Temperature dependence of polymer-gel dosimeter nuclear magnetic resonance response.
The purpose of this study was to find a physical-mathematical description capable to correct a polymer-gel dosimeter relaxation rate R2-dose response for different temperatures. Four different modifications of polymer-gel dosimeters were used in this study. Samples with polymer-gel dosimeter in glass test vessels were homogeneously irradiated by 60Co gamma photons. A multi-echo sequence with 16 equidistant echoes was used for evaluation of irradiated polymer-gel dosimeters. The sequence parameters were as follows: TR 2000 ms, TE 22.5-360.0 ms, slice thickness 5 mm, FOV 255 mm, one acquisition. The proposed description recommends to subtract R2 response of the nonirradiated dosimeter from the total R2-dose response. The relaxation rate for the irradiated dosimeter can be expressed as a function of temperature and dose. The temperature dependence has an exponential behavior in the measured range. The proposed description allows to correct the measured NMR R2-dose responses for different temperatures.
Spevacek
V
V
Czech Technical University in Prague, Faculty of Nuclear Science and Physical Engineering, Department of Dosimetry and Application of Ionizing Radiation, Brehova 7, 110 00 Prague 1, The Czech Republic.
Novotny
J
J
Dvorak
P
P
Novotny
J
J
Vymazal
J
J
Cechak
T
T
D004307:Dose-Response Relationship, Radiation; D005782:Gels; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation* / Q000379:methods*; D008962:Models, Theoretical; D017785:Photons; D055585:Physical Phenomena; D010825:Physics; D011874:Radiometry / Q000379:methods*; D013696:Temperature
D005782:Gels