Quality control of CT image using American College of Radiology (ACR) phantom

Abstract

Objective: To study image quality of CT scanner using the American College of Radiology (ACR) phantom. Material and methods: A multidetector CT scanner was used to measure parameters of image quality using ACR phantom. The phantom included four modules to measure these parameters. We obtained CT image for each module to measure these parameters for the brain protocol. Results: The acceptable levels of image quality were obtained for the positioning, CT number accuracy, slice thickness, low contrast resolution, uniformity and high contrast resolution tests that represent the parameters of image quality. In positioning test, the three BBs were visible. In CT number accuracy, the CT number of three materials was in the range of tolerance values unlike the bone value which was 846 HU. In low contrast resolution test the smallest contrast groups were seen. In High contrast resolution test the 5 lp/cm was visible. All these tests of image quality were accepted because they were within the tolerance values, so the quality of Philips CT scanner was improved. Ring artifact was indicated also, which is a type of scanner performance errors. Conclusions: Image quality tests are very important tests in acceptance of any CT scanner after installation and maintenance to approve that the image parameters are acceptable by using ACR phantom.

Keywords

• CT
• ACR phantom
• Image quality