A frequency dependent differential photoacoustic cross-section (DPACS) over a large frequency band (100–1000 MHz) was computed, and subsequently, morphological parameters of a photoacoustic (PA) source were quantified. The Green’s function approach was utilized for calculating the DPACS for spheroidal droplets with varying aspect ratios, Chebyshev particles with different waviness and deformation parameters, and normal red blood cells and cells affected by hereditary disorders (e.g., spherocytosis, elliptocytosis, and stomatocytosis). The theoretical framework considers that PA waves propagate through an acoustically dispersive and absorbing medium and are detected by a planar detector of finite size. The frequency dependent DPACS profile was fitted with tri-axial ellipsoid, finite cylinder, and toroid form factor models to obtain size and shape information of the PA source. The tri-axial ellipsoid form factor model was found to provide better estimates of the shape parameters compared to other models for a variety of sources. The inverse problem framework may motivate developing PA-based technology to assess single-cell morphology.

中文翻译：

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用于源尺寸估计的频率相关差分光声横截面数据的系统分析

计算了大频带（100-1000 MHz）上的频率相关微分光声截面（DPACS），随后量化了光声（PA）源的形态参数。格林函数方法用于计算具有不同纵横比的球形液滴、具有不同波纹度和变形参数的切比雪夫粒子以及正常红细胞和受遗传性疾病（例如，球形红细胞增多症、椭圆形红细胞增多症和口形细胞增多症）影响的细胞的 DPACS。理论框架认为 PA 波通过声学色散和吸收介质传播，并由有限尺寸的平面探测器检测到。与频率相关的 DPACS 剖面采用三轴椭球体、有限圆柱体、和环形形状因子模型，以获得 PA 源的尺寸和形状信息。与其他模型相比，三轴椭球形状因子模型被发现可以更好地估计各种来源的形状参数。逆问题框架可能会推动开发基于 PA 的技术来评估单细胞形态。