It takes two planets in resonance to tango around K2-146

Stars and planetary system

Pilot website to support international collaboration for dose assessments in a radiation emergency

Nuclear terrorism has emerged as a significant threat which could require timely medical interventions to reduce potential radiation casualties. Early dose assessments are critical since optimal care depends on knowing a victim's radiation dose. The dicentric chromosome aberration assay is considered the "gold standard" to estimate the radiation dose because the yield of dicentrics correlates positively with the absorbed dose. Dicentrics have a low background frequency, are independent of age and gender and are relatively easy to identify. This diagnostic test for radiation exposure, however, is labor intensive and any single or small group of laboratories could easily be overwhelmed by a mass casualty event. One solution to this potential problem is to link the global WHO BioDoseNet members via the Internet so multiple laboratories could work cooperatively to screen specimens for dicentric chromosomes and generate timely dose estimates. Inter-laboratory comparison studies have shown that analysis of electronic chromosome images viewed on the computer monitor produces scoring accuracy equivalent to viewing live images in the microscope. This functional equivalence was demonstrated during a comparative study involving five laboratories constructing 60Co gamma ray calibration curves and was further confirmed when comparing results of blind dose estimates submitted by each laboratory. It has been further validated in two recent WHO BioDoseNet trial exercises where 20 metaphase images were shared by e-mail and 50 images were shared on a test website created for this purpose. The Internet-based exercise demonstrated a high level of concordance among 20 expert scorers who evaluated the same 50 metaphase spreads selected to exhibit no, low, moderate and severe radiation damage. Nineteen of 20 scorers produced dicentric equivalent counts within the 95% confidence limits of the mean. The Chi-squared test showed strong evidence of homogeneity in the data (p = 0.999). Altogether, data obtained from these studies support the conclusion that Internet-based scoring is likely to overcome the "bottleneck" in workflow, reduce turn-a-round time for dose estimates and ultimately strengthen surge capacity. Use of the Internet for biodosimetry would obviously leverage the human and equipment resources throughout the world. As part of radiation emergency planning, we conclude that a global IT network/infrastructure is needed to serve the needs of an expanding biodosimetry community and should be given high priority to meet the growing threat of radiological and nuclear terrorism

Cytogenetic effects of radioiodine therapy a 20-year follow-up study

International audienceThe purpose of this study was to compare cytogenetic data in a patient before and after treatment with radioiodine to evaluate the assays in the context of biological dosimetry. We studied a 34-year-old male patient who underwent a total thyroidectomy followed by ablation therapy with 131I (19.28 GBq) for a papillary thyroid carcinoma. The patient provided blood samples before treatment and then serial samples at monthly intervals during the first year period and quarterly intervals for 5 years and finally 20 years after treatment. A micronucleus assay, dicentric assay, FISH method and G-banding were used to detect and measure DNA damage in circulating peripheral blood lymphocytes of the patient. The results showed that radiation-induced cytogenetic effects persisted for many years after treatment as shown by elevated micronuclei and chromosome aberrations as a result of exposure to 131I. At 5 years after treatment, the micronucleus count was tenfold higher than the pre-exposure frequency. Shortly after the treatment, micronucleus counts produced a dose estimate of 0.47 ± 0.09 Gy. The dose to the patient evaluated retrospectively using FISH-measured translocations was 0.70 ± 0.16 Gy. Overall, our results show that the micronucleus assay is a retrospective biomarker of low-dose radiation exposure. However, this method is not able to determine local dose to the target tissue which in this case was any residual thyroid cells plus metastases of thyroidal origin. © 2016, Springer-Verlag Berlin Heidelberg

Evaluation of the annual Canadian biodosimetry network intercomparisons

Purpose: To evaluate the importance of annual intercomparisons for maintaining the capacity and capabilities of a well-established biodosimetry network in conjunction with assessing efficient and effective analysis methods for emergency response. Materials and methods: Annual intercomparisons were conducted between laboratories in the Canadian National Biological Dosimetry Response Plan. Intercomparisons were performed over a six-year period and comprised of the shipment of 10-12 irradiated, blinded blood samples for analysis by each of the participating laboratories. Dose estimates were determined by each laboratory using the dicentric chromosome assay (conventional and QuickScan scoring) and where possible the cytokinesis block micronucleus (CBMN) assay. Dose estimates were returned to the lead laboratory for evaluation and comparison. Results: Individual laboratories performed comparably from year to year with only slight fluctuations in performance. Dose estimates using the dicentric chromosome assay were accurate about 80% of the time and the QuickScan method for scoring the dicentric chromosome assay was proven to reduce the time of analysis without having a significant effect on the dose estimates. Although analysis with the CBMN assay was comparable to QuickScan scoring with respect to speed, the accuracy of the dose estimates was greatly reduced. Conclusions: Annual intercomparisons are necessary to maintain a network of laboratories for emergency response biodosimetry as they evoke confidence in their capabilities

