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Concept of an upright wearable positron emission tomography imager in humans

View Article: PubMed Central - PubMed

ABSTRACT

Background: Positron Emission Tomography (PET) is traditionally used to image patients in restrictive positions, with few devices allowing for upright, brain‐dedicated imaging. Our team has explored the concept of wearable PET imagers which could provide functional brain imaging of freely moving subjects. To test feasibility and determine future considerations for development, we built a rudimentary proof‐of‐concept prototype (Helmet_PET) and conducted tests in phantoms and four human volunteers.

Methods: Twelve Silicon Photomultiplier‐based detectors were assembled in a ring with exterior weight support and an interior mechanism that could be adjustably fitted to the head. We conducted brain phantom tests as well as scanned four patients scheduled for diagnostic F18‐FDG PET/CT imaging. For human subjects the imager was angled such that field of view included basal ganglia and visual cortex to test for typical resting‐state pattern. Imaging in two subjects was performed ~4 hr after PET/CT imaging to simulate lower injected F18‐FDG dose by taking advantage of the natural radioactive decay of the tracer (F18 half‐life of 110 min), with an estimated imaging dosage of 25% of the standard.

Results: We found that imaging with a simple lightweight ring of detectors was feasible using a fraction of the standard radioligand dose. Activity levels in the human participants were quantitatively similar to standard PET in a set of anatomical ROIs. Typical resting‐state brain pattern activation was demonstrated even in a 1 min scan of active head rotation.

Conclusion: To our knowledge, this is the first demonstration of imaging a human subject with a novel wearable PET imager that moves with robust head movements. We discuss potential research and clinical applications that will drive the design of a fully functional device. Designs will need to consider trade‐offs between a low weight device with high mobility and a heavier device with greater sensitivity and larger field of view.

No MeSH data available.


Concept of a future ambulatory Helmet_PET with freedom of movement. These six panels demonstrate activities that could be monitored by a mobile device. Specifically, motor tasks, artistic/creative tasks, and complex social interactions could be more easily studied
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brb3530-fig-0001: Concept of a future ambulatory Helmet_PET with freedom of movement. These six panels demonstrate activities that could be monitored by a mobile device. Specifically, motor tasks, artistic/creative tasks, and complex social interactions could be more easily studied

Mentions: In this study we propose using compact PET detectors with silicon photomultiplier technology (SiPMs) to image the brain during both head and body motion by mounting these detectors in a ring or helmet which could move with the head (Fig. 1). Positron emission tomography (PET) is a well‐established molecular imaging modality and is considered to be one of the first brain imaging tools to allow high spatial resolution whole‐brain imaging, as it overcame the limitations of spatial resolution and surface‐only imaging of electroencephalography (EEG) (Mazziotta, 1985; Stephan et al., 1987). Behavioral studies showing whole‐brain activation patterns can be performed using markers of blood volume changes with O15‐H2O or metabolic changes with F18‐FDG. In addition, at higher spatial resolutions than MR spectroscopy, PET can image activity related to specific neurotransmitter systems, by using radiolabeled ligand targets such as D2 dopamine receptor antagonist C11‐raclopride (Carson et al., 1997; Kuhn et al., 2014), serotonin transporter binding agents C11‐Madam and C11‐Zient (Karlsson et al., 2013; Nye et al., 2013), and other ligands specific for opioids, as well as other targets (Weerts et al., 2012; Wey et al., 2014). Thus, a wearable PET scanner could be used in a variety of ways to uncover the mechanisms underlying behaviors, as well as psychological and neurological disorders.


Concept of an upright wearable positron emission tomography imager in humans
Concept of a future ambulatory Helmet_PET with freedom of movement. These six panels demonstrate activities that could be monitored by a mobile device. Specifically, motor tasks, artistic/creative tasks, and complex social interactions could be more easily studied
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036439&req=5

brb3530-fig-0001: Concept of a future ambulatory Helmet_PET with freedom of movement. These six panels demonstrate activities that could be monitored by a mobile device. Specifically, motor tasks, artistic/creative tasks, and complex social interactions could be more easily studied
Mentions: In this study we propose using compact PET detectors with silicon photomultiplier technology (SiPMs) to image the brain during both head and body motion by mounting these detectors in a ring or helmet which could move with the head (Fig. 1). Positron emission tomography (PET) is a well‐established molecular imaging modality and is considered to be one of the first brain imaging tools to allow high spatial resolution whole‐brain imaging, as it overcame the limitations of spatial resolution and surface‐only imaging of electroencephalography (EEG) (Mazziotta, 1985; Stephan et al., 1987). Behavioral studies showing whole‐brain activation patterns can be performed using markers of blood volume changes with O15‐H2O or metabolic changes with F18‐FDG. In addition, at higher spatial resolutions than MR spectroscopy, PET can image activity related to specific neurotransmitter systems, by using radiolabeled ligand targets such as D2 dopamine receptor antagonist C11‐raclopride (Carson et al., 1997; Kuhn et al., 2014), serotonin transporter binding agents C11‐Madam and C11‐Zient (Karlsson et al., 2013; Nye et al., 2013), and other ligands specific for opioids, as well as other targets (Weerts et al., 2012; Wey et al., 2014). Thus, a wearable PET scanner could be used in a variety of ways to uncover the mechanisms underlying behaviors, as well as psychological and neurological disorders.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Positron Emission Tomography (PET) is traditionally used to image patients in restrictive positions, with few devices allowing for upright, brain‐dedicated imaging. Our team has explored the concept of wearable PET imagers which could provide functional brain imaging of freely moving subjects. To test feasibility and determine future considerations for development, we built a rudimentary proof‐of‐concept prototype (Helmet_PET) and conducted tests in phantoms and four human volunteers.

Methods: Twelve Silicon Photomultiplier‐based detectors were assembled in a ring with exterior weight support and an interior mechanism that could be adjustably fitted to the head. We conducted brain phantom tests as well as scanned four patients scheduled for diagnostic F18‐FDG PET/CT imaging. For human subjects the imager was angled such that field of view included basal ganglia and visual cortex to test for typical resting‐state pattern. Imaging in two subjects was performed ~4 hr after PET/CT imaging to simulate lower injected F18‐FDG dose by taking advantage of the natural radioactive decay of the tracer (F18 half‐life of 110 min), with an estimated imaging dosage of 25% of the standard.

Results: We found that imaging with a simple lightweight ring of detectors was feasible using a fraction of the standard radioligand dose. Activity levels in the human participants were quantitatively similar to standard PET in a set of anatomical ROIs. Typical resting‐state brain pattern activation was demonstrated even in a 1 min scan of active head rotation.

Conclusion: To our knowledge, this is the first demonstration of imaging a human subject with a novel wearable PET imager that moves with robust head movements. We discuss potential research and clinical applications that will drive the design of a fully functional device. Designs will need to consider trade‐offs between a low weight device with high mobility and a heavier device with greater sensitivity and larger field of view.

No MeSH data available.