13C-NMR,1H-NMR, and FT-Raman study of radiation-induced modifications in radiation dosimetry polymer gels

Journal of Applied Polymer Science (Impact Factor: 1.4). 01/2001; 79(9):1572-1581. DOI: 10.1002/1097-4628(20010228)79:93.0.CO;2-B

ABSTRACT 1H- and 13C-NMR spectroscopy and FT-Raman spectroscopy are used to investigate the properties of a polymer gel dosimeter post-irradiation. The polymer gel (PAG) is composed of acrylamide, N,N′-methylene-bisacrylamide, gelatin, and water. The formation of a polyacrylamide network within the gelatin matrix follows a dose dependence nonlinearly correlated to the disappearance of the double bonds from the dissolved monomers within the absorbed dose range of 0–50 Gy. The signal from the gelatin remains constant with irradiation. We show that the NMR spin–spin relaxation times (T2) of PAGs irradiated to up to 50 Gy measured in a NMR spectrometer and a clinical magnetic resonance imaging scanner can be modeled using the spectroscopic intensity of the growing polymer network. More specifically, we show that the nonlinear T2 dependence against dose can be understood in terms of the fraction of protons in three different proton pools. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1572–1581, 2001

  • Source
    Macromolecular Theory and Simulations 11/2009; 18(9):495 - 510. · 1.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: An absorbed X-radiation dose in the range of radiotherapy for cancer patients (0-12 Gy) was measured and characterized in a polymer/Gel dosimeter (Polym/Gel) which composed of normoxic hydroxyl-ethyl-acrylate/Gel (HEA/Gel). The characterization of the irradiated HEA/Gel by Nuclear Magnetic Resonance (NMR) showed that the relaxation rate R 2 (t) for proton was increased following the radiation dose indicating the polymerization of HEA/Gel monomer to poly(hydroxyl-ethyl-acrylate/Gel) PHEA/Gel. The PHEA/Gel was characterized by Raman spectroscopy which confirmsed the polymerization of HEA/Gel with reference to the a new chemical bond formation at Raman shift of 1415 cm -1 which in turn was being increased following the radiation dose. The color change of PHEA/Gel due to radiation polymerization was been studied by optical density-meter out of MRI image which showed that the optical density increased along the axis of the radiation field in depth profile for a limited distance then decreased by increasing the radiation. KEYWORDS: Polymer Dosimeter in Radiotherapy,HEA . INTRODUCTION For the high secured accuracy of radiation therapy dose that should not exceed ± 5% of the prescribed tumor dose
    J. Sc. Tech. 01/2011; 12(1):45-50.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, a two-level full factorial design was used to identify the effects of the interactions between compositions in an N-isopropylacrylamide (NIPAM) gel dosimeter involving the following variables: (A) gelatin, (B) NIPAM, (C) the crosslinker N, N'-methylene-bis-acrylamide (Bis), and (D) the antioxidant tetrakis (hydroxymethyl) phosphonium chloride (THPC). The dose range was from 0 Gy to 5 Gy. Optical computed tomography was used to scan the polymer gel dosimeter. Each component was set to two levels for all four variables, including (A) 4% and 6%, (B) 4% and 6%, (C) 2% and 4%, as well as (D) 5 and 15 mM. Response surface methodology and a central composite design were adopted for the quantitative investigation of the respective interaction effects on the dose response curve of the gel. The results showed that the contributions of the interaction effects, i.e., AB (6.22%), AC (8.38%), AD (7.74%), BC (9.44%), ABC (18.24%), BCD (12.66%), and ABCD (13.4%), were greater than those of the four main effects, accounting for over 76.08% of the total variability. These results also indicated that the NIPAM gel recipe with the highest sensitivity was at 40%C (mass fraction of Bis).
    PLoS ONE 01/2012; 7(10):e44905. · 3.53 Impact Factor

Full-text (2 Sources)

Available from
Jul 9, 2014

View other sources