University of Georgia, Regenerative Bioscience Center, Rhodes Center for ADS, Athens, Georgia, United States.
University of Georgia, College of Engineering, Athens, Georgia, United States.
J Biomed Opt. 2017 Mar 1;22(3):36012. doi: 10.1117/1.JBO.22.3.036012.
Optical aberrations significantly affect the resolution and signal-to-noise ratio of deep tissue microscopy. As multiphoton microscopy is applied deeper into tissue, the loss of resolution and signal due to propagation of light in a medium with heterogeneous refractive index becomes more serious. Efforts in imaging through the intact skull of mice cannot typically reach past the bone marrow ( ? 150 ?? ? m of depth) and have limited resolution and penetration depth. Mechanical bone thinning or optical ablation of bone enables deeper imaging, but these methods are highly invasive and may impact tissue biology. Adaptive optics is a promising noninvasive alternative for restoring optical resolution. We characterize the aberrations present in bone using second-harmonic generation imaging of collagen. We simulate light propagation through highly scattering bone and evaluate the effect of aberrations on the point spread function. We then calculate the wavefront and expand it in Zernike orthogonal polynomials to determine the strength of different optical aberrations. We further compare the corrected wavefront and the residual wavefront error, and suggest a correction element with high number of elements or multiconjugate wavefront correction for this highly scattering environment.
光学像差会显著影响深层组织显微镜的分辨率和信噪比。随着多光子显微镜在组织中应用得越来越深，由于光在具有不均匀折射率的介质中传播而导致的分辨率和信号损失变得更加严重。在不破坏完整老鼠颅骨的情况下进行成像的尝试通常无法穿透骨髓（深度为? 150??? m），而且分辨率和穿透深度有限。机械性骨变薄或骨的光消融可以实现更深的成像，但这些方法具有高度侵入性，可能会影响组织生物学。自适应光学是一种有前途的非侵入性替代方法，可以恢复光学分辨率。我们使用胶原的二次谐波成像来描述骨中的像差。我们模拟了光在高度散射的骨中的传播，并评估了像差对点扩散函数的影响。然后，我们计算波前并将其展开为泽尼克正交多项式，以确定不同光学像差的强度。我们进一步比较了校正后的波前和残余波前误差，并建议在这种高度散射的环境中使用具有高元件数或多共轭波前校正的校正元件。
