Ms. Margaret M. Allard Profile

Margaret M. Allard

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Publications (4)

Proceedings Article | 4 March 2019 Paper

New microcontroller unit improving stability and functionality of the optical chopper for atmospheric LIDAR

Margaret Allard, Jens Lautenbach, Luis Quintero

Proceedings Volume 10925, 1092518 (2019) https://doi.org/10.1117/12.2508060

KEYWORDS: Control systems, Optical choppers, LIDAR, Microcontrollers, Potassium, Laser stabilization, Observatories, Alexandrite lasers

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Proceedings Article | 12 March 2018 Presentation + Paper

Technical note: feasibility of photoacoustic guided hysterectomies with the da Vinci robot

Margaret Allard, Joshua Shubert, Muyinatu Lediju Bell

Proceedings Volume 10576, 105760A (2018) https://doi.org/10.1117/12.2293176

KEYWORDS: Photoacoustic spectroscopy, Surgery, 3D modeling, Acoustics, Arteries, Visualization, Photoacoustic imaging, Injuries, Ultrasonography, Tissue optics

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This technical note provides an overview of our work to explore the combination of photoacoustic imaging with the da Vinci surgical robot, which is often used to perform teleoperated hysterectomies (i.e., surgical removal of the uterus). Hysterectomies are the prevailing solution to treat medical conditions such as uterine cancer, endometriosis, and uterine prolapse. One complication of hysterectomies is accidental injury to the ureters located within millimeters of the uterine arteries that are severed and cauterized to hinder blood flow and enable full uterus removal. By introducing photoacoustic imaging, we aim to visualize the uterine arteries (and potentially the ureter) during this surgery. We developed a specialized light delivery system to surround a da Vinci curved scissor tool and an ultrasound probe was placed externally, representing a transvaginal approach to receive the resulting acoustic signals. Photoacoustic images were acquired while sweeping the tool across a custom 3D uterine vessel model covered in ex vivo bovine tissue that was placed between the 3D model and the light delivery system, as well as between the ultrasound probe and the 3D model (to introduce optical and acoustic scattering). Four tool orientations were explored with the scissors in either open or closed configurations. The optimal tool orientation was determined to be closed scissors with no bending of the tool’s wrist, based on measurements of signal contrast and background signal-to-noise ratios in the corresponding photoacoustic images. We also introduce a new metric, dθ, to determine when the image will change during a sweep, based on the tool position and orientation (i.e., pose), relative to previous poses. Overall, results indicate that photoacoustic imaging is a promising approach to enable visualization of the uterine arteries and thereby guide hysterectomies (and other gynecological surgeries). In addition, results can be extended to other minimally invasive da Vinci surgeries and laparoscopic instruments with similar tip geometry.

SPIE Journal Paper | 8 February 2018 Open Access

Feasibility of photoacoustic-guided teleoperated hysterectomies

Margaret Allard, Joshua Shubert, Muyinatu Lediju Bell

JMI, Vol. 5, Issue 02, 021213, (February 2018) https://doi.org/10.1117/12.10.1117/1.JMI.5.2.021213

KEYWORDS: Photoacoustic spectroscopy, Surgery, Arteries, Visualization, 3D modeling, Ultrasonography, Tissue optics, Acoustics, Signal to noise ratio, Visibility

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SPIE Journal Paper | 24 August 2017 Open Access

Photoacoustic-based approach to surgical guidance performed with and without a da Vinci robot

Neeraj Gandhi, Margaret Allard, Sungmin Kim, Peter Kazanzides, Muyinatu Lediju Bell

JBO, Vol. 22, Issue 12, 121606, (August 2017) https://doi.org/10.1117/12.10.1117/1.JBO.22.12.121606

KEYWORDS: Surgery, Visualization, Tissues, Optical fibers, Distance measurement, Imaging systems, Blood vessels, 3D modeling, Acoustics, Transducers

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