DIET An emerging noninvasive portable and lowcost

DIET – An emerging noninvasive, portable and lowcost approach to breast cancer screening Prof J. Geoffrey Chase Univ of Canterbury Dept of Mechanical Engineering, Centre for Bio-Engineering Christchurch, New Zealand

Overview 1. Background 2. DIET Technology 3. Clinical results 4. Summary

The Problem § Breast cancer was the most common cause of female cancer death in 1999 § Over the period 1972 to 1997, the annual number of breast cancer deaths increased from 427 to 643[1] § Breast cancer is over represented among Maori (in NZ) and other ethnic groups worldwide [1] NZ Ministry of Health, 2002

Breast Cancer Screening Reduces Mortality (Tabar et al, 2003) • Screening = More early detection +20% • No real difference • Results due to improving care

Why? Low Compliance & Access What you don’t see can kill you! [Breast Screen Aotearoa] Goal is 70% every 2 years, but we get ~60% -- 40% missing! • Predominant compliance rates in the US and EU range from 50 -80% based on many factors • Eligible populations (over 50 years) are growing demographically for next 10 -20 years • Certain sub-groups have very low screening rates and thus much higher mortality Source: NZ Ministry favor any group • Occurrence rates don’t seem to particularly of Health, Trends and Projections 2002.

Screening § Screening has resulted is fewer deaths and earlier treatment § Concerns of screening § Patient dose § When should women start screening § Costs § Resources § Impacts of false positives (in a gold-standard test that can only be done infrequently at older ages) § However, fundamentally, mammography is a scarce and increasingly costly resource … § One thus cannot simply go get a repeat test to confirm, especially if you are younger

Current Diagnostic Techniques § Palpation/Clinical Breast Examination (CBE) § § § Mammography High level of operator skills Significant (sensor) noise MRI § § only modality recommended for screening X-rays, breast compression (painful) Lower compliance due to pain, cost and access Ultrasound § § § Very subjective Primary form of diagnosis Most mammograms occur after being found this way first Very accurate, but expensive Very few can be served No screening programs in most developing nations! Cost and X-Ray dose are major factors MRI

Problems with Existing Techniques § Currently, predominant breast cancer screening methods are: § Uncomfortable § Subject the patient to doses of radiation § Require expensive, location specific equipment and clinical staff. § They thus have relatively limited throughput (not enough capacity) § They are also low contrast as cancerous tissue density varies only ~5 -10% from healthy tissue § Coupled with resulting low compliance rates the average tumour size detected is ~1 cm = 10 x larger than possible

What’s Needed? § An all new approach § Must be clinically and commercially feasible § Must address compliance (w/ screening) issues § Must offer high throughput in terms of speed to test and access § An ideal design list would include: § § § Low cost equipment with no need for specialist technician Portable No X-Ray dose Equal efficacy (1 cm detection) compared to mammography Greater comfort (no compression) § Succinctly: less invasive, low cost screening system with more objective diagnosis (less ‘human error’)

The DIET Concept § DIET = Digital Imaging-based Elasto-Tomography § Can we meet all these needs? Governors Bay, Christchurch Sunset over Southern Alps, Christchurch

The DIET System Concept

Advantages of the DIET Concept § Screening from a younger age (no radiation dose) § Possible to build a history (every year!) § Less painful alternative (equals higher compliance) § Accuracy (initial target 1 cm) § Portability and ease of use (no specialised technician and no loss of compliance due to travel) § Scalability (will improve as silicon technology used improves) § Should be low cost (low-cost technologies used)

Prototype Development Laboratory Hardware 1 st Clinical prototype

DIET device at Canterbury BC

So, does it work? ? § If we could measure surface motions could we detect cancerous lesions, from surface data only? Lake Mathieson, Mirror Lakes West Coast of S. Island Lindis Pass and into Wanaka Cental Otago, S. Island

So, how does it work? And does it? § 3 main steps: § Vibration and image capture § Surface motion: (a) tracking and (b) characterisation § Diagnose based on surface motion § Proof of concept clinical trials as part of ergonomic and comfort trials shown § Multiple volunteers, multiple frequencies of actuation § Test of technology and proof of clinical concept

Step 1: Vibration & Image Capture § Vibrate breast from underneath and capture digital image sequences from 5 cameras Silicone gel with fiducial markers Simulation of human breast

Step 2 a: Surface Motion Tracking § Markers tracked in 2 D, then 3 D correspondences Camera 1 § Camera 2 Full 3 D reconstruction Optical flow skin tracking (better resolution) Fiducial tracking Skin tracking

Step 2 b: Motion characterisation Z-amplitude § § Z-phase Motion data is parameterised to allow diagnostic processing Elliptical path characterises motion in 3 D (at each frequency) § Motion flows around a hard tumor like water around a rock changing amplitude and phase asymmetrically

Step 3: Diagnosis from tumour effect on motion § § § Silicone phantom with 20 mm tumour at 6 o’clock Motion images alone can potentially give yes/no answer about tumour inclusion Readily automated. . . Entirely objective Re Amplitude z-phase

In vivo results (preliminary) § Breast from ongoing trial § 30 mm tumour between 1 -2 o’clock, left outer upper quadrant § Same effects as in phantoms are observed TOP RIGHT LEFT BOTTOM Rez-amplitude Z-phase

Some more visual outcomes § Both breasts of each subject shown at one frequency 30 mm @ 1: 30 o’clock 20 + 8 mm @ 2: 30 o’clock 11 mm @ 10: 30 o’clock § 120 mm not shown, as it is almost entire breast

DIET human trial summary § Ergonomics/Calibration trial § 18 Subjects, age 49. 3 (SD 8. 5) § 36 breasts imaged (both on each subject) § 4 breasts with malignant tumors (11, 30, 20+8, 120 mm) § 2 breasts with benign cysts (clusters of 10 -21 mm, ) § 30 healthy breasts § Range of sizes and shapes see below.

First Uses: A 3 word case § Under-age § Under-served § Under-equipped Plenty of “room” for a new modality like this

A Brief Summary § DIET is an all new approach to breast cancer screening that offers several potential advantages over current methods § Initial simulation and experimental proof of concept studies showed that it might be possible to achieve realistic screening (~1 cm inclusion size detection) § The main imaging and reconstruction steps are technologically challenging § Initial proof of concept experiments on silicone phantoms have been successful in identifying inclusions both via reconstruction and from disturbances in surface motion

Acknowledgements Prof Geoff Chase Arnaud Milsant Dr Geoff Shaw Jerome Rouze Richard Brown Dr Thomas Desaive Ashton Peters Wili Berger Dr. Richard Wien & Dr. Larry Ray Christina Starfinger Rodney Elliot Crispen Berg DIET Project Team 2004 Ben Petit Michael Wiertlewski DIET Project Team 2005 Fabrice Jandet Shig Kinoshita Edouard Ravni Anthony Hii Dr. Chris Hann Stefan Wortmann

Questions?