Celebrating 20 Years of SPECT/CT the Introduction of Hawkeye, the World’S First Hybrid Imaging System

CLINICAL VALUE HAWKEYE SPECT/CT Celebrating 20 Years of SPECT/CT The introduction of Hawkeye, the world’s first hybrid imaging system Nearly 20 years ago, a pivotal event shaped the future of The unclear medicine nuclear medicine. Once called the “unclear medicine,” nuclear Invented by Hal O. Anger in the mid-1950s, nuclear medicine medicine was forever changed with the introduction of cameras detect gamma radiation to depict metabolic Hawkeye, the world’s first clinical hybrid imaging system. processes within a living body. While gamma cameras helped GE Healthcare (at that time known as GE Medical Systems) revolutionize the field of functional medical imaging, there was introduced Hawkeye, a dual-modality SPECT and CT system, at one key limitation: the lack of anatomical markers in the image. the 1999 Society of Nuclear Medicine (SNM) Annual Meeting, heralding in a new era of “more clear medicine.” “We always understood that we needed anatomical and structural data to provide the best details and a precise answer to the clinical question,” says Ora Israel, MD, Director Emeritus of Nuclear Medicine/PET (retired) at Rambam Healthcare Campus, Haifa, Israel. She recalls using fiducial markers placed on the patient’s body to identify the location of key anatomical areas, such as the chest or abdomen. In some cases, Professor Israel and her colleagues would try to repeat the nuclear medicine study on a CT with the patient in the same position. It was a difficult and time-consuming process that she says never really worked well. “There was a clear purpose to improve the specificity of nuclear medicine by defining the anatomical relationship between isotope imaging and anatomy,” says Martin Sandler, MD, Professor of Radiology and Radiological Sciences and formerly Chairman of the Department of Radiology and Radiological Sciences at Vanderbilt University School of Medicine. Although fusion software was being utilized in some institutions, the applications were limited. “The brain was fairly simple, but the key problems came in the abdomen as a result of respiratory motion,” Dr. Sandler explains. Figure 1. Hawkeye combined a Millenium VG camera with an X-ray tube and detector that rotated around the This key clinical challenge in nuclear medicine was also“ shared patient. with Elscint, and later ELGEMS, a joint venture between Elscint At the moment we saw the first images, there was an understanding of the power of this new modality. “ Professor Ora Israel CLINICAL VALUE HAWKEYE SPECT/CT CLINICAL VALUE HAWKEYE SPECT/CT and GE Medical Systems (now GE Healthcare) to develop overlay of radiotracer functional distribution on an anatomic gamma camera technology. According to Nathan Hermony, image. According to a biography in the Journal of Nuclear Millennium VG Hawkeye Millennium VG5 Hawkeye VP Nuclear Medicine Business, the company started to look Medicine, he borrowed equipment from GE and placed a A B at the issues surrounding nuclear medicine, primarily the single-head SPECT camera close to a CT ring and then took “unclear medicine.” sequential scans using the same patient bed. Dr. Hasegawa also developed the algorithms to co-register the two images.1 “The perception of nuclear medicine being the ‘unclear medicine’ was one of the key issues in the specialty,” Hermony Dr. Patton recalls Dr. Hasegawa as the “ultimate gentleman says. “Referrers couldn’t understand what they were looking and researcher. I wanted to use his bilinear model and figure in at. So we asked our medical advisory board, what can we do to a publication, so I emailed him for a formal release. He emailed improve this?” me back with permission to use anything in any article he had ever published. Unfortunately, he passed away a few months For the non-nuclear medicine physician who was often treating after that.” the patient, using the information from gamma cameras could be a very frustrating process. James A. Patton, PhD, DABR, Professor of Radiology and Program Director of Nuclear Overcoming challenges Medicine Technology, Vanderbilt University Medical Center, While CT could certainly address the issue of anatomical recalls watching nuclear medicine physicians examining X-rays markers in nuclear medicine, there were other challenges that and CT images to try and discern where the hot spot was at Figure 2. GE Healthcare print advertising depicting some of the first clinical images obtained from the Hawkeye systems. (B) The Millennium it could resolve as well. Dr. Turkington had worked as a post- TM anatomically in the nuclear medicine study. VG5 Hawkeye was capable of PET Coincidence Imaging (CoDe ), as shown in the clinical image. doc with Ronald J. Jaszczak, who at that time was Professor “It was also very difficult to convey to the clinicians exactly in the Department of Radiology at Duke, on improving “The idea of moving from gadolinium to CT came up as a more “Our primary goal was to examine the underlying issue of what diagnostic