Intracranial hypertension is a serious threat to the health of neurosurgical patients. At present, there is a lack of a safe and effective technology to monitor intracranial pressure (ICP) accurately and nondestructively. In this paper, based on near infrared technology, the continuous nondestructive monitoring of ICP change caused by brain edema was studied. The rat brain edema models were constructed by lipopolysaccharide. The ICP monitor and the self-made near infrared tissue parameter measuring instrument were used to monitor the invasive intracranial pressure and the reduced scattering coe±cient of brain tissue during the brain edema development. The results showed that there was a negative correlation between the reduced scattering coe±cient (690nm and 834nm) and ICP, and then the mathematical model was established. The experimental results promoted the development of nondestructive ICP monitoring based on near infrared technology.

Because the brain edema has a crucial impact on morbidity and mortality, it is important to develop a noninvasive method to monitor the process of the brain edema effectively. When the brain edema occurs, the optical properties of the brain will change. The goal of this study is to access the feasibility and reliability of using noninvasive near-infrared spectroscopy (NIRS) monitoring method to measure the brain edema. Specifically, three models, including the water content changes in the cerebrospinal fluid (CSF), gray matter and white matter, were explored. Moreover, these models were numerically simulated by the Monte Carlo studies. Then, the phantom experiments were performed to investigate the light intensity which was measured at different detecting radius on the tissue surface. The results indicated that the light intensity correlated well with the conditions of the brain edema and the detecting radius. Briefly, at the detecting radius of 3.0 cm and 4.0 cm, the light intensity has a high response to the change of tissue parameters and optical properties. Thus, it is possible to monitor the brain edema noninvasively by NIRS method and the light intensity is a reliable and simple parameter to assess the brain edema.

During neurosurgery, an optical probe has been used to guide the micro-electrode, which is punc-tured into the globus pallidus (GP) to create a lesion that can relieve the cardinal symptoms. Accurate target localization is the key factor to affect the treatment. However, considering the scattering nature of the tissue, the “look ahead distance (LAD)" of optical probe makes the boundary between the different tissues blurred and difficult to be distinguished, which is defined as artifact. Thus, it is highly desirable to reduce the artifact caused by LAD. In this paper, a real-time algorithm based on precise threshold was proposed to eliminate the artifact. The value of the threshold was determined by the maximum error of the measurement system during the calibration procession automatically. Then, the measured data was processed sequentially only based on the threshold and the former data. Moreover, 100 m double-fiber probe and two-layer and multi-layer phantom models were utilized to validate the precision of the algorithm. The error of the algorithm is one puncture step, which was proved in the theory and experiment. It was concluded that the present method could reduce the artifact caused by LAD and make the real boundary sharper and less blurred in real-time. It might be potentially used for the neurosurgery navigation.

为了解决现有光学塑料镜片表面易划伤、高温时容易发生膜裂的问题, 选取机械性能稳定的Ti3O5、SiO2作为高、低折射率材料, 依据光学薄膜理论, 采用TFCalc软件设计膜系, 通过电子束加热蒸发和离子源辅助沉积薄膜, 在膜系的最外层用电阻加热法镀制防水膜。通过选择新材料SV-55作为连接层, 增强了塑料镜片与膜层的附着力, 解决了膜系与塑料镜片膨胀系数不匹配的问题, 提高了塑料镜片的抗温能力。通过优化工艺参数, 得到400 nm~700 nm反射率R≤1%的绿色减反膜。测试结果显示, 研制的薄膜具有耐摩擦、抗老化、防水和防油污的特性。