Technology Overcomes the Limitations of Traditional Bed-Based PET/CT

New positron emission tomography/computed tomography (PET/CT) technology provides continuous motion scanning for precise imaging, and eliminates doses related to overscanning, while achieving optimum efficiency.

At the 2013 annual meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) held June 8-12, 2013, in Vancouver (BC, Canada), Siemens Healthcare (Erlangen, Germany) presented the Biograph mCT Flow, a new positron emission tomography/computed tomography (PET/CT) system that for the first time, overcomes the limitations of conventional bed-based PET/CT with FlowMotion, a cutting-edge new technology that moves the patient smoothly through the system’s gantry, while continuously capturing PET data.

Biograph mCT Flow with FlowMotion’s imaging protocols are based on the organ’s need. FlowMotion expands precise and reproducible quantification in all dimensions for detailed disease characterization in therapy monitoring, while enabling physicians to offer as low as reasonably achievable (ALARA) dose to every patient. Furthermore, the combination of a 78-cm bore with five-minute ultrafast scanning and a continuous feeling of progress throughout the scan provides the patient with a more comfortable scan experience. The new Biograph mCT Flow PET•CT system with FlowMotion technology demonstrates Siemens’ innovation and competitiveness—key components of the Healthcare Sector’s Agenda 2013 two-year initiative.

With traditional PET/CT scanners, planning and scanning is limited to the fixed size of the system’s detector field-of-view (FOV) for each bed position. Whereas the adjustment of scan parameters in clinical stop-and-go PET/CT protocols is technically possible, the complexity of adjustment has limited its routine use.

mCT Flow PET•CT with FlowMotion technology changes how PET imaging is performed, eliminating the need for stop-and-go, bed-based planning with planning and scanning based on the single continuous motion of the patient table. Without the limitations of bed positions, the technician can be easily adjust the examination parameters such as image resolution, speed, and motion management to the precise dimensions of organs and routinely incorporated into a single scan for every patient.

To help physicians make sound decisions, imaging must provide effective and reproducible quantification. Traditional PET/CT suffers from intrinsic sensitivity degradation from the center to the edge of the axial FOV. Overlapping sequential bed positions are employed to counteract for this limitation, but this approach can lead to axially varying noise sensitivity. This noise can distort the quantitative values of a detected lesion, which may prompt a physician to mischaracterize the severity of a tumor. By constantly moving the patient through the detection system, FlowMotion technology eliminates overlapping bed acquisitions and maintains uniform noise sensitivity across the entire scan range.

FlowMotion eliminates CT dose due to over-scanning by enabling the user to precisely define the beginning and end of the PET scan, and because the CT scan of Biograph mCT Flow begins and ends at the same points as the system’s PET scan, the patient is not irradiated in regions of the body that do not require a CT scan. With Biograph mCT Flow, the user can realize a CT dose decrease of up to 32%. Meanwhile, the new Biograph mCT Flow, combined with TrueV, is the only solution that enables continuous scanning at twice the speed of conventional PET/CT. TrueV technology provides a 30% wider axial FOV of 21.6 cm—the largest in the PET/CT industry—enabling Biograph mCT Flow to provide a 70% increase in count rate performance. When combined with ultraHD•PET, which provides increased image quality, routine clinical scans can be performed in five minutes. Throughput is further optimized by one click FAST planning. The user can employ a simple protocol setup to determine the scan type and duration for up to four zones: for example, the head, abdomen, lungs, and legs. The user can then tailor the scan in each region using Siemens’ established image quality techniques.

Healthcare providers require a system that accommodates the individual needs of a wide patient demographic. A standard PET/CT scan can last 25 to 30 minutes, with the patient frequently falling asleep or zoning out while the system acquires a bed position. When the bed shifts to the next scanning position, the patient is frequently alarmed, which results in an image that is flawed by motion artifacts. The patient also can feel anxiety during the lengthy scanning process, perceiving no progress until the bed shifts to a new scanning position.

In addition to the elimination of patient motion due to surprise, the continuously moving patient table of Biograph mCT Flow gives the patients a sense of progress, which can additionally optimize patient satisfaction. Moreover, the large 78-cm bore, short tunnel, and a 227-kg table capacity can improve patient accessibility and comfort.

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