2010 Student Practice in JINR Fields of Research. Established calibration curve for unstable chromosomal aberrations induced by therapeutic protons beam for retrospective dose estimation. 1) Agnieszka Frącka; 2) Ilona Głowacka; 2 ) Wojciech Wróblewski
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1) Agnieszka Frącka; 2) Ilona Głowacka; 2) Wojciech Wróblewski
1) University of Wrocław; 2) University of Łódź
Supervisors: Marta Deperas- Kaminska and Polina Kutsalo
Laboratory of Radiation Biology, Joint Institute for Nuclear Research
Biological dosimetry – allows to assess an accidental dose of ionising radiation by analysis of changes induced in chromosomes of human peripheral blood lymphocytes
The yield of chromosome aberrations
in peripheral blood lymphocytes is the most sensitive indicator for past irradiation exposure, therefore it is used in biological dosimetry for retrospective dose estimation.
How are aberrations formed?
The purpose of our investigation were to establish calibration curve for unstable aberrations induced by proton beam routinely use to cancer therapy at Laboratory of Nuclear Problems at JINR.
What it is calibration curves?
Calibration curves are performed for chromosomal aberrations yields scored in lymphocytes of several voluntaries exposed in vitro to the known radiation doses
SCHEME OF THE EXPERIMENT
for the standard metaphase analysis (dicentric assay)
Culture of Irradiated blood
Staining with Fluorescence Plus Giemsa (FPG)
Reference: Cytogenetic analysis for radiation dose assessment.
A manual. (2001) International Atomic Energy Agency. Vienna.
An example of metaphase stained with Giemsa. Cell carried unstable aberrations: dicentrics, acentric fragmentsandcentricandacentric rings.
Image visible under light microscope
CABAS is intended for fitting dose-response curves.
Thesoftware is intended for fitting a linear-quadratic dose-response relationship by the maximum-likelihood method. It was designed for the purpose of biological dosimetry based on the analysis of chromosomal aberrations - dicentrics and rings, scored on Giemsa stained slides.
Reference: Deperas J. et. al. (2007) CABAS - a freely available PC program for
fitting calibration curves in chromosome aberration dosimeter. Radiat Prot Dosimetry 124:115-123, 2007.
Y- aberration yield;
A – control frequency
D – dose [Gy]
α- linear coefficient
β- dose squared coefficient
Figure 1. Fitted dose response curves for sum of dicentrics and centric rings induced by protons in chromosomes of 4 donors. Error bars represent the 95% confidence intervals calculated for the mean values.
We established dose calibration curve for unstable chromosomal aberrations induced by therapeutic proton beam in the dose range from 0 to 3 Gy.
The calibration curve may be useful to retrospective dose estimation in case of accidental exposure to protons.
Special thanks to:
X-ray photo - 1896
Thanks for your attention