Photoacoustic Spectroscopy Pre-test Of Thyroid Tissue Based On Focused Ultrasonic Transducer

Photoacoustic spectrum technology (PAST) is a novel noninvasive testing technology, which provides an effective and noninvasive way for biomedical materials research, being highly sensitive and without sample pretreatment. Compared with the traditional spectrum technology, photoacoustic spectrum technology effectively combine the good transmission characteristics of ultrasonic with the selective absorption of light, effectively overcome the traditional spectrum technology is interfered seriously by the scattered light and the reflected light while scanning depth is limited.so the PAST Can be achieved noninvasive spectral detection to organization body in a larger depth, which exists great potential to achieve the early diagnosis of some diseases. In this thesis, based on the powerful advantages of photoacoustic detection technology in biological tissue, and make full use of the research condition in our laboratory to carry out research of spectrum of biological tissue based on the focused Photoacoustic spectrum detection system, and explore the influence of irradiation light spot size to the system resolution. The main research works of this thesis are as follows:1. The development situation of photoacoustic spectroscopy technology is reviewed, including its basic principle, technological advantages, and photoacoustic spectral technology in domestic and overseas research progress, achievements, and in the field of biomedical applications.2. Photoacoustic spectral technology theoretical basis is discussed, including the mechanism of photoacoustic signal and the formation and transmission of photoacoustic signal in the biological tissue, and introduced various typical experimental apparatus of photoacoustic spectrum according to different samples,as well as the advantages and disadvantages of them.3. The focused photoacoustic spectrum detection system based on focused ultrasound transducer is introduced in detail, and the superiority of the system is analyzed.4. Under the condition of Photoacoustic detection depth is not affected, make Preliminary study to the method of improve system resolution by adjusting focus light spot size of the excitation light source, hoping make help to achieve early diagnosis of the disease.5. The studies of photoacoustic spectrum of in vitro malignant lesions and normal tissue of human thyroid were carried out based on focus photoacoustic spectroscopy experiment system. This pilot study could verify the difference between both tissues in the photoacoustic spectroscopy. It has been shown that the method has the potential to distinguish between malignant thyroid tissue and normal thyroid tissue.