An advanced photoacoustic tomography system based on a ring geometry design

Alshahrani, Suhail S.; Yan, Yan; Avrutsky, Ivan; Malyarenko, Eugene; Anastasio, Mark A.; Mehrmohammadi, Mohammad

doi:10.1117/12.2296595

Cited by 8 publications

(6 citation statements)

References 20 publications

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“…The design of our combined UST/PAT imaging system has been previously presented [39][40][41][42]. This setup uses a ring illumination in conjunction with a ring US transducer for combined UST/PAT imaging.…”

Section: Laser Source and Light Illumination Schemesmentioning

confidence: 99%

Photoacoustic Tomography with a Ring Ultrasound Transducer: A Comparison of Different Illumination Strategies

et al. 2019

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Photoacoustic (PA) imaging is a methodology that uses the absorption of short laser pulses by endogenous or exogenous chromophores within human tissue, and the subsequent generation of acoustic waves acquired by an ultrasound (US) transducer, to form an image that can provide functional and molecular information. Amongst the various types of PA imaging, PA tomography (PAT) has been proposed for imaging pathologies such as breast cancer. However, the main challenge for PAT imaging is the deliverance of sufficient light energy horizontally through an imaging cross-section as well as vertically. In this study, three different illumination methods are compared for a full-ring ultrasound (US) PAT system. The three distinct illumination setups are full-ring, diffused-beam, and point source illumination. The full-ring system utilizes a cone mirror and parabolic reflector to create the ringed-shaped beam for PAT, while the diffuse scheme uses a light diffuser to expand the beam, which illuminates tissue-mimicking phantoms. The results indicate that the full-ring illumination is capable of providing a more uniform fluence irrespective of the vertical depth of the imaged cross-section, while the point source and diffused illumination methods provide a higher fluence at regions closer to the point of entry, which diminishes with depth. In addition, a set of experiments was conducted to determine the optimum position of ring-illumination with respect to the position of the acoustic detectors to achieve the highest signal-to-noise ratio.

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Section: Laser Source and Light Illumination Schemesmentioning

confidence: 99%

Photoacoustic Tomography with a Ring Ultrasound Transducer: A Comparison of Different Illumination Strategies

et al. 2019

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“…This image will ideally represent the optical properties (dominated by absorption) map of the imaged tissue. As existing US hardware can be utilized for PA, there is a natural synergy and justification to combine the two modalities [3] , [4] , [5] . This allows for the co-registration of structural information from the US and functional and molecular information from PA.…”

Section: Introductionmentioning

confidence: 99%

“…This algorithm takes advantage of the synergistic relationship between UST and PAT ( Fig. 1 a ) [3] , [4] to estimate the optical light fluence via Monte Carlo light simulations ( Fig. 1 b ) and through an accurate tissue morphology image provided through UST [19] , [20] , [21] .…”

Section: Introductionmentioning

confidence: 99%

Wavelength-dependent error minimization for quantitative spectroscopic photoacoustic tomography with a ring-array system

Pattyn

Yan

Mehrmohammadi

2023

Zeitschrift für Medizinische Physik

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“…Photoacoustic (PA) imaging has been applied for the evaluation of different organs [36][37][38][39][40], such as the brain [41,42], liver [43], cervix [44][45][46][47][48], lymph nodes [49], aorta [50], and breast [51], to quantify biochemical constituents and to aid in cancer diagnosis and management, such as skin [52], cervical [53], and breast cancers [54][55][56][57]. Given its ability to acquire functional and molecular images with a high resolution at clinically relevant depths, in addition to sharing common signal-acquisition hardware with ultrasound, PA imaging can serve as a valuable adjunct to cervical length measurement [46,58] by providing additional information on the cervix's composition.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic photoacoustic imaging of cervical tissue composition in excised human samples

et al. 2021

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Objective Cervical remodeling is an important component in determining the pathway of parturition; therefore, assessing changes in cervical tissue composition may provide information about the cervix’s status beyond the measurement of cervical length. Photoacoustic imaging is a non-invasive ultrasound-based technology that captures acoustic signals emitted by tissue components in response to laser pulses. This optical information allows for the determination of the collagen-to-water ratio (CWR). The purpose of this study was to compare the CWR evaluated by using spectroscopic photoacoustic (sPA) imaging in cervical samples obtained from pregnant and non-pregnant women. Methods This cross-sectional study comprised cervical biopsies obtained at the time of hysterectomy (n = 8) and at the scheduled cesarean delivery in pregnant women at term who were not in labor (n = 8). The cervical CWR was analyzed using a fiber-optic light-delivery system integrated to an ultrasound probe. The photoacoustic signals were acquired within the range of wavelengths that cover the peak absorption of collagen and water. Differences in the CWR between cervical samples from pregnant and non-pregnant women were analyzed. Hematoxylin and eosin and Sirius Red stains were used to compare the collagen content of cervical samples in these two groups. Results Eight cervix samples were obtained after hysterectomy, four from women ≤41 years of age and four from women ≥43 years of age; all cervical samples (n = 8) from pregnant women were obtained after 37 weeks of gestation at the time of cesarean section. The average CWR in cervical tissue samples from pregnant women was 18.7% (SD 7.5%), while in samples from non-pregnant women, it was 55.0% (SD 20.3%). There was a significantly higher CWR in the non-pregnant group compared to the pregnant group with a p-value <0.001. A subgroup analysis that compared the CWR in cervical samples from pregnant women and non-pregnant women ≤41 years of age (mean 46.3%, SD 23.1%) also showed a significantly higher CWR (p <0.01). Lower collagen content in the pregnancy group was confirmed by histological analysis, which revealed the loss of tissue composition, increased water content, and collagen degradation. Conclusion The proposed bimodal ultrasound and sPA imaging system can provide information on the biochemical composition of cervical tissue in pregnant and non-pregnant women. Photoacoustic imaging showed a higher collagen content in cervical samples from non-pregnant women as compared to those from pregnant women, which matched with the histological analysis. This novel imaging method envisions a new potential for a sensitive diagnostic tool in the evaluation of cervical tissue composition.

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An advanced photoacoustic tomography system based on a ring geometry design

Cited by 8 publications

References 20 publications

Photoacoustic Tomography with a Ring Ultrasound Transducer: A Comparison of Different Illumination Strategies

Photoacoustic Tomography with a Ring Ultrasound Transducer: A Comparison of Different Illumination Strategies

Wavelength-dependent error minimization for quantitative spectroscopic photoacoustic tomography with a ring-array system

Spectroscopic photoacoustic imaging of cervical tissue composition in excised human samples

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