AbstractID: 7316 Title: Dose resolution of polymer gel dosimeters imaged by x-ray computed
tomography
Post-irradiation changes in the linear attenuation coefficient of polymer gel
dosimeters enable the imaging of dose distributions by x-ray computed tomography.
In this work we vary the compositions of polymer gel dosimeters manufactured from
acrylamide (AA), and N,N’-methylene-bis-acrylamide (BIS) comonomers and gelatin
and agarose gelling agents. Increasing the monomer concentration is shown to
increase the CT-dose sensitivity, and replacing gelatin with agarose as the gelling
agent can further increase this. Dose resolution ( D∆95% ) was optimal for polymer gel
dosimeters comprising 1% agarose, 4% AA, 4% BIS and 91% water up to 3 Gy, and
5% gelatin, 6% AA, 6% BIS, and 89% water above 3 Gy. Noise can be decreased and
dose resolution improved by averaging several CT images together. It is also shown
that the primary cause of the change in linear attenuation coefficient is due to a
change in the physical density of the polymer gel dosimeter.