Features:

• DICOM Compatible.

• Graphical Result Screens

• Summary Report

• Database File Output Results

• Provides for Variations in Phantom Configurations and Physical Tests.

• System Adaptable to the Catphan^(R) Phantom.

• Monitors System Performance and Service Delivery.

• Helps Fulfill Regulatory Requirements.

Spatial Resolution Modulation Transfer Function (MTF):
The MTF is calculated from the discrete Fourier Transform of the average vertical and horizontal Line Spread Function (LSF's) of the point spread function from a scan of a bead object or wire. The program reports the 50%, 10% and cutoff MTF values.

Noise-Mean CT:
The mean and standard deviation (noise) is calculated from several Regions of Interest (ROI's) positioned over the uniformity image section.

Linearity:
The program computes the CT values for each reference material contained in the phantom test section. The contrast scale is determined for a linear least squares fit relating CT number and attenuation coefficients.

Pixel Size:
The Pixel size is determined from a set of four "calibration pins" at a known physical location whereby the size of a pixel can be calculated for the x and y directions.

Slice Width:
This test determines the average FWHM of the CT number profile for each wire ramp present. A trigonometric conversion is calculated based on the known ramp angle to yield the slice width. When the ramps are pairs of opposing angles, the phantom off-set (z-axis) can be determined. This verifies the accuracy of the patient localizer scan and table incrementation.

Uniformity:
Vertical and horizontal profiles are generated through the phantom's center. The fractional uniformity is calculated as the percentage of the profile pixels within an acceptable range determined by +/-2 times the central noise or +/-10 H whichever is smaller.

Contrast Detail:
A theoretical Contrast-Detail Curve is calculated based on the measured noise of the uniformity image. This represents a conservative estimate of the minimum contrast level required so that a cylindrical object of the given diameter should be detected.

System Requirements:

The system requirements for the IRIS, Inc software packages are as follows:

Pentium Processor
3.5" HD Floppy Drive
DICOM Supported System:Network Interface
Windows 95 Required
Interfaces for Non-DICOM Systems Available