Development of image quality measurement methods for nonlinear CT images, and elucidation of iterative reconstruction methods and their realities.

2014 Fiscal Year Final Research Report

• Project/Area Number: 24601003
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: 医学物理学・放射線技術学
• Research Institution: Tohoku University
• Principal Investigator: MORI Issei 東北大学, 医学(系)研究科(研究院), 大学院非常勤講師 (90375171)
• Co-Investigator(Kenkyū-buntansha): MACHIDA Yoshio 東北大学, 大学院医学系研究科, 教授 (30507083)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 医用画像工学 / Ｘ線ＣＴ

Outline of Final Research Achievements

The most important agenda of X-ray CT is its radiation dose. All CT manufactures are concentrating their effort to develop and refine iterative reconstruction methods (IR type reconstruction). By use of IR, it is claimed to achieve lower noise (i.e. lower dose) while maintaining high resolution. Many reports which are supportive to this view are incessantly published.
However, images by IR type method behave non-linearly. Ordinary image quality indexes presuppose linearity of image. Applying them to nonlinear images without extreme care will fall into serious errors. We developed proper measurement methods so that ordinary image quality indexes can be applicable to nonlinear images. Using our methods, we shed light on pitfalls of image quality measurement for nonlinear images. We have confirmed that there is no net gain of image quality at least for some type of IR method. Through our many lectures, our view is now shared to some extend by researchers in this field.

Free Research Field

医歯薬学