The Debate Between SPECT vs. PET

For doctors, diagnosticians and other clinical medical professionals, having access to the most powerful molecular imaging tools is essential.

The two most widely used are SPECT and PET, which create images using gamma-rays and radiotracers. However, there are many important factors that need thorough understanding in order to get the best results with this equipment in any medical situation.

We will explore both technical information, and an overall assessment, along with an analysis of the strengths and weaknesses of both, as well as things to consider regarding the future of these technologies.

What is SPECT?

Single Photon Emission Computed Tomography (SPECT) is a form of nuclear medicine imaging that provides both anatomical and metabolic information. This differentiates it from CT scans and MRIs, which are often used in combination with SPECT imaging to provide the most complete picture possible.

SPECT offers several major advantages,the biggest of which is cost. When implemented properly, SPECT-based systems offer a complete analysis package at a reasonably lower cost, which is why they’re widely available and frequently used.

Another advantage is the type of tracers they use. SPECT systems work based on gamma-emitting radioisotopes that combine technetium-99M, iodine-123 and iodine-131. These tracers have a half-life of up to six hours, which is much longer compared to PET systems. These tracers are also less expensive and more readily available than their PET counterparts.

Application-wise, SPECT is typically used for nuclear cardiology and myocardial perfusion imaging. Almost 16 million SPECT procedures were performed in 2007 and, while the technology was rumored to be going away, continue to be widely performed today. The reason why is that issues formerly associated with SPECT technology have already been solved.

The time it takes for SPECT scans has also been cut significantly by the use of triple-headed cameras and cameras with higher capability levels. Now, the systems typically have computer-aided image enhancement and have implemented improved tracking systems that can account for patient movement during the scan and adapt accordingly.

What is PET?

Positron Emission Tomography (PET) is considered state of the art in many medical situations. It is a technique that uses radiotracers to monitor changes in metabolic processes and other physiological functions including blood flow, absorption and chemical composition.

Some advantages of PET scanning include higher spatial resolution, the ability to perform accurate measurements during peak periods of patient stress and speed.

The 30-40 minute time required for most PET images to be created means that multiple scans can be processed in a day, as opposed to the 2+ hours it takes to process a single SPECT scan.

Improvements in PET scanning include the development of F-18, which is a fluorine radiotracer that has a half-life of 2-2.5 hours. This eliminates one of its current biggest disadvantages, which is a very short half-life of just 75 seconds.

What Will SPECT and PET Be Capable Of In The Future?

There are also advances on the horizon that will increase both the effectiveness of SPECT and PET technology and their  cost factors.

Many companies, such as CE, Philips and Siemens, are developing smaller, less expensive gamma-ray cameras that are specifically designed for cardiac imaging. These cameras are inexpensive enough to become an attractive option for private cardiac practices.

As for the short-term future, another improvement upon SPECT or PET scanning is the addition of a CT scanner with a gamma camera. This gives clinicians anatomical sign posts that allow them to accurately identify and locate the affected tissue in a nuclear image. The CT data can also allow clinicians to correct attenuation and can be used for calcium scoring as well.

However, the CT/PET and CT/SPECT combinations are currently in their infancy as an imaging modality. While they are fairly expensive now, the cost is projected to go down in the future. Companies like GE, Philips and Siemens have gotten involved in furthering this technology, and more and more systems are rapidly becoming available on the market. Smaller footprints and lower costs are becoming the norm for both kinds of imaging technologies.

Some medical analysts expect quantum leaps in the performance of these kinds of systems, which may render the ongoing debate between SPECT vs. PET increasingly pointless as both technologies become optimized for the future.

How Can TTG Fulfill Your SPECT and PET Needs?

At TTG Imaging Solutions, we provide state-of-the-art new and refurbished SPECT and PET equipment units, among other medical imaging tools and parts. We also provide maintenance and diagnostics for your equipment purchases and schedule these appointments at your convenience. Specific parts are also available through our parts store which boasts a nationwide network of suppliers, along with the option of speedy, next day delivery. Contact us today to receive quality equipment and quality service. We are committed to fulfilling your SPECT and PET needs.