Download pdf - The Multifaceted Use of Swept-Source OCT in Tissue Imaging...Background Abstract Biomedical optics is a multidisciplinary field that seeks to improve human health using the tools of

Background

Abstract

Biomedical optics is a multidisciplinary field that seeks to improve human health using the tools of opticalengineering. To be effective in this environment, a broad understanding of biology and optics is necessary.Optical Coherence Tomography (OCT) is a powerful imaging technique and is currently being explored as amethod for detecting minute tissue changes on, and beneath, the tissue surface. Small animals are usedprimarily for this research, with human application the ultimate goal. Histology, or tissue structure, is the goldstandard to verify conclusions drawn from the OCT images. Specifically, a Thorlabs OCS1050SS Swept-SourceOCT system is in use in the Tissue Optics Lab, to image the colon and female reproductive system in order toidentify cancerous tissue, as well as on tendons to monitor the healing response to therapeutic ultrasound.

NSF Research in Optics (RiO)Grant # 1460723John KoshelMelissa Sarmiento AyalaAshley ValdezStephanie Celaya-ServentiCaitlin Howard

Support References1 Drexler, Wolfgang, and James G. Fujimoto. "Introduction to Optical Coherence Tomography." Optical Coherence Tomography: Technology and Applications. Berlin: Springer, 2008. 1-45. Print.2 "Optical Coherence Tomography." Wikipedia. Wikimedia Foundation, 15 July 2015. Web. 15 June 2015.3 Kuo, Frank. "CLEO BLOG by Frank Kuo." : A Glimpse (or Primer) of the Plenary Session. 27 Dec. 2010. Web. 10 July 2015.

The Multifaceted Use of Swept-Source OCT in Tissue Imaging

Exposure to an interdisciplinary biomedical engineering labUnderstanding of OCT functionalityUnderstanding of current applications and research with OCTUse of an OCT to image tissuePractical Optics Workshops:

Cleaning and Handling Lenses Interferometry

Skills Learned

Exposure to research with small animalsTraining and protocols completed as related to small animal

research as outlined by IACUCLaboratory Microscope use ImageJ familiarization (software)MATLAB use (software)Detailed lab notebook documentation process

OCT produces two-dimensional, cross-sectional images or three-dimensionalvolumetric images with <10 μm resolution andis therefore capable of showing fine tissuestructure [1]. It functions similarly toultrasound, using infrared light instead ofsound [1]. Due to the high speed of light, OCTuses interferometry to distinguish scatterers indepth [1]. The short wavelength of light (≈1μm) enables higher resolution thanultrasound at the expense of reducedpenetration depth [1].

Optical Coherence Tomography (OCT)

Regenerated MATLAB code toimprove resolution by correctingdispersion due to custom endoscope

The MATLAB code mitigated thedispersion, increasing the resolution ofpreviously taken images. The axial pointspread function showed a narrower peakafter the correction, indicating the codewas successful. It will be used to calibratethe endoscope for future images; in orderto run the code, the capture of a mirrorwith the endoscopic OCT will be necessaryimmediately prior to the in vivo imaging ofthe mouse colon.

Used OCT to image ex vivorat tendons to determine ifthe images showedevidence of the IntensiveTherapy Ultrasound (ITU)treatment or incision made

Reviewed explanted samples under Laboratory Microscope to identify lesions and incision site

Designed an everting catheterto surround a Falloposcopeduring an imaging procedure

The ITU and the incisionsites were both visible onthe tissue sections. TheOCT images showed theincision site clearly,despite the thickenedtissue at the incision. ITUsites were not observedon the OCT images.

A preliminary non-everting singlespherical balloon prototype wasconstructed with plastic tubing,plastic wrap, and suture. Itsuccessfully inflated and deflatedwith liquid. Further designmodification is needed to build adual balloon everting catheter.

Colon Application

Methods Results Conclusions

Female Reproductive System Application


Tendon Application


Custom Endoscope Pre and Post Point Spread Function

OCT image showing cut in tendonHistology slice showing lesion from ITU

SS: Swept-Source, BS: Beamsplitter, REF: Reference Mirror, PD: Photodetector, SMP: Sample, CPU: Central Processing Unit,

IMG: Image2

Chart shows the resolution and depth capabilities of OCT relative to other imaging

methods1,3

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9

12

15

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New Cases and Death Rates Over Time of Ovarian Cancer

New Cases Deaths - US

Ovary Application

“SEER Stat Fact Sheets: Ovary Cancer”, National Cancer Institute

Amorette Dudgeon1,2, Weston Welge2, Photini Rice3, Melissa Lynn4, Jennifer Barton2,3

1RiO 2Optical Sciences 3Biomedical Engineering 4Physiological Sciences, University of Arizona

IMG

BS

SS

REF

SMP

PD

CPU

λ

231,840 221,200 220,800

132,700

74,000

40,290

158,040

27,54049,700

16,000

BreastCancer

(Female)

Lung andBronchus

Cancer

ProstateCancer

ColonCancer

BladderCancer

Estimated New Cases and Deaths: Top 5 Prevalent Cancers

New Cases Deaths

"SEER Stat Fact Sheets: Colon and Rectum Cancer”, National Cancer Institute

Colon Application

Non-sports29%

Basketball29%

Tennis8%

Football7%

Racquetball5%

Volleyball3%

Soccer1%

Other Sports

18%

Other9%

Achilles Tendon Rupture

“Achilles Tendon Injuries in a United States Population”, Raikin et al.

Tendon Application

Single balloon prototype using the folding method shown to the left

Optical Diagram of Swept-Source OCT

Image Penetration (log)

Res

olu

tio

n (

log)

1 mm

100 µm

10 µm

1 µm

10 cm1 cm

Optical Coherence Tomography

Ultrasound

Confocal Microscopy

100 µm 1 mm

Magnetic Resonance Imaging

Image Comparison