PET-CT Hybrid Scans

PET-CT scans combine positron emission tomography (PET) and computed tomography (CT) into one imaging tool. The joint scans combine the detailed images of a CT scan with the metabolic data of a PET scan.  

 

One of the main limitations of PET imaging is the lack of clear reference frame (determining where organs/tissues are) and a relatively low spatial resolution. This can be overcome by integrating a structural imaging method such as CT into the scan.

 

Until 2001, only separate PET and CT scanners were available for use on patients. Separate scans were taken, and image fusion software was used to merge the images. Differences in patient orientation and position in the scanner, internal changes between scans, and patient burden all posed challenges for non-integrated hybrid scans. [1] 

 

The introduction of integrated PET-CT scanners enabled hybrid scans to be quickly and easily performed, with little extra patient inconvenience. Their huge success means that most manufacturers now only offer PET-CT hybrid scanners. These hybrid scanners consist of two devices (a PET scanner and a CT scanner) that are configured for sequential imaging. The short CT scan duration means that simultaneous imaging (which is technologically much more challenging) is not required. After the CT scan has been taken, the patient bed is advanced slightly into the PET scanner field of view. 

 

More recent developments in PET technology can also be incorporated into PET-CT hybrids. These include time-of-flight technology and 3D imaging.

 

For more information about these advances, and PET scanning in the future, please click here. 

​

References:

[1] Basu, S. et al. (2011). Fundamentals of PET and PET-CT scanning, New York: New York Academy of Sciences. pp. 3-5.