Who invented photoacoustic imaging?
Alexander Graham Bell
The photoacoustic effect was discovered more than 125 years ago by Alexander Graham Bell. He created a device he called the photophone, and several derivative devices such as the spectrophone shown in figure 1a, in which a rotating thin disk emitted sound when exposed to a focused beam of light.
How does photoacoustic tomography work?
Photoacoustic imaging allows the delivery of light energy that is absorbed by tissues causing a thermoelastic expansion. This expansion then generates ultrasound waves that are detected by the transducer and produce images of optical absorption contrast within tissues.
What is photoacoustic computed tomography?
Photoacoustic computed tomography (PACT), also referred to as thermoacoustic tomography (TAT), or optoacoustic tomography (OAT), is a biomedical imaging modality in which a combination of optical and ultrasound techniques are leveraged to acquire images of biological tissue/structures while avoiding the use of ionizing …
When was photoacoustic imaging invented?
1880
Research into the underlying physics of photoacoustic (PA) techniques has a relatively long, if sporadic, history dating back to 1880 when Alexander Graham Bell first discovered the PA effect following his observation of the generation of sound owing to the absorption of modulated sunlight [1].
What is photoacoustic laser?
Photoacoustic (or optoacoustic) imaging is a high-resolution hybrid imaging technique utilizing the sensitivity and contrast of optical imaging with the depth of ultrasound. Laser light is absorbed causing thermoelastic expansion and an acoustic wave follows which is detected by an ultrasound transducer.
What is photoacoustic emission?
Photoacoustic emissions occurred when the sample absorbed the energy from the excitation laser due to thermoelastic effects. Different from a conventional method of using a piezoelectric ultrasound transducer for the detection of photoacoustic signals, we used a probe beam deflection technique (PBDT) [32,33].
What are the advantages of photoacoustic imaging?
Photoacoustic imaging (PAI) has many interesting advantages, such as deep imaging depth, high image resolution, and high contrast to intrinsic and extrinsic chromophores, enabling morphological, functional, and molecular imaging of living subjects.
What is a photoacoustic wave?
Photoacoustic Signal Generation The photoacoustic effect is the physical phenomenon of an acoustic wave excited through the interaction of modulated electromagnetic waves (i.e., laser pulses) with matter.
What is the importance of photoacoustic spectroscopy?
A photoacoustic spectrum of a sample can be recorded by measuring the sound at different wavelengths of the light. This spectrum can be used to identify the absorbing components of the sample. The photoacoustic effect can be used to study solids, liquids and gases.
What is acoustic imaging?
[ə′küs·tik ′im·ij·iŋ] (acoustics) The use of ultrasound to produce real-time images of the internal structure of a metallic or biological object that is opaque to light. Also known as sonography; ultrasonic imaging; ultrasonography.
What is photoacoustic spectroscopy for a Molecules?
Photoacoustic spectroscopy is the measurement of the effect of absorbed electromagnetic energy (particularly of light) on matter by means of acoustic detection. This spectrum can be used to identify the absorbing components of the sample. The photoacoustic effect can be used to study solids, liquids and gases.
Why does Photo acoustic spectroscopy require pulses of light instead of a continuous steady source of light to hit the sample?
Having a constant source of light will prevent waves from forming and the spectrum will only show up as a straight line. The point of the pulsing light is to have the material absorb the energy, convert it to heat, send out the acoustic waves, and let it rest before allowing it to absorb another amount of energy.
What is optoptoacoustic (photoacoustic)?
Optoacoustic (photoacoustic) imaging is intrinsically a three-dimensional imaging method, since photoechoes (optoacoustic waves) propagate in all three spatial dimensions. Optimal tomographic imaging is therefore achieved by recording time-resolved pressure waves along a closed surface volumetrically surrounding the target tissue.
What is MSOT (multi-spectral optoacoustic tomography)?
Multi-spectral optoacoustic tomography (MSOT), also known as functional photoacoustic tomography (fPAT), is an imaging technology that generates high-resolution optical images in scattering media, including biological tissues. MSOT illuminates tissue with light of transient energy, typically light pulses lasting 1-100 nanoseconds.
What is optoacoustic tomography and what is it for?
Optoacoustic tomography has found applications in dermatology since the late 1990s. Several groups have developed optoacoustic imaging devices that allow for the visualization of human skin to a depth of several millimeters.
What is the resolution of optoacoustic imaging?
In 1999, the first optoacoustic imaging device applied to human skin achieved in-depth resolution of 10–15 μm and light penetration of up to 4 mm, but suffered from a low lateral resolution of 200 μm [14].