Abstract
Linearly polarized light that illuminates skin is backscattered by superficial layers and rapidly depolarized by birefringent collagen fibers. It is possible to distinguish such superficially backscattered light from the total diffusely reflected light that is dominated by light penetrating deeply into the dermis. The method involves acquisition of two images through an analyzing linear polarizer in front of the camera, one image (lpar) acquired with the analyzer oriented parallel to the polarization of illumination and one image (lper) acquired with the analyzer oriented perpendicular to the illumination. An image based on the polarization ratio, Pol=(lpar-lper)/(lpar+lper), is created. This paper compares normal light images, represented by lper, and Pol images of various skin pathologies in a pilot clinical study using incoherent visible-spectrum light. Images include pigmented skin sites (freckle, tattoo, pigmented nevi) and unpigmented skin sites [nonpigmented intradermal nevus, neurofibroma, actinic keratosis, malignant basal cell carcinoma, squamous cell carcinoma, vascular abnormality (venous lake), burn scar]. Images of a shadow cast from a razor blade onto a forearm skin site illustrate the behavior of Po[ values near the shadow edge. Near the shadow edge, Pol approximately doubles in value because no lper photons are superficially scattered into the shadow-edge pixels by the shadow region while lpar photons are directly backscattered from the superficial layer of these pixels. This result suggests that the point spread function in skin for cross-talk between Poi pixels has a half-width-half-max of about 390 μm.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 329-340 |
| Number of pages | 12 |
| Journal | Journal of Biomedical Optics |
| Volume | 7 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jul 2002 |
Fingerprint
Keywords
- Biomedical optics
- Imaging
- Polarized light
- Skin
ASJC Scopus subject areas
- Clinical Biochemistry
- Radiology Nuclear Medicine and imaging
- Atomic and Molecular Physics, and Optics
- Radiological and Ultrasound Technology
Cite this
Imaging skin pathology with polarized light. / Jacques, Steven; Ramella-Roman, Jessica C.; Lee, Ken.
In: Journal of Biomedical Optics, Vol. 7, No. 3, 07.2002, p. 329-340.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Imaging skin pathology with polarized light
AU - Jacques, Steven
AU - Ramella-Roman, Jessica C.
AU - Lee, Ken
PY - 2002/7
Y1 - 2002/7
N2 - Linearly polarized light that illuminates skin is backscattered by superficial layers and rapidly depolarized by birefringent collagen fibers. It is possible to distinguish such superficially backscattered light from the total diffusely reflected light that is dominated by light penetrating deeply into the dermis. The method involves acquisition of two images through an analyzing linear polarizer in front of the camera, one image (lpar) acquired with the analyzer oriented parallel to the polarization of illumination and one image (lper) acquired with the analyzer oriented perpendicular to the illumination. An image based on the polarization ratio, Pol=(lpar-lper)/(lpar+lper), is created. This paper compares normal light images, represented by lper, and Pol images of various skin pathologies in a pilot clinical study using incoherent visible-spectrum light. Images include pigmented skin sites (freckle, tattoo, pigmented nevi) and unpigmented skin sites [nonpigmented intradermal nevus, neurofibroma, actinic keratosis, malignant basal cell carcinoma, squamous cell carcinoma, vascular abnormality (venous lake), burn scar]. Images of a shadow cast from a razor blade onto a forearm skin site illustrate the behavior of Po[ values near the shadow edge. Near the shadow edge, Pol approximately doubles in value because no lper photons are superficially scattered into the shadow-edge pixels by the shadow region while lpar photons are directly backscattered from the superficial layer of these pixels. This result suggests that the point spread function in skin for cross-talk between Poi pixels has a half-width-half-max of about 390 μm.
AB - Linearly polarized light that illuminates skin is backscattered by superficial layers and rapidly depolarized by birefringent collagen fibers. It is possible to distinguish such superficially backscattered light from the total diffusely reflected light that is dominated by light penetrating deeply into the dermis. The method involves acquisition of two images through an analyzing linear polarizer in front of the camera, one image (lpar) acquired with the analyzer oriented parallel to the polarization of illumination and one image (lper) acquired with the analyzer oriented perpendicular to the illumination. An image based on the polarization ratio, Pol=(lpar-lper)/(lpar+lper), is created. This paper compares normal light images, represented by lper, and Pol images of various skin pathologies in a pilot clinical study using incoherent visible-spectrum light. Images include pigmented skin sites (freckle, tattoo, pigmented nevi) and unpigmented skin sites [nonpigmented intradermal nevus, neurofibroma, actinic keratosis, malignant basal cell carcinoma, squamous cell carcinoma, vascular abnormality (venous lake), burn scar]. Images of a shadow cast from a razor blade onto a forearm skin site illustrate the behavior of Po[ values near the shadow edge. Near the shadow edge, Pol approximately doubles in value because no lper photons are superficially scattered into the shadow-edge pixels by the shadow region while lpar photons are directly backscattered from the superficial layer of these pixels. This result suggests that the point spread function in skin for cross-talk between Poi pixels has a half-width-half-max of about 390 μm.
KW - Biomedical optics
KW - Imaging
KW - Polarized light
KW - Skin
UR - http://www.scopus.com/inward/record.url?scp=0036629486&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036629486&partnerID=8YFLogxK
U2 - 10.1117/1.1484498
DO - 10.1117/1.1484498
M3 - Article
C2 - 12175282
AN - SCOPUS:0036629486
VL - 7
SP - 329
EP - 340
JO - Journal of Biomedical Optics
JF - Journal of Biomedical Optics
SN - 1083-3668
IS - 3
ER -