Program Information
Quantitative Research in the Quality of X-Ray Image and Amount of Radiation in Accordance with Grid Specification for Selecting An Optimal Grid
S Lee*, W Chung , Y Kang , J Jung , JPI Healthcare Co.,Ltd., Ansan-si, Gyeonggi-do
Presentations
SU-I-GPD-I-6 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: A grid prevents X-ray images from fogging by removing scattered X-rays which can be generated when X-rays penetrate through a body. The improvement effectiveness of a grid is dependent on the line density and ratio of a grid. In this paper, we analyze quantitatively the degree of image improvement and the decreased amount of absorbed radiation to a detector in accordance with grid specification.
Methods: We acquired X-ray images and measured amount of absorbed radiations with two phantoms, the Primus L and the X-ray test pattern, piling up 20cm thickness PMMA which is able to generate scattered X-rays similar to abdomen. In the image improvement effectiveness analysis, firstly, we measured contrast and SNR of ROI in Primus L images. Secondly, we measured MTF by using profiles of ROIs extracted from specific spatial resolutions (LP/mm) in X-ray test pattern images. Finally, we measured amount of absorbed radiations in each image’s radiation conditions, respectively. Based on the non-grid image condition, we compared measured values by changing exposure conditions adjusted to each grid.
Results: Level of image improvement effectiveness and amount of absorbed radiations in accordance with grid were increased at contrast (25%~40%), SNR (30%~100%), and MTF (11%~19%) compare to the non-grid conditions. In contrast, amount of absorbed radiations to detector were decreased (67%~77%).
Conclusion: In this research, we have quantitatively analyzed the variation of X-ray image and amount of absorbed radiation in accordance with grid specification to select an optimal grid in DR system. In results, the grid ratio have direct proportional relationship to contrast, SNR, and MTF. However, it have inverse proportional relationship to the amount of absorbed radiations. Therefore, high ratio grids are recommended when subjects have much scattered rays such as chest and abdomen. For organs to dose (e.g. breast) low ratio grids are recommended.
Funding Support, Disclosures, and Conflict of Interest: JPI Healthcare, Co., Ltd.
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