Saha Ratan K
Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India.
J Acoust Soc Am. 2014 Oct;136(4):2039-49. doi: 10.1121/1.4894794.
A theoretical approach to model photoacoustic (PA) signals from mixtures of melanoma cells (MCs) and red blood cells (RBCs) is discussed. The PA signal from a cell approximated as a fluid sphere was evaluated using a frequency domain method. The tiny signals from individual cells were summed up obtaining the resultant PA signal. The local signal to noise ratio for a MC was about 5.32 and 5.40 for 639 and 822 nm illuminations, respectively. The PA amplitude exhibited a monotonic rise with increasing number of MCs for each incident radiation. The power spectral lines also demonstrated similar variations over a large frequency range (5-200 MHz). For instance, spectral intensity was observed to be 5.5 and 4.0 dB greater at 7.5 MHz for a diseased sample containing 1 MC and 22,952 RBCs than a normal sample composed of 22,958 RBCs at those irradiations, respectively. The envelope histograms generated from PA signals for mixtures of small numbers of MCs and large numbers of RBCs seemed to obey pre-Rayleigh statistics. The generalized gamma distribution found to facilitate better fits to the histograms than the Rayleigh and Nakagami distributions. The model provides a means to study PAs from mixtures of different populations of absorbers.
讨论了一种对来自黑色素瘤细胞（MCs）和红细胞（RBCs）混合物的光声（PA）信号进行建模的理论方法。使用频域方法评估了近似为流体球体的细胞的PA信号。将单个细胞的微小信号相加得到合成PA信号。对于MC，在639和822 nm光照下，局部信噪比分别约为5.32和5.40。对于每次入射辐射，PA幅度随MC数量的增加呈单调上升。功率谱线在较大频率范围（5 - 200 MHz）内也表现出类似变化。例如，在那些照射下，对于含有1个MC和22,952个RBCs的患病样本，在7.5 MHz处观察到的光谱强度分别比由22,958个RBCs组成的正常样本高5.5和4.0 dB。由少量MC和大量RBCs混合物的PA信号生成的包络直方图似乎服从瑞利前统计。发现广义伽马分布比瑞利分布和中谷分布更能拟合直方图。该模型提供了一种研究来自不同吸收体群体混合物的PA的方法。
