Nuclear Medicine: Where Hybrid and Molecular Rule

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Hybrid imaging systems, including multislice PET/CT and SPECT/CT systems, made a big splash at this year's RSNA, as did molecular imaging and the new technologies that are expanding its R&D and clinical capabilities.
Nuclear medicine vendors were sure to exhibit their standalone PET as well as combined PET/CT systems. Philips Medical Systems launched an enhanced PET/CT system, while GE showed a 64-slice PET/CT scanner as a works-in-progress.  Studies have shown the diagnostic superiority of PET/CT in the evaluation of different cancers as well as heart disease. Neurology and targeted radiotherapy are additional specialties benefiting from the combination of metabolic and anatomic function.
PET is making its mark. In a keynote session titled "Molecular Imaging: From Nanotechnology to Patients," Michael E. Phelps, PhD, the Norton Simon Professor and chairman of the Department of Molecular & Medical Pharmacology at the University of California Los Angeles School of Medicine, said approximately one million clinical PET procedures will be performed in the United States, with a projected growth rate of 20 to 30 percent per year over the next four years. PET today is the most widely considered molecular imaging modality. The PET scanner was the first device to allow noninvasive measurement of the biochemistry and biology of normal organ function and to enable molecular diagnosis of disease.
SPECT/CT is knocking at its doors - vendors say the hybrid imaging modality is advancing mainstream molecular imaging. Siemens announced at the show the first clinical installation of its TruePoint SPECT/CT system, and both Philips and GE showed of enhanced hybrid imaging systems.     
Additional highlights included a new web-delivered suite of software tools that can assist a facility in starting and maintaining a successful PET imaging practice. The versatility of fusion imaging software showed its strengths too, as the clinical tool can be used to combine images captured on PET/CT and SPECT/CT systems, as well as merge data sets acquired from different modalities, such as CT, MR, PET and SPECT. A new fusion capability was shown by Hitachi that allows precise contouring of tumors on fused data to be exported in DICOM RT format to a radiation therapy planning system.

(Note: companies appear in alphabetical order.)

CTI Molecular Imaging demonstrated PETConnect, an integrated source of web-delivered software tools and workstations for image analysis, education and practice management. Created in partnerships between CTI Mirada Solutions and CTI PETNET, the technology includes a range of IT products, educational programs and service offerings, designed to provide all the capabilities necessary to run a successful PET imaging practice.
PETConnect consists of applications for image analysis, PET education and marketing, and practice management. The image analysis software in PETConnect, created by CTI Mirada Solutions, includes diagnostic applications spanning oncology, neurology, and cardiology. The PET education and marketing programs are designed to provide the user with all the tools necessary to educate their community on the advantages of PET and PET/CT. The integrated practice management applications provide the necessities and understanding to stabilize the daily operations of a PET center, CTI said.  
For clinicians already using PET or PET/CT, PETConnect provides tools to increase productivity, improve diagnostic accuracy, facilitate communication with referring physicians and grow a PET practice. Highlights include: Scenium, for detailed analysis of FDG uptake in patients with suspected Alzheimer's disease; Ostiview, the first application specifically designed for the visualization and analysis of PET sodium fluoride bone scans; PET/CT U, a comprehensive web-based educational tool, designed to provide clear answers to all your questions about PET/CT; and Call It With Confidence, a complete educational resource designed to assist the interpreting physician with proper reporting of PET and PET/CT studies.
For radiologists and nuclear medicine physicians, PETConnect includes the MiraView workstation for image review and analysis and Fusion7D (available both as a workstation plug-in and a PACS/OEM offering), with both rigid and non-rigid image fusion algorithms.  New capabilities include Novisis, an application that facilitates direct comparison of several images, including PET/CT studies, acquired at a range of different time points. These systems support a wide range of MR, SPECT, PET and CT scanners and allow radiologists not currently using PET to integrate molecular imaging should their practice move in this direction.

