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Ito H, Kubo H, Takahashi K, Nishijima KI, Ukon N, Nemoto A, Sugawara S, Yamakuni R, Ibaraki M, Ishii S. Integrated PET/MRI scanner with oxygen-15 labeled gases for quantification of cerebral blood flow, cerebral blood volume, cerebral oxygen extraction fraction and cerebral metabolic rate of oxygen. Ann Nucl Med 2021; 35:421-428. [PMID: 33502738 DOI: 10.1007/s12149-021-01578-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 01/04/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Measurement of cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) by PET with oxygen-15 labeled gases is useful for diagnosis and treatment planning in cases of chronic occlusive cerebrovascular disease. In the present study, CBF, CBV, OEF and CMRO2 were measured using the integrated design of PET/MRI scanner system. This is a first attempt to measure cerebral perfusion and oxygen metabolism using PET/MRI with oxygen-15 labeled gases. METHODS PET/MRI measurements with the steady-state method of oxygen-15 labeled gases, carbon monoxide (C15O), oxygen (15O2), and carbon dioxide (C15O2) were performed on nine healthy men. Two kinds of attenuation correction for PET were performed using MRI with Dixon sequence (DIXON) and Dixon sequence with model-based bone segmentation (DIXONbone). A real-time motion correction of PET images was also performed using simultaneously measured MR images to detect head motion. RESULTS Mean and SD values of CBF, CBV, OEF, and CMRO2 in the cerebral cortices with attenuation correction by DIXON were 31 ± 4 mL/100 mL/min, 2.7 ± 0.2 mL/mL, 0.40 ± 0.07, and 2.5 ± 0.3 mL/100 mL/min without real-time motion correction, and 33 ± 4 mL/100 mL/min, 2.7 ± 0.2 mL/mL, 0.40 ± 0.07, and 2.6 ± 0.3 mL/100 mL/min with real-time motion correction, respectively. Values with of CBF, CBV, OEF, and CMRO2 with attenuation correction by DIXONbone were 35 ± 5 mL/100 mL/min, 2.8 ± 0.2 mL/mL, 0.40 ± 0.07, and 2.8 ± 0.3 mL/100 mL/min without real-time motion correction, and 38 ± 5 mL/100 mL/min, 2.8 ± 0.2 mL/mL, 0.40 ± 0.07, and 3.0 ± 0.4 mL/100 mL/min with real-time motion correction, respectively. CONCLUSIONS Using PET/MRI with oxygen-15 labeled gases, CBF, CBV, OEF, and CMRO2 could be measured. Values of CBF, CBV, and CMRO2 measured with attenuation correction by DIXON were significantly lower than those measured with correction by DIXONbone. One of the reasons for this is that attenuation correction of DIXON does not take into consideration of the photon absorption by bone. OEF values, corresponding to ratios of CMRO2 to CBF, were not affected by attenuation correction methods. Values of CBF and CMRO2 with a real-time motion correction were significantly higher than those without correction. Using PET/MRI with adequate corrections, similar values of CBF, CBV, OEF, and CMRO2 as PET alone scanner system reported previously were obtained. TRAIL REGISTRATION The UMIN clinical trial number: UMIN000033382.
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Affiliation(s)
- Hiroshi Ito
- Department of Radiology and Nuclear Medicine, Fukushima Medical University, 1 Hikariga-oka, Fukushima, 960-1295, Japan.
- Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan.
