Optimization of the collimator mask for the rotational modulation collimator-based gamma-ray/neutron dual-particle imager

다국어 초록 (Multilingual Abstract)

The purpose of this study is to optimize the collimator mask design for the rotational modulation collimator (RMC) imaging system. First, we optimized the slat and slit width of the collimator mask which affects the number of particles entering the detector and, thus, alters the morphology of modulation patterns. However, the conventional collimator mask design with bilateral symmetry posed an inherent ambiguity issue in the estimation of the source location in the reconstructed image. Therefore, we propose a new asymmetric collimator mask design which can solve the ambiguity problem for the development of the dual-particle imaging system.
Modulation patterns for various types of asymmetric mask designs were calculated with Monte Carlo simulations, and modulation and transmission efficiencies were compared with ones for the conventional RMC mask design to evaluate the nominal performance of the new mask designs. The proposed asymmetric collimator mask removed the ambiguous artifact from the reconstructed image without compromising transmission and modulation efficiencies. In addition, one can even expect to achieve better spatial resolution in the reconstructed image with the proposed new asymmetric mask design, as compared with the asymmetric mask design suggested from the previous study.

참고문헌 (Reference)

1 Hyun Suk Kim, "Radiation Imaging with a Rotational Modulation Collimator (RMC) Coupled to a Cs2LiYCl6:Ce (CLYC) Detector" 한국물리학회 69 (69): 1644-1650, 2016

2 T. Goorley, "Initial MCNP6 Release Overview" Informa UK Limited 180 (180): 298-315, 2017

3 B. Budden, "Image reconstruction with a LaBr3-based rotational modulator" Elsevier BV 652 (652): 610-614, 2011

4 Z. Wang, "Image Quality Assessment: From Error Visibility to Structural Similarity" Institute of Electrical and Electronics Engineers (IEEE) 13 (13): 600-612, 2004

5 R.C. Gonzalez, "Digital Image Processing" John Wiley and Sons, Inc 715-716, 2007

6 Amy C. Sharma, "Design and Development of a High-Energy Gamma Camera for Use With NSECT Imaging: Feasibility for Breast Imaging" Institute of Electrical and Electronics Engineers (IEEE) 54 (54): 1498-1505, 2007

7 김현숙, "Characterization of a CLYC Detector and Validation of the Monte Carlo Simulation by Measurement Experiments" 대한방사선방어학회 42 (42): 48-55, 2017

8 B.S. Budden, "Angular resolution obtained with a LaBr3-based rotational modulator" 7449 : 1-10, 2009

9 B.R. Kowash, "A unified near- and far-field imaging model for rotating modulation collimators" Elsevier BV 637 (637): 178-184, 2011

10 B.R. Kowash, "A rotating modulation imager for locating mid-range point sources" Elsevier BV 602 (602): 477-483, 2009

11 W.E. Althouse, "A balloon-borne imaging gamma-ray telescope" 3 : 299-302, 1985

12 H. S. Kim, "A Monte Carlo simulation study for the gamma-ray/neutron dual-particle imager using rotational modulation collimator(RMC)" 38 : 299-399, 2018