Reationship between image quality and exposure dose in chest X-ray CT

2014 Fiscal Year Final Research Report

• Project/Area Number: 24601010
• 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: Nagoya University
• Principal Investigator: IKEDA MITSURU 名古屋大学, 医学(系)研究科(研究院), 教授 (50184437)
• Co-Investigator(Kenkyū-buntansha): IMAI Kuniharu 名古屋大学, 大学院医学系研究科, 教授 (20335053) ; KAWAURA Chiyo 名古屋大学, 大学院医学系研究科, 助教 (60324422)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: X線CTの画質評価 / X線CTの被ばく線量

Outline of Final Research Achievements

We have derived the approximated analytical relationship between MTF and NPS, and have confirmed that the accuracy of this relationship is rather high expect for the low and high spatial frequency region. We have devised the analytical expression of noise SD of each pixel in a CT image reconstructed by the filtered back projection method and the estimation method of the absorbed dose for each pixel from the successive difference of numbers of photons penetrating along each X-ray path line; their accuracies have been shown to be are relatively high through simulation and measurements. We also showed that the CT image noise in a soft tissue region with a sufficiently large size was almost normally distributed. Results of this study indicate that, under an ideal condition, the absorption dose for each pixel of a CT image can be estimated from its noise SD.

Free Research Field

医用画像工学