Supervisors:Prof. dr. ir. Fred van Keulen Prof. dr. ir. Kees GrimbergenDr. Ir. Hans Goosen Ir. Jerry de GrootPatrick van HolstHarry Jansen

Anne-Floor VetDepartment of BioMedical Engineering

A PREL IMINARY STUDY TO IMPROVE THE MAMMOGRAPHIC BREAST CANCER SCREENING WITH THE IMPLEMENTATION OF A LOCAL PRESSURE SENSING SYSTEM

Master Thesis Colloquium 18-2-2011

1

INTRO

DUCTIO

N

Breast cancer

Introduction Objective Theoretical study Experimental study Conclusions Recommendations

Most common cancer in women

1 out 8 women get any form of breast cancer

15% of all cancer deaths caused by breast cancer

Fairly treatable disease when detected early

2

INTRO

DUCTIO

N

Mammography

Population screening every 2 yearspost meno-pausal women25% less death cases

False-positive 68%False-negative 23-37%

Breast cancer detectionScreening (mammography)Diagnosing

Objective Theoretical study Experimental study Conclusions RecommendationsIntroduction Objective Theoretical study Experimental study Conclusions Recommendations 3

INTRO

DUCTIO

N

Mammography

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INTRO

DUCTIO

N

Mammography

Two x-ray images each breastCranial CaudalMedio Lateral Oblique

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X-ray CC

X-ray MLO

6

INTRO

DUCTIO

N

Mammography

Compression especially applied toLower X-ray doseKeep tissue in position

Compression 111-200 N 1/3 breast thickness reduction

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OBJECTIVE

A preliminary study to improve mammographic breast cancer screening with the implementation of a local pressure sensing system.

Title

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Attached to the compression plate

A preliminary study to improve mammographic breast cancer screening with the implementation of a local pressure sensing system.

A preliminary study to improve mammographic breast cancer screening with the implementation of a local pressure sensing system.

Same protocol as used in standard mammography• No additional time and operation • Same compression

OBJECTIVE

Pre-menopausal breast

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Fat

Mammary gland

Cooper’s ligaments

Elasticity fat converges to elasticity glandular tissue in large deformations [1]

[1] Azar et al.

Fat

Mammary gland

Cooper’s ligaments

Healthy breast tissue

OBJECTIVE

Post-menopausal breast

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Glandular tissue atrophies

OBJECTIVE

Cancerous breast

TumorSpherical shapeHigher stiffness (8-20 times)

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OBJECTIVE

Breast containing a tumor Cylinder containing an inclusion

Problem description

Simplification of the problem:Geometry

Physiology

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30 mm

12

CON

TENTSIntroduction Objective Recommendations

Theoreticalstudy

Conclusions

Experimentalstudy

Contents

Objective Theoretical study Experimental study Conclusions RecommendationsIntroduction Objective Theoretical study Experimental study Conclusions Recommendations

13

CON

TENTS

Contents

Objective Theoretical study Experimental study Conclusions RecommendationsIntroduction Objective Theoretical study Experimental study Conclusions Recommendations

Introduction Objective Recommendations

Theoreticalstudy

Conclusions

Experimentalstudy

14

CON

TENTS

Contents

Objective Theoretical study Experimental study Conclusions RecommendationsIntroduction Objective Theoretical study Experimental study Conclusions Recommendations

Introduction Objective Recommendations

Theoreticalstudy

Conclusions

Experimentalstudy

THEORETICAL STU

DY

Finite Element Analysis

Th

PR

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THEORETICAL STU

DY

Finite Element Analysis

Input parameters:

Relative elasticity (Ehealty tissue : Etumor )Depth (P)

Radius (R)

Relative elasticity (E1/E2)Depth (P)

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THEORETICAL STU

DY

Finite Element Analysis

Input parameters:

Relative elasticity (Ehealty tissue : Etumor )Depth (P)

Radius (R)

Relative elasticity (E1/E2)Depth (P)

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THEORETICAL STU

DY

Results

Footprint (L)

Peak value

Depression

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Rela

tive

stre

ss

0 1-1

THEORETICAL STU

DY

Peak value

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2RP

Peak value

E1 E2

19

Relative depth (P/R)Relative elasticity (E1/E2)

Peak

Peak

THEORETICAL STU

DY

Footprint

E2

Objective Theoretical study Experimental study Conclusions RecommendationsIntroduction Objective Theoretical study Experimental study Conclusions Recommendations

2RPFootprint (L)

20

Foot

prin

t (D/

L)

Foot

prin

t (D/

L)

Relative depth (P/R)Relative elasticity (E1/E2)

E1

CON

TENTS

Contents

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Introduction Objective Recommendations

Theoreticalstudy

Conclusions

Experimentalstudy

EXPERIMEN

TAL STUDY

Setup

Tensile tester Line-array pressure sensorsSilicone tissue phantom

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EXPERIMEN

TAL STUDY

Setup

Tensile tester Line-array pressure sensorsSilicone tissue phantom

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EXPERIMEN

TAL STUDY

Setup

Tensile tester Line-array pressure sensorsSilicone tissue phantom

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EXPERIMEN

TAL STUDY

Setup

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EXPERIMEN

TAL STUDY

Problems during experimental study

Lubrication layer to overcome shear stresses at the surface

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EXPERIMEN

TAL STUDY

Results

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X (mm)

Rela

tive

stre

ss

EXPERIMEN

TAL STUDY

Results

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X (mm)

Rela

tive

stre

ss

EXPERIMEN

TAL STUDY

Results

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X (mm)

Rela

tive

stre

ss

EXPERIMEN

TAL STUDY

results

12mm inclusion

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Rela

tive

stre

ss

X (mm)

CON

TENTS

Contents

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Introduction Objective Recommendations

Theoreticalstudy

Conclusions

Experimentalstudy

Objective: Feasibility of implementing local pressure sensors in standard mammographic devices

CON

CLUSIO

NS

Conclusions

•A peak is found in vertical stress distribution around an inclusion

•Relative depth (P/R) Does influence the stress distribution•Relative elasticity (E1 / E2 ) Does not influence the stress distribution

Theoretical study

Experimental study

•Inclusions smaller than 10 mm are not detected in the experimental study•Implementation in standard mammography is possible• Radio lucent pressure sensors• Filtering of shear stresses along surface

PROMISING FEATURE TO DETECT TUMORS

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CON

CLUSIO

NS

Where will this lead to..

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CON

TENTS

Contents

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Introduction Objective Recommendations

Theoreticalstudy

Conclusions

Experimentalstudy

RECOM

MEN

DATION

S

Theoretical study

Better geometry of the breast

Extending material properties:• Absolute elastic behavior• Viscoelastic behavior

Analytical definition of stress behavior around inclusionvalidate finite element analysis.

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RECOM

MEN

DATION

S

Better geometry to the breast

Experimental study

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Improving pressure sensing system• Radio-lucent pressure sensing system

• 2-dimensional instead of 1-dimensional

• Higher accuracy of the sensors• Higher resolutions of the sensors

THANK YOU FOR YOUR ATTENTION!

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38

39

EXPERIMEN

TAL STUDY

results

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41

Single sensor circuit

Single sensor setup

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OBJECTIVE

Analytical problem

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44