DigRad

The DigRad module (Fig. 19) can be used to generate new detector modells for a CR (Computed Radiography) system or a DDA (Digital Detector Array). The DigRad module is a simplified detector model compared to the model used in the DetectorCalc module. The input parameters are related to the standards for detector characterisation (ASTM E 2446-16 Standard Practice for Manufacturing Characterization of Computed Radiography Systems, ASTM E 2597-22 Standard Practice for Manufacturing Characterization of Digital Detector Arrays, and DIN EN ISO 16371-1:2011 Non-destructive testing - Industrial computed radiography with storage phosphor imaging plates - Part 1: Classification of systems).

DigRad calculator

Fig. 19 DigRad calculator.

  • Pixel size (mm) to set the pixel size of the detector.

  • Basic spatial resolution SRb (mm) to set the basic spatial resolution (SRb) of the detector, measured according to ASTM E 2002-22 Standard Practice for Determining Image Unsharpness and Basic Spatial Resolution in Radiography and Radioscopy or DIN EN ISO 19232-5:2018 Non-destructive testing - Image quality of radiographs - Part 5: Determination of the image unsharpness and basic spatial resolution value using duplex wire-type image quality indicators.

Note

The basic spatial resolution (SRb) of an X-ray detector is typically larger than the pixel size, but never smaller. The detector unsharpeness value is the double of the SRb measuered according to ASTM E 2002-22.

  • Internal scatter radiation ISR (%) to set the internal scatter radiation ISR (%) describing the scattered radiation contribution generated within the detector. The percentage can be determined from an edge profile (Fig. 20).

  • ISR correlation length (mm) to set the the ISR correlation length which describes the mean internal extension of the scattered radiation generated within the detector applying only for imaging plates and flat panel detectors. The ISR correlation length of the detector can be determined from an edge profile (Fig. 20).

Note

Two times the ISR correlation length gives the long range unsharpness of the aRTist detector model.

  • Gray response (GV/mGy) to set the gray response given in GV/mGy, i.e., the increase in gray values for a dose increase of 1 mGy.

  • SNRn,max to set the maximum normalilzed signal to noise ratio as limited by the detector correction image.

  • Efficiency (SNRn/mGy^0.5) to set the normalized SNR of the detector output at 1 mGy dose input.

Edge profile indicating internal scatter radiation

Fig. 20 Edge profile indicating internal scattered radiation. Simulation of an edge penetration with a DigRad detector model with 5 % ISR and 5 mm correlation length. Right: Edge profile with reading of the ISR measurands (ISR = (2 * a / b) * 100 %; ISR correlation length = c).