Optical Coherence Tomography (OCT) is a non-invasive imaging technology with high spatial resolution, primarily used for diagnosing diseases such as ocular conditions, heart disease, and cancer. It operates on the principle of measuring the echo delay and intensity of back-reflected infrared light using Michelson interferometry, with advances including time domain OCT and Fourier domain OCT for improved efficiency. Despite its advantages like broad dynamic range and high resolution, OCT has limitations such as penetration depth and acquisition rates, and it has applications in various medical fields including ophthalmology and gastroenterology.

1. ARJUN A G
ROLL NO.2
ME4

2. ABSTRACT
OCT is an emerging technology
Non-invasive imaging
 High spatial resolution.
Extensions of OCT:
Utilization with endoscopes
Based on a Michelson interferometer.

3. IMAGING TECHNIQUES
 X RAY
 CT scan
 MRI
 PET
 OCT

4. INTRODUCTION
 James G. Fujimoto, 1991
 What is OCT:
Diagnostic medical imaging
technology
 Why OCT:
better diagnose and treat
disease
 Main application areas:
finding ocular diseases
heart disease
cancer

6. OPTICAL COHERENCE TOMOGRAPHY
The Principle
 By measuring echo delay &
 Intensity of back reflected infra-red light
 Based on Michelson interferometry

7. OPTICAL COHERENCE TOMOGRAPHY
MICHELSON INTERFEROMETRY

8. OCT PRINCIPLE

9. OCT BLOCK DIAGRAM

10. OCT vs. STANDARD IMAGING

11. OCT vs. USG
 OCT Resolving power is about 10 microns vertically and 20
microns horizontally.
 Resolution of a good ophthalmic ultrasound at 100 microns.

12. TYPES OF OCT
 Time Domain OCT
 Fourier Domain OCT

13. Time Domain OCT
 Mirror in the reference arm moved to
match the delay
 Mirror must move one cycle for each
axial scan.
 Movement limits the speed of image
acquisition.
 Serial axial scanning is inefficient.

14. Fourier Domain OCT
 Reference mirror is kept stationary
 The absence of moving parts makes image to be
acquired very rapidly.
 This parallel axial scan is much more efficient
 Greater speed
 Higher signal-to-noise ratio.

15. FD-OCTimplemented in two ways:
 swept-source implementation (SS-OCT)
 Spectrometer based implementation(spectral domain(SD)
OCT )

16. Swept-Source Implementation
(SS-OCT)
 Tuneable laser is used
 Signal is collected by a single-element photo detector.

17. Spectrometer based implementation
(Spectral Domain OCT )
 Super luminescent diode(SLD) is used
 spectrometer uses a grating or a prism
 detected by a line camera

18. Time Domain vs Spectral Domain OCT

19. FD OCT vs. TD OCT

20. THE OCT MACHINE
 The OCT system comprises:
 Fundus viewing unit
 Interferometric unit
 Computer display
 Control panel
 Colour inkjet printer

21. PROCEDURE

22. PRODUCTION AND DISPLAY
OF IMAGE
 1024 points are capture over 2mm depth
 Repeated up to 512 times
 Image has 10u axial and 20u transverse resolution
 Image display either in grey scale or HD computer image.

23. Cancer imaging by OCT

24. Advantage of OCT
 Broad dynamic range
 High resolution
 Rapid data acquisition rate
 Small inexpensive catheter/endoscope design
 Compact portable structure
 The frame rate for OCT systems are four to eight frames
per second.

25. Limitation
 Penetration: 2-3mm Ideal: 4mm
 Femto second laser is expensive (1 μm)
 Acquisition rate: <10frames/second
 Lack of large-scale clinical trials

26. APPLICATIONS
 Ophthalmology
 Early cancer diagnosis
 Gastroenterology
 urology
 gynecology

27. FUTURE WORKS
 Penetration
 Need more complex catheter/ endoscope designs.
 Acquisition rates

28. CONCLUSION
 Best imaging technology.
 Can use in different fields.

29. Thank you for your kind attention….