Speaker
Mrs
Karolina Krefft
(Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland)
Description
Electron Paramagnetic Resonance (EPR) dosimetry is based on ex vivo detection of radicals generated by ionizing radiation such tissues as tooth enamel and bone. This method was proved to be applicable in dosimetry of victims in radiation accidents. However, procedures regarding technical conditions of a reliable dosimetry in bone are still under study. The spectra of irradiated bones consist of an asymmetric component assigned to CO2- radicals generated in hydroxyapatite and a second one, symmetrical component, the origin of which is assigned to the bone’s organic content. The intensity of the asymmetric component was shown to be stable in time in both dry and water-soaked samples and is used for dosimetry.
The aim of this study was to investigate the possibility of reduction of the “non-dosimetric” spectral components in irradiated human bone by chemical treatment and determination of consequences of this treatment on the dosimetric signal.
The EPR study were performed on samples treated by 2M KOH and intensities of the two spectral components, numerically isolated from the measured EPR spectra, were calculated. The KOH hydrolysis of an irradiated bone resulted in a significant decrease of the “organic” spectral component and caused 25-30% reduction in the sample mass - apparently due to loss of organic bone constituents, which make about 30% of cortical bone. The signal measured in the deproteinized bone consisted only from the asymmetric signal of high stability. The intensity of this component per unit mass of the sample was about 6 % lower and its peak-to-peak amplitude was 7% higher than before the hydrolysis. The KOH treatment resulted in about 30-35 % loss in intensity of the signal attributed to CO2- radicals, however, the remaining dosimetric signal was not masked by the symmetric spectral component.
It is concluded, that the KOH hydrolysis of irradiated bone considerably reduces the spectral components obscuring the dosimetric signal and can allow for increased accuracy of dosimetry in a low dose region.
Primary authors
Dr
Bartłomiej Ciesielski
(Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland)
Mrs
Karolina Krefft
(Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland)
Co-authors
Dr
Barbara Drogoszewska
(Department of Oral and Maxillofacial Surgery, Medical University of Gdansk, Smoluchowskiego 17, 80-214 Gdańsk, Poland)
Mrs
Małgorzata Juniewicz
(Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland)
Dr
Michał Penkowski
(Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland)
