Development of skin surface radiation detector system to monitor radioactivity in arterial blood along with positron emission tomography

1995 ◽  
Vol 42 (4) ◽  
pp. 1455-1459 ◽  
Author(s):  
H. Watabe ◽  
M. Miyake ◽  
Y. Narita ◽  
T. Nakamura ◽  
M. Itoh
Keyword(s):  
Positron Emission Tomography ◽  
Radiation Detector ◽  
Skin Surface ◽  
Detector System ◽  
Surface Radiation ◽  
Emission Tomography ◽  
Arterial Blood ◽  
Positron Emission

Validation and optimisation of an automatic blood sampler for preclinical positron emission tomography research in domestic pigs

2021 ◽  
pp. 002367722110490
Author(s):  
Sofia Vestergaard Nielsen ◽  
Mie Ringgaard Dollerup ◽  
Simone Larsen Bærentzen ◽  
Anne M Landau ◽  
Ole Lajord Munk ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Animal Studies ◽  
Time Course ◽  
Activity Concentration ◽  
Blood Sampling ◽  
Emission Tomography ◽  
Domestic Pigs ◽  
Arterial Blood ◽  
Positron Emission

In preclinical positron emission tomography animal studies, continuous blood sampling is used to measure the time course of the activity concentration in arterial blood. However, pigs have hypercoagulable blood that tends to clot inside plastic tubes. We tested several tube materials and lengths and the use of three-way connectors. We validated set-ups for automated blood sampling with and without blood recirculation that could run for 90 minutes without problematic clots and without any evidence of emboli formation during necropsy.

scholarly journals Evaluation of Various Scintillator Materials in Radiation Detector Design for Positron Emission Tomography (PET)

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 869
Author(s):  
Siwei Xie ◽  
Xi Zhang ◽  
Yibin Zhang ◽  
Gaoyang Ying ◽  
Qiu Huang ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
High Performance ◽  
Radiation Detector ◽  
Experimental Studies ◽  
Light Output ◽  
Radiation Detectors ◽  
Emission Tomography ◽  
Timing Resolution ◽  
Positron Emission ◽  
Co Doped

The performance of radiation detectors used in positron-emission tomography (PET) is determined by the intrinsic properties of the scintillators, the geometry and surface treatment of the scintillator crystals and the electrical and optical characteristics of the photosensors. Experimental studies were performed to assess the timing resolution and energy resolution of detectors constructed with samples of different scintillator materials (LaBr3, CeBr3, LFS, LSO, LYSO: Ce, Ca and GAGG) that were fabricated into different shapes with various surface treatments. The saturation correction of SiPMs was applied for tested detectors based on a Tracepro simulation. Overall, we tested 28 pairs of different forms of scintillators to determine the one with the best CTR and light output. Two common high-performance silicon photomultipliers (SiPMs) provided by SensL (J-series, 6 mm) or AdvanSiD (NUV, 6 mm) were used for photodetectors. The PET detector constructed with 6 mm CeBr3 cubes achieved the best CTR with a FWHM of 74 ps. The 4 mm co-doped LYSO: Ce, Ca pyramid crystals achieved 88.1 ps FWHM CTR. The 2 mm, 4 mm and 6 mm 0.2% Ce, 0.1% Ca co-doped LYSO cubes achieved 95.6 ps, 106 ps and 129 ps FWHM CTR, respectively. The scintillator crystals with unpolished surfaces had better timing than those with polished surfaces. The timing resolution was also improved by using certain geometric factors, such as a pyramid shape, to improve light transportation in the scintillator crystals.

scholarly journals Comparison of cerebral blood flow measurement with [15O]-water positron emission tomography and arterial spin labeling magnetic resonance imaging: A systematic review

2016 ◽  
Vol 36 (5) ◽  
pp. 842-861 ◽  
Author(s):  
Audrey P Fan ◽  
Hesamoddin Jahanian ◽  
Samantha J Holdsworth ◽  
Greg Zaharchuk
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Spin Labeling ◽  
Brain Perfusion ◽  
Spin Labeling ◽  
Emission Tomography ◽  
Flow Measurements ◽  
Arterial Blood ◽  
Positron Emission

Noninvasive imaging of cerebral blood flow provides critical information to understand normal brain physiology as well as to identify and manage patients with neurological disorders. To date, the reference standard for cerebral blood flow measurements is considered to be positron emission tomography using injection of the [15O]-water radiotracer. Although [15O]-water has been used to study brain perfusion under normal and pathological conditions, it is not widely used in clinical settings due to the need for an on-site cyclotron, the invasive nature of arterial blood sampling, and experimental complexity. As an alternative, arterial spin labeling is a promising magnetic resonance imaging technique that magnetically labels arterial blood as it flows into the brain to map cerebral blood flow. As arterial spin labeling becomes more widely adopted in research and clinical settings, efforts have sought to standardize the method and validate its cerebral blood flow values against positron emission tomography-based cerebral blood flow measurements. The purpose of this work is to critically review studies that performed both [15O]-water positron emission tomography and arterial spin labeling to measure brain perfusion, with the aim of better understanding the accuracy and reproducibility of arterial spin labeling relative to the positron emission tomography reference standard.

scholarly journals Evaluation of [13N]ammonia positron emission tomography as a potential method for quantifying glutamine synthetase activity in the human brain.

