Hybrid photoacoustic and optical imaging of pigments in vegetative tissues

Tserevelakis, George J.; Tsagkaraki, Margarita; Zacharakis, Giannis

doi:10.1111/jmi.12396

Cited by 20 publications

(11 citation statements)

References 33 publications

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“…During the last decade, photoacoustic imaging has gained a wide acceptance in biomedical research, finding numerous applications in cancer metabolism, and drug delivery studies . Beyond the frontiers of biomedicine, photoacoustic modalities have started being used in other fields, such as optometry and plant biology with highly promising results. Only very recently, photoacoustic imaging was introduced as a novel diagnostic tool in the context of cultural heritage (CH) science, with emphasis on the uncovering of hidden underdrawings in paintings .…”

Section: Discussionmentioning

confidence: 99%

Uncovering the hidden content of layered documents by means of photoacoustic imaging

Tserevelakis

Tsagkaraki

Siozos

et al. 2018

Strain

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We introduce a novel diagnostic approach for the uncovering of hidden content in layered documents, based on a photoacoustic imaging set‐up with optimised acoustic detection parameters. By exploiting the laser‐induced ultrasound following the intense absorption of pulsed optical radiation by printed ink, this traditional biomedical imaging method is proven capable of revealing text characters buried under several layers of stacked paper sheets at high spatial resolution and excellent contrast levels. Such a remarkable performance benefits from the effective combination of strong light scattering by paper fibrils and the virtually unobstructed propagation of the generated ultrasonic waves through multiple layers, enabling thus the accurate recording of text, even in double‐sided prints, with minimum shadowing artefacts. The imaging effectiveness, the implementation simplicity, the robustness, and the relatively low‐cost features offered by the proposed photoacoustic modality are anticipated to contribute in its wide adoption by the preservation of cultural heritage community, as a powerful diagnostic tool for the in‐depth investigation of complex multilayered objects.

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Section: Discussionmentioning

confidence: 99%

Uncovering the hidden content of layered documents by means of photoacoustic imaging

Tserevelakis

Tsagkaraki

Siozos

et al. 2018

Strain

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“…In this direction, the highly promising capabilities of PA diagnosis have been recently exploited in several applications involving the in vivo acquisition of valuable anatomical, molecular, functional, and flow dynamic information, towards the understanding of fundamental biological mechanisms such as cancer formation and growth [ 1 ]. PA imaging is based on the formation of acoustic waves following the absorption of intensity-modulated (typically pulsed) optical radiation by a material [ 2 ]. During the incidence of a short light pulse, a portion of the absorbed optical energy is converted into heat, inducing a rapid thermoelastic expansion of the medium and the subsequent generation of an initial pressure that propagates in space in the form of ultrasonic waves.…”

Section: Introductionmentioning

confidence: 99%

Revealing Hidden Features in Multilayered Artworks by Means of an Epi-Illumination Photoacoustic Imaging System

et al. 2021

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Photoacoustic imaging is a novel, rapidly expanding technique, which has recently found several applications in artwork diagnostics, including the uncovering of hidden layers in paintings and multilayered documents, as well as the thickness measurement of optically turbid paint layers with high accuracy. However, thus far, all the presented photoacoustic-based imaging technologies dedicated to such measurements have been strictly limited to thin objects due to the detection of signals in transmission geometry. Unavoidably, this issue restricts seriously the applicability of the imaging method, hindering investigations over a wide range of cultural heritage objects with diverse geometrical and structural features. Here, we present an epi-illumination photoacoustic apparatus for diagnosis in heritage science, which integrates laser excitation and respective signal detection on one side, aiming to provide universal information in objects of arbitrary thickness and shape. To evaluate the capabilities of the developed system, we imaged thickly painted mock-ups, in an attempt to reveal hidden graphite layers covered by various optically turbid paints, and compared the measurements with standard near-infrared (NIR) imaging. The obtained results prove that photoacoustic signals reveal underlying sketches with up to 8 times improved contrast, thus paving the way for more relevant applications in the field.

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“…The ability of PA sensing to provide molecular absorption specificity [ 3 ], and the low attenuation of PA waves [ 4 ], provide unique advantages towards developing novel systems for biomedical imaging and sensing applications that can obtain valuable diagnostic information deeper in highly scattering tissues when compared to pure optical imaging approaches [ 5 ]. In this direction, special emphasis has been given to developing reconstruction-based PA tomography (PAT) [ 6 ], PA microscopy (PAM) [ 7 ], or even hybrid imaging systems integrating both PA and optical [ 8 , 9 , 10 ], or ultrasound [ 11 ] techniques into a single instrument. Moreover, several spectral unmixing techniques [ 12 , 13 ] have been utilized with multispectral PA imaging systems to provide spectroscopic information for endogenous and exogenous chromophores in tissues.…”

Section: Introductionmentioning

confidence: 99%

A Cost-Efficient Multiwavelength LED-Based System for Quantitative Photoacoustic Measurements

Orfanakis

Tserevelakis

Zacharakis

2021

Sensors

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The unique ability of photoacoustic (PA) sensing to provide optical absorption information of biomolecules deep inside turbid tissues with high sensitivity has recently enabled the development of various novel diagnostic systems for biomedical applications. In many cases, PA setups can be bulky, complex, and costly, as they typically require the integration of expensive Q-switched nanosecond lasers, and also presents limited wavelength availability. This article presents a compact, cost-efficient, multiwavelength PA sensing system for quantitative measurements, by utilizing two high-power LED sources emitting at central wavelengths of 444 and 628 nm, respectively, and a single-element ultrasonic transducer at 3.5 MHz for signal detection. We investigate the performance of LEDs in pulsed mode and explore the dependence of PA responses on absorber’s concentration and applied energy fluence using tissue-mimicking phantoms demonstrating both optical absorption and scattering properties. Finally, we apply the developed system on the spectral unmixing of two absorbers contained at various relative concentrations in the phantoms, to provide accurate estimations with absolute deviations ranging between 0.4 and 12.3%. An upgraded version of the PA system may provide valuable in-vivo multiparametric measurements of important biomarkers, such as hemoglobin oxygenation, melanin concentration, local lipid content, and glucose levels.

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Hybrid photoacoustic and optical imaging of pigments in vegetative tissues

Cited by 20 publications

References 33 publications

Uncovering the hidden content of layered documents by means of photoacoustic imaging

Uncovering the hidden content of layered documents by means of photoacoustic imaging

Revealing Hidden Features in Multilayered Artworks by Means of an Epi-Illumination Photoacoustic Imaging System

A Cost-Efficient Multiwavelength LED-Based System for Quantitative Photoacoustic Measurements

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