Medical photonics research direction

Concerning the laws and knowledge of the interaction of light, especially laser and biological tissue, has attracted international attention and has become the application basis and premise of the laser biomedicine that is booming. For example, one of the key issues in the photodynamic therapy and diagnosis of tumors currently on the edge of clinical applications is how to design and confirm the light distribution in human tissues, which involves theoretical and experimental issues in various disciplines, among which The most important are the special ways in which light travels in tissues, the description of the optical properties of tissues, and the development and improvement of experimental techniques. All new problems in these research work must be solved with new thinking and means.

Although the model of light propagation in biological tissues has been initially established, the unified theory of biological tissue optics is far from mature. In this context, "Tissue optics" has emerged as a specialized discipline for studying the optical properties of biological tissues. It involves the most fundamental theoretical issues in medical photonics and further develops photomedicine (including photodiagnosis and light). The premise of treatment). Tissue optics is the theoretical basis of medical photonics technology. The problems of kinematics (such as the propagation of light) and dynamics (such as the detection of light) in the biological tissue are the main content of the research. The current main research tasks are: studying the optical properties of biological tissues and determining the rate of light energy per unit area of ​​a target. The former involves determining the optical basic parameters of the tissue from the measured light distribution and a certain light propagation model, which is called the "positive" problem; the latter derives the light distribution in the tissue from the optical basic parameters of the tissue and the light propagation model, belonging to " Reverse problem. In the current combination of consideration of international development trends and the possibilities offered by domestic realities, research should be carried out in the following areas:

Theoretical study on the transmission of light in biological tissues

At present, although the propagation model of light in biological tissues is preliminarily established by reference to neutron transmission theory, there is still a long way to go with the establishment of a unified theoretical framework system for tissue optics. The optical theory of biological tissues is far from mature, and there are many theoretical blank spots. To be filled. The reason for this situation naturally stems from the diversity and complexity of the biological tissue structure itself, and on the other hand is the result of insufficient theoretical tools. There is a need for more elaborate and accurate theories to replace existing models that are too simplistic, that is, to use more complex theories to describe the optical properties of biological tissues and the propagation behavior of light in them. One of the tasks that need to be done is to establish an accurate tissue optical model that reflects the spatial structure and size distribution of biological tissues, the scattering and absorption characteristics of various parts of the tissue, and the changes in refractive index under certain conditions; The second is to transform the transmission equation to adapt to the new conditions, and in some cases to find the basic properties of light transmission in biological tissues.

Monte Carlo simulation of optical transmission

Monte Carlo's computational simulation method has played an irreplaceable role in many fields. There have been some more successful algorithms, but new and more efficient algorithms should continue to be developed to accommodate the diversity and complexity of biological organizations. In addition to understanding the distribution of light in tissues, it is also exploring the empirical relationship between the macroscopic distribution of light in biological tissues and the fundamental parameters of its optical properties from a large number of numerical simulations. In addition, the Monte Carlo simulation method for developing unsteady optical transmission is also an important research direction, from which more information can be obtained than under steady-state conditions.

Measurement methods and techniques for tissue optical parameters

After the theory of light transmission in tissue is established, a key task is to determine the basic parameters of the optical properties of the tissue, especially the human body, namely the absorption coefficient, the scattering coefficient and the scattering phase function or the average scattering cosine g and the refractive index n. Once these light-to-tissue interaction parameters are known, the distribution of light energy flow rate or other parameter total reflectance R total transmittance T can be uniquely determined by the relevant transmission model under given illumination and boundary conditions. . At present, the measurement methods for the optical properties of biological tissues have yet to be further developed and improved, and non-destructive testing of living organisms is particularly important. In this respect, the measurement method of time resolution and frequency resolution is striking.

Biological tissue refractive index and dispersion relation

The assumed refractive index data (1.33-1.38) is used in various cases, but studies on the refractive index of biological tissues have been neglected to some extent. So far, people have not made a deep analysis of the refractive index of biological tissues in terms of concept, and have not yet fully grasped the accurate measurement method of refractive index of living body or even ex vivo tissue. Due to the difficulty of accurate measurement caused by the strong scattering of the tissue, reliable experimental data of various tissues of the human body have not yet been obtained. It has been proven that the refractive index and dispersion parameters of biological tissues are important both theoretically and experimentally for the in-depth study of tissue optics. In view of this, research should be conducted on the measurement and method of refractive index and dispersion parameters of biological tissues.

Flunixin Meglumine Injection COMPOSITION
Each 1ml contains Flunixin Meglumine 50mg.
DESCRIPTION
It is colorless to yellowish clear liquid.
INDICATIONS
For treatment of fever, inflammatory diseases, muscle pain and soft tissue pain in livestock, such as sow agalactia syndrome.
DOSAGE AND ADMINISTRATION
For intramuscular or intravenous administration.
Pigs: 0.04ml/kg body weight for a single dose.
Dogs and cats: 0.02-0.04ml/kg body weight for a single dose.
1-2 times daily, not more than 5 consecutive days.

Flunixin Meglumine

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