Gamma Medica Inc. introduced at RSNA the LumaGEM 3200S/12K breast imaging camera.
The LumaGEM 3200S/12K is a solid-state gamma camera that employs gamma ray detector technology based on cadmium zinc telluride crystals. The camera attaches to existing upright mammography systems, mounting directly onto the system in place of the film bucky. Its compact size and small dead edge allows it to image all the way up to the chest wall, Gamma Medica said.
LumaGEM 3200S/12K contains an array of more than 12,000 pixels, each 1.6-by-1.6 mm. The smaller crystals offer a better than 40 percent improvement in camera spatial resolution than that delivered by Gamma Medica's 3200S model, the company said. It also offers greater than 100 percent improvement in the camera's space bandwidth product.
Gamma said the system's improvements in the 3200S/12K system will make the LumaGEM a powerful diagnostic tool, especially for women who have dense breasts and are at high risk of breast cancer.
The Mayo Clinic in Rochester, N.Y., will be the first United States institution to obtain a LumaGEM 3200S/12K in February. The hospital will use the system to evaluate its ability to improve the sensitivity of molecular breast imaging for the detection of small (sub-10 mm) breast lesions.

GE Healthcare showcased as a works-in-progress a 64-slice version of its Discovery PET/CT platform and directed attention to its second-generation SPECT/CT system.
The Discovery VCT incorporates GE's LightSpeed Volume CT 64-slice scanner with GE's Discovery PET technology. GE said it designed the LightSpeed VCT (introduced this year) to easily integrate with its Discovery PET technology. The fusion marries the high-speed, high-resolution capabilities of GE's volumetric CT with the metabolic and physiologic capabilities of GE's PET.
According to Phil Vernon, global research manager for PET, the Discovery VCT has all the PET performance of the other members of the Discovery ST family. The main CT parameters include 40-mm axial coverage at 0.65-mm line spacing, with 0.35 second rotation.
The performance of Discovery VCT in emission scanning is the same as that of the latest Discovery ST products. The Discovery systems have high PET sensitivity and allow imaging with septa to reduce scatter in larger patients (2D imaging), as well as septaless imaging (3D imaging) for thinner patients.
The improvements in Discovery VCT will be most valuable in cardiology, GE noted. The company said it anticipates releasing the system in the next 12 to 18 months.
GE also showed its second-generation Infinia Hawkeye SPECT/CT system. It has been upgraded with the x-ray technology on its Infinia system with a 5-mm step option with Hawkeye for better resolution.

Hitachi Medical Systems America Inc. (HMSA) introduced RTist, a software package for use with its new SceptreP3 PET/CT system and the Avia multimodality PACS workstation.
RTist complements the multimodality fusion capabilities of Avia and SceptreP3 by allowing precise contouring of tumors on fused data to be exported in DICOM RT format to a radiation therapy planning system.
Mirada Solutions Ltd., a subsidiary of CTI Molecular Imaging Inc., develops advanced software packages for Avia, such as Fusion7D and RTist. Hitachi said the software is slated for release in March.
Hitachi also showed its Sceptre P3 PET/CT hybrid imaging system. The unit combines three technologies in one: lutetium oxyorthosilicate (LSO) PET technology, HMSA's fast quad-slice CT and connectivity to Avia PACS workstation. The system features dual attenuation correction (DAC technology) and FDA-approved, non-rigid fusion7D algorithm that provides precise registration by correcting for respiration differences between PET and CT acquisitions.  
The Sceptre P3 is designed with a field upgrade capability and allows Sceptre dedicated PET customers an opportunity to cost-effectively upgrade to the benefits of PET/CT.  The "Evolve" upgrade program is available to all Sceptre dedicated PET scanners including both installed and forward production systems.

Med Image highlighted a new volume registration function of MedView version 11 that is a component of the DELTAmanager package.
Volume registration is a method for aligning two volumes of data in which the patient was imaged at different angles. After alignment, the two volumes may then be overlaid atop each other and compared. The goal may be to overlay a functional PET or SPECT scan with a CT or MR scan which shows anatomical detail, or compare a patient's PET scan from three months ago with one performed today.
MedView's volume registration feature utilizes a user-guided approach. Aligning volumes is done using a rigid body process. The procedure to register two volumes consists of fusing the two volumes together in a template window and manipulating one volume so that it aligns with the second volume by translating and rotating the first volume.
Tools for image registration analysis review include contrast and brightness presets for different organs and modalities, ROIs, SUV calculations and on screen ruler.  Users can choose one of several standard fused-window layouts or customize one to fit their screen size and review methodology.
MedView can be used to compare pre- and post-therapy images and provides clinicians with a fast, efficient way of detecting tumor change. Volume registration is available for both Windows and MacOS X.