| | - Hitoshi Kubo
- Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
| | - Kazuhiro Takahashi
- Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
| | - Ken-Ichi Nishijima
- Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
| | - Naoyuki Ukon
- Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
| | - Ayaka Nemoto
- Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
| | - Shigeyasu Sugawara
- Department of Radiology and Nuclear Medicine, Fukushima Medical University, 1 Hikariga-oka, Fukushima, 960-1295, Japan
- Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
| | - Ryo Yamakuni
- Department of Radiology and Nuclear Medicine, Fukushima Medical University, 1 Hikariga-oka, Fukushima, 960-1295, Japan
| | - Masanobu Ibaraki
- Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita, Japan
| | - Shiro Ishii
- Department of Radiology and Nuclear Medicine, Fukushima Medical University, 1 Hikariga-oka, Fukushima, 960-1295, Japan
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Kudomi N, Maeda Y, Yamamoto H, Yamamoto Y, Hatakeyama T, Nishiyama Y. Reconstruction of input functions from a dynamic PET image with sequential administration of 15O 2 and [Formula: see text] for noninvasive and ultra-rapid measurement of CBF, OEF, and CMRO 2. J Cereb Blood Flow Metab 2018; 38:780-792. [PMID: 28595496 PMCID: PMC5987943 DOI: 10.1177/0271678x17713574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/19/2017] [Accepted: 05/15/2017] [Indexed: 11/16/2022]
Abstract
CBF, OEF, and CMRO2 images can be quantitatively assessed using PET. Their image calculation requires arterial input functions, which require invasive procedure. The aim of the present study was to develop a non-invasive approach with image-derived input functions (IDIFs) using an image from an ultra-rapid O2 and C15O2 protocol. Our technique consists of using a formula to express the input using tissue curve with rate constants. For multiple tissue curves, the rate constants were estimated so as to minimize the differences of the inputs using the multiple tissue curves. The estimated rates were used to express the inputs and the mean of the estimated inputs was used as an IDIF. The method was tested in human subjects ( n = 24). The estimated IDIFs were well-reproduced against the measured ones. The difference in the calculated CBF, OEF, and CMRO2 values by the two methods was small (<10%) against the invasive method, and the values showed tight correlations ( r = 0.97). The simulation showed errors associated with the assumed parameters were less than ∼10%. Our results demonstrate that IDIFs can be reconstructed from tissue curves, suggesting the possibility of using a non-invasive technique to assess CBF, OEF, and CMRO2.
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Affiliation(s)
- Nobuyuki Kudomi
- Department of Medical Physics, Kagawa University, Kagawa, Japan
| | - Yukito Maeda
- Department of Radiology, Kagawa University Hospital, Kagawa, Japan
| | | | - Yuka Yamamoto
- Department of Radiology, Kagawa University, Kagawa, Japan
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Abstract
OBJECTIVE Extensive cortical β-amyloid (Aβ positivity) has been linked to cognitive decline, but the clinical significance of elevations in Aβ within the negative range is unknown. METHODS We examined amyloid and cognitive trajectories (memory, executive function) in 142 cognitively normal older individuals enrolled in the Alzheimer's Disease Neuroimaging Initiative who were Aβ-negative at baseline and who had at least 2 [18F]-florbetapir PET scans over 3.9 ± 1.4 years. We determined whether Aβ accumulation was associated with longitudinal changes in memory or executive function. RESULTS Among baseline-negative individuals, florbetapir slope (mean annual increase 0.002 ± 0.008 standardized uptake value ratio units/y) was not related to age, sex, education, APOE4 status, baseline memory or executive function, temporoparietal glucose metabolism, baseline hippocampal volume, or hippocampal volume change; but it was related to higher baseline cortical florbetapir, indicating that Aβ accumulation was ongoing at baseline in those who accumulated during the study. Over the course of follow-up, 13 individuals converted to florbetapir+ and 14 nearly nonoverlapping individuals converted to mild cognitive impairment or Alzheimer disease. Amyloid accumulation among baseline-negative individuals was associated with poorer longitudinal memory performance (p = 0.019), but it was not associated with changes in executive function. Reducing the sample to individuals with at least 3 timepoints to estimate the florbetapir slope strengthened the relationship further between florbetapir accumulation and memory decline (p = 0.007). CONCLUSIONS Memory decline accompanies Aβ accumulation in otherwise healthy, Aβ-negative older adults. Amyloid increases within the negative range may represent the earliest detectable indication of pathology with domain-specific cognitive consequences.
