Integrating photoacoustic tomography into a multimodal automated breast ultrasound scanner

Abstract

Significance: Photoacoustic tomography (PAT) is a promising emergent modality for the screening and staging of breast cancer. To minimize barriers to clinical translation, it is common to develop PAT systems based upon existing ultrasound hardware, which can entail significant design challenges in terms of light delivery. This often results in inherently non-uniform fluence within the tissue and should be accounted for during image reconstruction. Aim: We aim to integrate PAT into an automated breast ultrasound scanner with minimal change to the existing system. Approach: We designed and implemented an illuminator that directs spatially non-uniform light to the tissue near the acquisition plane of the imaging array. We developed a graphics processing unit-accelerated reconstruction method, which accounts for this illumination geometry by modeling the structure of the light in the sample. We quantified the performance of this system using a custom, modular photoacoustic phantom and graphite rods embedded in chicken breast tissue. Results: Our illuminator provides a fluence of 2.5 mJ cm −2 at the tissue surface, which was sufficient to attain a signal-to-noise ratio (SNR) of 8 dB at 2 cm in chicken breast tissue and image 0.25-mm features at depths of up to 3 cm in a medium with moderate optical scattering. Our reconstruction scheme is 200× faster than a CPU implementation; it provides a 25% increase in SNR at 2 cm in chicken breast tissue and lowers image error by an average of 31% at imaging depths >1.5 cm compared with a method that does not account for the inhomogeneity of the illumination or the transducer directivity. Conclusions: A fan-shaped illumination geometry is feasible for PAT; however, it is important to account for non-uniform fluence in illumination scenarios such as this. Future work will focus on increasing fluence and further optimizing the ultrasound hardware to improve SNR and overall image quality.

Clinical photoacoustic/ultrasound dual-modal imaging: Current status and future trends

“…For clinicians or radiologists, “seeing is believing”. In the last several years, several clinical studies on PAT/US dual-modality were reported, including human thyroid ( Dima and Ntziachristos, 2016 ; Yang et al, 2017 ; Kim et al, 2021 ), breast ( Garcia-Uribe et al, 2015 ; Becker et al, 2018 ; Neuschler et al, 2017 ; Nyayapathi and Xia, 2019 ; Kelly et al, 2020 ; Goh et al, 2019 ; Yang et al, 2020 ), skin ( Oraevsky et al, 2018 ; Park et al, 2021 ), extremities ( Xia et al, 2015 ; Mercep et al, 2015 ; Liu and Zhang, 2016 ; Kim et al, 2016 ; Jo et al, 2017 ; Oeri et al, 2017 ; van den Berg et al, 2017 ; Feng et al, 2020 ; Daoudi et al, 2021 ), prostate ( Agrawal et al, 2020 ; Kothapalli et al, 2019 ), bowels ( Knieling et al, 2017 ; Leng et al, 2018 ; Yang et al, 2019 ), vascular ( Karpiouk et al, 2012 ; Wu et al, 2015 ; Andrei et al, 2021), placenta ( Xia et al, 2015 ; Maneas et al, 2020 ) and others ( Jose et al, 2009 ; Gonzalez et al, 2021 ; Mozaffarzadeh et al, 2021 ). With the combination of the two modalities in one imaging system, it is acceptable for radiologists or clinicians to adapt and associate morphological features with functional information.…”