Program Information
Simulation Study for Removing Scatter Radiation in Cesium-Iodine Based Flat Panel Detector System
Y Yoon1*, M Park2 , H Kim3, 4 , K Kim4 , J Kim4 , J Morishita5 , (1) Department of Health sciences, Graduate school of Medical sciences, Kyushu University, Fukuoka, Japan (2) Radiation Safety & Section, Korea Institute of Radiological and Medical Sciences, Seoul, Korea (3) Medical Radiation TF, Center for Disease Prevention, Korea Centers for Disease Control & Prevention, Cheongju, Chungchongbuk-do, Korea, (4) School of Health and Environmental Science, Korea University, Seoul, Korea (5) Department of Health sciences, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
Presentations
SU-E-I-49 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: This study aims to identify the feasibility of a novel cesium-iodine (CsI)-based flat-panel detector (FPD) for removing scatter radiation in diagnostic radiology.
Methods: The indirect FPD comprises three layers: a substrate, scintillation, and thin-film-transistor (TFT) layer. The TFT layer has a matrix structure with pixels. There are ineffective dimensions on the TFT layer, such as the voltage and data lines; therefore, we devised a new FPD system having net-like lead in the substrate layer, matching the ineffective area, to block the scatter radiation so that only primary X-rays could reach the effective dimension.
To evaluate the performance of this new FPD system, we conducted a Monte Carlo simulation using MCNPX 2.6.0 software. Scatter fractions (SFs) were acquired using no grid, a parallel grid (8:1 grid ratio), and the new system, and the performances were compared.
Two systems having different thicknesses of lead in the substrate layer—10 and 20μm—were simulated. Additionally, we examined the effects of different pixel sizes (153Χ153 and 163Χ163μm) on the image quality, while keeping the effective area of pixels constant (143Χ143μm).
Results: In case of 10μm lead, the SFs of the new system (~11%) were lower than those of the other system (~27% with no grid, ~16% with parallel grid) at 40kV. However, as the tube voltage increased, the SF of new system (~19%) was higher than that of parallel grid (~18%) at 120kV. In the case of 20μm lead, the SFs of the new system were lower than those of the other systems at all ranges of the tube voltage (40–120kV).
Conclusion: The novel CsI-based FPD system for removing scatter radiation is feasible for improving the image contrast but must be optimized with respect to the lead thickness, considering the system’s purposes and the ranges of the tube voltage in diagnostic radiology.
Funding Support, Disclosures, and Conflict of Interest: This study was supported by a grant(K1422651) from Institute of Health Science, Korea University.
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