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Affiliation(s)
- Susan M Landau
- From Helen Wills Neuroscience Institute, University of California; and Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA.
| | - Andy Horng
- From Helen Wills Neuroscience Institute, University of California; and Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - William J Jagust
- From Helen Wills Neuroscience Institute, University of California; and Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA
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4
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Abstract
OBJECTIVES Parkinson's disease (PD) may be associated with increased energy metabolism in overactive regions of the basal ganglia. Therefore, we hypothesized that treatment with the N-methyl-d-aspartate receptor (NMDAR) antagonist memantine would decrease regional cerebral blood flow (rCBF) and oxygen metabolism in the basal ganglia of patients with early-stage PD. METHODS Quantitative positron emission tomography (PET) recordings were obtained with 15O]water and 15O]oxygen in 10 patients, scanned first in a baseline condition, and again 6 weeks after treatment with a daily dose of 20 mg memantine. Dynamic PET data were analyzed using volume of interest and voxel-based approaches. RESULTS The treatment evoked rCBF decreases in basal ganglia, and in several frontal cortical areas. The regional cerebral metabolic rate of oxygen (rCMRO2) did not decrease in any of the a priori defined regions, and consequently the oxygen extraction fraction was increased in these regions. Two peaks of significantly decreased rCMRO2 were detected near the frontal poles in both hemispheres, using a posteriori voxel-based analysis. CONCLUSIONS Although we did not find the predicted decrease in basal ganglia oxygen consumption, our data suggest that treatment with memantine actively modulates neuronal activity and/or hemodynamic response in basal ganglia of PD patients. This finding may be relevant to the putative neuroprotective properties of NMDAR antagonists.
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Affiliation(s)
- P Borghammer
- PET Center, Aarhus University Hospital, Aarhus, Denmark.
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Coles JP, Fryer TD, Smielewski P, Rice K, Clark JC, Pickard JD, Menon DK. Defining ischemic burden after traumatic brain injury using 15O PET imaging of cerebral physiology. J Cereb Blood Flow Metab 2004; 24:191-201. [PMID: 14747746 DOI: 10.1097/01.wcb.0000100045.07481.de] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Whereas postmortem ischemic damage is common in head injury, antemortem demonstration of ischemia has proven to be elusive. Although 15O positron emission tomography may be useful in this area, the technique has traditionally analyzed data within regions of interest (ROIs) to improve statistical accuracy. In head injury, such techniques are limited because of the lack of a priori knowledge regarding the location of ischemia, coexistence of hyperaemia, and difficulty in defining ischemic cerebral blood flow (CBF) and cerebral oxygen metabolism (CMRO2) levels. We report a novel method for defining disease pathophysiology following head injury. Voxel-based approaches are used to define the distribution of oxygen extraction fraction (OEF) across the entire brain; the standard deviation of this distribution provides a measure of the variability of OEF. These data are also used to integrate voxels above a threshold OEF value to produce an ROI based upon coherent physiology rather than spatial contiguity (the ischemic brain volume; IBV). However, such approaches may suffer from poor statistical accuracy, particularly in regions with low blood flow. The magnitude of these errors has been assessed in modeling experiments using the Hoffman brain phantom and modified control datasets. We conclude that this technique is a valid and useful tool for quantifying ischemic burden after traumatic brain injury.
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Affiliation(s)
- Jonathan P Coles
- The Division of Anesthesia, and The Wolfson Brain Imaging Center, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
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Seki C, Kershaw J, Toussaint PJ, Kashikura K, Matsuura T, Fujita H, Kanno I. 15O Radioactivity clearance is faster after intracarotid bolus injection of 15O-labeled oxyhemoglobin than after 15O-water injection. J Cereb Blood Flow Metab 2003; 23:838-44. [PMID: 12843787 DOI: 10.1097/01.wcb.0000071889.63724.1f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The authors tested the hypothesis that the oxygen content of brain tissue is negligible by injecting an intracarotid bolus of 15O-labeled tracer into rats. Under the hypothesis, the clearance rates of 15O radioactivity from the brain after injections of both 15O-labeled water (H(2)15O) and 15O-labeled oxyhemoglobin (HbO15O) should be identical. However, the logarithmic slope of the 15O radioactivity curve after HbO15O injection (0.494 +/- 0.071 min-1) was steeper than that after H(2)15O injection (0.406 +/- 0.038 min-1) (P<0.001, n = 13), where the time range used in the comparison was between 60 and 120 seconds after the injection. A possible interpretation of this result is that nonmetabolized O15O may dwell in the brain tissue for a finite period of time before it is eventually metabolized or returned to the blood stream unaltered. These findings contradict assumptions made by models currently used to measure cerebral oxygen metabolism.
