近红外光谱的阵列扫描式灵敏度法探测颅脑血肿

Detection of Craniocerebral Hematoma by Array Scanning Sensitivity Based on Near Infrared Spectroscopy

利用近红外光谱技术对脑组织进行检测实现脑血肿的定位一直以来都是无损光学诊断的研究热点。为了实现开放式全方位的精准探测,基于功能性近红外光谱技术提出一种新的方法—阵列扫描式灵敏度法,即建立全方位阵列探测器,通过单边阵列式扫描检测来获取不同探测位置的光通量,计算每个探测器的探测灵敏度,就能得到全方位的探测信息。首先,建立单层有限元模型,设置光学参数、光源、探测位置及边界条件,将仿真结果与蒙特卡洛的运行结果进行对比,验证有限元模型条件设置的准确性。其次,根据人脑组织结构建立脑部模型,在模型中插入血肿,选择波长为850 nm的近红外光作为光源,设置该波长下各层生物组织的光学参数,模拟光子在正常脑组织与含血肿脑组织中的传播,在距光源不同位置的探测器处检测到多组光通量数据,处理数据后发现有限元仿真软件在图像、数据方面反映了血肿对光的传播有极大影响。为研究探测到的光通量信息与血肿位置之间的关系,基于近红外光谱技术采用阵列扫描式灵敏度法分别改变组织内血肿的方位、横向位置与纵向深度,在距光源不同的探测位置处检测到多组光通量数据,处理数据后建立血肿位置与对应探测灵敏度之间的关系图进行分析。结果显示采用阵列扫描式灵敏度法,近红外光谱技术能准确探测血肿的方位信息与横向信息,且血肿位于源—探测距离中间时,探测效果最佳,而纵向深度只影响光子穿过较深层组织的概率,位置越深,光子的穿过率越小,探测灵敏度越小。由此得出,基于阵列扫描式灵敏度法可以实现颅脑组织内一定深度处血肿的快速准确定位,为近红外光谱技术的光学成像、检测组织内部肿瘤等提供了新思路和有效参考。

The localization of brain hematoma by using functional near-infrared Spectroscopy has always been a research hotspot in the field of nondestructive optical diagnosis.To achieve open and all-around accurate detection,this paper proposes a new method based on functional near-infrared spectroscopy,the Array scanning sensitivity method.Namely to establish an omni-directional array detector,unilateral array scanning tests to get the fluence rate of different probe locations.By calculating the detection sensitivity,we can get a full range of detection information.Firstly,establish the monolayer finite element model,set optical parameters,light source,detection position and boundary conditions.The simulation results are compared with Monte Carlo to verify the accuracy of the conditions.Secondly,build a brain model with hematoma based on the structure of the brain,the light source selects near-infrared light with a wavelength of 850 nm,the optical parameters of biological tissue at this wavelength are set,simulate the propagation of photons in normal brain tissue and brain tissue with hematoma,and multiple sets of luminous flux data are detected at different locations.After processing the data,it is found that the finite element simulation software can reflect the significant influence of hematoma on the transmission of light in images and data.To study the relationship between luminous flux and the location of the hematoma,the azimuth,horizontal position and depth of the hematoma were changed respectively.Multiple sets of luminous flux data were also detected,the relationship between sensitivity and hematoma location was established for analysis.The results show that the azimuth and horizontal position of the hematoma can be accurately detected by the array scanning sensitivity method,and the detection effect is the best when the hematoma is located between the source and the detection distance.The depth only affects the overall luminous flux,and the deeper the position,the smaller the sensitivity.It is concluded that the array scanning sensitivity method can be used to quickly and accurately locate hematoma in a certain depths of brain tissue,which provides a new way of thinking and an effective reference for detecting tumors and optical imaging in tissue by near-infrared spectroscopy.