title: Effects of water treatment and sample granularity on radiation sensitivity and stability of EPR signals in X-ray irradiated bone samples.
abstract: The article describes effects of sample conditions during its irradiation and electron paramagnetic resonance (EPR) measurements on the background (BG) and dosimetric EPR signals in bone. Intensity of the BG signal increased up to two to three times after crushing of bone to sub-millimetre grains. Immersion of samples in water caused about 50 % drop in intensity of the BG component followed by its regrowth in 1-2 months. Irradiation of bone samples produced an axial dosimetric EPR signal (radiation-induced signal) attributed to hydroxyapatite component of bone. This signal was stable and was not affected by water. In samples irradiated in dry conditions, EPR signal similar to the native BG was also generated by radiation. In samples irradiated in wet conditions, this BG-like component was initially much smaller than in bone irradiated as dry, but increased in time, reaching similar levels as in dry-irradiated samples. It is concluded that accuracy of EPR dosimetry in bones can be improved, if calibration of the samples is done by their irradiations in wet conditions.
authors.affiliation: Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland bciesiel@gumed.edu.pl.
authors.forename: Bartlomiej
authors.initials: B
authors.lastname: Ciesielski
authors.affiliation: Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Krefft
authors.affiliation: Department of Physics and Biophysics, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Penkowski
authors.affiliation: Department of Oncology and Radiotherapy, Medical University of Gdansk, Debinki 7, 80-211 Gdansk, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Kaminska
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical University of Gdansk, Smoluchowskiego 17, 80-214 Gdańsk, Poland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Drogoszewska
mesh_terms: D000328:Adult; D001842:Bone and Bones / Q000737:chemistry* / Q000528:radiation effects*; D017886:Durapatite / Q000737:chemistry / Q000528:radiation effects; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006801:Humans; D008297:Male; D011829:Radiation Dosage; D011836:Radiation Tolerance; D011874:Radiometry / Q000379:methods*; D014867:Water / Q000737:chemistry*; D014965:X-Rays
chemical_list: D014867:Water; D017886:Durapatite