A Novel Dermoscopic Probe for Determining Elasticity

Measurements of the Skin

Group 7:Erica BozemanMarkesha CookStephanie Cruz

January 24, 2007

Design Objective "Structural alterations within cancerous skin-lesions

cause unexpected patterns of anatomical deformation in response to mechanical forces."

Dr. Michael Miga

Hypothesis:If structural alterations in skin cancer lesions differs from that of normal skin when a mechanical force is applied, then a systematic method of measuring the force response of a skin lesion can be compared to that of normal skin to determine the presence of skin cancer.

Conduct phantom experiments Design skin-friendly stretching apparatus Develop systematic method of testing skin forces

Skin Cancer Types of skin cancer

Basal Cell carcinoma Squamous cell carcinoma Melanoma

Facts and Statistics Over 1 million new cases of

skin cancer diagnosed in US (2006)

1 American dies of melanoma every 67 minutes

Treating melanoma costs about $740 million each year

World Health Organization 60,000 deaths worldwide/yr 48,000 melanoma; 12,000

other

http://images.main.uab.edu/healthsys/ep_0137.jpg

http://www.aad.org/aad/Newsroom/2005+Skin+Cancer+Fact+Sheet.htm

Current Methods of Detection Clinical eye

Accuracy varies with experience Biopsy

Dermoscopy 10X magnification, liquid

polarizing lens Only ~75-80% accurate

Serial photography Software expensive (~30,000) Slow Specialty clinics

In vivo confocal microscopy Experimental

http://www.jfponline.com/images/5206/5206JFP_AppliedEvidence-fig4.jpg

Dermatologist Recommendations

Dr. Darrel Ellis Faster More accurate Less expensive

Ideal device Small enough to carry in pocket and use with one hand

Our Proposed Device

Safe Easy Non-invasive Quick Effective Cost-efficient

Force Sensor

Initial Design:

Sony XCD-X710CR camera

Mild Skinadhesive

Potential Design

SKIN25.4

mm

Sony XCD-X710CR camera

Mild Skinadhesive

Force Sensor

130 mm

FOV: 32mm

Design Specifications:Ultra-Low Profile Load Cell - S215 Strain Gauge Technology

Mechanical motion electronic signal

Measures up to 8 N (2 lb-force)

Dimensions: 27.94 x 5.99 mm (1.1

x .236 in) Rigidly mounted on

platform beam Cost:$155

Using the PDE Toolbox:

Assessing the Expected Outputs of

our Device

Step 1:

Step 2:

Melanoma

Е ≈ 52 kPa

ν ≈ 0.485

Normal Skin

Е ≈ 10 kPa

ν ≈ 0.485

Colormap of Stress in the X-direction

σx= Force/ Area

σx ≈ 18 kPa

Area=0.01m x .02m

Force ≈ 3.6 N

Now Let’s Compare the Geometric Shapes:

Rectangular CrescentCube

Budget

Force Sensor $155.00

Probe Materials $50

3M Micropore Surgical tape $10.00

Important Design Dates

End of January Finalize Device Design

Mid February Independent Testing Completed

End of February Device Built

Mid March Comparative analysis using Dr. Miga’s model

April Finalize results; prepare for design presentation

References www.skincancer.org http://www.eurekalert.org/pub_releases/2006-10/osoa-ltt

101606.php http://www.smdsensors.com/detail_pgs/s100.htm http://www.omega.com/literature/transactions/volume3/s

train.html M. I. Miga, M. P. Rothney, J. J. Ou, "Modality independent

elastography (MIE): Potential applications in dermoscopy", Medical Physics, vol. 32, no. 5, pp. 1308-1320, 2005.

Tsap, Leonid V. et al. Efficient Nonlinear Finite Element Modeling of Nonrigid Objects via Optimization of Mesh Models. Computer Vision and Image Understanding. Vol 69, No. 3 March 1998 pp. 330-350.

Wan Abas, W.A.B and J.C. Barbenal. Uniaxial Tension Test of Human Skin In Vivo. J. Biomed. Engng. Vol 4 January 1982 pp.65-71.

Questions