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Affiliation(s)
- Chie Seki
- Akita Laboratory, Japan Science and Technology Corporation, Akita, Japan
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Froomes PR, Sachinidis J, Ghabrial H, Tochon-Danguy H, Scott A, Ching MS, Morgan DJ, Angus PW. A novel method for determining hepatic sinusoidal oxygen permeability in the isolated perfused rat liver using [15O]O2. Nucl Med Biol 2003; 30:93-100. [PMID: 12623107 DOI: 10.1016/s0969-8051(02)00386-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Measurement of hepatic sinusoidal permeability of oxygen and other substrates may help elucidate the mechanisms responsible for impaired liver function in cirrhosis. However studies of sinusoidal oxygen permeability in normal liver and various disease states have been limited due to the considerable technical difficulties involved in the use of standard techniques. We have developed a new method for measuring sinusoidal oxygen permeability in the isolated perfused rat liver that overcomes the difficulties of previous methods by using [(15)O]O(2) and an in-line fluid monitor. This method uses data obtained from impulse response curves of radiolabelled red cells, albumin and oxygen that are fitted mathematically using the axial dispersion model to yield rate constants that describe oxygen transit through the liver. We have demonstrated the utility and reproducibility of this method by comparing multiple injections and permeability determinations in the same preparation. This approach could be used in isolated perfused organs to study oxygen permeability in a range of disease states.
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Affiliation(s)
- Paul R Froomes
- Department of Gastroenterology & Hepatology, University of Melbourne, Melbourne, Australia
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8
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Foerstendorf H, Benda C, Gärtner W, Storf M, Scheer H, Siebert F. FTIR studies of phytochrome photoreactions reveal the C=O bands of the chromophore: consequences for its protonation states, conformation, and protein interaction. Biochemistry 2001; 40:14952-9. [PMID: 11732915 DOI: 10.1021/bi0156916] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The molecular changes of phytochrome during red --> far-red and reverse photoreactions have been monitored by static infrared difference spectroscopy using the recombinant 65 kDa N-terminal fragment assembled with a chromophore chemically modified at ring D or with a chromophore isotopically labeled with (18)O at the carbonyl group of ring A. This allows the identification of the C=O stretching vibrations of rings D and A. We exclude the formation of an iminoether in Pfr. The positions of both these modes show that the chromophore always remains protonated. The upshift of the C=O stretch of ring D in the first photoproducts is explained by a twisted methine bridge connecting rings C and D. The changes in the vibrational pattern during the red --> far-red conversion show that the backreaction is not just the reversal of the forward reaction. The infrared difference spectra of the fragment deviate very little from those of the full-length protein. The differences which are related to the lack of the C-terminal half of the protein constituting the signaling domain are possibly important for the understanding of the signaling mechanism.
