AAPM-CT Performance Phantom

The increasing use of computed tomography (CT) as a diagnostic tool creates the need for an efficient means of evaluating the performance of the CT scanners now in use. Recognizing

this requirement, the American Association of Physicists in Medicine established the AAPM Task Force on CT Scanner Phantoms. Its goals are to define CT scanner performance and present practical methods of performance testing through the utilization of special phantoms.

This phantom design is based on the guidelines presented in Report #1 of the Task Force and approved by the AAPM. The modular 76-410-4130 AAPM CT Performance Phantom offers the CT user a single system with which to measure nine performance parameters. This phantom permits the routine standardization of alignment, beam width, spatial uniformity, linearity/contrast, spatial resolution, line spread, noise, size independence, and absorbed dose. All components of the phantom are housed in a compact, transparent tank that holds the system

together in the correct orientation.

The phantom consists of an 8.5-inch diameter acrylic tank containing a beam-width insert, a spatial resolution and linespread block, a high-contrast insert, and a means for inserting alignment

pins and/or TLD holders. Additionally, a 0.25-inch thick Teflon® band, positioned at the base of the tank and concentric to the 8-inch internal diameter, simulates human bone. Attached to the base of the tank is a low-contrast section with resealable cavities (from 1 in to 0.125 in diameter) which can be filled with a diluted dextrose or other appropriate solution to provide a low-contrast media. The optional external resolution and noise ring slides snugly over the outside diameter of the tank, allowing whole-body scanner systems to be evaluated.