Medical imaging techniques, such as X-ray imaging, magnetic resonance imaging and ultrasound imaging, have played an important role in preoperative accurate diagnosis and postoperative efficacy evaluation. However, in the course of surgery, there is still no objective and effective imaging technology. Surgeons mainly rely on the eyes and hands to distinguish the color, texture and morphology between tissues to remove the lesions. There is an urgent need for an objective and effective imaging technique to display the location and shape of the lesion in real-time during the operation to assist the doctor in performing precise resection. In addition, avoiding damage to important tissue structures such as nerves, blood vessels, urinary tracts, and bile ducts can help achieve better surgical outcomes and prognosis. How to accurately locate the boundary of the lesion during the operation, find small lesions, and identify important tissue structures is a challenging problem in current clinical practice.
The emerging optical molecular imaging technology is expected to solve this clinical challenge. Optical molecular imaging is a new in-vivo and real-time imaging technology, which can truly reflect the expression of a gene or the biological characteristics of a macromolecular, and dynamically record and display molecular events and their dynamic processes. Near infrared fluorescence imaging technology uses a light source of specific wavelength to stimulate cells or reporter genes or fluorescent dyes in the organism to obtain fluorescence information of the target region. The technology has the advantages of high sensitivity, high specificity, low background noise and large penetration depth, and has become a hotspot of international research. This paper focuses on the navigation technology in near-infrared fluorescence imaging, and carries out the whole-chain and series work in three aspects: imaging method, equipment development and clinical application. The main research content and innovation points of this paper are as follows:
1. In the aspect of imaging method, aiming at the noise distribution characteristics of near-infrared fluorescence images, a noise reduction algorithm based on wavelet threshold and fuzzy c-means clustering is proposed, which effectively removes interference signals, reduces the inherent noise and improves the resolution of the device. In order to better display the information contained in fluorescent images, a real-time visualization method of surgical navigation based on image fusion is proposed, which maximizes the efficiency of fluorescence information transmission while minimizing the loss of original anatomical structure information, and realizes real-time fusion and high-definition display of dual-channel color images and fluorescent images.
2. In the aspect of equipment development, aiming at the problem of weak fluorescence signal and strong ambient light interference, we have established a high-sensitivity high-precision detection mathematical model based on weak fluorescence signal, and designed an optical system with large field of view and large relative aperture and high uniformity. The signal acquisition capability and anti-interference ability of the device enable high signal-to-background ratio and low noise imaging. For the simultaneous rapid imaging of color images and fluorescent images, a high-sensitivity high-resolution near-infrared fluorescence image-guided device for clinical open and minimally invasive surgery have been developed through innovative light path and optical components and modular system design. Simultaneous imaging of high frame rate of color images and fluorescent images is realized.
3. In the aspect of clinical application, in response to the low detection rate of traditional blue staining in breast cancer sentinel lymph node biopsy, a multi-center clinical trial was conducted in conjunction with Chinese PLA General Hospital, Yijishan Hospital and the affiliated Cancer Hospital of Shantou University Medical College. A total of 99 breast cancer patients were enrolled, and the detection rate of sentinel lymph nodes was increased from 69.9% to 95.5%. For the problem that sympathetic nerves could not be accurately located in thoracic surgery, a single-center clinical trial was conducted jointly with Peking University People's Hospital. A total of 15 patients with pulmonary nodules were enrolled, and the ganglion detection rate was 100%, which achieved significant clinical results.