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Affiliation(s)
- H Foerstendorf
- Sektion Biophysik, Institut für Molekulare Medizin und Zellforschung, Albert-Ludwigs-Universität, Albertstrasse 23, D-79104 Freiburg, Germany
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9
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Stoll HP, Hutchins GD, Winkle WL, Nguyen AT, Appledorn CR, Janzen I, Seifert H, Rübe C, Schieffer H, March KL. Advantages of short-lived positron-emitting radioisotopes for intracoronary radiation therapy with liquid-filled balloons to prevent restenosis. J Nucl Med 2001; 42:1375-83. [PMID: 11535728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
UNLABELLED Balloon catheters filled with liquid radioisotopes provide excellent dose homogeneity for intracoronary radiation therapy but are associated with risk for rupture or leakage. We hypothesized that the safety of liquid-filled balloons may be improved once positron emitters with half-lives below 2 h are used instead of the high-energy beta-emitters 166Ho, 186Re, or 188Re, all of which have a longer half-life of at least 17 h. METHODS To support this concept, the suitability of 18F (half-life, 109.8 min), 68Ga (half-life, 67.6 min), 11C (half-life, 20.4 min), 13N (half-life, 9.97 min), and 15O (half-life, 2.04 min) for intracoronary radiation therapy was evaluated. Potential tissue penetration of positron radiation was assessed in a series of phantom experiments using Gafchromic film. Antiproliferative efficacy of positrons emitted by 68Ga was investigated in vitro using cultured bovine aortic smooth muscle cells (BASMCs), and was compared with gamma-radiation emitted by 137Cs. To characterize the remaining risk, we estimated radiotoxicity after accidental intravascular balloon rupture on the basis of tabulated isotope-specific doses (ICRP 53) and compared these values with 188Re. RESULTS Half-dose depth of tissue penetration measured in phantom experiments was 0.29 mm for 18F, 0.42 mm for 11C, 0.54 mm for 13N, 0.79 mm for 15O, and 0.9 mm for 68Ga. Irradiation of cultured BASMCs with positron radiation (68Ga) induced dose-dependent inhibition of proliferation with complete proliferative arrest at doses exceeding 6 Gy. ED(50) and ED(80) were 2.5 +/- 0.4 Gy (mean +/- SD) and 4.4 +/- 0.8 Gy, respectively. Antiproliferative efficacy was equal to that of the 662-keV gamma-radiation emitted by 137Cs (ED(50), 3.8 +/- 0.2 Gy; ED(80), 8.0 +/- 0.3 Gy). Estimates made for patient whole-body and organ doses were generally below 50 mSv/1.85 GBq for all investigated positron emitters. The same dose estimates for 188Re were 6-20 fold higher. CONCLUSION Among the studied radioisotopes, 68Ga is the most attractive source for liquid-filled balloons because of its convenient half-life, sufficient positron energy (2.92 MeV), documented antiproliferative efficacy, and uncomplicated availability from a radioisotope generator. The safety profile for 68Ga is significantly better than that of 188Re, which suggests this radioisotope should be evaluated further in preclinical studies.
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Affiliation(s)
- H P Stoll
- Medical Clinic III, Cardiology, Department of Radiation Oncology, University Hospital Homburg/Saar, Germany
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10
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Ho D, Feng D. Rapid algorithms for the construction of cerebral blood flow and oxygen utilization images with oxygen-15 and dynamic positron emission tomography. Comput Methods Programs Biomed 1999; 58:99-117. [PMID: 10092026 DOI: 10.1016/s0169-2607(98)00069-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two rapid estimation algorithms for construction of cerebral blood flow (CBF) and oxygen utilization (CMRO) images with dynamic positron emission tomography (PET) are presented. These algorithms are based on the linear least squares (LLS) and generalized linear least squares (GLLS) methodologies. Using the conventional two-compartmental model and multiple tracer studies, we derived a linear relationship for brain tissue activity to arterial blood activity, time-integrated arterial blood activity and time-integrated brain tissue activity. The LLS technique is computationally efficient as no regression analysis is required, while GLLS is used to refine the estimates obtained from LLS. A comparative study using non-linear least squares regression (NLS) revealed excellent correlation between the new algorithms for various noise levels expected in clinical applications. A sensitivity analysis was performed to examine reliability and identifiability of the parameter estimates. In view of the results, LLS and GLLS provide rapid and reliable estimates of CBF and CMRO when applied to dynamic PET data. These algorithms are particularly suitable for pixel-by-pixel construction of high resolution and highly accurate PET functional images.
