Radiant energy – Invisible radiant energy responsive electric signalling – Infrared responsive
Patent
1994-09-06
1997-03-11
Hannaher, Constantine
Radiant energy
Invisible radiant energy responsive electric signalling
Infrared responsive
G01N 2149
Patent
active
056103999
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an apparatus and a process for the spatially resolving optical determination of density distributions in biological tissues.
A series of apparatuses or processes have long been known for the imaging investigation of human tissues. Thus, for example, X-rays are used in order to obtain images of the human skeletal structure with good contrast. In the detection of tumors, where the density differences to be detected between the different tissue constituents are in some cases smaller than 5%, the image quality which can attained in this fashion is however often insufficient for a reliable diagnosis. The use of X-rays is moreover disadvantageous in that they have an ionizing effect on the irradiated body parts.
NMR spectroscopic in vivo investigations are also known and offer only limited possibilities of evaluation in the case of such small optical density differences in the tissue. Moreover, such processes are expensive and require long measurement times.
Therefore, for the imaging diagnosis of biological tissues, optical processes which are to avoid the known disadvantages of X-ray or NMR spectroscopic investigation processes have been sought for a considerable time. Such apparatuses or processes on an optical basis are described, for example, in U.S. Pat. No. 4,972,331. It is furthermore known from the publication by J. M. Schmitt et al., "Use of polarized light to discriminate shortpath photons in a multiply scattering medium" (Applied Optics, Vol. 31, No. 30, pp. 6353-6546) how the detection of "foreign bodies" in strongly scattering media can be effected by means of infrared irradiation and in particular by the evaluation of the components of the scattered radiation.
However, the optically based apparatuses or processes from the said publications have in common the disadvantage that only qualitative statements can be made concerning the presence of certain tissue components, e.g., tumors. Thus it is however not possible to localize such tissue components precisely in the tissue or to exactly determine their dimensions.
The object of the present invention is therefore to provide a process for eliminating the above mentioned disadvantages of the prior art. The process of the present invention comprises as a first step irradiating a biological tissue by directing a locally confined beam of electromagnetic radiation at an incidence position of the tissue, keeping the incidence position fixed, determining the thickness of the tissue being irradiated, and sensing and recording the directly transmitted radiation component and the scattered radiation components in a spatially resolved manner over a defined spatial angle. The process further comprises, as a second step, changing the incidence position of the beam of electromagnetic radiation and repeating the first step. Additionally, the process comprises as a third step repeating the second step a number of times to obtain a reconstructive representation of the tissue through which the radiation has passed, based on the spatially resolved recordings of the transmitted and scattered radiation components and the tissue thickness determined in each repetition of the first step.
The use, according to the invention, of a scanning unit which makes possible both the defined positioning of a locally confined beam of radiation from a radiation source and also the simultaneous spatially resolved recording of the transmitted radiation components now makes possible the highly precise, spatially resolved determination of density distributions or density changes in biological tissues. Thus, for example, precise statements can be made concerning the localization in human tissues of tumors which have different optical densities in comparison with the surrounding healthy tissue. Likewise exact information is now accessible concerning the dimensions of such altered density distributions.
Besides the primarily desired spatially resolving detection of local density changes in the tissue, the apparatus according to the invention can however also be
REFERENCES:
patent: 4515165 (1985-05-01), Carroll
patent: 4948974 (1990-08-01), Nelson et al.
patent: 5148022 (1992-09-01), Kawaguchi et al.
Beuthan Jurgen
Kaschke Michael
Minet Olaf
Muller Gerhard
Carl-Zeiss-Stiftung
Hannaher Constantine
LandOfFree
Apparatus and process for the spatially resolved optical determi does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and process for the spatially resolved optical determi, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and process for the spatially resolved optical determi will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-445163