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Combined PAT/US imaging of skin cancers. PAT image of a skin melanoma acquired simultaneously with a US image. (A) Clinical photo and (B) histopathology of melanoma on human chest, (C) PAamp MAP and (B) PAunmixed MAP images along the area of red dashed box in (A); (E) US image of melanoma; (F) PAamp/US image and (G) PAunmixed/US image along the white dashed lines in (C,D), respectively. PAT: photoacoustic tomography; US: ultrasound; PAamp, photoacoustic amplitude; PAunmixed, photoacoustic unmixed melanoma; MAP, maximum amplitude projection. Reprinted with permission from Park et al. (2021).
Source publication
Photoacoustic tomography (PAT) is an emerging biomedical imaging modality that combines optical and ultrasonic imaging, providing overlapping fields of view. This hybrid approach allows for a natural integration of PAT and ultrasound (US) imaging in a single platform. Due to the similarities in signal acquisition and processing, the combination of...
Context in source publication
Context 1
... unique PAT/US imaging here opens unprecedented capabilities for high-resolution skin imaging at scalable depths in vivo. A pilot study showed six melanoma patients examined in vivo using the 3D MSOT imaging system ( Figure 5). By using a MSOT/US system, melanoma of various sizes, locations (chest, thigh, heel, feet, and palm) and forms (1.3-30 mm lateral diameter, 0.6-9.1 mm depth) were detected by US technology. ...
Citations
... It yields valuable information about hemodynamics and oxygenation status, enabling the identi cation of breast cancer through tumor-associated angiogenesis and hypoxia levels in diseased tissue [12,13]. Furthermore, the dual-system mode of photoacoustic-ultrasound combination offers overlapping elds of view, minimizing artifacts and resulting in high-resolution, high-contrast breast cancer imaging [14]. In comparison to radiography and magnetic resonance imaging (MRI), photoacoustic imaging is independent of breast density and boasts the advantages of versatility, cost-effectiveness, and absence of radiation exposure [15,16]. ...
Objective
This study aimed to develop and validate a radiomic nomogram utilizing photoacoustic imaging to predict Ki-67 status in breast cancer patients.
Methods
A retrospective analysis included 223 breast cancer patients diagnosed between October 2022 and October 2023. Patients underwent multimodal photoacoustic/ultrasound imaging and Ki-67 detection. Random allocation into training (n = 178) and test sets (n = 45) followed an 8:2 ratio. Tumor regions were outlined, and radiomic features were extracted from both photoacoustic and ultrasound images. Feature screening involved independent samples t-tests and the least absolute shrinkage with selection operator (LASSO). Rad-Score was computed for each radiomic score, and logistic regression integrated Rad-Score with clinical risk factors to construct the nomogram. Comparative analysis between nomogram models of the two images was performed. Model performance was assessed using receiver operating characteristic (ROC) curves, decision curve analysis (DCA), and calibration curves.
Results
In both cohorts, the nomogram model outperformed clinical and radiomic models. In the test cohort, the area under the curve (AUC) for photoacoustic and ultrasound-based nomogram models were 0.87 (95% CI: 0.69–0.89) and 0.84 (95% CI: 0.67–0.86), respectively, indicating superior performance of the photoacoustic-based nomogram in predicting Ki-67 expression. DCA further demonstrated the clinical utility of the model.
Conclusions
The nomogram model based on photoacoustic radiomics shows promise as a potential tool for predicting Ki-67 levels in breast cancer.
... Furthermore, two different domains, US and PA, present a promising opportunity for unsupervised learning such as CycleGAN, offering considerable enhancements in real-time photoacoustic ultrasound (PAUS) images. They have the potential to strengthen PA/US dual-mode imaging [115]- [117], offering complementary information that can enhance its translation into practical clinical applications. ...
Photoacoustic imaging provides optical contrast at relatively large depths within the human body, compared to other optical methods, at ultrasound spatial resolution. By integrating real-time photoacoustic and ultrasound (PAUS) modalities, PAUS imaging has the potential to become a routine clinical modality bringing the molecular sensitivity of optics to medical ultrasound imaging. For applications where the full capabilities of clinical US scanners must be maintained in PAUS, conventional limited view and bandwidth transducers must be used. This approach, however, cannot provide high-quality maps of PA sources, especially vascular structures. Deep learning (DL) using data-driven modeling with minimal human design has been very effective in medical imaging, medical data analysis, and disease diagnosis, and has the potential to overcome many of the technical limitations of current PAUS imaging systems. The primary purpose of this article is to summarize the background and current status of DL applications in PAUS imaging. It also looks beyond current approaches to identify remaining challenges and opportunities for robust translation of PAUS technologies to the clinic.
... In recent years, some studies reviewed the clinical application of PAI (Steinberg et al. 2019;Wang et al. 2016;Wen et al. 2022), and some studies have reviewed the emerging applications of PAI in cancer-related fields Mallidi et al. 2011, Valluru andWillmann 2016), however, the research status of PAI in the field of cancer and other related subject areas has not been fully investigated. ...
... Although photoacoustic is a promising imaging method, its ability to perceive the anatomy of the tumor is limited and therefore needs to be combined with other imaging modalities. Ultrasound uses the same transducer and receiver electronics as photoacoustic, which are highly synergistic and can be used to obtain anatomical details about the tumor and its surroundings (Wen et al. 2022). Cluster 3 included 13 keywords, mainly related to the application of molecular imaging, PAT, and photoacoustic microscopy in the field of breast cancer. ...