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Affiliation(s)
- D Ho
- Basser Department of Computer Science, The University of Sydney, NSW, Australia
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11
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Abstract
Oxygen, an essential molecule for life, is utilized not only for cellular respiration but also for biosynthesis and metabolism of various important biomolecules such as steroids, eicosanoids, and neuroactive substances. Since the oxygenases, oxygen-fixating enzymes, were found in 1950s, only stable isotopes (17O and 18O) have been utilized as a tracer for demonstration of oxygen incorporation into organic substances. This stable isotopic method is established, but is hardly applicable to complicated (crude and multi-cellular) systems. Therefore, we here developed a novel radiotracer technique for oxygen metabolism that employs the positron emitter 15O2, whose physical half-life is 2.07 min. In a model reaction with metapyrocatechase, one of the well-known dioxygenases, the substrate catechol was converted to the radioactive product which was identified as alpha-hydroxymuconic epsilon-semialdehyde by a very sensitive LC-radio-UV-MS combined method.
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Affiliation(s)
- Y Watanabe
- Subfemtomole Biorecognition Project, Japan Science and Technology Corporation, UUPC/JRDC Laboratory, Uppsala, Sweden.
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12
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Abstract
Epilepsy research using positron emission tomography (PET) has provided considerable new information about ictal and interictal dysfunctions in human epilepsy. Neuroreceptor mapping with PET ligands has revealed altered central benzodiazepine receptor and opiate receptor densities in partial epilepsies interictally, and regional increases in endogenous opioid peptide concentrations during absence seizures. Imaging of perfusion and glucose metabolism during cognitive processing has shown interictal abnormalities of regional activation in partial and generalized epilepsies. The diagnostically robust patterns of interictal glucose hypometabolism are not adequately explained by macrostructural and microstructural alterations in temporal lobe epilepsy. Current investigations of the pathophysiology of interictal hypometabolism must address ultrastructural and neurochemical factors. Clinical PET in presurgical evaluation of medically refractory epilepsies remains an active area of research, but remarkably little antiepileptic drug research has exploited PET techniques.
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MESH Headings
- Anticonvulsants/pharmacokinetics
- Anticonvulsants/pharmacology
- Brain/diagnostic imaging
- Brain/metabolism
- Brain/physiopathology
- Cerebrovascular Circulation
- Deoxyglucose/analogs & derivatives
- Epilepsy/diagnostic imaging
- Epilepsy/metabolism
- Epilepsy/physiopathology
- Epilepsy, Temporal Lobe/diagnostic imaging
- Epilepsy, Temporal Lobe/metabolism
- Epilepsy, Temporal Lobe/physiopathology
- Flumazenil/metabolism
- Fluorodeoxyglucose F18
- Glucose/metabolism
- Humans
- Oxygen Radioisotopes/metabolism
- Receptors, GABA-A/metabolism
- Receptors, GABA-A/physiology
- Receptors, Muscarinic/metabolism
- Receptors, Muscarinic/physiology
- Receptors, Opioid/metabolism
- Receptors, Opioid/physiology
- Tomography, Emission-Computed
- Water
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Affiliation(s)
- T R Henry
- Department of Neurology, Entory University School of Medicine, Atlanta, Georgia, USA
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13
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Abstract
PURPOSE The purpose of this work was to measure blood flow in tumors using a coincidence counting technique on patients undergoing treatment with neutrons. METHODS AND MATERIALS The half-time, Tw, for the washout of 15O from neutron-activated tumors was measured with two 10 cm NaI(Tl) crystals coupled to a PC-based coincidence counting system. Blood flow measurements were made in 33 patients, 19 of whom had cancers of the head and neck region, 6 had breast cancer, 5 had sarcomas, and 3 patients had mesotheliomas. RESULTS Blood flow as indicated by Tw of mobile 15O formed by neutron activation could be readily determined in tumors of patients undergoing neutron radiotherapy. The general reduction in the value for Tw was noted towards the end of treatment and did not seem to be dependent on the initial tumor volume. There was a tendency for larger lesions to be associated with longer half-times of 15O washout. CONCLUSION It appears possible to obtain a reasonable estimate of tumor blood flow using a simple coincidence counting technique. In view of the large variation in blood flow between tumors, it did not appear to be possible to identify potentially hypoxic tumors that would respond to neutron therapy.