2020 ◽  
Author(s):  
Alice Egerton ◽  
Joel Dunn ◽  
Nisha Singh ◽  
Zilin Yu ◽  
Jim O'Doherty ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Glutamine Synthetase ◽  
Human Brain ◽  
Kinetic Modelling ◽  
Emission Tomography ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Kinetic Rate Constant ◽  
Arterial Blood ◽  
Positron Emission

Abstract Purpose: The conversion of synaptic glutamate to glutamine in astrocytes by glutamine synthetase (GS) is critical to maintaining healthy brain activity and may be disrupted in several brain disorders. As the GS catalysed conversion of glutamate to glutamine requires ammonia, we evaluated whether [13N]ammonia positron emission tomography (PET) could reliability quantify GS activity in humans.Methods: In this test-retest study, eight healthy volunteers each received two dynamic [13N]ammonia PET scans on the morning and afternoon of the same day. Each [13N]ammonia scan was preceded by a [15O]water PET scan to account for effects of cerebral blood flow (CBF).Results: Concentrations of radioactive metabolites in arterial blood were available for both sessions in five of the eight subjects. Our results demonstrated that kinetic modelling was unable to reliably distinguish estimates of the kinetic rate constant k3 (related to GS activity) from K1 (related to [13N]ammonia brain uptake), and indicated a non-negligible back-flux of [13N] to blood (k2). Model selection favoured a reversible one-tissue compartmental model, and [13N]ammonia K1 correlated reliably (r2 = 0.72 - 0.92) with [15O]water CBF.Conclusion: The [13N]ammonia PET method was unable to reliably estimate GS activity in the human brain but may provide an alternative index of CBF.

scholarly journals Kinetic Compartment Modeling of [11C]-5-Hydroxy-L-Tryptophan for Positron Emission Tomography Assessment of Serotonin Synthesis in Human Brain

2002 ◽  
Vol 22 (11) ◽  
pp. 1352-1366 ◽  
Author(s):  
Gisela E. Hagberg ◽  
Richard Torstenson ◽  
Ina Marteinsdottir ◽  
Mats Fredrikson ◽  
Bengt Långström ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
White Matter ◽  
Tissue Concentration ◽  
Compartment Model ◽  
Anterior Cingulate ◽  
Emission Tomography ◽  
Serotonin Synthesis ◽  
Compartment Modeling ◽  
Arterial Blood ◽  
Positron Emission

The substrate for the second enzymatic step in serotonin synthesis, 5-hydroxy-L-tryptophan, labeled in the β-position ([11C]-HTP), was used for positron emission tomography (PET) measurements in six healthy human participants, examined on two occasions. One- and two-tissue kinetic compartment modeling of time-radioactivity curves was performed, using arterial, metabolite-corrected [11C]-HTP values as input function. The availability of unchanged tracer in arterial blood plasma was ⩽ 80% up to 60 minutes after injection, while [11C]-hydroxyindole acetic acid and [11C]-serotonin accounted for the remaining radioactivity, amounting to ⩽16% and ⩽4%, respectively. Compartment modeling was performed for brain stem, putamen, caudate nucleus, anterior cingulate, white matter, and superior occipital, occipitotemporal, and temporal cortices. The average biologic half-life for plasma-to-tissue equilibrium was 7 to 12 minutes, and the volume of distribution was 0.2 to 0.5 μL·mL−1. In all regions except white matter, the kinetic compartment model that included irreversible [11C]-HTP trapping showed significantly improved model fits with respect to a one-tissue compartment model. The [11C]-HTP trapping rate constant depended on the estimated tissue availability of the serotonin precursor tryptophan, known to reflect serotonin synthesis in healthy individuals, and correlated with serotonin tissue concentration and synthesis rates reported previously in literature. These findings suggest the use of [11C]-HTP PET measurements to investigate serotonin synthesis.

