David J. Sandgren

Multiple parameter radiation injury assessment using a nonhuman primate radiation model-biodosimetry applications.

There are urgent needs to establish capability to rapidly assess radiation injury in mass casualty and population monitoring scenarios. This studys objective was to evaluate several currently available biomarkers that can provide early diagnostic triage information after radiation exposure. Hematology and blood chemistry measurements were performed on samples derived from a nonhuman primate (Macaca mulatta; n = 8) total-body irradiation (TBI) model (6.5-Gy 60Co &ggr; rays at 0.6 Gy min−1). The results from this study demonstrate: a) time course for changes in C-reactive protein (CRP) (−2 d to 15 d after TBI); b) time-dependent (−2 d, 1–4 d after TBI) changes in blood cell counts [i.e., lymphocytes decrease to 5–8% of pre-study levels at 1 to 4 d after TBI; ratio of neutrophil to lymphocytes increases by 44 ± 18 (p = 0.016), 12 ± 4 (p = 0.001), 8 ± 2 (p = 0.0020), and 5.0 ± 2 (p = 0.002) fold at 1, 2, 3, and 4 days after TBI, respectively]; and c) 4.5 ± 0.8 (p = 0.002)-fold increases in serum amylase activity 1 d after TBI. Plasma CRP levels at 1 d after exposure were 22 ± 13 (p = 0.0005) (females) and 44 ± 11 (p = 0.0004) (males)-fold elevated above baseline levels. One hundred percent successful separation of samples from exposed macaques (24 h after TBI) vs. samples from the same macaque taken before irradiation using a discriminant analysis based on four biomarkers (i.e., lymphocytes, neutrophils, ratio of neutrophils to lymphocytes, and serum amylase activity) was demonstrated. These results demonstrate the practical use of multiple parameter biomarkers to enhance the discrimination of exposed vs. non-exposed individuals and justify a follow-on rhesus macaque dose-response study.

Combined approach of hematological biomarkers and plasma protein SAA for improvement of radiation dose assessment triage in biodosimetry applications.

Early treatment of populations exposed to ionizing radiation requires accurate and rapid biodosimetry with a precision as high as possible to determine an individuals exposure level and risk for morbidity and mortality. The purpose of this study was to evaluate the utility of multiple blood biomarkers for early-response assessment of radiation exposure using a murine (BALB/c, males) in vivo radiation model. Present results for mice exposed to whole-body 60Co &ggr;-rays (0.1 Gy min−1) over a broad dose range (0–7 Gy) demonstrate at 24 h after exposure: 1) dose-dependent increase in the acute phase protein serum amyloid A or SAA; 2) dose-dependent changes in blood cell counts (lymphocytes, neutrophils, and ratio of neutrophils to lymphocytes); 3) SAA results coupled with peripheral blood cell counts analyzed with use of multivariate discriminant analysis established very successful separation of irradiated animals; 4) an enhanced separation as the number of biomarkers increased. These results also demonstrate proof-in-concept that plasma protein SAA shows promise as a complimentary approach to conventional biodosimetry for early assessment of radiation exposures and, coupled with peripheral blood cell counts, provides early diagnostic information to effectively manage radiation casualty incidents.

Protein biomarkers for enhancement of radiation dose and injury assessment in nonhuman primate total-body irradiation model.

Development and validation of early-response radiation injury biomarkers are critical for effective triage and medical management of irradiated individuals. Plasma protein and haematological profiles were evaluated using multivariate linear-regression analysis to provide dose-response calibration curves for photon-radiation dose assessment in 30 rhesus macaques total-body-irradiated to 1-8.5 Gy with (60)Co gamma rays (0.55 Gy min(-1)). Equations for radiation dose received were established based on different combinations of protein biomarkers [i.e. C-reactive protein (CRP), serum amyloid A (SAA), interleukin 6 (IL-6) and Flt3 Ligand (Flt3L)] at samples collection time-points 6 h, 1, 2, 3, 4 and 7 d post-total-body irradiation. Dynamic changes in the levels of CRP, SAA, IL-6 and Flt3L may function as prognostic indicators of the time course and severity of acute radiation sickness (ARS). The combination of protein biomarkers provides greater accuracy for early radiation assessment than any one biomarker alone.

