The only other obstacle to the wider use of PET-CT is the difficulty and cost of producing and transporting the radiopharmaceuticals used for PET imaging, which are usually extremely short-lived.

[3] The first PET-CT systems were constructed by David Townsend (at the University of Geneva) and Ronald Nutt (at CPS Innovations in Knoxville, TN) with help from colleagues.

FDG doses in quantities sufficient to carry out 4–5 examinations are delivered daily, twice or more per day, by the provider to the diagnostic imaging center.

For uses in image-guided radiation therapy of cancer, special fiducial markers are placed in the patient's body before acquiring the PET-CT images.

The slices thus acquired may be transferred digitally to a linear accelerator which is used to perform precise bombardment of the target areas using high energy photons (radiosurgery).