Reconstructing 3D x-ray CT images of polymer gel dosimeters using the zero-scan method

7th International Conference on 3D Radiation Dosimetry

Kakakhel, M.B.^1,3 ; Kairn, T.^1,2 ; Kenny, J.^2 ; Trapp, J.V.^1

School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, GPO Box2434, Brisbane, QLD 4001, Australia^1

Premion Cancer Care, Wesley Medical Centre, 40 Chasely St, Auchenflower, QLD 4066, Australia^2

Department of Physics and Applied Mathematics, DPAM, Pakistan Institute of Engineering and Applied Sciences, PO Nilore, Islamabad 45650, Pakistan^3

关键词: Dose distributions;    Extrapolation methods;    Hounsfield units;    Important features;    Longitudinal direction;    Polymer gel dosimeter;    Slice thickness;    Spatial resolution;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/444/1/012091/pdf
DOI  :  10.1088/1742-6596/444/1/012091

来源: IOP

【 摘 要 】

In this study x-ray CT has been used to produce a 3D image of an irradiated PAGAT gel sample, with noise-reduction achieved using the 'zero-scan' method. The gel was repeatedly CT scanned and a linear fit to the varying Hounsfield unit of each pixel in the 3D volume was evaluated across the repeated scans, allowing a zero-scan extrapolation of the image to be obtained. To minimise heating of the CT scanner's x-ray tube, this study used a large slice thickness (1 cm), to provide image slices across the irradiated region of the gel, and a relatively small number of CT scans (63), to extrapolate the zero-scan image. The resulting set of transverse images shows reduced noise compared to images from the initial CT scan of the gel, without being degraded by the additional radiation dose delivered to the gel during the repeated scanning. The full, 3D image of the gel has a low spatial resolution in the longitudinal direction, due to the selected scan parameters. Nonetheless, important features of the dose distribution are apparent in the 3D x-ray CT scan of the gel. The results of this study demonstrate that the zero-scan extrapolation method can be applied to the reconstruction of multiple x-ray CT slices, to provide useful 2D and 3D images of irradiated dosimetry gels.