CBET Award Achievements
Notable Accomplishments from CBET Awards
 

Imaging Early-stage Breast Cancer with UltraWideBand (UWB) Radar Techniques: A New Modality

Susan Hagness, University of Wisconsin-Madison

Dr. Susan Hagness’ research team at the University of Wisconsin-Madison has demonstrated the feasibility of ultrawideband (UWB) microwave imaging for early stage breast cancer detection.  UWB microwave imaging uses the measurement of the transmission of microwave energy through an object to define its dielectric (insulating) properties.  In this case the biophysical mechanisms (e.g. water content, blood flow rate, or temperature) of normal fatty breast tissue are contrasted with those of malignant tissue, making it possible to identify extremely small malignant tumors and to differentiate between benign and malignant tumors.  This approach can also be used to treat detected lesions by focusing microwave radiation on the malignant tissue.

The researchers’ approach to UWB microwave based-imaging provides a safe, low cost, non-invasive, highly reliable approach to tumor detection.  It avoids the problems of radiation exposure, false positives (and unnecessary biopsies), patient discomfort, and high cost associated with conventional X-ray mammography.  Microwaves also offer exceptionally high contrast compared to other imaging modalities, such as X-ray mammography.

Hagness’ approach transmits microwave signals into the breast from multiple locations and focuses the backscattered signals using both temporal and spatial dimensions to precisely determine the presence of a malignant tumor.  The space-time microwave imaging system, with an array of antennas for radiating and receiving microwaves, overcomes problems of poor resolution with prior microwave imaging approaches.  This system enhances the response from malignant lesions while minimizing clutter signals, thereby overcoming challenges presented by breast heterogeneity and enabling the detection of lesions as small as 1-2 mm.

The Principal Investigator (PI) developed 3-D anatomically realistic numerical breast phantoms and used them to test both the imaging approach and to evaluate its safety.  This is the first formal evaluation of the absorption in the breast from microwave imaging and the results will provide valuable guidance in the design of future clinical systems.  The PI also modeled three different shapes of tumors and found that UWB microwave radar data have great promise in classifying the physical features of breast tumors.

Susan Hagness Image
 
Cross-sections of the 3-D dielectric-properties grid for the nine MRI-derived numerical breast phantoms used to compute representative ultrawideband microwave signals scattered by heterogeneous normal breast tissue (known as clutter):

(a) & (b) phantoms are examples of the “almost entirely fat” class;

(c) & (d) phantoms are examples of the “scattered fibroglandular” class;

(e), (f) & (g) phantoms are examples of the “heterogeneously dense” class;

(h) & (i) phantoms are examples of the “extremely dense” classThe antenna cross-section is shown to the left of each breast phantom, positioned at one of the 48 antenna locations in the scanning arrayThese phantoms are being made available to the international community for use in research on microwave breast cancer detection and treatment.
Credit:  Susan Hagness, University of Wisconsin-Madison


Impact on Industry and/or SocietyThe societal implications of improved technology for detecting early stage breast cancer are enormousThis work has the potential to directly impact the lives of women worldwide through improved health care and treatment.  The promise of low-cost hardware for implementing our technology means that this emerging breast cancer screening technology could be made widely available to the general public, including medically under-served populations.  The safety and comfort associated with UWB microwave imaging should improve public compliance with annual screening recommendations.  This project emphasizes breast cancer detection (as well as treatment, although not highlighted here), but the results are more broadly applicable to other biological applications of microwave imaging and hyperthermia treatment.  The signal processing and microwave expertise developed in this project are directly relevant to other remote sensing problems in heterogeneous media, including seismology, subsurface radar for land mine detection, and sonar.

This work is notableOne particularly notable aspect of our work is as follows:  The Pi’s 3-D numerical phantoms offer the highest possible level of realism in terms of both the spatial distribution of tissue (rigorously derived from MRI data) and the dielectric properties of breast tissue (obtained from recently completed large-scale NIH-supported dielectric characterization study), and they are specifically designed for use in one of the most powerful computational electromagnetics techniques – the finite-difference time-domain (FDTD) method.  International research activity in the field of UWB microwave breast cancer detection and treatment has been growing steadily over the past couple of years.  This research team believes that these phantoms, along with the large database of numerical tumor phantoms they created for the classification study, will be of great use to the international research community.  Therefore, the PI is presently developing a web site - - an online repository - - that will enable the team to share these phantoms with other research groups.

This work is inherently multidisciplinaryThe research team includes faculty from several diverse areas within electrical and computer engineering (two of whom have affiliate appointments in biomedical engineering) as well as radiology.  Graduate students involved in this project have been exposed to multidisciplinary training at the interface of electromagnetics, signal processing, microwave engineering, and biomedical imaging.

This project addresses the NSF Strategic Outcome Goals of the NSF Strategic Plan 2006-2011 as follows

(1Discovery:  The work crosses disciplinary boundaries and has required a systems approach to address the complex problem of breast cancer detection using novel UWB radar techniques.

(2Learning:  The work has contributed towards the goal of preparing a diverse STEM (Science, Technology, Engineering, & Mathematics) workforce by broadening participation of women and underrepresented minorities in the pursuit of Ph.D.s in electrical engineering.

This Nugget represents Transformative Research.  The PI's team has pioneered an entirely new modality for imaging and treating early-stage breast cancer.  This emerging breast cancer screening technology could be made widely available to the general public, including medically under-served populations.  The safety and comfort associated with UWB microwave imaging should improve public compliance with annual screening recommendations.

These advances are likely to transform other biological applications of microwave imaging and hyperthermia treatment as well as a diverse spectrum of other remote sensing problems.

This Nugget represents Broadening Participation.  The topic of breast cancer detection and treatment has proven to be very appealing to women and has helped the PI to recruit and retain women for graduate studies in electrical engineering.  Specifically, this grant has directly or indirectly supported the work of five women Ph.D. students (one of whom is an underrepresented minority) and one additional underrepresented minority male Ph.D. student.



     
Program Officer:   Semahat Demir
     
NSF Award Number:   0201880
     
Award Title:
 
  Microwave Imaging via Space-Time Signal Processing for Early-Stage Breast Cancer Detection, Monitoring, and Treatment
     
PI Name:   Susan Hagness
     
Institution Name:   University of Wisconsin-Madison
     
Program Element:   5345
     
NSF Investment:   American Competitiveness Initiative (ACI)
     

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This CBET Nugget was approved by ENG on 5 March 2008.