Background: Estimation of eye lens dose is important in head computed tomography (CT) examination since the eye lens is a sensitive organ to ionizing radiation.
Objective: The purpose of this study is to compare estimations of eye lens dose in head CT examinations using local size-specific dose estimate (SSDE) based on size-conversion factors of the American Association of Physicists in Medicine (AAPM) Report No. 293 with those based on size-conversion factors of the AAPM Report No. 220.
Material And Methods: This experimental study is conducted on a group of patients who had undergone nasopharyngeal CT examination. Due to the longitudinal (-axis) dose fluctuation, the average global SSDE and average local SSDE (i.e. particular slices where the eyes are located) were investigated. All estimates were compared to the measurement results using thermo-luminescent dosimeters (TLDs). The estimated and measured doses were implemented for 14 patients undergoing nasopharyngeal CT examination.
Results: It was found that the percentage differences of the volume CT dose index (CTDI), average global SSDE based on AAPM No. 220 (SSDE), average local SSDE based on AAPM No. 220 (SSDE), average global SSDE based on AAPM No. 293 (SSDE) and average local SSDE based on AAPM No. 293 (SSDE) against the measured TLD doses were 22.5, 21.7, 15.0, 9.3, and 2.1%, respectively. All comparisons between dose estimates and TLD measurements gave -values less than 0.001, except for SSDE (-value = 0.566).
Conclusion: SSDE based on AAPM Report No. 293 can be used to accurately estimate eye lens radiation doses by performing the calculations on a number of specific slices containing the eyes.
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http://dx.doi.org/10.31661/jbpe.v0i0.2104-1304 | DOI Listing |
J Contemp Brachytherapy
June 2024
Department of Medical Physics, German Oncology Center, University Hospital of the European University, Limassol, Cyprus.
Purpose: The aim of this study was a retrospective dosimetric comparison of iridium-192 (Ir) high-dose-rate (HDR) interstitial brachytherapy plans using model-based dose calculation algorithm (MBDCA) following TG-186 recommendations and TG-43 dosimetry protocol for breast, head-and-neck, and lung patient cohorts, with various treatment concepts and prescriptions.
Material And Methods: In this study, 59 interstitial Ir HDR brachytherapy cases treated in our center (22 breast, 22 head and neck, and 15 lung) were retrospectively selected and re-calculated with TG-43 dosimetry protocol as well as with Acuros BV dose calculation algorithm, with dose to medium option based on computed tomography images. Treatment planning dose volume parameter differences were determined and their significance was assessed.
J Appl Clin Med Phys
November 2024
Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia.
Purpose: The aim was to develop and evaluate an EPID-based MLC positional test that addresses known weaknesses of the picket fence test and has sufficient accuracy so that the AAPM MPPG 8.b. MLC position action limit of ± 0.
View Article and Find Full Text PDFRadiography (Lond)
November 2024
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Kampus UI Depok 16424, Indonesia; Radiology Unit, Universitas Indonesia Hospital, Kampus UI Depok 16424, Indonesia. Electronic address:
Introduction: American Association of Physicists in Medicine (AAPM) Task Group (TG) 238 provides guidance on quality control procedures to ensuring optimal three-dimensional rotational angiography (3DRA) image quality. The uniformity test outlined in this guideline utilizes a sampling method, which provide limited information on image uniformity and has been found to be a sub-optimum predictor of image quality issues. Despite this limitation, numerous automated quality control software solutions for uniformity testing have been developed using the available method.
View Article and Find Full Text PDFJ Med Phys
September 2024
Department of Biomedical Imaging, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Malaysia.
Background And Purpose: Size-specific dose estimates (SSDE) have been introduced into computed tomography (CT) dosimetry to tailor patients' unique sizes to facilitate accurate CT radiation dose quantification and optimization. The purpose of this study was to develop and validate an automated algorithm for the determination of patient size (effective diameter) and SSDE.
Materials And Methods: A MATLAB platform was used to develop software of algorithms based on image segmentation techniques to automate the calculation of patient size and SSDE.
Med Phys
January 2025
UC Davis Medical Center, Sacramento, California, USA.
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