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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

2012 Student Practice in JINR Fields of Research Modiba R.Victor1 and Ntshinga K2; 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

dicentric translocation analysis of the frequencies

• f unstable aberrations

by Giemsa staining Fluorescence in situ hybridyzation (FISH)

Chromosomal aberrations

Ionising radiation

Primary lesions

acentric fragments M icronuclei assay

SCHEME OF AN EXPER SCHEME OF AN EXPERI IMENT MENT

for the standard metaphase analysis (dicentric assay)

Colcemid 46h

Fixation

Giemsa 48-50h Image visible under light microscope Culture of Irradiated blood 0-24 h

PHA

Dic Centric ring Acentric ring deletion ace

An exaple of cell with unstable aberrations – dicentrics, acentric fragments , centric and acentric rings in Giemsa stained metaphase

Dicentrics assay Dicentrics assay (unstable exchanges analysis): (unstable exchanges analysis):

Calibration curve

• Established
• n

the basis

• f

the level

• f

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

• f

accidental

• verexposure 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

Cпасибо!