What types of PET-CT scanners are used in the workup of secondary lung cancer?

Updated: Feb 08, 2019
  • Author: Daniel S Schwartz, MD, MBA, FACS; Chief Editor: John Geibel, MD, DSc, MSc, AGAF  more...
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Answer

The terminology for PET-CT software and hardware can be confusing. The three primary modalities of PET-CT scanners are hybrid, fusion, and visually correlated. The hybrid, or integrated, PET-CT scanner creates two images, with one relying on CT and the other on PET. A computer then merges the two scans into a single image. This is the most accurate and specific system to date for the staging of non-small cell lung cancer (NSCLC). It is more expensive than PET, CT, or fusion software alone.

Fusion PET-CT scanners use software to create a 3D model of the CT study and a 3D model of the PET study; the scanners then use an algorithm to compare and provide an overlay of the images. This modality is less costly than hybrid PET-CT, but it may not be as accurate as integrated PET-CT for NSCLC. [19]

With fusion software, the CT and PET scans may be obtained on different dates; however, this increases the artifact, because there is different positioning, respiration, and other movement between scans. The fusion software can also be used with MRI.

With visually correlated PET-CT, the radiologist visually and manually compares CT and PET scans side by side. The examinations can be performed on different dates or at different facilities; however, this modality has been shown in several studies to be far less accurate. [19, 20]


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