Standard Practice for Direct Determination of Computed Tomography (CT) Detail Detection Sensitivity and Calculation of Numerical Detection Limit

Importancia y uso:

5.1 This practice provides instructions for determining the detail detection sensitivity (DDS) and its numerical limit, DDS_Limit, in X-ray computed tomography (CT) volumes from disk IQIs. DDS, along with modulation transfer function (MTF), contrast discrimination function (CDF), and contrast-detail-diagram (CDD), provides a way to determine the image quality in a reconstructed CT slice. See Test Method E1695 for a detailed description to measure and numerically evaluate MTF and CDF, and to document the result. See Guide E1441 for a detailed description of CDD.

5.2 DDS, along with Test Method E1695 MTF and CDF, and the derived DDS_Limit enable evaluation of the performance and image quality of CT systems at the CT settings selected for the examination. These values are used to verify CT system performance and monitor long-term stability of CT systems related to the CT settings.

Note 1: In a CT application, image quality can be affected by setup parameters and other circumstances. Some examples include image artifacts, position of flaws within the examination object, external factors (monitor quality, lighting, digital image format), human factors, and software performance, such as reconstruction, filters, and others. More application-oriented tests of image quality may be conducted using RQIs; see Practice E1817.

Subcomité:

E07.01

Volúmen:

03.04

Palabras clave:

computed tomography; contrast discrimination function; contrast sensitivity; CT; detail detection sensitivity; geometrical unsharpness; modulation transfer function; spatial resolution;