the medical staff. Additional dosimeters and a stationary shield for the eye lens are strongly recommended.

Evaluation of failed and high blocks associated with spinal anesthesia for Cesarean delivery following inadequate labour epidural: a retrospective cohort study.

The purpose of this retrospective cohort study was to investigate factors associated with failed and high spinal blocks in patients who received spinal anesthesia for Cesarean delivery following a labour epidural that was inadequate for surgical anesthesia. We searched our perioperative database for women with a labour epidural who received spinal or combined spinal-epidural anesthesia for Cesarean delivery due to the inadequacy of the existing epidural. The primary outcome was the occurrence of failed spinal blocks, and the secondary outcome was the occurrence of high blocks following spinal administration. Of the 263 patients in the analysis, there were 29 (11%) failed spinals and nine (3%) high spinals. There was a significant difference between patients with failed spinals and those with successful spinals with regards to receipt of an epidural top-up dose for Cesarean delivery within 30 min of the spinal, type of neuraxial block, body mass index, age, and dose of hyperbaric bupivacaine. In a multivariable analysis, only receipt of an epidural top-up dose was associated with failure (OR, 6.0; 95% CI, 2.1 to 17.0; P < 0.001). As for the risk of a high spinal, patient characteristics and block details were not different amongst patients, except for a younger age in those with a high block. Administration of spinal anesthesia within 30 min of an epidural top-up dose is associated with increased risk of failure. We speculate that this may be due in part to the presence of a large volume of local anesthetic in the epidural space, which may be mistaken for cerebrospinal fluid during spinal placement.

Biplane interventional pediatric system with cone-beam CT: dose and image quality characterization for the default protocols.

The aim of this study was to assess image quality and radiation dose of a biplane angiographic system with cone‐beam CT (CBCT) capability tuned for pediatric cardiac procedures. The results of this study can be used to explore dose reduction techniques. For pulsed fluoroscopy and cine modes, polymethyl methacrylate phantoms of various thicknesses and a Leeds TOR 18‐FG test object were employed. Various fields of view (FOV) were selected. For CBCT, the study employed head and body dose phantoms, Catphan 504, and an anthropomorphic cardiology phantom. The study also compared two 3D rotational angiography protocols. The entrance surface air kerma per frame increases by a factor of 3–12 when comparing cine and fluoroscopy frames. The biggest difference in the signal‐to‐noise ratio between fluoroscopy and cine modes occurs at FOV 32 cm because fluoroscopy is acquired at a 1440×1440 pixel matrix size and in unbinned mode, whereas cine is acquired at 720×720 pixels and in binned mode. The high‐contrast spatial resolution of cine is better than that of fluoroscopy, except for FOV 32 cm, because fluoroscopy mode with 32 cm FOV is unbinned. Acquiring CBCT series with a 16 cm head phantom using the standard dose protocol results in a threefold dose increase compared with the low‐dose protocol. Although the amount of noise present in the images acquired with the low‐dose protocol is much higher than that obtained with the standard mode, the images present better spatial resolution. A 1 mm diameter rod with 250 Hounsfield units can be distinguished in reconstructed images with an 8 mm slice width. Pediatric‐specific protocols provide lower doses while maintaining sufficient image quality. The system offers a novel 3D imaging mode. The acquisition of CBCT images results in increased doses administered to the patients, but also provides further diagnostic information contained in the volumetric images. The assessed CBCT protocols provide images that are noisy, but with very good spatial resolution.PACS number(s): 87.59.‐e, 87.59.‐C, 87.59.‐cf, 87.59.Dj, 87.57. uq

In-Utero Low-Dose Irradiation Leads to Persistent Alterations in the Mouse Heart Proteome.

Prenatal exposure to stress such as increased level of reactive oxygen species or antiviral therapy are known factors leading to adult heart defects. The risks following a radiation exposure during fetal period are unknown, as are the mechanisms of any potential cardiac damage. The aim of this study was to gather evidence for possible damage by investigating long-term changes in the mouse heart proteome after prenatal exposure to low and moderate radiation doses. Pregnant C57Bl/6J mice received on embryonic day 11 (E11) a single total body dose of ionizing radiation that ranged from 0.02 Gy to 1.0 Gy. The offspring were sacrificed at the age of 6 months or 2 years. Quantitative proteomic analysis of heart tissue was performed using Isotope Coded Protein Label technology and tandem mass spectrometry. The proteomics data were analyzed by bioinformatics and key changes were validated by immunoblotting. Persistent changes were observed in the expression of proteins representing mitochondrial respiratory complexes, redox and heat shock response, and the cytoskeleton, even at the low dose of 0.1 Gy. The level of total and active form of the kinase MAP4K4 that is essential for the embryonic development of mouse heart was persistently decreased at the radiation dose of 1.0 Gy. This study provides the first insight into the molecular mechanisms of cardiac impairment induced by ionizing radiation exposure during the prenatal period.

Optimized automated data analysis for the cytokinesis-block micronucleus assay using imaging flow cytometry for high throughput radiation biodosimetry.

The cytokinesis‐block micronucleus (CBMN) assay is a well‐established technique that can be employed in triage radiation biodosimetry to estimate whole body doses of radiation to potentially exposed individuals through quantitation of the frequency of micronuclei (MN) in binucleated lymphocyte cells (BNCs). The assay has been partially automated using traditional microscope‐based methods and most recently has been modified for application on the ImageStreamX (ISX) imaging flow cytometer. This modification has allowed for a similar number of BNCs to be automatically scored as compared to traditional microscopy in a much shorter time period. However, the MN frequency measured was much lower than both manual and automated slide‐based methods of performing the assay. This work describes the optimized analysis template which implements newly developed functions in the IDEAS® data analysis software for the ISX that enhances specificity for BNCs and increases the frequency of scored MN. A new dose response calibration curve is presented in which the average rate of MN per BNC is of similar magnitude to those presented in the literature using automated CBMN slide scoring methods. In addition, dose estimates were generated for nine irradiated, blinded samples and were found to be within ±0.5 Gy of the delivered dose. Results demonstrate that the improved identification accuracy for MN and BNCs in the ISX‐based version of the CBMN assay will translate to increased accuracy when estimating unknown radiation doses received by exposed individuals following large‐scale radiological or nuclear emergencies. © 2016 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of ISAC