Digital Reference Object Extension
Updated: 14 August 2014
The PET/CT Digital Reference Object Extension (DROe) is a set of synthetically generated DICOM
image files of known voxel values for positron emission tomography (PET) and x-ray
computed tomography (CT). The PET/CT DROe is intended to test three specific features of medical image viewing software:
The DROe contains two 'blobs' of known voxel values that allow testing of SUV-peak calculations.
PET/CT Fusion Alignment:
The DROe contains multiple test objects within the PET and CT DICOM volumes that are designed to test the PET/CT fusion alignment in the axial, sagittal, and coronal views.
When an ROI is drawn around a lesion, it is not always clear which voxels are included in the ROI or how those voxels are used to compute ROI metrics. The DROe has test objects designed to help determine which voxels are included within an ROI drawn on the screen and intuit how those voxels are used in ROI computations.
The PET/CT DROe was developed at the
University of Washington Imaging Research Laboratory
and is supported by the
Quantitative Imaging Biomarker Alliance (QIBA)
The PET and CT components of the Images of the DRO are each a set of
file per image slice. Each set of files are typically grouped as a stack to form an image volume.
Representative sections through the CT and PET image volumes are shown below. The synthetic test object
is based on the body of the NEMA NU-2 PET test phantom [J Nucl Med, vol. 43 no. 10 1398-1409, 2002] with similar contrast levels, but with different internal structures.
Representative axial views through the DROe image volumes.
Left: PET/CT Fusion alignment test patterns
Center: SUV-peak calculation test objects
Right: ROI Fidelity test object
Users of the DROe are asked to download the package, import the PET and CT objects into their viewing
software, perform the tests, and submit the results back to this website.