Prof. Bell Receives JHU Discovery Award

Dr. Muyinatu Bell and gynecologic surgeon collaborator Dr. Karen Wang were among the 30 interdisciplinary faculty teams at Johns Hopkins selected to receive one of the 2018 JHU Discovery Awards. This award is designed to support cross-divisional research teams who are poised to arrive at important discoveries or creative works. The expectation is that these awards will spark new, synergistic interactions between investigators across the institution and lead to work of the highest quality and impact. This award will support their research topic of “Photoacoustic Image Guidance of Gynecological Surgeries.”

JHU Office of Research Announcement

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Malone Center Announcement

HEMI Announcement

Whiting School of Engineering Announcement

Arun Presents A Deep Learning Based Alternative to Beamforming Ultrasound Images at IEEE ICASSP 2018

Congrats to Arun on the successful presentation of his research paper entitled “A Deep Learning Based Alternative to Beamforming Ultrasound Images” at IEEE ICASSP 2018 in Calgary, Alberta, Canada. This work is the first to propose deep learning as an alternative to the traditional ultrasound beamforming process and it was implemented for a single plane wave transmission. Check out  our associated conference paper for more details!

Citation: Nair AA, Tran T, Reiter A, Bell MAL, A deep learning based alternative to beamforming ultrasound images, IEEE International Conference on Acoustics, Speech and Signal Processing, Calgary, Alberta, Canada, April 15-20, 2018 [pdf]

Journal Paper Accepted to IEEE TMI

Congratulations to Derek Allman! His paper entitled “Photoacoustic Source Detection and Reflection Artifact Removal Enabled by Deep Learning” was accepted to the IEEE Transactions on Medical Imaging. This paper is expected to appear in the Special Issue on Machine Learning for Image Reconstruction.

This work is the first to use deep convolutional neural networks (CNNs) as an alternative to the photoacoustic beamforming and image reconstruction process. We used simulations to train CNNs to identify sources and reflection artifacts in raw photoacoustic channel data, reformatted the network outputs to usable images that we call CNN-Based images, and transferred these trained networks to operate on experimental data. Multiple parameters were varied during training (e.g., channel noise, number of sources, number of artifacts, sound speed, signal amplitude, transducer model, lateral and axial locations of sources and artifacts, and spacing between sources and artifacts). The classification accuracy of simulation and experimental data  ranged from 96-100% when the channel signal-to-noise ratio was -9 dB or greater and when sources were located in trained locations. Over 99% of the results had submillimeter location accuracy. Our CNN-Based images have high contrast,  no artifacts, and resolution that rivals the traditional photoacoustic image resolution of low-frequency ultrasound probes.

Citation: D Allman, A Reiter, MAL Bell, Photoacoustic Source Detection and Reflection Artifact Removal Enabled by Deep Learning, IEEE Transactions on Medical Imaging (accepted) [pdf]

Datasets Available:


Prof. Bell will give CS Seminar on April 10

Prof. Bell will give a seminar to the JHU Computer Science Department on April 10th, 2018.

“Directing Light and Learning from Sound to Guide Surgeries”


Just like programming a robot requires meticulous planning, coding, and execution, these same requirements are ever present when designing and controlling the individual optical and acoustic components of photoacoustic imaging systems. Photoacoustic imaging utilizes light and sound to make images by transmitting laser pulses that illuminate regions of interest, which subsequently absorb the light, causing thermal expansion and the generation of sound waves that are detected with conventional ultrasound transducers. The Photoacoustic and Ultrasonic Systems Engineering (PULSE) Lab is developing novel methods that use photoacoustic imaging to guide surgeries with the ultimate goal of eliminating surgical complications caused by injury to important structures – like major blood vessels and nerves – that are otherwise hidden from a surgeon’s immediate view.

In this talk, I will describe our novel light delivery systems that attach to surgical tools in order to direct light toward the surgical site. I will also introduce how we learn from the physics of sound propagation in tissue to develop acoustic beamforming algorithms that improve image quality, using both state-of-the-art deep learning methods and our newly developed spatial coherence theory. These light delivery and acoustic beamforming methods hold promise for robotic tracking tasks, visualization and visual servoing of surgical tool tips, and assessment of relative distances between the surgical tool and nearby critical structures (e.g., major blood vessels and nerves that if injured will cause severe complications, paralysis, or patient death). Impacted surgeries and procedures include neurosurgery, spinal fusion surgery, hysterectomies, and biopsies.


