# Development and Application of MAGIC-f Gel in Cancer Research and Medical Imaging
## 2 Development of MAGIC-f Gel  
The development trends of MAGIC-f gel can be described from the development of a precursor form of polymer gel, such as dye made up of methylene, to the latest important innovation in the polymer gel dosimetry using MAGIC-f gel. Before the polymer gel dosimeter's innovation, dosimetry calculations were made only through ion chambers and film, which only gives point dose and two-dimensional dose distribution, respectively [3]. The use of a sensitive gel to irradiation was first proposed by [PERSON] in 1950, where the gel containing dye such as methylene blue gives color changes when subjected to radiation [8]. However, the use of polymer system/gel for radiation dosimetry was first initiated by [PERSON] et al. in 1954 [9]; [PERSON] et al., in 1958, worked on radiation dosimetry using liquid polymer [10]; and [PERSON]. Et al. used polyacrylamide in 1961 [11]. [PERSON] et al. found improvements in measurements of irradiated polyethylene oxide transverse relaxation by NMR [12]. The credit of discovery of the currently used radiation-sensitive polymer gel for radiation dosimetry goes to [PERSON] et al. [13], who investigated the relaxation properties after irradiation of previously developed ferrous sulfate chemical dosimeter by [PERSON] et al. [14; 15], by nuclear NMR. [PERSON] et al. showed that radiation-induced shifts could be quantified by using NMR relaxation steps where irradiation causes iron ions to gain a higher oxidation state, i.e., from ferrous (Fe\({}^{2+}\)) into ferric (Fe\({}^{3+}\)) ions [13]. Later, [PERSON] et al. observed increased relaxation rates with the absorbed dose from the longitudinal relaxation studies of NMR conducted on irradiated \(N\),\(N^{\prime}\)-methylene-bis-acrylamide form of aqueous solution [16]. The polymer gel proposed by [PERSON] et al. is a precursor version of the currently utilized polymer gel dosimeter for radiation dosimetry, which requires significant improvements due to many difficulties encountered during use. The polymer-gel dosimeter is based on radiation-induced polymerization and crosslinking of acrylic monomers [17]. In contrast, Fricke gel is not a polymer-based dosimeter; it is based on radiation-induced oxidation of ferrous ions which modifies NMR relaxation rates. In 1986, [PERSON] et al. 's research showed that a gel matrix with Fricke dosimetry solutions could be used to obtain spatial three-dimensional dose distribution using magnetic resonance imaging [18]. Further, opposing the claim of previous researchers, failure of irradiated gel dosimeters of Fricke-type to maintain stable distribution of dose in three-dimensional space was shown for the purpose of ion diffusion in the dosimeters that are irradiated [19; 20], and several authors' publications also support this claim. As diffusion was the big problem in the innovation in polymer gel dosimetry, attempts made by [PERSON] et al. to investigate the Fricke solution with different gelling agents, such as gelatin, agarose, Sephadex, polyvinyl alcohol (PVA), and xylenol orange (XO), where xylenol orange gives the best result, but performance is minimal, and the diffusion cannot be omitted and remain as a problem [21]. Prior to [PERSON] et al., [PERSON] et al. also investigated to cope up with diffusion effect, where they  
Figure 1: The process of obtaining dose distribution, using MAGIC-f. The figures were adapted from difference cited sources [6; 7]. proposed to use fast T1 imaging sequence to reduce the acquisition time and, ultimately, diffusion effect; they also found that diffusion can be lowered by adding chelating agents, such as xylenol orange to the gel, and found that diffusion was slower in gelatin gels [22]. Another system of polymer gel dosimetry that goes by the acronym BANANA polymer gel, due to the use of Bis (\(N\),\(N\)-methylene-bis-acrylamide), AAm (acrylamide), nitrous oxide, and agarose, was formulated in 1992 by [PERSON] et al., without having the diffusion problem [23].