scholarly journals Global Cerebral Blood Flow Decreases during Pain

1998 ◽  
Vol 18 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Robert C. Coghill ◽  
Christine N. Sang ◽  
Karen Faith Berman ◽  
Gary J. Bennett ◽  
Michael J. Iadarola
Keyword(s):  
Positron Emission Tomography ◽  
Heart Rate ◽  
Brain Regions ◽  
Intradermal Injection ◽  
Emission Tomography ◽  
Intravenous Bolus ◽  
Arterial Blood Sampling ◽  
Arterial Blood ◽  
Positron Emission ◽  
Global Cerebral Blood Flow

Positron emission tomography studies have identified a common set of brain regions activated by pain. No studies, however, have quantitatively examined pain-induced CBF changes. To better characterize CBF during pain, 14 subjects received positron emission tomography scans during rest, during capsaicin-evoked pain (250 μg, intradermal injection), and during innocuous vibration. Using the H215O intravenous bolus method with arterial blood sampling, global CBF changes were assessed quantitatively. Painful stimulation produced a 22.8% decrease in global CBF from resting levels ( P < 0.0005). This decrease was not accounted for by arterial PCO2 or heart rate changes. Although the exact mechanism remains to be determined, this pain-induced global decrease represents a previously unidentified response of CBF.

scholarly journals Noninvasive Blood-Free Full Quantification of Positron Emission Tomography Radioligand Binding

2014 ◽  
Vol 35 (1) ◽  
pp. 148-156 ◽  
Author(s):  
Francesca Zanderigo ◽  
R Todd Ogden ◽  
Ramin V Parsey
Keyword(s):  
Positron Emission Tomography ◽  
Radioligand Binding ◽  
Partial Agonist ◽  
Brain Regions ◽  
Emission Tomography ◽  
Simultaneous Estimation ◽  
Arterial Line ◽  
Blood Samples ◽  
Arterial Blood ◽  
Positron Emission

Full quantification of a positron emission tomography (PET) radioligand binding to its target is preferred because it requires the fewest assumptions, but generally involves measuring the concentration of free radioligand in the arterial plasma by collecting blood samples from the subject's radial artery during the scan, and performing metabolite analysis. This invasive, costly procedure deters subjects’ participation, and requires specialized staff and equipment. Simultaneous estimation (SIME) can fully quantify binding using only PET data from multiple brain regions and one individual anchor value, which is based on a single arterial blood sample. Drawing this sample can still be challenging in clinical settings, particularly when using simultaneous PET/magnetic resonance scanners. Here we propose a methodology for full quantification of binding that does not require any blood samples. The methodology substitutes the SIME blood-based anchor with a value predicted using multiple linear regression of noninvasive, easy-to-collect variables related to the radioligand blood concentration, and individual metabolism, such as injected dose, body mass index, or body surface area. As a study case, we show here the methodology in comparison to analysis with full arterial-line blood sampling in a cohort of 23 available scans with [11C]CUMI-101, a partial agonist of the serotonin 5-HT1A receptors.

scholarly journals Changes in the Arterial Fraction of Human Cerebral Blood Volume during Hypercapnia and Hypocapnia Measured by Positron Emission Tomography

2005 ◽  
Vol 25 (7) ◽  
pp. 852-857 ◽  
Author(s):  
Hiroshi Ito ◽  
Masanobu Ibaraki ◽  
Iwao Kanno ◽  
Hiroshi Fukuda ◽  
Shuichi Miura
Keyword(s):  
Positron Emission Tomography ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Venous Blood ◽  
Capillary Blood ◽  
Emission Tomography ◽  
Arterial Blood ◽  
Positron Emission ◽  
Capillary Blood Volume ◽  
Arterial Blood Volume

Hypercapnia induces cerebral vasodilation and increases cerebral blood volume (CBV), and hypocapnia induces cerebral vasoconstriction and decreases CBV. Cerebral blood volume measured by positron emission tomography (PET) is the sum of three components, that is, arterial, capillary, and venous blood volumes. Changes in arterial blood volume ( Va) and CBV during hypercapnia and hypocapnia were investigated in humans using PET with H215O and 11CO. Arterial blood volume was determined from H215O PET data by means of a two-compartment model that takes Va into account. Baseline CBV and values during hypercapnia and hypocapnia in the cerebral cortex were 0.034 ± 0.003, 0.038 ± 0.003, and 0.031 ± 0.003 mL/mL (mean ± s.d.), respectively. Baseline Va and values during hypercapnia and hypocapnia were 0.015 ± 0.003, 0.025 ± 0.011, and 0.007 ± 0.003 mL/mL, respectively. Cerebral blood volume changed significantly owing to changes in PaCO2, and Va changed significantly in the direction of CBV changes. However, no significant change was observed in venous plus capillary blood volume (= CBV- Va). This indicates that changes in CBV during hypercapnia and hypocapnia are caused by changes in arterial blood volume without changes in venous and capillary blood volume.

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