Standards Development

Scope

This standard applies to CT SCANNERS which can provide dual or multi-energy imaging. Where applicable, it also applies to associated workstation software to generate spectral images, provided with the CT SCANNER. This standard is not intended to apply to workstations that are not supplied with the CT SCANNER.

NOTE 1: the 3rd party SW manufactures will be invited and discuss applicability during the drafting phase.

The purpose of this standard is to provide methods and metrics for imaging performance with spectral image type, e.g. virtual monoenergetic image, materi al differentiation image, material quantifications and material identification images.

NOTE 2: Where applicable, these methods may include conventional image quality metrics such as noise, HU value, homogeneity, spatial resolution and low contrast resolut ion for CT Spectral Imaging.

NOTE 3: The results obtained using the methods of this standard do not replace spectral
performance specifications and testing protocols as defined by the CT SCANNER manufacturer.

Additionally, standardized phantom requirements are specified accordingly

Purpose

With the development of Computed Tomography (CT) technology, CT Spectral Imaging and corresponding applications have been already widely introduced as common functionalities for CT products from nearly all manufactures. With current available CT Spectral I maging techniques, data contains attenuation properties under different energy/spectrum can be acquired. Together with special image reconstruction or processing procedure, images which reflects material composition correspondingly can be obtained to enable certain application purpose.

Over the last years CT Spectral Imaging has increasingly been included into clinical routine application.

However, there are still no standardized methods and metrics to characterize performance of CT Spectral Imaging across different realization technologies and differences in CT system/component.

Prior to specifying performance requirements and/or quality acceptance criteria, the methods and metrics need to be defined and standardized, which is the purpose of this standard.

From CT standardization point of view, it will be necessary to establish standardized procedure to provide further consensus as international standard, by covering aspects as:

- The applicability for traditional metrics like image noise, HU value ac curacy or Homogeneity need to be clarified for dedicated image type.

- Methodologies to evaluate performance of special CT images types correlated with spectral imaging, e.g. Material Concentration Images or Virtual Monoenergetic Images

Corresponding terms, definitions and mythologies have be also summarized by either work from well accepted standardization documents (DICOM 188 supplement), or academic literature (e.g. AAPM TG 291), which could be taken into account in proposed IEC standard.