By Robert BruceShowcasing by four manufacturers of dedicated PET/CT combinations at last month's RSNA exhibit demonstrates that fusion imaging is not only here to stay but will likely become a powerhouse in oncology applications. Three systems have FDA
By Robert Bruce
Showcasing by four manufacturers of dedicated PET/CT combinations at last month's RSNA exhibit demonstrates that fusion imaging is not only here to stay but will likely become a powerhouse in oncology applications. Three systems have FDA clearance, while two other works-in-progress may become products in the next year or two.
Siemens' Biograph is ready to go, having obtained FDA clearance OCT. 31. Its prototype has been in clinical operation for two years at the University of Pittsburgh. The Biograph combines the Somatom Emotion CT, with an 800-millisec rotation, and the Ecat Exact HR+ top-of-the-line PET scanner.
GE's Millennium VG Hawkeye, introduced in June as a SPECT/CT system, fuses functional and anatomic images. This system has now been cleared for PET/CT. SMV's Positrace, which received the FDA nod in September, was the first PET/CT system to clear the agency. SMV has subsequently been acquired by GE Medical Systems.
"SMV's PET/CT product will allow GE to expand our PET/CT offerings and enter new market segments," said Beth Klein, GE Medical's vice president and general manager of Global Functional Imaging.
The Philips/ADAC collaboration is known as the Gemini Project. It was shown with both companies' logos, although Philips is in the process of acquiring ADAC. Philips showed a dedicated CT detector that establishes the foundation for real-time volumetric display, but the scanner on the Gemini is based on slower technology, according to Jeff Nelson, ADAC's senior vice president for sales and marketing.
Nuclear medicine's strength lies in imaging disease processes with SPECT or PET functional imaging, but its weakness is that it is often difficult to pin the images to underlying structures. These dual scanners allow radiologists to combine the clear anatomical images created by CT with the functional images of nuclear medicine generated by PET.
"The results of the studies we performed clearly demonstrate that anatomical and biological, or functional data provides valuable clinical information that permits accurate tumor detection and localization and establishes appropriate disease staging," said David Townsend, Ph.D., Siemens' PET/CT project director and codirector of the PET facility at the University of Pittsburgh.
Other promising potential applications include reducing biopsy sampling errors, improving therapy planning, and assessing response to treatments such as chemotherapy or radiation therapy, he said.
The hybrid systems probably won't be a do-it-all product for hospitals, said Randy Weatherhead, vice president of marketing for Siemens' nuclear medicine group.
"It could be run as a CT separate from PET, but because it's a fairly costly device, most will go to large diagnostic centers (that) already have a CT scanner and a dedicated PET system," Weatherhead said.
The Biograph fully loaded will cost around $2.5 million, he said. It was developed with CTI PET Systems, a joint venture of CTI and Siemens.
Although Siemens' PET/CT will have a high-end CT scanner, the relatively slow speed of PET scanning (25 to 50 minutes versus perhaps two minutes for a CT scan) means the value of a powerful CT is diminished in the dual system.
GE's top-of-the-line PET/CT is a works-in-progress combination of the GE LightSpeed multislice CT scanner and the company's new PET system, the GE Advance NXi. FDA clearance is pending.
"While nuclear medicine and PET are renowned for detecting lesions, sometimes months before they can be seen by CT and MR alone," Klein said, "the ability to pinpoint the location of those lesions has eluded physicians for years." n