Novel materials for low-contrast phantoms for computed tomography

Article type: Research Article

Authors: Allert, Keana D. | Vangala, Sravanthi | DiBianca, Frank A.

Affiliations: Department of BioImaging, College of Health Science Engineering, The University of Tennessee Health Science Center, 920 Madison Avenue, Suite 1005, Memphis, TN 38163, USA

Note: [] Corresponding author. Tel.: +1 901 448 7099; Fax: +1 901 448 7387; E-mail: [email protected]

Abstract: Acceptance testing and quality control of computed tomography (CT) scanners are of great importance. While most procedures and phantoms for testing other parameters are widely accepted, there is still discussion and uncertainty about low-contrast (LC) performance tests that measure the capability of a CT scanner to discriminate low-contrast objects. This work investigated the development of LC phantoms with available, low-cost polystyrene resin materials and some selected additives. We designed and tested phantoms with several different contrast steps by generating contrast in two different ways, one based on 'physical density difference' and the other on 'atomic number difference'. Physical density difference was achieved by adding a small amount of glycerin to the polystyrene resin, both having similar low atomic-number elements but differing in the density of their atoms. Atomic number difference was achieved by adding a small amount of iodobenzene to the resin, both having approximately the same physical density (less than 1% variation in density) but different atomic (i.e., elemental) composition. Prototypes were evaluated using a Philips Tomoscan LX system and varying beam properties. The behavior and validity of the results are discussed.

Keywords: Computed tomography, contrast, low-contrast performance, phantoms, atomic number, density

Journal: Journal of X-Ray Science and Technology, vol. 15, no. 1, pp. 9-18, 2007