Naviscan PET Systems Inc. showed its new PEM Flex PET scanner that is designed to provide high-resolution images of the breast and to guide radiological and surgical procedures.
The compact device employs lutetium-based crystals and can be operated in a small room or mobile environment. Featuring a four- to 10- minute scan time and producing 3D tomographic PET images, PEM flex provides a spatial resolution of 1-mm to 2-mm.

Numa was at RSNA highlighting its newest nuclear medicine connectivity offerings, NumaList. The product enables non-worklist compliant systems to gain the advantages of DICOM modality worklist. NumaList adds or corrects DICOM modality worklist information in DICOM image files. This enables the correct patient demographic information to be added to the DICOM images with little or no user input.

Philips Medical Systems was on board at RSNA highlighting a new PET/CT system, its Precedence SPECT/CT unit, and new software called Molecular Imaging Suite.
Philips unveiled a new PET/CT scanner, the Gemini GXL PET/CT system. The system leverages advances in PET technology, featuring 3D LOR reconstruction to provide high image quality across a wide range of patients and applications, the company said. 
The Gemini GXL features an OpenView gantry which provides patient comfort, clinician access and imaging flexibility. The design reduces patient rejection rates and improves accessibility by providing open airspace between the CT and PET acquisition components. Separable gantries enable easier use of the CT component as a diagnostic tomography system and the PET component as a stand-alone PET scanner. Philips Gemini GXL Workspace reduces the critical exam review time as well as scan time. The Workspace simplifies use and integrates with other modalities and hospital information networks.
The company also showed its Precedence SPECT/CT system, which combines Philips' SPECT technology with its Brilliance multislice CT scanner. The system is available in 6- and 16-slice configurations. The system can be used as a hybrid and stand-alone SPECT or CT system, providing fused SPECT and CT data sets as well as individual data sets.
Philips said it foresees the Precedence advancing the mainstream adoption of molecular imaging. In addition to improving the usefulness of current agents, it could help accelerate the development of new molecular imaging agents and applications, which could potentially lead to improved diagnostics, increased prognostic value and more effective disease treatment. The system is easy to upgrade and integrate with other imaging modalities and the Philips JETStream Workspace environment. For diagnostic effectiveness, it offers dual datasets and attenuation correction.
Philips also debuted the Philips Molecular Imaging Suite, comprehensive software that provides tools to support the key elements required for molecular imaging. The Suite may help expand the functional capabilities of SPECT and hybrid imaging systems by integrating molecular imaging applications into the JETStream Workspace. The workspace provides enhanced display tools and enables evaluation of individual SPECT and CT images. Highlights of the software include: combined functional and anatomical information; auto-registered SPECT and CT datasets, autofiducial marker registration; radiation therapy interoperability; attenuation and scatter correction; new Astonish algorithms for planar and dynamic planar imaging; and new Astonish SPECT reconstruction resolution recovery capabilities.