Muyinatu Bell is an Assistant Professor of Electrical and Computer Engineering with a joint appointment in the Biomedical Engineering Department at Johns Hopkins University, where she founded and directs the Photoacoustic and Ultrasonic Systems Engineering (PULSE) Lab. Dr. Bell earned a B.S. degree in Mechanical Engineering (biomedical engineering minor) from Massachusetts Institute of Technology (2006), received a Ph.D. degree in Biomedical Engineering from Duke University (2012), and conducted research abroad as a Whitaker International Fellow at the Institute of Cancer Research and Royal Marsden Hospital in the United Kingdom (2009-2010). Prior to joining the faculty, Dr. Bell completed a postdoctoral fellowship with the Engineering Research Center for Computer-Integrated Surgical Systems and Technology at Johns Hopkins University (2016), where she was co-mentored by faculty in the Computer Science Department and the School of Medicine. Dr. Bell has published over 40 scientific journal articles and conference papers, holds a patent for short-lag spatial coherence beamforming, and is the recipient of numerous awards, grants, and fellowships, including the NIH K99/R00 Pathway to Independence Award (2015), MIT Technology Review’s Innovator Under 35 Award (2016), and the NSF CAREER Award (2018).

[Watch seminar video / JHU login required]

Five PULSE Lab Abstracts Accepted to UITC 2018

PULSE Lab members will present the following five talks at the International Symposium on Ultrasonic Imaging and Tissue Characterization, May 30 – June 1, 2018:

  1. Application of robust short-lag spatial coherence beamforming to breast ultrasound data, Alycen Wiacek, Ole Marius Hoel Rindal, Kelly Fabrega-Foster, Susan Harvey, Muyinatu
    A. Lediju Bell, Johns Hopkins U. and U. Oslo
  2. Implications of theoretical photoacoustic spatial covariance for short-lag spatial coherence imaging, Michelle T. Graham, Muyinatu A. Lediju Bell
  3. Deep learning alternative to beamforming ultrasound images, Arun Asokan Nair, Trac D. Tran, Austin Reiter, Muyinatu A. Lediju Bell
  4. Deep learning for photoacoustic source detection and reflection artifact removal, Derek M. Allman, Austin Reiter, Muyinatu A. Lediju Bell
  5. Comparative study of CT-US registration performance with DAS and SLSC ultrasound beamforming techniques, Eduardo Gonzalez,  Michelle Graham,  Muyinatu A. Lediju Bell

Symposium website:

Prof. Bell Receives NSF CAREER Award

Congratulations to Prof. Bell for being selected to receive the NSF CAREER Award. The Faculty Early Career Development (CAREER) Program is a Foundation-wide activity that offers the National Science Foundation’s most prestigious awards in support of early-career faculty who have the potential to serve as academic role models in research and education and to lead advances in the mission of their department or organization.  The objective of Prof. Bell’s proposal entitled CAREER: Technical & Theoretical Foundations for Photoacoustic-Guided Surgery is to apply optical analyses, spatial coherence theory, and independent resolution models to describe fundamental performance limits of photoacoustic-based navigation during robotic and nonrobotic surgery.

ECE Department Announcement

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JMI Paper Accepted

Congrats to undergraduate student Margaret Allard on the acceptance of her first-author journal paper entitled Feasibility of photoacoustic-guided teleoperated hysterectomies. This paper will appear in the Journal of Medical Imaging (JMI) Special Section on Image-Guided Procedures, Robotic Interventions, and Modeling.

This paper is the first to describe the feasibility of photoacoustic integration with the da Vinci surgical robot to potentially guide minimally invasive hysterectomies and other gynecological surgeries.  To implement photoacoustic imaging, a novel light delivery system was designed and implemented  to surround da Vinci tools. This new light delivery system uniquely enabled the investigations described in the paper, including  the first known analysis of the optimal tool orientations for photoacoustic-guided hysterectomies using a da Vinci scissor tool (which partially blocks the transmitted light in some cases). This work can be extended to other da Vinci tools and laparoscopic instruments with similar tip geometry.

Margaret completed this work through her participation in our NSF Research Experience for Undergraduates in Computational Sensing and Medical Robotics.

Brooke Wins Second Place in Undergrad Poster Competition

Congratulations to PULSE Lab undergraduate student Brooke Stephanian on her 2nd place win in the Optics and Photonics Conference at JHU! She presented a poster that summarized the work she completed this semester on the topic “Theoretical Simulation to Optimize Short-Lag Spatial Coherence (SLSC) Photoacoustic Image Quality”.

Conference website:

Journal Paper Accepted to IEEE UFFC

Congrats to Arun Nair on the acceptance of his paper entitled “Robust Short-Lag Spatial Coherence Imaging” to the IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. This paper will appear in the special issue on sparsity driven methods in medical ultrasound.