Early-response biomarkers for assessment of radiation exposure in a mouse total-body irradiation model.

AbstractNuclear accidents or terrorist attacks could expose large numbers of people to ionizing radiation. Early biomarkers of radiation injury will be critical for triage, treatment, and follow-up of such individuals. The authors evaluated the utility of multiple blood biomarkers for early-response assessment of radiation exposure using a murine (CD2F1, males) total-body irradiation (TBI) model exposed to 60Co &ggr; rays (0.6 Gy min−1) over a broad dose range (0–14 Gy) and timepoints (4 h–5 d). Results demonstrate: 1) dose-dependent changes in hematopoietic cytokines: Flt‐3 ligand (Flt3L), interleukin 6 (IL‐6), granulocyte colony stimulating factor (G-CSF), thrombopoietin (TPO), erythropoietin (EPO), and acute phase protein serum amyloid A (SAA); 2) dose-dependent changes in blood cell counts: lymphocytes, neutrophils, platelets, and ratio of neutrophils to lymphocytes; 3) protein results coupled with peripheral blood cell counts established very successful separation of groups irradiated to different doses; and 4) enhanced separation of dose was observed as the number of biomarkers increased. Results show that the dynamic changes in the levels of SAA, IL‐6, G-CSF, and Flt3L reflect the time course and severity of acute radiation syndrome (ARS) and may function as prognostic indicators of ARS outcome. These results also demonstrate proof-in-concept that plasma proteins show promise as a complimentary approach to conventional biodosimetry for early assessment of radiation exposures and, coupled with peripheral blood cell counts, provide early diagnostic information to manage radiation casualty incidents effectively, closing a gap in capabilities to rapidly and effectively assess radiation exposure early, especially needed in case of a mass-casualty radiological incident.

Overview of hazard assessment and emergency planning software of use to RN first responders.

There are numerous software tools available for field deployment, reach-back, training and planning use in the event of a radiological or nuclear terrorist event. Specialized software tools used by CBRNe responders can increase information available and the speed and accuracy of the response, thereby ensuring that radiation doses to responders, receivers, and the general public are kept as low as reasonably achievable. Software designed to provide health care providers with assistance in selecting appropriate countermeasures or therapeutic interventions in a timely fashion can improve the potential for positive patient outcome. This paper reviews various software applications of relevance to radiological and nuclear events that are currently in use by first responders, emergency planners, medical receivers, and criminal investigators.

Further biodosimetry investigations using murine partial-body irradiation model

This study evaluates both the effects of physical restraint and use of candidate biomarkers in a CD2F1 male mouse partial-body irradiation model for biological dosimetry diagnostic assays. Mice were irradiated (6-Gy, 250-kVp X ray) to 3/3rd (total body), 2/3rd (gut and torso), 1/3rd (gut only) and 0/3rd (sham) of total body. Blood was sampled for haematology and blood plasma proteomic biomarkers at 1 and 2 d after exposure. Increases in the body fraction exposed showed progressive decreases in lymphocyte counts and increases in the neutrophil-to-lymphocyte ratios with no significant differences in the neutrophil and platelet counts. The radioresponse for plasma biomarker Flt3L showed proportional increases; however, G-CSF and SAA levels exhibited dramatic and non-proportional increases in levels. Physical restraint at 1 d post-exposure increased lymphocyte counts and SAA, decreased neutrophil-to-lymphocyte ratio and Flt3L and showed no effects on neutrophil and platelet counts or G-CSF.

Biodosimetry medical recording-use of the Biodosimetry Assessment Tool.

