Deprecated ‐ Configuration parameter definitions - xcist/documentation GitHub Wiki

Simulation experiments are defined by five configuration files

• Scanner_name.cfg : configuration file that defines the scanner itself, including the geometry and some inherent parameters of the particular scanner
• Phantom_name.cfg : configuration file that defines the phantom to be ‘scanned’
• Protocol_name.cfg : configuration file that defines the scan protocol, including scan technique, spectrum, filtration, etc.
• Physics_name.cfg : configuration file that defines the simulation-level parameters that determine the accuracy at which the simulation is performed
• Recon_name.cfg : configuration file that defines the reconstruction parameters

We recommend to stick to these configuration filename conventions and parameter grouping. This will allow for easily mix-and-matching phantoms, scanner models, etc.

The specific configuration parameters include :

• Scanner geometry
  scanner.detectorCallback = “Detector_ThirdgenCurved” # name of function that defines the detector shape and model
  scanner.sid = 540.0 # source-to-iso distance (mm)
  scanner.sdd = 950.0 # source-to-detector distance (mm)
  scanner.detectorColsPerMod = 1 # number of detector columns per module
  scanner.detectorRowsPerMod = 16 # number of detector rows per module
  scanner.detectorColOffset = 0.0 # detector column offset relative to centered position (in detector columns)
  scanner.detectorRowOffset = 0.0 # detector row offset relative to centered position (in detector rows)
  scanner.detectorColSize = 1.0 # detector column pitch or size (mm)
  scanner.detectorRowSize = 1.0 # detector row pitch or size (mm)
  scanner.detectorColCount = 900 # total number of detector columns
  scanner.detectorRowCount = scanner.detectorRowsPerMod # total number of detector rows
  scanner.detectorPrefilter = [‘Al’, 0.1, ‘water’, 2] # material file name(s) and material thickness(es) (mm)

• X-ray tube
  scanner.focalspotCallback = “Source_Uniform” # name of function that defines the focal spot shape and model
  scanner.targetAngle = 7.0 # target angle relative to scanner XY-plane (in degrees)
  scanner.focalspotWidth = 1.0
  scanner.focalspotLength = 1.0

• Detector
  scanner.detectorMaterial = “Lumex” # detector sensor material
  scanner.detectorDepth = 3.0 # detector sensor depth (mm)
  scanner.detectionCallback = “Detection_EI” # name of function that defines the detection process (conversion from X-rays to detector signal)
  scanner.detectionGain = 15.0 # factor to convert energy to electrons (electrons / keV)
  scanner.detectorColFillFraction = 0.9 # active fraction of each detector cell in the column direction
  scanner.detectorRowFillFraction = 0.9 # active fraction of each detector cell in the row direction
  scanner.eNoise = 5000.0 # standard deviation of Gaussian electronic noise (in electrons)

• Photon counting CT
  scanner.detectorMaterial = “CZT” # detector sensor material
  scanner.detectorDepth = 1.6 # detector sensor depth (in mm)
  scanner.detectionCallback = “Detection_PC” # name of function that defines the detection process (conversion from X-rays to detector signal)
  scanner.detectionResponseFilename = ‘PC_spectral_response_CZT0.25×0.25×1.6.mat’ # name of the response data file
  scanner.detectorBinThreshold = [20, 30, 40, 60, 80, 100, 160] # energy thresholds (keV), n bins has n+1 thresholds; the first and last are the min and max energy thresholds.
  scanner.detectorSumBins = 0 # 1: sum all bins (gray scale output), data dim [view row col]; 0: output multiple bins [view row col bin]

• simulations sequence
  protocol.scanTypes = [1, 1, 1] # flags for airscan, offset scan, phantom scan

