Presentation on theme: "Sensitivity of Human Lymphocytes to Low-Dose Radiation"— Presentation transcript:
1Sensitivity of Human Lymphocytes to Low-Dose Radiation Gordon K. Livingston, PhDTechnical Director, Cytogenetic Biodosimetry LaboratoryRadiation Emergency Assistance Center Training SiteOak Ridge Insitute for Science and EducationOak Ridge, TN
2Cytogenetic Biodosimetry Cytogenetic analysis provides a method to estimate radiation dose to individuals exposed to ionizing radiation when physical dosimetry devices are not available.
3LymphocytesLymphocytes serve as ideal biological dosimeters because they:are very sensitive to radiation,are readily available in routine blood samples,circulate throughout the body,can be easily cultured and induced to divide in vitrorespond consistently to ionizing radiation exposure by expressing chromosomal DNA damage in a dose-dependent manner.
6Dicentric Chromosome Assay Low background rate (1-2 per 1,000 cells)Independent of age and genderSensitivity range (0.2 – 5 Gy)Specificity to radiation is highConsistent radiation dose-responseProven in accidents over four decadesConsidered the gold standard
15X-ray Exposure Conditions Westinghouse Orthovoltage Therapy Unit78 kV, 5 mA, 2mm Al added filtrationoutput measured at 19.8 cGy/min at 50 cm30 cm field size with +/- 10 % uniformitygraded doses of 0, 5, 10, 15, 20 & 25 cGy10 ml media (3-4 x 105 cells/ml) in 25 cm2 culture flasks at 37 C for 72 hr
18The Micronucleus Test as a Biological Dosimeter Linear Dose Response to X-raysy = x35.5 = xX = 11.4 c GyNCRP Dose to red marrow is 0.2 m rad / micro Ci48,000 micro Ci x 0.2 m rad = 9,600 m rad= 9.6 rad (9.6 c Gy)
24Cytogenetic Biodosimetry LimitationsLarge event could overwhelm resourcesLabor intensiveSamples require shipmentAdvantagesProven method for dose estimationAmenable to web-based image scoringExisting resource of clinical laboratories
25Cytogenetic Dosimetry Capacity Worldwide Cytogenetic labs and regional networks already collaborating with WHO:North-AmericanLatin American (with IAEA support)EuropeanScandinavianEastern Europe: RF and UkraineWestern-Pacific: Japan, S. Korea, AustraliaNeed to integrate and coordinate these networks globallyNeed a clear concept of operations for emergencies and in "quiet" time to make the most of these labs joint capabilities
26Consortium Lab in Consortium (Metafer System) REAC/TS CBL Secure Central Server (Access Limited)Lab in Consortium (Metafer Software)Satellite Scoring Station (Metafer Software)
27The re-establishment of the REAC/TS-Cytogenetic Biodosimetry Laboratory, operated by the Oak Ridge Institute for Science and Education (ORISE), was supported by:DOE-NNSA,DOE-EH, andNuclear Regulatory Commission.Establishing a Web-Based International Radiation Cytogenetic Biodosimetry Consortium at REAC/TS is being funded by DOE-NNSA.