Effective and dynamic recording of radiation exposure and medical diagnostic information for individuals suspected or known to have been exposed to ionizing radiation contributes to appropriate formulation of medical treatment strategies and radiation protection management. The objectives of this article are to report the database entry templates or screens, provide general use guidelines, and discuss the application to selected radiation exposure scenarios for the Armed Forces Radiobiology Research Institute’s software application, Biodosimetry Assessment Tool (BAT). BAT data entry screens were developed based on consensus generic guidance and organized into discrete categories (i.e., physical dosimetry, contamination, prodromal symptoms, hematology, lymphocyte cytogenetics, erythema/wound, and infection) to facilitate its practical use during the early-phase response for radiological incidents. The summary report provides a concise output of information on radiation exposure, radionuclide contamination, dose assessment based on biological indicators (i.e., cytogenetic chromosome aberration bioassays, time to onset of vomiting, lymphocyte cell counts or depletion kinetics), and relevant clinical signs and symptoms. The BAT report template is compliant with NATO and international guidance for recording ionizing radiation exposures for medical purposes.

Biodosimetry Assessment Tool (BAT) software-dose prediction algorithms.

Purpose:Medical management of suspected radiation casualties requires use of multiparameter biodosimetry because no single biodosimetric measurement is sufficiently robust. This report describes the design and algorithms used in a radiation exposure assessment software application that serves as a diagnostic utility for triage and medical treatment formulation, as well as to convey psychological reassurance, for early-phase assessment of radiation exposures, and for surge response assessment for mass radiological casualties. Methods:The Armed Forces Radiobiology Research Institutes Biological Dosimetry Research Program developed the integrated multiparameter Biodosimetry Assessment Tool computer program using Microsoft Visual Basic 6 with various second party plug-ins and add-ons. Dose-predicting algorithms were adopted by analyzing data from merged databases of human radiation exposure incidents and normal controls (non-irradiated) volunteers. The results are summarized in user-friendly screens. Summary:BAT algorithms are presented and compared to other previously published dose assessment algorithms based on biological indicators (i.e., onset of vomiting, lymphocyte depletion kinetics). These new algorithms are incorporated into a computer-based program that assists responders and medical providers in recording relevant diagnostic information and assessing significant radiation exposures. It promotes early-phase (<10 d) data collection after a radiation exposure incident and provides data templates for entry of diagnostic information using multiparameter indices. It allows for recording of relevant clinical information and summarizes diagnostic information such as estimated multiparameter doses. Data can be printed and archived in accordance with civilian and military guidelines.

Application of Multivariate Modeling for Radiation Injury Assessment: A Proof of Concept

Multivariate radiation injury estimation algorithms were formulated for estimating severe hematopoietic acute radiation syndrome (H-ARS) injury (i.e., response category three or RC3) in a rhesus monkey total-body irradiation (TBI) model. Classical CBC and serum chemistry blood parameters were examined prior to irradiation (d 0) and on d 7, 10, 14, 21, and 25 after irradiation involving 24 nonhuman primates (NHP) (Macaca mulatta) given 6.5-Gy 60Co Υ-rays (0.4 Gy min−1) TBI. A correlation matrix was formulated with the RC3 severity level designated as the “dependent variable” and independent variables down selected based on their radioresponsiveness and relatively low multicollinearity using stepwise-linear regression analyses. Final candidate independent variables included CBC counts (absolute number of neutrophils, lymphocytes, and platelets) in formulating the “CBC” RC3 estimation algorithm. Additionally, the formulation of a diagnostic CBC and serum chemistry “CBC-SCHEM” RC3 algorithm expanded upon the CBC algorithm model with the addition of hematocrit and the serum enzyme levels of aspartate aminotransferase, creatine kinase, and lactate dehydrogenase. Both algorithms estimated RC3 with over 90% predictive power. Only the CBC-SCHEM RC3 algorithm, however, met the critical three assumptions of linear least squares demonstrating slightly greater precision for radiation injury estimation, but with significantly decreased prediction error indicating increased statistical robustness.