Post on 16-May-2015
1 David Levitz, PhD – Ariel Beery, MPA/MA
Introduction to multimodal imaging An introduction to MobileOCT’s proprietary method, combining high resolution structural, polarization difference, and spectral imaging modalities
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We believe the only cure is early screening
We can save more lives in the ba1le against cancer, if only we catch cancer earlier. Our proprietary technology can augment any digital camera to provide clinicians with revoluConary access to informaCon about Cssue microstructure and composiCon, including biomarkers, so they can beGer idenCfy and characterize cancers.
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More is more
• Current clinical imaging techniques relies primarily on bright-‐field imaging
• Tissue is not uniform – it contains mulCple layers and components
• No single mode of imaging can quickly and reliably achieve high sensi7vity and specificity
• By combining the strengths of mulCple imaging modaliCes, we can provide the clinician with a more complete picture of the Cssue
Freckle, before and aPer PDI:
Standard Image PolarizaCon Difference Image
Malignant Basel Cell Carcinoma
Standard Image PolarizaCon Difference Image
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MobileOCT’s Multimodal Technology
MobileOCT’s proprietary technology does this by using: • High resolu:on bright-‐field imaging to provide the ‘standard view’ that clinicians are used to working with
• Polariza:on difference imaging (PDI) to provide informaCon about the micro-‐structural paGerns in the superficial layer of the Cssue
• Spectral imaging to provide the clinician with informaCon about the composiCon of Cssue (water, oxy-‐ and deoxy-‐hemoglobin), including some biomarkers
MobileOCT’s adaptor in blue, on a Welch Allyn video colposcope
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Why multimodal is so important:
15% returns from the surface, mainly as glare
• Image seen is formed by light returning from different layers of Cssue, containing someCmes conflicCng informaCon.
• To beGer analyze a sample, MobileOCT analyzes each element separately.
4% returns from the superficial layer (where most cancers form)
~80% of the light returns from the deeper dermis (or stroma), where informaCon on certain biomarkers is found
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Mode 1: bright-field imaging, the standard
MobileOCT’s technology can be mounted on any digital camera, enabling the same high resoluCon images physicians are used to seeing
Stratum Corneum
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Mode 2: Polarization Difference Imaging(PDI)
1. Linearly polarized light is sent into the sample ( )
2. Light returning from superficial layer maintains polarizaCon
3. Light returning from deeper layer is diffuse, with its polarizaCon evenly split between the PAR ( ) and ORTH ( ) orientaCons
4. We isolate the superficial layer with the following equaCon:
Camera/Sensor
PDI = PAR – ORTH
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Why PDI works: examples from skin
Freckle:
Malignant basal cell carcinoma
Standard PDI
N. squamous cell carcinoma
The freckle, a surface feature, does not impact the superficial layer
The disrupCon occurring amongst the basal cells is hidden when observing the sample under even high resoluCon imaging
The faded area observed in the high resoluCon image ‘pops out’ when PDI is applied, because one can now observe the distrupCon in the superficial layer
Jacques et al, J Biomed Opt 2002
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Mode 3: multi-spectral imaging
• All the wavelengths of light are analyzed together, to quanCfy biomarker content in dermis (stroma)
• Tissue chromophores are known a priori (i.e: Water, oxy-‐ and deoxy-‐hemoglobin, melanin, bilirubin)
• The quanCfied makeup of the deep layer provides more details on the structural changes visualized with PDI
Tsumra et al., internal paper, Chiba University, Liu et al., Applied Optics, 46, 8328-8334 (2007) Jacques et al Biomed Opt Express (2011)
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Better Together
• Each mode has its own inherent strengths and challenges
• MobileOCT’s technology enables the clinician to view each mode separately, and soon will enable viewing a composite of all three models
• By increasing the power available to clinicians, MobileOCT hopes to help find cancer, sooner.