title: Evaluation of Imaging Dose From Different Image Guided Systems During Head and Neck Radiotherapy: A Phantom Study.
abstract: This work evaluated and compared the absorbed doses to selected organs in the head and neck region from the three image guided radiotherapy systems: cone-beam computed tomography (CBCT) and kilovoltage (kV) planar imaging using the On-board Imager® (OBI) as well as the ExacTrac® X-ray system, all available on the Varian Novalis TX linear accelerator. The head and neck region of an anthropomorphic phantom was used to simulate patients' head within the imaging field. Nanodots optically stimulated luminescent dosemeters were positioned at selected sites to measure the absorbed doses. CBCT was found to be delivering the highest dose to internal organs while OBI-2D gave the highest doses to the eye lenses. The setting of half-rotation in CBCT effectively reduces the dose to the eye lenses. Daily high-quality CBCT verification was found to increase the secondary cancer risk by 0.79%.
authors.affiliation: Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Chun Shing
authors.initials: CS
authors.lastname: Cheng
authors.affiliation: Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Wei Loong
authors.initials: WL
authors.lastname: Jong
authors.affiliation: Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Ngie Min
authors.initials: NM
authors.lastname: Ung
authors.affiliation: Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
authors.forename: Jeannie Hsiu Ding
authors.initials: JHD
authors.lastname: Wong
mesh_terms: D054893:Cone-Beam Computed Tomography; D006257:Head / Q000000981:diagnostic imaging; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D009333:Neck / Q000000981:diagnostic imaging; D010315:Particle Accelerators; D019047:Phantoms, Imaging; D061089:Radiotherapy, Image-Guided