Validity of a theoretical model to examine blood oxygenation dependent optoacoustics

Saha, Ratan K.; Karmakar, Subhajit; Hysi, Eno; Roy, Madhusudan; Kolios, Michael C.

doi:10.1117/1.jbo.17.5.055002

Cited by 20 publications

(23 citation statements)

References 35 publications

(53 reference statements)

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“…Experimental measurements have shown that the frequency location of these spectral minima shift depending on the RBC morphology, which can be used to differentiate healthy and unhealthy RBCs [31]. Other theoretical and experimental studies of RBCs show that UHF spectral features can be used to detect RBC morphological variations due to malaria infection [32], RBC oxygenation [33], and RBC aggregation [34] due to changes in the UHF spectrum.…”

Section: Resultsmentioning

confidence: 99%

High frequency label-free photoacoustic microscopy of single cells

2013

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Photoacoustic measurements of melanoma cells and red blood cells (RBCs) using ultra-high frequency (UHF) wide-bandwidth transducers are reported. In this detection system, the resolution typically depends on the parameters of the receiving transducer, and not the focus of the laser. A single melanoma cell was imaged with 200, 375 and 1200 MHz transducers. As the frequency increased, the resolution increased, resulting in greater detail observed. A single RBC was imaged at 1200 MHz, showing the contours of the cell. While lateral and axial resolutions approaching 1 μm are possible with this microscope, the key advantage is the ability to perform a wide-bandwidth quantitative signal analysis of the photoacoustic signals. The power spectrum of the signals measured from RBCs showed distinct spectral minima around 800 and 1500 MHz which are directly related to the RBC geometry. This study reports on the high-resolution imaging capabilities and quantitative analyses using UHF photoacoustic microscopy.

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Section: Resultsmentioning

confidence: 99%

High frequency label-free photoacoustic microscopy of single cells

2013

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“…In the past five years, several groups have employed the use of PA radiofrequency analysis to differentiate prostate adenocarcinoma tumors from normal tissue [31], detect the presence of red blood cell aggregation [30], [32], identify various stages of liver disease [29], [33] and characterize bone and joint microstructure in osteoporosis [34] and rheumatoid arthritis [35]. Theoretical models have also been developed for understanding the spectral features that arise from tissue microstructural changes [36], [37], [38], [39], [40], [41], [42]. Combining functional aspects of PA imaging (based on optical spectroscopy) with structural information (based on RF frequency analysis) can potentially be used to better monitor cancer treatment response.…”

Section: Introductionmentioning

confidence: 99%

Photoacoustic signal characterization of cancer treatment response: Correlation with changes in tumor oxygenation

et al. 2017

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Frequency analysis of the photoacoustic radiofrequency signals and oxygen saturation estimates were used to monitor the in-vivo response of a novel, thermosensitive liposome treatment. The liposome encapsulated doxorubicin (HaT-DOX) releasing it rapidly (<20 s) when the tumor was exposed to mild hyperthermia (43 °C). Photoacoustic imaging (VevoLAZR, 750/850 nm, 40 MHz) of EMT-6 breast cancer tumors was performed 30 min pre- and post-treatment and up to 7 days post-treatment (at 2/5/24 h timepoints). HaT-DOX-treatment responders exhibited on average a 22% drop in oxygen saturation 2 h post-treatment and a decrease (45% at 750 nm and 73% at 850 nm) in the slope of the normalized PA frequency spectra. The spectral slope parameter correlated with treatment-induced hemorrhaging which increased the optical absorber effective size via interstitial red blood cell leakage. Combining frequency analysis and oxygen saturation estimates differentiated treatment responders from non-responders/control animals by probing the treatment-induced structural changes of blood vessel.

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“…(2) as a Gaussian function. 36 Equation (3) then becomes the expression for the band-limited (BL) PA pressure field for a collection of RBCs by multiplying its pressure by the Gaussian function representing the transducer frequency profile 29,37 …”

Section: Theoretical Modelmentioning

confidence: 99%

Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

2012

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Abstract. Red blood cell (RBC) aggregation and oxygenation are important markers for a variety of blood disorders. No current technique is capable of simultaneously measuring aggregation/oxygenation levels noninvasively. We propose using photoacoustic ultrasound spectroscopy (PAUS) for assessing both phenomena. This technique relies on frequency-domain analysis of the PA signals by extracting parameters such as the ultrasound spectral slope and the midband fit. To investigate the effect of hematocrit, aggregation, and oxygenation levels on PAUS parameters, a Monte Carlo-based theoretical model and an experimental protocol using porcine RBCs were developed. The samples were illuminated at 750 and 1064 nm and changes in the PAUS parameters were compared to the oxygendependent optical absorption coefficients to assess the oxygenation level. Good agreement between the theoretical and experimental spectral parameters was obtained for the spectral slope of the nonaggregated spectra (∼0.3 dB∕MHz). The experimental midband fit increased by ∼5 dB for the largest aggregate size. Based on the analysis of the PA signals, the oxygen saturation level of the most aggregated sample was >20% greater than the nonaggregated sample. The results provide a framework for using PA signals' spectroscopic parameters for monitoring the aggregation and oxygenation levels of RBCs.

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Validity of a theoretical model to examine blood oxygenation dependent optoacoustics

Cited by 20 publications

References 35 publications

High frequency label-free photoacoustic microscopy of single cells

High frequency label-free photoacoustic microscopy of single cells

Photoacoustic signal characterization of cancer treatment response: Correlation with changes in tumor oxygenation

Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

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