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The correct position to determine the image quality indicators (IQIs)

In this article:
  • IQIs Should Be Placed on the Source Side for Accurate Sharpness Evaluation: To effectively assess geometric unsharpness and radiographic image quality, image quality indicators (IQIs) must be positioned on the source side of the object being examined
  • Film-Side Placement Is a Secondary Option: If source-side placement is not feasible, IQIs may be placed on the film side, but this must be clearly marked with a lead letter “F” to indicate the alternate positioning
  • Source-Side Placement Reflects True Imaging Conditions: Only source-side IQI placement allows for accurate evaluation of beam penetration, contrast, and resolution, which are critical for flaw detection and compliance with standards
  • Film-Side IQIs Still Validate Exposure and Processing: While not suitable for assessing geometric unsharpness, film-side IQIs can still confirm proper exposure settings and development quality
  • Correct IQI Positioning Is Mandated by Industry Codes: International standards and radiographic testing codes universally recommend source-side IQI placement to ensure consistent, high-quality inspection results

To be of any value in checking the factors defining sharpness and quality, the IQI must be placed on the source side of the specimen. If the source side is not accessible, the IQI is placed on the film side. In the latter position visibility is no longer an indication of geometric unsharpness, but still a check on the developing process and radiation energy used.

What are common image quality indicators (IQIs)?