1. Photoacoustic Tomography The Future Of Medical Imaging Techniques
Imaging techniques for diagnostic purposes have been around since the development of X-rays in Since then, there has been an explosion in the advancement of the technology engineered to diagnose patients with conditions ranging from bone fractures to terminal cancers.

2. Current Technologies in Optical Imaging
Now many technologies exist, but it is optical imaging that is really in the forefront of its game in diagnosis. This technique relies on the use of visible, ultraviolet, and infrared light to develop images that allow physicians to pinpoint the location of cancers or any irregularities and make judgment on its development, effects and required treatment.
Methods such as confocal microscopy, two-photon microscopy, optical coherence tomography have fundamentally impacted the field of biomedicine. However there is a major issue faced by researches with these technologies…
Matthews et al. Biomed. Opt. Express 2, 1576 (2011).
Optical Coherence Tomography
Confocal Microscopy
Two-Photon Microscopy

3. Problems with Optical Imaging Technology
Cannot penetrate biological tissue deeper than a few mm.
Low Resolution Images
^. which is the optical transport mean free path .
Leaving doctors assuming what is below those few mms, and any further investigation will involve invasive methods.
However researchers have developed a method where both problems have been addressed.

4. Photoacoustic Imaging: The latest in optical diagnostic imaging technology
1. Strong Optical Contrast
2. High Ultrasonic Resolution
It is called PAT
combines strong optical contrast and high ultrasonic resolution in a single modality to create images with greater specificity than conventional methods
It is based on the photo-acoustic effect which has allowed engineers to break through the fundamental depth limitation and provide high-resolution structural, functional, and molecular imaging in biological tissue.

5. How It Works Optical irradiation Ultrasonic detection Image formation
Now it is based on three basic principals:
The PA effect uses light to visualise different types of tissue within the body.
The way it works is that a transducer is put against the skin
Optical Irradiation: Light in the near infra-red is sent in a very short pulse.
Light then generates heat, and this temp rise causes thermo expansion. The transducer then translates this light energy into sound energy, which is the acoustic wave.
Ultrasonic Detection: The acoustic waves are detected by ultrasounds (which convert light into sound, because sound scatters a thousand times less than light, therefore can penetrate skin deeper) identical to the ones used in conventional ultrasound exams.
Image Formation: Once the projections are captured, the data is used to create an image
This image is amongst the first to capture breast vessels in such clarity and resolution. 1mm vessel, with cross section of just over half a mm several cm’s below the skin.

6. Pros Vs Cons Pros Relatively low-cost Real-time Portable Cons
Deeper the light, lower the quality
Speed of sound distorted by bone
Integrating PAT into existing ultrasound imaging systems can potentially accelerate acceptance of the new technology by physicians.
Relatively low-cost: Involve a laser or radio frequency source in addition to the detection components of an ultrasound imaging system.
Real-time: When ultrasound arrays are used as in ultrasonography, PAT and TAT can be performed in real time.
Portable: A standard ultrasound imaging system is portable and can be used at bedside. With the addition of a laser or radio frequency source, the entire imaging system can still be made relatively portable for bedside or operating-room applications
New Scientist: Dr Paul Beard 2007

7. Conclusion Potoacoustic Tomography : Break through depth limitation
Produce high quality, high contrast images
Low Cost
Engineers hope to commercialise the technology and see doctors and patients benefit from it on a grand scale.
So with the advancement of this new technology, researches can now overcome the optical transport free mean path to develop high contrast, super depth images.
With ongoing research and further investigations, engineers hope to commercialize this technology and see doctors and patients benefit from it on a grand scale.