Biomedical subjects

S Caorsi

Publications and source records attributed to S Caorsi.

6 recordsLinked to original sources

PubMed2000

Prediction of electromagnetic field distributions inside biological bodies by using an inverse scattering procedure based on a statistical cooling algorithm.

This paper presents an inverse scattering procedure based on a statistical cooling algorithm to predict the electromagnetic field inside a biological body. By knowing only the scattered electric field distribution in a set of observation points external to the biological model, this method seems to be able to predict the electromagnetic field distributions in the investigation domain, minimizing a suitable cost function. To this end, a numerical statistical procedure is used, which allows to treat functions with a large number of unknowns in an efficient manner and to exploit the so called a priori knowledge in the reconstruction process. Some preliminary results are reported, concerning simplified biological geometries, which clearly show the capabilities and effectiveness, and also the current limitations of the proposed approach. Finally, further advances for the proposed imaging technique are indicated and discussed.

Algorithms↗

PubMed2000

Analytical SAR computation in a multilayer elliptic cylinder: the near-field line-current radiation case.

In this paper, a previously proposed analytical procedure for the computation of the specific absorption rate (SAR) inside a biological elliptic cylinder model is extended to the case in which the body is illuminated under near-field conditions. The elliptic model is made up of layers of different biological tissues and the source is constituted by a line-current distribution. The recursive procedure in which the field is expressed in terms of Mathieu function is modified to express the incident electromagnetic wave produced by the line current. The new procedure makes it possible to check and validate numerical solutions obtained by accurate numerical techniques for SAR prediction, under more realistic illumination condition.

Absorption↗

PubMed1999

EM field prediction inside lossy multilayer elliptic cylinders for biological-body modeling and numerical-procedure testing.

In this paper, a biological model made up of a multilayer elliptic cylinder is considered. This canonical scattering problem is solved by a recursive procedure, which has been generalized to the case of lossy materials by using the analytical properties of Mathieu functions. Although it is a simplified model, this stratified configuration may simulate better than circular cylinders the local behavior of biological subsystems. In addition, it represents an effective tool for producing analytical data for testing direct-scattering numerical codes in biomedical applications and for the evaluation of reconstruction procedures in medical imaging.

Animals↗

PubMed1999

Analytic SAR computation in a multilayer elliptic cylinder for bioelectromagnetic applications.

The specific absorption rate (SAR) is usually considered as the basic quantity to derive the reference levels for the exposure of workers and general population. In this paper, we propose an analytical procedure for the SAR computation inside a biological elliptic cylinder model made up of layers of different biological tissues. The procedure makes it possible to obtain accurate SAR values in simplified models of biological subsystems, and it is also helpful to test numerical techniques to be used for more realistic models and to generate synthetic input data for diagnostic methodologies. For the assumed model, the calculation of the analytical solution has been obtained by generalizing a known procedure that deals only with lossless materials, and the model makes possible the calculation of the SAR for realistic human tissues. Various calculations prove the reliability of the technique.

Biophysical Phenomena↗

PubMed1994

An electromagnetic imaging approach using a multi-illumination technique.

An approach to microwave imaging using a multi-illumination technique is proposed. The numerical solution is reached by a multi-illumination-angle multiview approach based on the moment method. The aim is to extend the application range of the Born approximation by utilizing a-priori information about a scatterer. The basic idea of the approach is outlined, and preliminary results are reported.

Bias↗

PubMed1991

Numerical algorithm for dielectric-permittivity microwave imaging of inhomogeneous biological bodies.

A two-dimensional microwave system is developed to explore the possibility of imaging the distribution of dielectric permittivity in an inhomogeneous biological body. A multiview approach is presented, which can notably improve the system's performance; it makes use of an illumination source that rotates jointly with the observation domain in which the scattered electric field is to be measured. The equation for inverse electromagnetic scattering is transformed into matrix form through the application of the moment method. A pseudoinversion algorithm is used to determine the distribution of the dielectric properties of the scattering body. A look-up table is devised to quickly form the final image. The results of some numerical simulations are reported to point out the capabilities and limitations of the method.

Algorithms↗