AutoQA Plus CT
CT ACR 464 Gammex Phantom now included in the list of supported CT phantoms!
New Application Highlights
- Designed for simple and intuitive navigation
- Pass/Fail performance evaluation
- User can create Report Profiles to control Pass/Fail limits, output of images, overlays and graphs
- Instant trend analysis using our HTML ‘Trend Report Links’
- Reports available in HTML and PDF formats
- Support local date and number formats
- Multiple language support
- Simple database export to Excel
- Supports compressed and enhanced DICOM images
- Self-service option for offline license activation
Image Quality Parameters Evaluated
- Pixel size (geometric distortion)
- CT Number Linearity (Sensitometry)
- Slice Thickness
- Patient Alignment System and Table Movement Accuracy
- Spatial resolution (MTF)
- Image Uniformity and Noise
- Uniformity Index
- Contrast Detail (Low Contrast Detectability)
- Low Contrast - Contrast-to-noise ratio (CNR) (Catphan 600, 700)
- Slice Sensitivity Profile (SSP)
- Phantoms: Catphan CTP700, CTP605, CTP604, CTP600, CTP549(Catphan Lite), CTP500, CTP504(Varian), CTP503 (Elekta), CTP410, CTP411, CTP549, ACR CT 464 Gammex, water/uniformity phantoms of all diameters
AutoSelection Screen - One image per Catphan Phantom module section - Catphan 600 CTP528 two images selected - Resolution gauge and bead image 10 mm off axis from resolution gauge.
Standard Processing Features
- Pixel Size – verifies the expected pixel size using the measured distance between four pins (3 air, 1 Teflon) in Catphan® sections CTP401 and CTP404. Measurement not supported by Catphan 700.
- CT Linearity (Sensitometry) – A least squares fit for the mean CT numbers and the attenuation coefficients is calculated for 20 energies (40-140 keV), the keV with the minimum variance is selected as the effective beam energy.
- Slice Thickness – The full-width at half-maximum (FWHM) of the CT number profile for each wire or bead ramp is measured. A trigonometric conversion is calculated based on the known ramp angle to yield the slice thickness.
- Patient Alignment System and Table Movement Accuracy – assessed from the slice thickness opposing wire angled ramps. The slice thickness test outputs the Table Position Offset; the z-axis offset.
- Spatial Resolution (MTF) – The modulation transfer function (MTF) is calculated from the discrete Fourier transform of the average vertical and horizontal LSF’s of the point spread function for a wire or bead impulse source. The program reports the 50%, 10% and 2% MTF values.
- Image Uniformity and Noise – Uniformity is calculated from regions of interest (ROI) positioned over a uniformity phantom section. Five ROI’s are defined: one at the phantom center and the other four along the axes at the same radius. Uniformity is the maximum absolute difference between the center and peripheral ROI means. Noise is calculated from one centered ROI, 40% of the phantom diameter, following the IEC guidelines for noise.
- Uniformity Index– Vertical and horizontal profiles 10 pixels wide are generated passing through the phantom’s center. The fractional uniformity of the profile is calculated as the percentage of the pixels within an acceptable range determined by the mean + 2 times the central noise or + 10H, whichever is smaller.
- Contrast Detail (Low Contrast Detectability) – The Contrast-Detail curve data is calculated using the measured noise sampled at the center of the low contrast module (CTP263 or CTP515).
- Low Contrast - CNR measurements for the low contrast supra-slice targets (5-15mm) in the CTP515 module
- SSP (Slice sensitivity profile) - FWHM processing of an impulse source (bead) in a series of sequential axial or helical images
Trend Analysis Reports
- Auto populates the hospital names and CT serial numbers
- Provides a thumbnail list of all the unique data sets based on the scan parameters used for easy selection
- User defined baseline values by either selecting the option for averaging the first 5, 10 or manually select data records or entering an arbitrary baseline
- User selects tolerances from a list of operators; + %, + , >, <, =
- Trend graphs provided of key fields
- Exportable reports to Microsoft’s Excel including trend graphs
Trend Analysis - Click icon on HTML report positioned next to each CT linearity sample.
Software Version Notes
- TE DICOM tag parsing added when number of echoes DICOM tag is not found
- Added to MR Report profiles on/off control over low contrast and high contrast UI and output.
- Corrected Dutch regional settings/number formatting issues
- Addressed display scaling issues for CT and MR report profiles tab settings
- Support added for reading long file names
- Folders with more than 5000 files will no longer be sorted. Message displayed 5000 + more files found. This prevents system crash. User should change folder selected
- MTF report profile with a '0' cutoff value select will not report a measurement.
- CTP504 and 604 default report profile for the manual low contrast modified by turning on the image output and adds the CNR measurement as a pass/fail
- ACR CT phantom analysis supports patient orientation FFS (orientation 13)