Effect of Composition Interactions on the Dose Response of an N-Isopropylacrylamide Gel Dosimeter

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).

Dosimetric characteristics of intensity-modulated radiation therapy and RapidArc® therapy using a 3D N-isopropylacrylamide gel dosimeter

“…10 Two cylindrical acrylic phantoms (10 cm in diameter, 10 cm in height, and 3 mm in thickness) filled with NIPAM gel were used for IMRT and RapidArc® irradiation. The gel was placed in a water bath and cooled in a refrigerator for at least 6 h until solidification to reduce deviation in dose distribution.…”

“…The spatial uniformity of the gel phantom indicates the quality of gel preparation and the stability of the measurement system. Seven different depths of transverse slices (10,20,30,40,50,60, and 70 mm) were used to evaluate spatial uniformity. We used standard deviation (SD) to estimate the dispersion of optical density at each location between different depths.…”

“…Many gel formulations have been developed, including polyacrylamide gel, methacrylic and ascorbic acid in gelatin initiated by copper, BANG, and N-isopropylacrylamide (NIPAM). [5][6][7][8][9][10] NIPAM gel dosimeters exhibit low toxicity, high linearity, high sensitivity, and easy benchtop preparation without requiring a glove box. [11][12][13] In addition, NIPAM gel dosimeters present high spatial stability and can retain the dose distribution between 24 and 72 h post-irradiation.…”

Use of a speckle reduction technique to improve the reconstruction image quality of CCD-based optical computed tomography scanner

“…Gel comprising 5% gelatin (300 Bloom Type A, Sigma-Aldrich), 5% N-Isopropylacrylamide (NIPAM) (97% pure; Sigma-Aldrich), 3% N, N'-methylene bisacrylamide (Bis), and 5 mM Tetrakis (hydroxymethyl) phosphonium chloride (THPC) was prepared [8][9][10]. An acrylic phantom (diameter ¼10 cm, height ¼10 cm) was filled with polymer gel and then stored in a refrigerator at a fixed temperature (4 1C) by water cooling until complete solidification [11].…”

Implementation of a parallel-beam optical-CT apparatus for three-dimensional radiation dosimetry using a high-resolution CCD camera

“…The gel phantom, filled with NIPAM (5% gelatin (300 bloom type A, Sigma-Aldrich), 5% NIPAM (97% pure; Sigma Aldrich), 3% N, N 0 -methylene bisacrylamide (bis), and 5 mM tetrakis (hydroxymethyl) phosphonium chloride), was prepared according to previous descriptions [11,12]. The preparation process followed previous research [9][10][11][12].…”