Offering double benefits—clinical and economic—the newest hybrids bring hope to hospitals.

A quick glance at the sessions featured at RSNA 2010 reveals a pronounced interest in hybrid modalities: from the use of functional hybrid imaging in the diagnosis of neuroendocrine tumors to PET/CT imaging of the pancreas to MR-based attenuation correction for MR/PET imaging.

This year, RSNA is also the ideal venue to uncover the latest hybrid modalities from vendors, which are focused on delivering solutions that improve dose management and image acquisition times, while helping to increase diagnosis accuracy. After RSNA, health care providers with their eyes on the bottom line can return to their facilities with a solid business case for investing in these hybrid modalities.

PET/MR for Sequential Image Acquisition

The whole-body PET/MR imaging system from Philips Healthcare, which is currently pending FDA approval, integrates the molecular imaging capabilities of PET with the soft tissue contrast of MR. It is a low-dose hybrid modality solution?the only dose received is from the contrast used for the PET scan.

Physically, Philips Healthcare’s PET/MR imaging system is a combination of two scanners face-to-face that are connected by a single bed that allows for sequential image acquisition. Since it has long been understood that combining the two modalities in one gantry is technically impossible, Philips Healthcare developed a novel shield between the two modalities to enable this hybrid technology to work.

Three beta sites, including the University Hospital of Geneva in Switzerland, are conducting clinical validation studies and are using the technology to support their own research projects. Osman Ratib, MD, PhD, FAHA, professor and chief of nuclear medicine in the department of radiology at the University Hospital of Geneva, is currently using the PET/MR imaging system to investigate more accurate diagnosis of recurrence in prostate cancer, earlier detection of breast cancer in lymph nodes, and, most importantly, improved diagnosis of cancer recurrence in patients with head and neck cancers.

Ratib believes that the use of this PET/MR imaging system can have a tangible impact on patient care, since it allows patients to have two studies performed in a single session—and reduces radiation exposure by eliminating the need for a CT scan.

While he believes that not every PET/CT scan will be replaced by a PET/MR scan, areas of possible benefit are those where MRI imaging provides valuable additional diagnostic information. “It’s not uncommon today for a patient to have a PET/CT and an MRI as part of their clinical workup, and this represents about 20% to 30% of the PET/CTs that could be replaced by PET/MRs,” said Ratib.

“With the development of PET/MR protocols, it’s expected that this ratio could increase significantly,” he said. “The future development of integrated systems allowing simultaneous acquisition of PET and MR images will also enable new applications in neuroimaging and cardiology imaging, two areas that will benefit greatly from this hybrid technology.”

An added benefit to health care providers is that the images are acquired almost at the same time, says Ratib. “That’s important for things that change from day to day, such as tumors. When you have two studies that are taken at different times, it can be difficult to match those studies later.”

Ratib theorizes that in order to establish a viable business plan for leveraging such expensive technology, health care facilities will need to conduct financial planning that depends on study reimbursements that will need to be carefully validated in order to define the exact mix of cases that must be performed on this machine. He says that the “high throughput of standard MRI studies should compensate for the longer acquisition scans of hybrid PET/MR studies.”

SPECT/CT Innovation Draws on Years of Hybrid Modality Experience

GE Healthcare’s Discovery NM/CT 670 system combines its BrightSpeed Elite 16-slice CT, a newly designed SPECT gantry for greater positional flexibility, and the latest advancements in nuclear medicine detectors. According to the company, this system has the capability to shorten acquisition times, improve dose management, and enable more convenient patient scheduling, since facilities will need to schedule only one exam—rather than two, as with conventional SPECT and CT exams.

Kevin Boyle, global marketing manager for nuclear medicine at GE Healthcare, says that this new hybrid solution provides many new advancements on the company’s legacy technologies and points out that GE Healthcare introduced the first SPECT/CT technology in 2000.

The Discovery NM/CT 670 was introduced in October 2009 and first shipped in July, according to Boyle, who adds that there are seven systems currently in use at facilities in Russia, Belgium, the United Kingdom, and Israel.

With this new hybrid system, a bone imaging procedure that once took between 35 and 50 minutes now takes approximately 16 minutes. Boyle notes that by reducing the imaging time by up to 50% for SPECT and planar bone imaging, each exam requires less time on the camera, which may result in improved throughput and flexibility in patient scheduling.

“Some departments [also] have a need for overflow CT, especially on the weekends when the nuclear medicine department is closed,” said Boyle. “The economic considerations here are quite clear. The NM/CT 670 is a faster, productive system that can deliver on a hospital’s need for overflow CT availability.

“The NM/CT 670 was designed with stand-alone CT usage in mind,” he says. “This was one of the reasons we integrated the GE BrightSpeed Elite 16 so that the same speed, image quality, and dose management tools available on a clinician’s stand-alone CT were available on the NM/CT 670 for many of the same protocols.

“Additionally, the user interface was designed to allow it to be operated as a SPECT/CT or CT-only system, [thus] providing trained CT operators with a familiar user interface, while still delivering to nuclear medicine operators the hybrid efficiency they demand,” he said.

Another distinguishing feature of this hybrid technology is the Xeleris workstation, which is used to share information throughout the nuclear medicine department. According to the company, Xeleris allows a physician in the reading room, a technologist with a patient, and another physician in the office to examine the same data—at the same time.

Overall, Boyle believes that the Discovery NM/CT 670 accomplishes the goal of “meeting the needs of nuclear medicine today and in the future.” Our challenge was to create an integrated solution, one that was easy for clinicians to use—with a workflow they expect—and to maintain upgradability for the future.”

The World’s First Molecular CT

Siemens Medical Solutions’ Biograph mCT, which the company calls the world’s first molecular CT, is an integration of its HD?PET and adaptive spiral CT platforms. Offering whole-body PET/CT scanning in 5 minutes and the flexibility of day-in, day-out CT scanning, this hybrid solution has been available since October 2008 and is in use in health care facilities such as Cleveland Clinic in Cleveland, and Memorial Hospital in Springfield, Ill.

“We focused on optimizing the utilization of an expensive system and on offering hospitals a solution that can work as either [a CT or PET scanner],” said Sergio Calvo, director of marketing for the molecular imaging division of Siemens Medical Solutions.

Calvo notes that, from a financial point of view, “it makes total sense” for a hospital to purchase this hybrid PET/CT. In fact, he shares this as a business case for the investment: If they purchased a PET/CT to do only PET/CT exams, hospitals would need to work with five to six patients each day. If the hospital had approximately two to three PET patients, administrators could justify the additional investment in the hybrid PET/CT scanner.

In addition, Siemens Medical Solutions has also developed the multimodality imaging software syngo.via, which offers integrated reading solutions for physicians trained to interpret both PET and CT exams.

According to the company, with this PET/CT solution in use, the patient will have a much better experience, given the quicker scan time and the lower radiation dose than they would experience if they had to undergo multiple scans. Further, physicians are going to be able to see a much better image, which will lead to much better treatment management.

“Some people, if you mention the idea of shared services, they’ll tell you that they heard about this back in 2001,” said Calvo. “They’ll say that this is an old idea. That’s true. The idea’s old. What’s new is that the whole environment around PET/CT has changed. Technologists are now trained on both [PET and CT]. Payors pay for PET and they know what it is; they know how to reimburse for it. And our machines are faster; a [PET] scan that used to take 40 minutes now takes 5 minutes.”

Aine Cryts is a contributing writer for Axis Imaging News.