Siemens Medical Solutions came to RSNA with a new 64-slice PET/CT system and announced the first clinical site using its new SPECT/CT system.
Siemens showed its FDA-approved Symbia system that incorporates TruePoint SPECT/CT technology. The system, which integrates Siemens SPECT with its CT technology, can be used in the diagnosis and treatment for cancer, cardiac and neurological diseases.
The hybrid system platform can perform three different scans - SPECT, diagnostic CT, and SPECT/CT - in a single procedure. The system is equipped with Siemens' syngo technology that offers a common user interface. The syngo software also includes automated and integrated workflows, so that SPECT and CT datasets can be acquired and processed on one single workstation.
Siemens announced at RSNA the first clinical installation of the hybrid unit. The University of Michigan Health System (UMHS) has deployed Siemens' Symbia and has definitive plans to install two more systems by the end of 2005. According to Markus Lusser, vice president worldwide sales and marketing, Siemens will release TruePoint SPECT/CT in the second half of 2005.
Siemens introduced the biograph 64 PET/CT system which incorporates Siemens' PET technology with its SOMATOM Sensation 64-slice CT system. Siemens 64-slice CT technology provides high image quality - especially for cardiovascular applications. The scanner can acquire images of the smallest intracranial, pulmonary, mesenteric and peripheral vessels in less than 10 seconds. It delivers 64-slices per rotation for sub-millimeter volume coverage and a fast gantry rotation time at 0.33 seconds. This allows for extremely short breath-hold times for the patient and motion-free images of the beating heart. Acquisition of 64 slices per rotation is possible through the new Straton x-ray tube's z-Sharp Technology, and Siemens' proprietary detector technology.
The biograph 64 employs a PET equipped with high count rate lutetium oxyorthosilicate (LSO) detector technology. The system incorporates HI-REZ, a high resolution PET feature that can provide greater than 250 percent improvement in volumetric image resolution, and the Pico-3D option, which includes ultra-fast detector electronics that substantially improve image quality.
In addition, Siemens featured its Leonardo post-processing workplace, which integrates more than 50 syngo-based multimodality imaging applications within one user interface. The workplace has been incorporated with the wide-ranging nuclear medicine capabilities of the company's e.soft software suite to create e.soft@Leonardo, which offers a grouping of multimodality applications, such as SPECT and PET processing, and FusedVision3D, combining CT volume rendered images with PET and SPECT data. Adherence to the DICOM standard provides smooth integration into clinical workflows and ensures cross-vendor compatibility with thee systems, and the automated workflows reduce administrative work and accelerate clinical processes.

Toshiba America Medical Systems showed its Signature series - an easy-to-use gamma camera for whole body, cardiac SPECT and general SPECT applications - that is available in three configurations: Variable, Cardio, and the Single. Features include: HD4 digital detectors, real-time automatic body contouring and advanced algorithms for diagnostic accuracy; patient comfort and entertainment system; 400-pound table weight; e.soft and e.soft express, software for remote review of nuclear medicine, cardiac and PET cases; and data and images integrated with multiple vendors and modalities.

TeraRecon in partnership with Acrorad unveiled at RSNA a handheld mini gamma camera (MGC) for intra-operative imaging, especially of sentinel nodes. The MGC achieves imaging through the use of cadmium telluride (CdTe) semiconductor detectors.


Fluke Biomedical, Radiation Management Services, formerly Cardinal Health, showed its ASM-990 series of advanced survey meter (ASM) instruments that detect alpha, beta, gamma, neutron or x-ray radiation. Visual indications of measured values, as well as selected parameters, are displayed on the instrument's handheld analog/digital display.
The ASM has three uses for nuclear medicine. It can be used as a survey meter, area monitor, or wipe test counter. The device is available in multiple models - 990, 992, and 993. In addition, being more than just a point and measure survey meter, the device is a smart advanced survey meter with the ability to log surveys, download the information into a PC, synchronize with nuclear medicine software, and help manage survey data. The meter can be carried in a soft holster or strap assembly.

Gammex rmi introduced a Mobile Laser Alignment System designed for use with mobile PET/CT systems. The system can be mounted directly to the floor and ceiling of a mobile trailer. This permits better stability for the lasers and reduces set-up time once the trailer reaches its destination. When the laser needs to be moved, the system can be unlocked and rolled out of the way, a procedure that can be performed in five minutes, Gammex said.
Gammex also showed the 467 Tissue Characterization Phantom, a quality-control phantom that can assist radiation therapists in making accurate corrections for tissue inhomogeneities when setting up their isodose treatment plan. The device can be used to establish the relationship between the electron density of various tissues and their corresponding CT number. The phantom consists of a solid water disk approximating the size of an average pelvis. A matrix of 16 holes in the disk hold interchangeable rods made of various tissue and water-simulating materials. Scans can be performed and collected data can be transferred to the user's treatment planning system for tissue inhomogeneity corrections. The optional titanium rod can be used when patients have inserts in the vicinity of the area targeted for treatment.
Physical densities and electron densities relative to water of the rod materials are provided. A pattern of small air holes with defined spacing are present in the phantom to allow a quick method for measuring CT scanner distance measurement accuracy, Gammex said.