Development of a quality assurance scattering phantom for cone beam optical CT

Standard water-based acrylic emulsion scattering solutions have been developed for use in optical scattering gel phantoms. These solutions display good uniformity and long term stability, and can be index matched to polymer gels through the addition of propylene glycol or molten gelatin. Preliminary quality assurance (QA) performed on the Vista cone beam optical computed tomography (OptCT) scanner (Modus Medical, London, ON) using these standard scattering solutions provides valuable information toward the establishment of protocols for scanner warm-up and dosimeter/bath temperature control. A characterization of Vista scanner response over a range of scattering concentrations indicates that improved dosimeter performance may be realized through lowering the %T concentration of the polymer gel into the linear response range of the scanner A gel molding process has been developed for these scattering solutions, with promising results obtained for early stage scattering gel phantoms.