Message From the President

Nicholas C. Friedman MD
2005-2006 Chapter President

PET/CT vs CT/PET: What’s in Name?

Rebecca Sajdak discusses in this issue the origins of terms commonly used in Nuclear Medicine. More recently, we are confronted with SPECT/CT and PET/CT referring to hybrid systems that are the latest technological feats of medical imaging. There is a certain bias in the choice of name. The isotope, or “molecular” part is usually placed first. This confirms that the study is primarily an isotope study, and the CT is ancillary to it.

I recently attended the Radiological Society of North America meeting in Chicago. The vast majority of the Nuclear Medicine posters were on PET, of which most utilized PET/CT. Some of the posters I found disturbing. There were CT scans, with adjacent fused PET/CT images. Traditional PET images alone were absent. This represents a paradigm shift in how we view PET/CT. Is CT a tool to improve PET in terms of improved patient throughput, attenuation correction and localization of PET abnormalities? Or is PET merely a new form of “contrast”, perhaps the ultimate contrast agent? Showing images of CT scans with adjacent fused PET/CT images suggests that there are clinicians who subscribe to the latter view.

So what’s in a name? Is not PET/CT the same as CT/PET? Are these differences merely semantics? I suspect not. As a nuclear medicine physician, PET is by far the biggest new modality to emerge from the research area of Nuclear Medicine in 20 years. When all the pieces of this fledging technology became a widely adapted clinical reality, Nuclear Medicine re-emerged in the spotlight of diagnostic imaging. The addition of CT enhances PET imaging in many ways, yet for most cases PET alone remains a remarkable tool without the need for concurrent CT.

Nuclear medicine is faced with many dangers in the sudden shift to high-end CT scanners attached to PET scan devices. Will the patient first get a diagnostic CT to go with the PET/CT? Will the initial CT be dropped to avoid repetitive studies? Who will read the CT? How will the Nuclear medicine physician face reading a PET/CT without a prior CT report? These questions make me want to reach into my desk drawer filled with the latest gastrointestinal cocktail. Getting PET in the first place required a few bottles of “TUMS”. Keeping PET in Nuclear Medicine is a challenge the Nuclear Medicine Community will need to tackle head on, perhaps armed with the latest proton pump inhibitors.

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