Established calibration curve for unstable chromosomal Established - PowerPoint PPT Presentation

2012 Student Practice in JINR Fields of Research Established calibration curve for unstable chromosomal Established calibration curve for unstable chromosomal aberrations induced by therapeutic protons beam for aberrations induced by therapeutic protons beam for retrospective dose estimation retrospective dose estimation Modiba R.Victor 1 and Ntshinga K 2 ; 1) University of Venda, South Africa; 2) University of Fort Hare Supervisors: Dr. Polina Kutsalo and Dr. Anna Rzjanina Laboratory of Radiation Biology, Joint Institute for Nuclear Research

Contents • Aim of our work • Introduction • Methodology • Results • Conclusion • Acknowledgements • References

AIM • Establishing calibration curve for unstable chromosomal aberrations induced by the proton beam used in cancer therapy at Laboratory of Nuclear Problems at JINR. � Calibration curves are performed for chromosomal aberrations yields scored in lymphocytes of several voluntaries exposed in vitro to the known radiation doses

BIOLOGICAL DOSIM ETRY • Is the measurement and calculation of the absorbed dose in matter and tissue resulting from the exposure to direct or indirect ionizing radiation. • It allows to assess an accidental dose on ionizing radiation by analysis of changes induced in chromosomes of human peripheral blood lymphocytes

LYM PHOCYTES

Human Cell DNA is our main target for the ionization radiation

SHAPES OF CHROM OSOM ES

Chromosomal aberrations Ionising radiation Primary lesions analysis of the frequencies of unstable aberrations by Giemsa staining Fluorescence in situ hybridyzation (FISH) translocation dicentric acentric fragments M icronuclei assay

SCHEME OF AN EXPERI IMENT MENT SCHEME OF AN EXPER for the standard metaphase analysis (dicentric assay) PHA Culture of Irradiated Colcemid blood Fixation 0-24 h 46h 48-50h Giemsa Image visible under light microscope

Dicentrics assay Dicentrics assay (unstable exchanges analysis): (unstable exchanges analysis): Centric ring ace deletion Dic Acentric ring An exaple of cell with unstable aberrations – dicentrics, acentric fragments , centric and acentric rings in Giemsa stained metaphase

Calibration curve • Established on the basis of the level of cytogenetic damage (chromosomal aberrations) induced by ionising radiation under in vitro conditions in human peripheral blood lymphocytes (PBL). • Used in biological dosimetry for retrospective dose estimation in case of accidental overexposure of people.

Conclusion: We established dose calibration curve for unstable chromosomal aberrations induced by therapeutic proton beam in the dose range from 0 to 5 Gy. The calibration curve may be useful to retrospective dose estimation in case of accidental exposure to protons.

Acknowledgement • Dr Polins Kutsalo • Dr. Anna Rzjanina • Dr Jacobs and Prof Lekala • Mavura Vusi • NRF and JINR • Dubna people

References: • IAEA (1986) Biological dosimetry: chromosome aberrations analysis for dose assessment. International Atomic Energy Agency Technical Report No 260.Vienna • IAEA (2001) Cytogenetic analysis for radiation dose assessment. A manual. I nternational Atomic Energy Agency. Vienna • IAEA (2011) Cytogenetic Dosimetry: Applications in the Preparedness for and Response for Radiation Emergences. International Atomic Energy Agency. Vienna

C пасибо !