... Cluster 3 included 13 keywords, mainly related to the application of molecular imaging, PAT, and photoacoustic microscopy in the field of breast cancer. PAT can provide structural information within the breast and hemoglobin-related functional information, which can aid in clinical diagnosis (Wen et al. 2022). The tissue of the breast is superficially located and healthy breast tissue has low optical absorption and ultrasound scattering, making it ideal for PAT imaging (Steinberg et al. 2019). ...
As a novel imaging modality based on photoacoustic effects, photoacoustic imaging (PAI) has shown great potential in biomedical applications, especially in the field of cancer. The purpose of our research was to identify collaborations between different institutions, authors, and countries, and to explore the hotspots and prospects of PAI research in the field of cancer. We downloaded publications on PAI research from the Science Citation Index-Expanded (SCI-E) of the Web of Science Core Collection database. Bibliometric analysis was performed using VOSviewer and CiteSpace software. A total of 2561 papers related to PAI research in the field of cancer were identified. A total of 10,105 authors participated in the PAI study, of which the majority (69.33%) authors participated in only 1 article. China (1638, 63.96%) was the country with the most articles in this field, and the Chinese Academy of Sciences (329, 12.85%) was the most productive institution. ACS Applied Materials & Interfaces (146, 5.70%) was the most productive journal and ACS Nano (7262 co-citations) was the most co-cited journal. Current hot topics of PAI research in the cancer field were the construction and development of multifunctional photoacoustic nanoprobes to achieve the integration of tumor detection and treatment. The application of photoacoustic imaging in the field of cancer is in the vigorous development stage and has a bright prospect. There was a wealth of cooperation between authors, countries, and institutions. Our findings can provide information about the future direction of funding agencies and research groups.
... For example, stimuli-responsive FL has high sensitivity but shallow tissue penetration. US can be used to realize deep tissue penetration, high spatial resolution, and real-time imaging at the cost of poor bone and gas penetration and nonwhole-body imaging [113]. PAI combining optical excitation and acoustic detection can provide a sub-millimeter spatial resolution with centimeter-level penetration depth [114][115][116]. ...
Emerging stimuli‐responsive composite probes active in the second near‐infrared window (NIR‐II, 1000–1700 nm) hold vast potential for improving in vivo imaging performance with minimized noise interference. The interactions among external irradiation, shell species, and the emissive core are key factors in the design of smart structures. The external irradiation provides energy for shell species and the emissive core to generate intense NIR‐II fluorescence signals, while the energy transfer process hinders NIR‐II emission in the inner structure of smart composite probes. However, if pathophysiological stimuli interrupt the above processes, then NIR‐II fluorescence signals are recovered. This review covers NIR‐II imaging based on diverse smart composite NIR‐II fluorescent probes responding to various biological stimuli, including ONOO⁻, overexpressed reactive sulfur species, abnormally expressed enzymes, and abnormal levels of physiological metabolites. Finally, to appreciate these advances, the challenges and perspectives of stimuli‐responsive composite NIR‐II probes are highlighted.
Traditional diagnostic techniques including visual examination, ultrasound (US), and magnetic resonance imaging (MRI) have limitations of in-depth information for the detection of nail disorders, resolution, and practicality. This pilot study, for the first time, evaluates a dual-modality imaging system that combines photoacoustic tomography (PAT) with the US for the multiparametric quantitative assessment of human nail. The study involved a small cohort of five healthy volunteers who underwent PAT/US imaging for acquiring the nail unit data. The PAT/US dual-modality imaging successfully revealed the fine anatomical structures and microvascular distribution within the nail and nail bed. Moreover, this system utilized multispectral PAT to analyze functional tissue parameters, including oxygenated hemoglobin, deoxyhemoglobin, oxygen saturation, and collagen under tourniquet and cold stimulus tests to evaluate changes in the microcirculation of the nail bed. The quantitative analysis of multispectral PAT reconstructed images demonstrated heightened sensitivity in detecting alterations in blood oxygenation levels and collagen content within the nail bed, under simulated different physiological conditions. This pilot study highlights the potential of PAT/US dual-modality imaging as a real-time, noninvasive diagnostic modality for evaluating human nail health and for early detection of nail bed pathologies.
Optoacoustic imaging (OAI) is an emerging field with increasing applications in patients and exploratory clinical trials for breast cancer. Optoacoustic imaging (or photoacoustic imaging) employs non-ionizing, laser light to create thermoelastic expansion in tissues and detect the resulting ultrasonic emission. By combining high optical contrast capabilities with the high spatial resolution and anatomic detail of grayscale ultrasound, OAI offers unique opportunities for visualizing biological function of tissues in vivo. Over the past decade, human breast applications of OAI, including benign/malignant mass differentiation, distinguishing cancer molecular subtype, and predicting metastatic potential, have significantly increased. We discuss the current state of optoacoustic breast imaging, as well as future opportunities and clinical application trends. CLINICAL RELEVANCE STATEMENT: Optoacoustic imaging is a novel breast imaging technique that enables the assessment of breast cancer lesions and tumor biology without the risk of ionizing radiation exposure, intravenous contrast, or radionuclide injection. KEY POINTS: • Optoacoustic imaging (OAI) is a safe, non-invasive imaging technique with thriving research and high potential clinical impact. • OAI has been considered a complementary tool to current standard breast imaging techniques. • OAI combines parametric maps of molecules that absorb light and scatter acoustic waves (like hemoglobin, melanin, lipids, and water) with anatomical images, facilitating scalable and real-time molecular evaluation of tissues.