information had been identified for them; quantitative SPECT imaging. precise way to achieve attenuation correction in cardiology nuclear medicine being the ‘unclear medicine’ and change all they would see was this glob representing abnormal “A key component of quantitative SPECT is attenuation studies,” Professor Israel explains. “At the same time, we that perception,” Hermony says. “Clearly, this was one of the radiopharmaceutical uptake,” he explains. In fact, Dr. Patton correction,” Dr. Turkington explains. “To do that, you need were trying to explain to our colleagues at Elscint and then primary reasons we pursued hybrid imaging. The other was spent hours trying to put together functional and anatomical information about the body. The methods to obtain this attenuation correction. So, we believed that combining an maps that clinicians could use as guidance when reviewing ELGEMS that we needed an easier way to facilitate the fusion information were fairly complicated using radioactive sources X-ray source, such as CT, could correct for the attenuation nuclear medicine images, first using ultrasound and then CT of functional and anatomical data.” and they weren’t widespread. Using X-ray CT to get the same in the body and also localize the activity within the patient’s after it was commercially introduced. information was a newer concept that Bruce and others were anatomy so physicians could see where that lesion was at.” Then, in the early-1990s, a new concept began to emerge. working on. In addition to enabling quantification, attenuation A vision for the future of nuclear medicine By bringing together anatomical with functional imaging in a Timothy G. Turkington, PhD, Associate Professor of Radiology correction makes the SPECT images more qualitatively While Dr. Hasegawa is widely considered the pioneer of single hybrid system, the team at ELGEMS was in pursuit of and Faculty Member in Medical Physics at Duke University, appealing, as well.” multimodality functional-anatomic imaging, several others improving image quality, attenuation and lesion localization in recalls attending a presentation at an IEEE Medical Imaging In the mid 1990s, Duke was performing several PET brain were following his lead and working on the development of nuclear medicine. According to Hermony, fusing the imaging Conference given by the research group of Bruce Hasegawa, studies on cancer patients each day. They routinely used a a commercially available SPECT/CT system. The formation of data from two separately acquired exams was fraught with the PhD, from the Radiology Department at the University of contrast-enhanced T1 MR image, which revealed breakdown ELGEMS in 1997 further propelled this effort. At the time, the potential for error and suboptimal results. California, San Francisco (UCSF). of the blood brain barrier, registered with the patient’s PET companies said by pooling their R&D capabilities their financial “If the nuclear medicine image is unclear with no body contour, “They presented their work on a combined SPECT and CT brain image, which provided more specific information about prospects in nuclear medicine could be enhanced. Elscint no algorithm can register the images from two different system,” Dr. Turkington says. “To me, it seemed very complicated the abnormalities. While there was rigidity and enough wavered at 10% market share while GE looked to enhance its systems acquired separately,” Hermony says. “That point was and I didn’t really get the point. Also, their system included fairly common features in the brain to fuse MR and PET, in the body variable-angle, dual-head camera product line. The partnership clear when we developed Hawkeye and it remains so today.” old technology for both SPECT and CT. I thought ‘why do this if it was much more challenging to provide this retrospective would be a win for both organizations. Although ELGEMS had several clinical-academic relationships, both systems will be updated’ (over time). But, when you put registration, whether the modalities were PET, SPECT, MR or CT. GE moved its manufacturing and R&D operations to Elscint it was the collaboration with Vanderbilt University, Duke these two modalities together, you actually get more than the Gadolinium was also being used to provide attenuation in Haifa, Israel, where the nuclear division remains today. University and Rambam that propelled the development sum of the two. Bruce saw this from the beginning.” correction for nuclear cardiology studies. However, it was a Elscint veteran Hermony was tapped as President and CEO of hybrid SPECT/CT. At that time, R. Edward Coleman, MD, Dr. Hasegawa is best known for his pioneering work on time consuming procedure, not a fail-proof solution, and didn’t of ELGEMS; today, he remains at the helm of GE Healthcare’s Professor of Radiology and Director of Nuclear Medicine, was multimodality imaging, combining CT with SPECT to provide an always provide the information needed. Nuclear Medicine business. leading the effort at Duke.

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