• Table and gantry
  protocol.scanTrajectory = “Gantry_Helical” # name of the function that defines the scanning trajectory and model
  protocol.viewsPerRotation = 1000 # total numbers of view per rotation
  protocol.viewCount = 1000 # total number of views in scan
  protocol.startViewId = 0 # index of the first view in the scan
  protocol.stopViewId = protocol.startViewId+protocol.viewCount-1 # index of the last view in the scan
  protocol.airViewCount = 1 # number of views averaged for air scan
  protocol.offsetViewCount = 1 # number of views averaged for offset scan
  protocol.rotationTime = 1.0 # gantry rotation period (in seconds)
  protocol.rotationDirection = 1 # gantry rotation direction (1=CW, -1 CCW, seen from table foot-end)
  protocol.startAngle = 0 # relative to vertical y-axis (n degrees)
  protocol.tableSpeed = 0 # speed of table translation along positive z-axis (mm/sec)
  protocol.startZ = 0 # start z-position of table
  protocol.tiltAngle = 0 # gantry tilt angle towards negative z-axis (in degrees)
  protocol.wobbleDistance = 0.0 # focalspot wobble distance
  protocol.focalspotOffset = [0, 0, 0] # focalspot position offset

• X-ray tube technique and filtration
  protocol.mA = 200 # tube current (in mA)
  protocol.spectrumCallback = “Spectrum” # name of function that reads and models the X-ray spectrum
  protocol.spectrumFilename = “tungsten_tar7_120_filt.dat” # name of the spectrum file
  protocol.spectrumScaling = 1 # scaling factor such that spectrum is in photons / mA / s / mm^2 at 1000 mm
  protocol.bowtie = “medium” # name of the bowtie file (or [])
  protocol.filterCallback = “Xray_Filter” # name of function to compute additional filtration
  protocol.flatFilter = [‘Al’,0.1] # additional filtration – materials and thicknesses (mm)
  protocol.dutyRatio = 1.0 # tube ON time fraction (for pulsed tubes)

• Phantom
  phantom.callback = “Phantom_Voxelized” # name of function that reads and models phantom
  phantom.projectorCallback = “C_Projector_Voxelized” # name of function that performs projection through phantom
  phantom.filename = ‘BIG.json’ # phantom filename
  phantom.centerOffset = [0, 0, 0] # offset of phantom center relative to origin (mm)

• Geometric and energy sampling
  physics.energyCount = 12
  physics.monochromatic = -1 # monochromatic energy in kVp. if negative, means polychromatic.
  physics.colSampleCount = 2
  physics.rowSampleCount = 2
  physics.srcXSampleCount = 2
  physics.srcYSampleCount = 2
  physics.viewSampleCount = 2

• Flags to determine what has to be recalculated each view
  physics.recalcDet = 0
  physics.recalcSrc = 0
  physics.recalcRayAngle = 0
  physics.recalcSpec = 0
  physics.recalcFilt = 0
  physics.recalcFlux = 0
  physics.recalcPht = 0
  physics.recalcDet = 0

• Noise on/off settings
  physics.enableQuantumNoise = 1
  physics.enableElectronicNoise = 1

• Internal physics models
  physics.rayAngleCallback = “Detector_RayAngles_2D”
  physics.fluxCallback = “Detection_Flux”
  physics.scatterCallback = ""
  physics.prefilterCallback = “Detection_prefilter”
  physics.crosstalkCallback = ""
  physics.lagCallback = ""
  physics.opticalCrosstalkCallback = ""
  physics.DASCallback = “Detection_DAS”

• I/O preferences
  physics.outputCallback = “WriteRawView”

• Reconstruction
  recon.fov = 500.0 # diameter of the reconstruction field-of-view (mm)
  recon.imageSize = 512 # number of columns and rows to be reconstructed (square)
  recon.sliceCount = 1 # number of slices to reconstruct
  recon.sliceThickness = 1.0 # reconstruction inter-slice interval (mm)
  recon.centerOffset = [0.0,0.0,0.0] # reconstruction offset relative to center of rotation (mm)