1 内蒙古科技大学 信息工程学院，内蒙古包头市0400
2 内蒙古工业大学 信息工程学院，内蒙古呼和浩特010051
U型网络结构的脑肿瘤自动分割方法由于多次卷积和采样操作会造成信息损失，导致分割效果不佳。为解决这一问题，提出了能够利用语义信息流引导上采样特征恢复的特征对齐单元，并在此基础上设计轻量级的双重注意力特征对齐网络（DAFANet）。首先，将特征对齐单元分别引入3D UNet、DMFNet和HDCNet三个经典网络，以验证其有效性和泛化性。其次，在DMFNet基础上构造轻量级的双重注意力特征对齐网络DAFANet，利用特征对齐单元强化上采样过程中的特征恢复，3D期望最大化注意力机制同时作用于特征对齐路径和级联路径，用于重点获取上下文的全程依赖关系。同时使用广义Dice损失函数提升数据不平衡时的分割精度并加快模型收敛。最后，在BraTS2018和BraTS2019公开数据集进行验证，文中所提算法在ET，WT和TC区域的分割精度分别达到80.44%，90.07%，84.57%和78.11%，90.10%，82.21%。相较于当前流行的分割网络，具有对增强肿瘤区域更好的分割效果，更擅长处理细节和边缘信息。
脑肿瘤 图像分割 特征对齐 注意力机制 轻量化 brain tumors image segmentation feature alignment attention mechanism lightweight
Author Affiliations
Abstract
1 Laser Microbeam and Medical Program Beckman Laser Institute, University of California Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA
2 Department of Radiation Oncology University of California, Irvine, California 92697, USA
Two-photon excited fluorescence (TPEF) spectroscopy and imaging were used to investigate the effects of gamma-irradiation on neural stem and precursor cells (NSPCs). While the observed signal from reduced nicotinamide adenine dinucleotide (NADH) was localized to the mitochondria, the signal typically associated with oxidized flavoproteins (Fp) was distributed diffusely throughout the cell. The measured TPEF emission and excitation spectra were similar to the established spectra of NAD(P)H and Fp. Fp fluorescence intensity was markedly increased by addition of the electron transport chain (ETC) modulator menadione to the medium, along with a concomitant decrease in the NAD(P)H signal. Three-dimensional (3D) neurospheres were imaged to obtain the cellular metabolic index (CMI), calculated as the ratio of Fp to NAD(P)H fluorescence intensity. Radiation effects were found to differ between low-dose (≤ 50 cGy) and high-dose (≥ 50 cGy) exposures. Low-dose irradiation caused a marked drop in CMI values accompanied by increased cellular proliferation. At higher doses, both NAD(P)H and Fp signals increased, leading to an overall elevation in CMI values. These findings underscore the complex relationship between radiation dose, metabolic state, and proliferation status in NSPCs and highlight the ability of TPEF spectroscopy and imaging to characterize metabolism in 3D spheroids.
Multiphoton microscopy cellular metabolic index gamma radiation brain tumors NAD(P)H flavoproteins Journal of Innovative Optical Health Sciences
2011, 4(3): 289
