title: Image reconstruction of optical computed tomography by using the algebraic reconstruction technique for dose readouts of polymer gel dosimeters.
abstract: Optical computed tomography (optical CT) has been proven to be a useful tool for dose readouts of polymer gel dosimeters. In this study, the algebraic reconstruction technique (ART) for image reconstruction of gel dosimeters was used to improve the image quality of optical CT. Cylindrical phantoms filled with N-isopropyl-acrylamide polymer gels were irradiated using a medical linear accelerator. A circular dose distribution and a hexagonal dose distribution were produced by applying the VMAT technique and the six-field dose delivery, respectively. The phantoms were scanned using optical CT, and the images were reconstructed using the filtered back-projection (FBP) algorithm and the ART. For the circular dose distribution, the ART successfully reduced the ring artifacts and noise in the reconstructed image. For the hexagonal dose distribution, the ART reduced the hot spots at the entrances of the beams and increased the dose uniformity in the central region. Within 50% isodose line, the gamma pass rates for the 2 mm/3% criteria for the ART and FBP were 99.2% and 88.1%, respectively. The ART could be used for the reconstruction of optical CT images to improve image quality and provide accurate dose conversion for polymer gel dosimeters.
authors.affiliation: National Tsing Hua University, Department of Biomedical Engineering and Environmental Sciences, No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan.
authors.forename: Cheng-Ting
authors.initials: CT
authors.lastname: Shih
authors.affiliation: Central Taiwan University of Science and Technology, Department of Management Information Systems, No. 666, Buzih Road, Beitun District, Taichung, Taiwan.
authors.forename: Yuan-Jen
authors.initials: YJ
authors.lastname: Chang
authors.affiliation: China Medical University, School of Dentistry, No. 91, Hsueh-Shih Road, Taichung, Taiwan.
authors.forename: Jui-Ting
authors.initials: JT
authors.lastname: Hsu
authors.affiliation: National Tsing Hua University, Department of Biomedical Engineering and Environmental Sciences, No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan.
authors.forename: Keh-Shih
authors.initials: KS
authors.lastname: Chuang
authors.affiliation: Atomic Energy Council, Institute of Nuclear Energy Research, Health Physics Division, No. 1000, Wenhua Road, Jiaan Village, Longtan Township, Taoyuan, Taiwan.
authors.forename: Shu-Jun
authors.initials: SJ
authors.lastname: Chang
authors.affiliation: National Yang-Ming University, Department of Biomedical Imaging and Radiological Sciences, No. 155, Sec. 2, Linong Street, Taipei, Taiwan. Electronic address: iamjaywu@gmail.com.
authors.forename: Jay
authors.initials: J
authors.lastname: Wu
mesh_terms: D000465:Algorithms; D005782:Gels; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D011829:Radiation Dosage; D011874:Radiometry; D014057:Tomography, X-Ray Computed
chemical_list: D005782:Gels; D011108:Polymers
keywords: Algebraic reconstruction technique; Optical computed tomography; Polymer gel dosimeter