This work is the first to re-examine the lag summation step of the Short-Lag Spatial Coherence (SLSC) algorithm and achieve additional robustness to coherence outliers through both weighted summation of individual coherence images (i.e., M-weighting) and the application of robust principal component analysis (i.e., Robust SLSC, or R-SLSC). Results show great promise for smoothing out the tissue texture of SLSC images, improving boundary delineation, and enhancing anechoic or hypoechoic target visibility at higher lag values. These improvements could be useful in clinical tasks such as breast cyst visualization, liver vessel tracking, and obese patient imaging.

Citation: AA Nair, T Tran, MAL Bell, Robust Short-Lag Spatial Coherence Imaging, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (accepted) [pdf]

Also Available on Journal Website:

Two PULSE Lab abstracts accepted to OSA Optics and Photonics Conference at JHU

Congrats to undergraduate student Brooke Stephanian and PhD student Derek Allman! Their abstracts were accepted to the 2017 Optics and Photonics Conference at Johns Hopkins University.

Brooke will present a poster entitled: Theoretical Simulation to Optimize Short-Lag Spatial Coherence (SLSC) Photoacoustic Image Quality 

Derek will give a presentation entitled: Using convolutional neural networks to eliminate reflection artifacts in experimental photoacoustic images

Conference details:

Free registration:

SPIE Medical Imaging Paper Accepted

Our paper, “Feasibility of photoacoustic guided hysterectomies with the da Vinci robot,” was accepted for Oral presentation at SPIE Medical Imaging in the Image-Guided Procedures, Robotic Interventions, and Modeling conference.

Session 2
Keynote and Medical Robotics

Tuesday 13 February 2018
10:10 AM – 12:10 PM

Feasibility of photoacoustic guided hysterectomies with the da Vinci robot
Paper 10576-9
Authors: Margaret Allard, Joshua Shubert, Muyinatu A. Lediju Bell

Congrats to Margaret, Josh, and Prof. Bell!

Three Abstracts Accepted to SPIE Photonics West

Three PULSE Lab abstracts were accepted to SPIE Photonics West in the BiOS Conference Track: Photons Plus Ultrasound: Imaging and Sensing 2018 (Conference 10494). This conference track will take place Sunday- Wednesday  January -28-31, 2018 at the The Moscone Center in San Francisco, California.

  1. A novel drill design for photoacoustic guided surgeries 
    Paper 10494-18
    Authors: Joshua Shubert, Muyinatu Bell
    Session 3: Therapy Monitoring and Guidance II
    Sunday 28 January 2018
    1:30 PM – 2:45 PM
  2. Using convolutional neural networks to eliminate reflection artifacts in experimental photoacoustic images
    Paper 10494-190
    Authors: Derek Allman, Austin Reiter, Muyinatu Bell
    Session PTue: Posters-Tuesday
    Tuesday 30 January 2018
    6:00 PM – 8:00 PM
  3. Development and validation of a short-lag spatial coherence theory for photoacoustic imaging
    Paper 10494-193
    Authors: Michelle Graham, Muyinatu Bell
    Session PTue: Posters-Tuesday
    Tuesday 30 January 2018
    6:00 PM – 8:00 PM

Congrats to  Josh, Derek, and Michelle!

Conference track website:

SLSC Beamforming Code Now Available on UltraSound Toolbox

The UltraSound Toolbox (USTB) is a free MATLAB toolbox for processing ultrasonic signals. The primary purpose of the USTB is to facilitate the comparison of imaging techniques and the dissemination of research results. The PULSE Lab is proud to collaborate on this effort to deliver SLSC beamforming to the broader ultrasound community. An example using the SLSC algorithm on a CIRS phantom and on human heart data was added today, as described here: The heart and phantom datasets and the SLSC code are now freely available to use. Additional datasets and beamforming code can be found by perusing the USTB website.

Congrats to Ole Marius Hoel Rindal (our visiting student from the University of Oslo) for putting in the work required to pull this together!

USTB Announcement

Margaret Allard Receives Best Presentation Award

Congratulations to PULSE Lab undergraduate student Margaret Allard who received the best presentation award from the NSF REU program in Computational Sensing and Medical Robotics. Her presentation was entitled Identifying Optimal da Vinci Tool Orientations for Photoacoustic Guided Hysterectomies. Prof. Jerry Prince presented Margaret with this award.

This award was shared by Margaret Allard and Mindy Wagenmaker.

JHU ECE Department Announcement

JBO Paper Accepted

Our paper entitled Photoacoustic-based approach to surgical guidance performed with and without a da Vinci robot was accepted for publication in the Journal of Biomedical Optics (JBO) Special Section on Translational Biophotonics.

Congrats to undergraduates Neeraj Gandhi and Margaret Allard!

