PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 3905256

Positron emission tomography.

A A Lammertsma·R S Frackowiak
View original source ↗Export metadata ↓

Abstract

Positron computed tomography allows for the in vivo measurement of the regional tissue concentration of positron-emitting radionuclides such as 15O, 11C, 13N, and 18F. By using different tracers, a variety of metabolic processes can be quantitated. These include blood flow, oxygen utilization, glucose utilization, amino acid transport, blood volume, cation exchange, pH, and others. This review will contain three sections. First, the principles of positron computed tomography and the progress in instrumentation will be discussed. Second, tracer models will be analyzed. These models are vital in the extraction of physiological data from the measurements of activity. Finally, clinical studies will be evaluated in terms of new pathophysiological information obtained.

Explore related subjects

Biomedical EngineeringBiometryBiophysical PhenomenaBiophysicsBlood VolumeBrainBrain DiseasesCoronary DiseaseElectronsGamma RaysGlucoseHeartHumansLungNeoplasmsOxygen ConsumptionRadioisotopesRegional Blood FlowTomography, Emission-ComputedJournal ArticleReview

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A A Lammertsma, R S Frackowiak. 1985. Positron emission tomography.. https://pubmed.ncbi.nlm.nih.gov/3905256/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Optimal design of non-Newtonian, micro-scale viscous pumps for biomedical devices.

The present paper addresses the numerical optimization of geometrical parameters of non-Newtonian micro-scale viscous pumps for biomedical devices. The objective is to maximize the mass flow rate per unit of shaft power consumed by the rotor when an external pressure load is applied along the channel that houses the rotor. Two geometric parameters are considered in the optimization process: (i) the height of the channel that houses the rotor (H) and (ii), the eccentricity (epsilon) of the rotor. Three different micro-scale viscous pump configurations were tested: a straight-housed pump (I-shaped housing) and two curved housed pumps (L- and U-shaped housings). The stress-strain constitutive law is modeled by a power-law relation. The results show that the geometric optimization of micro-scale viscous pumps is critical since the mass flow rate propelled by the rotor is highly dependent on epsilon and H. Numerical simulations indicate that mass flow rate is maximized when epsilon approximately 0, namely when the rotor is placed at a distance of 0.05 radii from the lower wall. The results also show that micro-scale viscous pumps with curved housing provide higher mass flow rate per unit of shaft power consumed when compared with straight-housed pumps. The results are presented in terms optimized dimensions of all three configurations (i.e., H(opt) and epsilon(opt)) and for values of the power-law index varying between 0.5 (shear thinning fluids) and 1.5 (shear-thickening fluids).

Biomedical Engineering↗