Interlaboratory comparison of the dicentric chromosome assay for radiation biodosimetry in mass casualty events

This interlaboratory comparison validates the dicentric chromosome assay for assessing radiation dose in mass casualty accidents and identifies the advantages and limitations of an international biodosimetry network. The assay's validity and accuracy were determined among five laboratories following the International Organization for Standardization guidelines. Blood samples irradiated at the Armed Forces Radiobiology Research Institute were shipped to all laboratories, which constructed individual radiation calibration curves and assessed the dose to dose-blinded samples. Each laboratory constructed a dose-effect calibration curve for the yield of dicentrics for 60Co γ rays in the 0 to 5-Gy range, using the maximum likelihood linear-quadratic model, Y = c + αD + βD2. For all laboratories, the estimated coefficients of the fitted curves were within the 99.7% confidence intervals (CIs), but the observed dicentric yields differed. When each laboratory assessed radiation doses to four dose-blinded blood samples by comparing the observed dicentric yield with the laboratory's own calibration curve, the estimates were accurate in all laboratories at all doses. For all laboratories, actual doses were within the 99.75% CI for the assessed dose. Across the dose range, the error in the estimated doses, compared to the physical doses, ranged from 15% underestimation to 15% overestimation

Biological dosimetry by the triage dicentric chromosome assay: Potential implications for treatment of acute radiation syndrome in radiological mass casualties

Biological dosimetry is an essential tool for estimating radiation dose. The dicentric chromosome assay (DCA) is currently the tool of choice. Because the assay is labor-intensive and time-consuming, strategies are needed to increase throughput for use in radiation mass casualty incidents. One such strategy is to truncate metaphase spread analysis for triage dose estimates by scoring 50 or fewer metaphases, compared to a routine analysis of 500 to 1000 metaphases, and to increase throughput using a large group of scorers in a biodosimetry network. Previously, the National Institutes for Allergies and Infectious Diseases (NIAID) and the Armed Forces Radiobiology Research Institute (AFRRI) sponsored a double-blinded interlaboratory comparison among five established international cytogenetic biodosimetry laboratories to determine the variability in calibration curves and in dose measurements in unknown, irradiated samples. In the present study, we further analyzed the published data from this previous study to investigate how the number of metaphase spreads influences dose prediction accuracy and how this information could be of value in the triage and management of people at risk for the acute radiation syndrome (ARS). Although, as expected, accuracy decreased with lower numbers of metaphase spreads analyzed, predicted doses by the laboratories were in good agreement and were judged to be adequate to guide diagnosis and treatment of ARS. These results demonstrate that for rapid triage, a network of cytogenetic biodosimetry laboratories can accurately assess doses even with a lower number of scored metaphases

The internet's role in a biodosimetric response to a radiation mass casualty event

Response to a large-scale radiological incident could require timely medical interventions to minimize radiation casualties. Proper medical care requires knowing the victim's radiation dose. When physical dosimetry is absent, radiation-specific chromosome aberration analysis can serve to estimate the absorbed dose in order to assist ph

Nonoperative Management of Blunt Splenic Trauma: Also Feasible and Safe in Centers with Low Trauma Incidence and in the Presence of Established Risk Factors

Background: Treatment of blunt splenic trauma has undergone dramatic changes over the last few decades. Nonoperative management (NOM) is now the preferred treatment of choice, when possible. The outcome of NOM has been evaluated. This study evaluates the results following the management of blunt splenic injury in adults in a Swedish university hospital with a low blunt abdominal trauma incidence. Method: Fifty patients with blunt splenic trauma were treated at the Department of Surgery, Lund University Hospital from January 1994 to December 2003. One patient was excluded due to a diagnostic delay of > 24 h. Charts were reviewed retrospectively to examine demographics, injury Severity score (ISS), splenic injury grade, diagnostics, treatment and outcome measures. Results: Thirty-nine patients (80%) were initially treated nonoperatively (NOM), and ten (20%) patients underwent immediate surgery (operative management, OM). Only one (3%) patient failed NOM and required surgery nine days after admission (failure of NOM, FNOM). The patients in the OM group had higher ISS (p < 0.001), higher grade of splenic injury (p < 0.001), and were hemodynamically unstable to a greater extent (p < 0.001). This was accompanied by increased transfusion requirements (p < 0.001), longer stay in the ICU unit (p < 0.001) and higher costs (p = 0.001). Twenty-seven patients were successfully treated without surgery. No serious complication was found on routine radiological follow-up. Conclusion: Most patients in this study were managed conservatively with a low failure rate of NOM. NOM of blunt splenic trauma could thus be performed in a seemingly safe and effective manner, even in the presence of established risk factors. Routine follow-up with CT scan did not appear to add clinically relevant information affecting patient management