Optical Coherant Tomography

SRI SAI COLLEGE OF DENTAL SURGERY DEPARTMENT OF CONSERVATIVE AND ENDODONTICS Presented by- Dr. Nikhil Saran, (Post graduate student in Dept of Conservative and Endodontics)

Guided by- Dr. Jayaprakash Patil, (Professor and Head of the Department Conservative and Endodontics )

OPTICAL COHERANT TOMOGRAPHY Nobel Non-invasive Non-destructive

Outline Introduction  Relevance in modern dental practice  Dental imaging in past and present  Optical coherent tomography 

qDesign qFunction  Application  Conclave  References

Introduction   

Providing quantitative and qualitative info.

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Can image hard and soft tissue both simultaneously

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Cross-sectional image of tissue of 3mm depth resolution of 1-10 μm

Relevance in modern dental practice  

Convenient for patient and operator

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Instant image generation (optical biopsy)

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High-speed acquisition (4-8 fps)

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No harmful effect to patient or to operator

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Use full in multi branch diagnosis and prognosis.

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Potential tool for unlocking the secrets in future

Dental imaging in past and present 

X-ray in the late 1800s using ionizing radiation .

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Ultrasound in 1965 using high frequency sound waves.

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Computed tomography in 1973 using x-ray and computer technology.

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Magnetic resonance imaging 1974 using magnetic field and pulses of radio wave energy.

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Positron emission tomography in 1999 was developed to measure metabolic changes in soft tissue cells.

OCT An idea for the future 

Sir Isaac Newton in 1642 worked on low coherence interferometry or white light interferometry

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Duguay in 1971 use this concept of light and optics to image biological tissues

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James G. Fujimoto in 1991 made the first working prototype

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Otis et al used this modality of imaging dental tissues

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Huang et al in 1991, used it in vivo method for crosssectional imaging of eye tissues

C ro ss-se ctio n a lim a g in g b y O C T 

Micro structural details about the health of teeth, periodontal tissue, mucosa and alveolar bone

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OCT provides “optical biopsy” Def. As a method for imaging tissue pathology, utilizing the optical imaging properties of OCT without the surgical removal of tissue.

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OCT uses optical scattering signatures within tissue structure.

Principle of Optical Coherence Tomography (Optical Analog of Ultrasound)

Cross sectional image VARIOUS STRUCTURE WITH IN 3MM OF DEPTH WILL BE SEEN AT A RESOLUTION 10 TIMES BETTER THEN X RAYS. 

Eg. SKIN

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Lig h t fo r d ia g n o sis 

Michelson interferometer involves interference between the reflected light and the reference beam. 

Application….

A d va n ta g e s 

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Broad dynamic range, High resolution

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Rapid data acquisition rate,

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Small inexpensive catheter/endoscope design

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Compact portable structure

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The frame rate for OCT systems are four to eight frames per second

Limitation 

Penetration: 2-3mm Ideal: 4mm

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Resolution :

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catheter/endoscope based image:10μm, noncatheter: 4 μm,

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Acquisition rate: <10franes/second

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Lack of large-scale clinical trials

Future works 

Peneration and Resolution: 

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1. Need to develop with similar median wavelength, power, and bandwidth to those of the mode locked laser. 2. Need more complex catheter/ endoscope designs to alleviate the focus falling off rapidly.

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Acquisition rates: video rate is anticipated with future embodiments.

The Conclave

Nowadays and future equipment

•Low-coherence Superluminescent diode:800 –1300 nm center waveength and severl milliwatts power.

DISPLAY AND KEYBOARD

INTEROMETER ELECTRONICS AND OPTICS

+COMPUTER

FIBEROPTIC PROBE

S preading S miles and C are through D ental Service

Thanks for the patience listening