Fourier transform Raman spectroscopy of polyacrylamide gels (PAGs) for radiation dosimetry

Abstract

Polyacrylamide gels (PAGs) are used for magnetic resonance imaging radiation dosimetry. Fourier transform (FT) Raman spectroscopy studies were undertaken to investigate cross-linking changes during the copolymerization of polyacrylamide gels in the spectral range of 200-3500 cm(-1). Vibrational bands of 1285 cm(-1) and 1256 cm(-1) were assigned to acrylamide and bis-acrylamide single CH2 deltaCH2 binding modes. Bands were found to decrease in amplitude with increasing absorbed radiation dose as a result of copolymerization. Principal component regression was performed on FT-Raman spectra of PAG samples irradiated to 50 Gy. Two components were found to be sufficient to account for 98.7% of the variance in the data. Cross validation was used to establish the absorbed radiation dose of an unknown PAG sample from the FT-Raman spectra. The calculated correlation coefficient between measured and predictive samples was 0.997 with a standard error of estimate of 0.976 and a standard error of prediction of 1.140. Results demonstrate the potential of FT-Raman spectroscopy for ionizing radiation dosimetry using polyacrylamide gels.

Raman Spectroscopy of Irradiated Normoxic Polymethacrylic Acid Gel Dosimeter

“…6(a), the band at 801 cm -1 seems to follow relatively the monoexponential decay curve, and the sensitivity parameter for it is 5.3 ± 1.5 Gy. It is clear that this value is much shorter than the 8.36 Gy and 12 Gy obtained by Baldock et al 8 and Jirasek et al, 7 respectively, for AA., being in good agreement with the report 1 that MAA has higher sensitivity than AA. This fact is supported by the results of other two vibrational However, the value for the band at 3114 cm -1 shows somewhat higher uncertainty of ± 2.6.…”

“…Owing to these advantages it has been applied in studies of gel dosimeters, where monomers are used for acrylamide (AA) and bis-acrylamide (bis-AA), which allows studies about the interaction between monomer consumption of gel dosimeter and polymer. [7][8][9] Owing to its lower toxicity as a carcinogen in methacrylic acid (MAA) than AA, interest in gel dosimeters using this substance is increasing. 4 The study aims to synthesize a polymer gel and indentify radiation action mechanism of gel dosimeter in accordance with analysis of characteristic vibrational mode of MAA monomers through a Raman experiment, which will be applied as basic necessary data to secure a greatly enhanced polymer gel dosimeter.…”

3D dosimetry fundamentals: gels and plastics

“…Since their inception, many different variations on the gel composition have been tested and used. Fundamental processes influencing the radiation response of these materials have been unveiled, yielding a thorough understanding of the factors affecting the radiation dose sensitivity and stability, both spatial and temporal [12,[28][29][30][31][32]. In 2001, an antioxidant was added to the gel composition, which scavenged oxygen molecules present in the gel during manufacture under normal atmosphere [33].…”

Trends in Radiation Dosimetry: preliminary overview of active growth areas, research trends and hot topics from 2011-2015

“…Different areas in a map correspond with different subfields. The term maps were used to assist in the understanding of active growth areas of the radiation dosimetry field and associated research trends and emerging hot topics such as 3-D dosimetry [3,4] …”