This work was completed in partnership with the NSF REU in Computational Sensing and Medical Robotics along with collaborators Sungmin Kim and Peter Kazanzides, and it is the first to integrate photoacoustic imaging with the da Vinci surgical robot. It was also featured on the journal homepage.

ECE Department Announcement

BioOptics World Article

Three Abstracts Accepted to IEEE IUS 2017

Three PULSE Lab abstracts were accepted for presentation during the 2017 IEEE International Ultrasonics Symposium (IUS) to be held on September 6-9, 2017 at the Omni Shoreham Hotel, Washington D.C., USA.

  1. “Theoretical Application of Short-Lag Spatial Coherence to Photoacoustic Imaging” to be presented by Michelle Graham in the MBB: Non linear and coherence imaging poster session, 3-4 pm on Thursday, September 7, 2017. (Abstract ID: 1526)
  2. “Photoacoustic Visual Servoing of Needle Tips to Improve Biopsy Targeting in Obese Patients” to be presented by Joshua Shubert in the MPA: Technical Developments in Photoacoustic Imaging poster session, 3-4 pm  on Friday, September 8, 2017. (Abstract ID: 1088)
  3. “Identification and removal of reflection artifacts in photoacoustic images using convolutional neural networks” to be presented by Derek Allman in the MIM: Machine learning poster session, 9:30-10:30 am on Saturday, September 9, 2017. (Abstract ID: 1523)

Congrats to Michelle, Josh, and Derek!

Symposium website:

Four PULSE Lab Presentations at UITC 2017

PULSE Lab members presented the following four talks at the International Symposium on Ultrasonic Imaging and Tissue Characterization, June 5-7, 2017:

  1. Principal component short-lag spatial coherence imaging (PC-SLSC), Arun Asokan Nair, Trac D. Tran and Muyinatu A. Lediju Bell
  2. Photoacoustic-based visual servoing of needle tips to improve surgery on obese patients, Joshua Shubert and Muyinatu Bell
  3. Theoretical application of short-lag spatial coherence to photoacoustic imaging, Michelle Graham and Muyinatu Lediju Bell
  4. Evaluation of a convolutional neural network for identifying reflection artifacts in photoacoustic imaging, Derek M. Allman, Austin Reiter and Muyinatu A. Lediju Bell

Michelle (left) and Derek (right) giving their first PULSE Lab research presentations:

Symposium website:

IEEE ISCAS 2017 Special Session: Innovations In Acoustics

Prof. Bell will co-chair the IEEE ISCAS 2017 Special Session entitled “Innovations In Acoustics”. This session will be held on May 29, 2017 at the Baltimore Marriott Waterfront in Baltimore, MD, and it provides unique access to acoustic researchers from various academic departments across Johns Hopkins University. This special session will cover acoustics on various levels, starting from background noise suppression in an electronic stethoscope, to bat echolocation processing to ultrasonic medical imaging and acoustic beamforming. It includes an invited talk from the father of microphone technology, Prof. Jim West, a National Medal of Technology and Innovation winner, a member of the National Academy of Engineering, and a recipient of countless additional high honors. The session also includes a technical talk from a local ultrasound imaging start-up company (Sonavex, Inc.) formed based on ideas born here in Baltimore at Johns Hopkins University, which uniquely supports the conference theme “from Dreams to Innovation”.

Session Details

NIH R00 Grant Awarded

The PULSE Lab received the 2nd phase of Dr. Bell’s NIH K99/R00 award to support our project entitled “Coherence-Based Photoacoustic Image Guidance of Transsphenoidal Surgeries”. This work is motivated by the clinical challenges surrounding the removal of pituitary tumors using the minimally invasive endonasal transsphenoidal approach, which incurs the deadly risk of causing injury to the internal carotid arteries. We propose to eliminate this risk by developing a sophisticated photoacoustic imaging system that visualizes blood vessels located behind bone during the surgical operation. This photoacoustic imaging system will be equipped with our novel coherence-based beamformers and our specialized light delivery systems.

JHU ECE Announcement

Three Abstracts Accepted to SPIE Photonics West

Three abstracts from the PULSE Lab were accepted to SPIE Photonics West, which will take place January 28 – February 2, 2017 in San Francisco, California:

  • Paper 10064-18: A machine learning approach to identifying point source locations in photoacoustic data (29 January 2017 • 5:30 – 7:30 PM)
  • Paper 10064-101: Optimizing light delivery for a photoacoustic surgical system (29 January 2017 • 3:00 – 3:15 PM)
  • Paper 10064-125: Accuracy of a novel photoacoustic-based approach to surgical guidance performed with and without a da Vinci robot (29 January 2017 • 5:30 – 7:30 PM)

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