Research Of Physical Mechanism And Improved Mechanism Based On Cerenkov Biological Imaging Technique

Molecular imaging technology is a novel research that shows the specific molecule of organization level, cellular and subcellular level using imaging technologies, reflects the molecular change in vivo, researches the biological behavior in terms of images qualitatively and quantitatively. With the application of the new technology, molecular imaging technology has become one of the most development potential of frontier science. In recent years, biological imaging technology based on Cerenkov Effect has become a research focus between domestic and foreign researchers.This dissertation mainly simulates the transport process of radioactive particles and Cerenkov photons in biological tissue by use of Monte Carlo method, analyzes and verifies the physical mechanism and feasibility of Cerenkov biological imaging, meanwhile discuss the effectiveness and physical mechanism of quantum dots extend the wavelength of Cerenkov light in order to improve the quality of Cerenkov luminescence imaging. The major research contents are outlined as follows:(1) Using the Monte Carlo method, simulate the process that Cerenkov light produced by decay particles from three kinds of radioactive source(18F, 131 I, 32P), transmit in the biological tissue and image, research the physical mechanism and feasibility of Cerenkov luminescence imaging, discuss the factors and laws that affect the quality of Cerenkov luminescence imaging.(2) Analyze the process of photons in different wavelengths within Cerenkov light wavelength range transport in the biological tissue. The results prove that make the wavelength of Cerenkov light "red-shift" over 650 nm, can increase the penetrability of Cerenkov light in biological tissue. Through experiment, analyze and verify the effectiveness that utilize Stokes effect produced by CdTe quantum dots, improve the quality of Cerenkov luminescence imaging of produced by 131 I.(3) Research of interaction mechanism between quantum dots and β particles, γ-rays, Cerenkov photons produced by radionuclide. The results prove that quantum dots excited by isotope with different radioactivity, the number of photons emitted from quantum dots and the radioactivity are fitted with a linear relationship; different concentration of quantum dots excited by isotope of same radioactivity, the number of photons and radioactivity are fitted with a linear relationship as well; the number of photons decrease exponentially when the distance between quantum dots and radionuclide is increasing; the quotient of the number of photons emitted from quantum dots excited by Cerenkov light is 20%, meanwhile the quotient excited by the β rays and γ rays are 80%...