A Karlsson et al 2007 Phys. Med. Biol. 52 4697 doi:10.1088/0031-9155/52/15/021
A Karlsson1, H Gustavsson1, S Månsson1, K B McAuley2 and S Å J Bäck1
Show affiliationsDose integration properties were investigated for normoxic polymer gels based on methacrylic acid (nMAG) and acrylamide/N, N'-methylenebisacrylamide (nPAG). The effect of sequential irradiation was studied for different fractionation schemes and varying amounts of methacrylic acid for the nMAG gels. Magnetic resonance imaging (MRI) was used for read out of the absorbed dose response. The investigated gels exhibited a dependence on the fractionation scheme. The response when the total dose was divided into fractions of 0.5 Gy was compared with the response when the total dose was delivered in a single fraction. The slope of the R2 versus the absorbed dose response decreased when the absorbed dose per fraction was increased. Also, for higher amounts of methacrylic acid in the nMAG system the difference in the response increased. For gels containing 2, 4, 6 and 8% methacrylic acid, the R2 versus the absorbed dose response increased by 35, 37, 63 and 93%, respectively. Furthermore, the effect of the fractionation was larger when a higher total absorbed dose was given. The effect was less pronounced for the investigated nPAG, containing 3% acrylamide and 3% N, N'-methylenebisacrylamide, than for the nMAG systems. Consequently, this study indicates that the nPAG system has preferable beam integration characteristics compared with the nMAG system.
Issue 15 (7 August 2007)
Received 9 May 2007, in final form 15 June 2007
Published 18 July 2007
A Karlsson et al 2007 Phys. Med. Biol. 52 4697
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Yung-Jin Hu and Corwin H Booth 2009 J. Phys.: Conf. Ser. 190 012029
Xiao-Hu Zhao et al 2001 J. Phys. D: Appl. Phys. 34 2308
A Poole et al 2007 J. Phys.: Condens. Matter 19 452201
R J Hill and G R Jones 1979 J. Phys. D: Appl. Phys. 12 1707
Hirotaka Takahashi et al 2003 Class. Quantum Grav. 20 S741
Hyo Seok Yi et al 2004 J. Phys. A: Math. Gen. 37 11017
N Bhattacharya et al 2009 Supercond. Sci. Technol. 22 125013