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Affiliation(s)
- E R Hering
- Department of Medical Physics, Groote Schuur Hospital, Observatory, South Africa
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Tyrrell PJ, Warrington EK, Frackowiak RS, Rossor MN. Progressive degeneration of the right temporal lobe studied with positron emission tomography. J Neurol Neurosurg Psychiatry 1990; 53:1046-50. [PMID: 2292695 PMCID: PMC488312 DOI: 10.1136/jnnp.53.12.1046] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A 79 year old man with a twelve year progressive history of prosopagnosia and recent naming difficulty, in whom other intellectual skills were preserved, is described. Positron emission tomography (PET) revealed an area of right temporal lobe hypometabolism, with an additional area of less severe hypometabolism at the left temporal pole. This may represent an example of progressive focal cortical degeneration similar to that associated with primary progressive dysphasia, but affecting the right temporal lobe.
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Affiliation(s)
- P J Tyrrell
- Medical Research Council Cyclotron Unit, Hammersmith Hospital, London, United Kingdom
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15
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Herscovitch P. Cerebral blood flow and metabolism measured with oxygen-15 radiotracers. J Neuropsychiatry Clin Neurosci 1989; 1:S19-29. [PMID: 2535416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- P Herscovitch
- Positron Emission Tomography Section, NIH Clinical Center, Bethesda, Maryland 20892
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Evelhoch JL, Sapareto SA, Nussbaum GH, Ackerman JJ. Correlations between 31P NMR spectroscopy and 15O perfusion measurements in the RIF-1 murine tumor in vivo. Radiat Res 1986; 106:122-31. [PMID: 3961103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The tumor physiological environment is one of the least understood and most important factors in determining the response of solid tumors to cancer therapy. To examine several important characteristics of the tumor physiological environment we have used in situ photon activation-15O decay measurements (perfusion characteristics) and 31P surface coil-NMR spectroscopy (metabolic characteristics) to observe in vivo subcutaneous RIF-1 tumors grown in female C3H/Anf mice. The following correlations between the 15O perfusion characteristics and the 31P NMR metabolic characteristics in individual tumors were observed: a negative correlation between pH, as measured by NMR (pHNMR), and the inorganic phosphate to nucleosides triphosphate peak height ratio (Pi:NTP); for the well-perfused fraction of the tumor there is a positive correlation with both pHNMR and the phosphocreatine to nucleosides triphosphate peak height ratio (PCr:NTP), and a negative correlation with Pi:NTP. These correlations are interpreted as evidence for a direct relationship between the distribution of cellular physiological environments and the tumor metabolic state. Because these physiological characteristics affect tumor response to various therapeutic modalities and both measurements can be made on humans, it is suggested that these techniques may be of prognostic value in the clinical management of human cancer.
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Lenzi GL, Jones T, McKenzie CG, Buckingham PD, Clark JC, Moss S. Study of regional cerebral metabolism and blood flow relationships in man using the method of continuously inhaling oxygen-15 and oxygen-15 labelled carbon dioxide. J Neurol Neurosurg Psychiatry 1978; 41:1-10. [PMID: 621525 PMCID: PMC492955 DOI: 10.1136/jnnp.41.1.1] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A new technique for assessing regional oxygen use and blood flow has been applied to a wide range of neurological patients. The method couples the brain's high metabolic demand for oxygen with a shortlived radioactive form of this metabolite, namely oxygen-15 (half life: 2.1 min). This combination produces during the continuous inhalation of either molecular oxygen-15 or labelled carbon dioxide, steady state functional images of the brain which are relatively free of contribution from extracerebral tissues. These are complementary images in that they relate to regional oxygen uptake and blood flow and hence offer a direct insight to the regional demand-to-supply relationships within the brain in physiological and pathological conditions. In the clinical groups studied, metabolic and circulatory defects were observed and instances of cerebrovascular insufficiency and relative luxury perfusion were defined which hitherto have been deduced from indirect methods. The clinical acceptability of this non-invasive approach allowed us to study those categories of patients which normally do not warrant invasive examination.
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