Standards for x-ray computed tomography

The objective of this project is to create low cost standards for use in x-ray computed tomography (CT) in medicine with emphasis on lung studies. Typically, CT images made of a patient are calibrated daily. However, due to the large variety of vendors with different hardware and software in a rapidly evolving field, it is not always possible to have meaningful time sequences of CT images to show changes in the size of tumors, for example. Moreover, the “CT numbers” as reported show a certain variability due to technical issues such as detector design as well as a lack of precision in the underlying definition.

Major Accomplishments

• A study showing that volumetric measurements can reduce the variation in size measurements of ideal objects compared to the standard RECIST measurement by a factor of ten
  
  
• Development of a low-cost device capable of reproducing lengths within a CT to better than 0.1 mm with data acquired with 0.6 mm voxels
  
  
• Identification of a commercially available foam for use as a density reference

• RECIST vs. Volume Measurements in Medical CT Using Ellipsoids of Known Size
  
  
• A Low-Cost Density Reference Phantom for Computed Tomography
  
  
• A Low-Cost Fiducial Reference Phantom for Computed Tomography