Random Euclidean matching problems in one dimension.

We discuss the optimal matching solution for both the assignment problem and the matching problem in one dimension for a large class of convex cost functions. We consider the problem in a compact set with the topology both of the interval and of the circumference. Afterwards, we assume the points' positions to be random variables identically and independently distributed on the considered domain.

Finite-size corrections in the random assignment problem.

We analytically derive, in the context of the replica formalism, the first finite-size corrections to the average optimal cost in the random assignment problem for a quite generic distribution law for the costs. We show that, when moving from a power-law distribution to a Γ distribution, the leading correction changes both in sign and in its scaling properties. We also examine the behavior of the corrections when approaching a δ-function distribution.

The ECAT ART Scanner for Positron Emission Tomography. 2. Research and Clinical Applications.

The ECAT ART is a low-cost positron emission tomography (PET) scanner design for which increasing interest in the use of PET, and specifically (18)FDG PET for oncological studies, has stimulated a demand. Although targeted primarily for the clinical market, the performance of the ART scanner can also meet the demands of a research environment where, in addition to [(18)F], more challenging, shorter-lived isotopes such as [(11)C], [(13)N] and [(15)O] are used. The ART has been used successfully to perform quantitative (18)FDG studies, blood flow measurements with [(15)O]water, and brain mapping studies with [(15)O]water (activation).

Image analysis in patients with cancer studied with a combined PET and CT scanner.

Purpose: To compare combined whole-body PET and CT images of different cancers with PET images alone.

Materials And Methods: Thirty-two patients with known or possible cancers were examined using a combined positron emission tomographic (PET) and computed tomographic (CT) scanner. All data were acquired using this same combined scanner.