Feature | PET Imaging | November 07, 2018 | By Greg Freiherr

Positron emission tomography (PET) is getting ready to venture outside oncology, cardiology and mainstream neurology. High on the list of new clinical turf is sports medicine.

If ongoing clinical studies validate early results, patients whose ACLs have been surgically repaired could be among the first to benefit. Others may include patients with other orthopedic injuries, as well as head trauma victims suspected of having concussions.

Michael Knopp, M.D., discussed these possibilities in the PODCAST: PET Ready To Expand Into Sports Medicine And Beyond.

“We lack information about pathophysiological processes (in orthopedics and neurology),” Knopp said, “information that is not readily detected even with our wonderful capabilities in MRI. PET adds another component. And if we can do this with precision and also ultralow radiation dose, then we can add to the diagnostic portfolio that we can offer to better diagnose and manage those ailments.”

PET imaging at one-tenth or less of typical radiotracer doses is essential if these new PET tests are to gain widespread use, he said in the podcast. The relatively high doses of positron-emitting radiotracers associated with currently prescribed PET studies — and the consequent radiation burdens they put on patients and staff — have precluded the use of this modality for any but the most essential applications, many of which have been in oncology.

“We have been shying away from other applications because of this radiation burden,” Knopp said. “Now our team and others have explored the capabilities of radically reducing the radiation dose (from) what we are using in current standard of care PET imaging. With this radical reduction in radiation dose, new applications that fundamentally leverage our ability in molecular imaging in sports medicine and orthopedics is really a very exciting development for the future.”

Author’s note: In a presentation scheduled for Nov. 26 at 1:15 pm at the Philips booth (N 6573) at the Radiological Society of North America’s Scientific Assembly (RSNA 2018), the long-time Philips luminary will describe the use of positron imaging in oncology, as well as cardiology and neurology. He will also address the value of integrating Philips Vereos PET/CT with the company’s visualization platform, IntelliSpace Portal.

 

Cutting PET Radiation

Dosages of PET radiotracers might be substantially reduced through the use of digital technology, according to Knopp, who has been researching ultralow dose applications using Philips’ Vereos. This PET/CT scanner features a solid-state detector as part of its digital architecture.

The digital technology, he said, provides “higher definition imaging capabilities with smaller voxel volumes” compared with what is typically achieved using commercial analog systems. Moreover, digital technology provides “the ability to substantially reduce the radiation dose from the tracer and also the ability to image substantially faster,” he said.

Digital PET images made with ultralow doses of sodium fluoride radio tracer might help assess ACL grafts following surgery and rehabilitation, according to Knopp: “This is really opening up the capabilities of molecular imaging for sports medicine and orthopedics.”

PET scans might add an objective measure to what today is a largely subjective assessment of when athletes with surgically repaired ACLs can begin playing sports again. One of the biggest challenges following ACL repair, Knopp said, is to determine whether the graft has been “appropriately ligamentized so it has the strength” needed by the athlete to play sports. PET also might help determine whether a complication of this surgery — infection — is present, he said. PET research into the graft process itself might help.

Knopp, professor of radiology and the Novatis chair of Imaging Research at Ohio State University, advocates gaining a more detailed understanding of the recovery process to better “guide physical therapy with more objective feedback.” This understanding might “facilitate bringing the athletes to recovery quicker and with a more certain outlook,” he said.

Ongoing studies by Knopp and his team at Ohio State University are now underway to validate PET as a tool in performing such evaluations. The technical advance enabling this clinical potential is digital technology, he said. 

 

Digital Enabler

Digital PET differs from the analog technology that underlies most commercial PET systems. Analog technology originated with the use of photomultiplier tubes (PMTs) to capture the scintillation events that indicate accumulations of radiotracer in patients. The precision of PMTs, however, is limited.

“With the introduction of solid-state digital detector technology and especially digital photon counting (technology, which is specific to Vereos), we have now the ability to acquire data with a much higher precision,” Knopp said. “This allows us to push the limits in image detail, as well as the ability to significantly reduce the necessary dose on a PET tracer.”

Compared with analog technology, solid-state detectors introduce less noise and deliver more precise signals, he said: “Therefore we have a better image quality at lower doses. And that is now translating — in the clinical studies we are performing — into better detection of lesions and better characterization.”

Analog technology has not been up to clinical tasks beyond those widely prescribed in oncology and to a lesser degree in cardiology and neurology. This has prevented PET from reaching its clinical potential.

“A lot of the enthusiasm that evolved over the decades was kind of limited by the relative high radiation dose,” Knopp noted. “That is where digital PET technology allows us to really leap forward.”

Listen to the first PODCAST PET Ready To Expand Into Sports Medicine And Beyond

Listen to the second PODCAST Hear and Now: Intervention Rising

Listen to the third PODCAST Hear and Now: What You Need to Know About Enterprise Imaging

For additional information, read the articles Interventional Radiology Profile Rises in Medicine and at RSNA Meeting and  PET Ready To Expand Into Sports Medicine And Beyond

Related Content

News | Radiopharmaceuticals and Tracers

May 16, 2022 — Blue Earth Diagnostics, a Bracco company and recognized leader in the development and commercialization ...

Time May 16, 2022
arrow
News | Contrast Media

May 13, 2022 — The ACR Committee on Drugs and Contrast Media, within the ACR Commission on Quality and Safety, is aware ...

Time May 13, 2022
arrow
News | Radiation Therapy

May 4, 2022 — RefleXion Medical, a therapeutic oncology company pioneering the use of biology-guided radiotherapy (BgRT) ...

Time May 04, 2022
arrow
Feature | Digital Radiography (DR) | By Melinda Taschetta-Millane

The COVID-19 pandemic turned the spotlight on diagnostic imaging by demanding a need for high-speed workflow and ...

Time May 03, 2022
arrow
Feature | Radiology Business | By Christine Book

At the Radiological Society of North America’s (RSNA) 2021 annual meeting in December, James Brink, MD, FACR ...

Time May 03, 2022
arrow
Feature | Radiology Business | By Christine Book

Reinforcing the critical role radiologists can, have and should play to remain relevant in the policy arena was the key ...

Time April 29, 2022
arrow
News | Cardiac Imaging

April 28, 2022 — Aspirin therapy, as opposed to statin use, for non-obstructive coronary artery disease does not reduce ...

Time April 28, 2022
arrow
Feature | Radiology Imaging | By Melinda Taschetta-Millane

The Software & Information Industry Association (SIIA) announced winners for the 68th Jesse H. Neal Awards – one of the ...

Time April 26, 2022
arrow
News | Radiology Imaging

April 21, 2022 — A novel mesh plug that has been traditionally used to treat brain aneurysms occurring where the blood ...

Time April 21, 2022
arrow
Feature | Radiology Business

Imaging Technology News (ITN) won the Regional Gold Award in both of its nominated categories from the American Society ...

Time April 15, 2022
arrow
Subscribe Now