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Dive into the research topics where Wes M. Allen is active.

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Featured researches published by Wes M. Allen.


Biomedical Optics Express | 2016

Wide-field optical coherence micro-elastography for intraoperative assessment of human breast cancer margins

Wes M. Allen; Lixin Chin; Philip Wijesinghe; Rodney W. Kirk; Bruce Latham; David D. Sampson; Christobel Saunders; Brendan F. Kennedy

Incomplete excision of malignant tissue is a major issue in breast-conserving surgery, with typically 20 - 30% of cases requiring a second surgical procedure arising from postoperative detection of an involved margin. We report advances in the development of a new intraoperative tool, optical coherence micro-elastography, for the assessment of tumor margins on the micro-scale. We demonstrate an important step by conducting whole specimen imaging in intraoperative time frames with a wide-field scanning system acquiring mosaicked elastograms with overall dimensions of ~50 × 50 mm, large enough to image an entire face of most lumpectomy specimens. This capability is enabled by a wide-aperture annular actuator with an internal diameter of 65 mm. We demonstrate feasibility by presenting elastograms recorded from freshly excised human breast tissue, including from a mastectomy, lumpectomies and a cavity shaving.


Biomedical Optics Express | 2018

Wide-field quantitative micro-elastography of human breast tissue

Wes M. Allen; Kelsey M. Kennedy; Q. Fang; Lixin Chin; Andrea Curatolo; Lucinda Watts; Renate R. Zilkens; Synn Lynn Chin; Benjamin F. Dessauvagie; Bruce Latham; Christobel Saunders; Brendan F. Kennedy

Currently, 20-30% of patients undergoing breast-conserving surgery require a second surgery due to insufficient surgical margins in the initial procedure. We have developed a wide-field quantitative micro-elastography system for the assessment of tumor margins. In this technique, we map tissue elasticity over a field-of-view of ~46 × 46 mm. We performed wide-field quantitative micro-elastography on thirteen specimens of freshly excised tissue acquired from patients undergoing a mastectomy. We present wide-field optical coherence tomography (OCT) images, qualitative (strain) micro-elastograms and quantitative (elasticity) micro-elastograms, acquired in 10 minutes. We demonstrate that wide-field quantitative micro-elastography can extend the range of tumors visible using OCT-based elastography by providing contrast not present in either OCT or qualitative micro-elastography and, in addition, can reduce imaging artifacts caused by a lack of contact between tissue and the imaging window. Also, we describe how the combined evaluation of OCT, qualitative micro-elastograms and quantitative micro-elastograms can improve the visualization of tumor.


Optics Letters | 2017

Depth-encoded optical coherence elastography for simultaneous volumetric imaging of two tissue faces

Q. Fang; Luke Frewer; Philip Wijesinghe; Wes M. Allen; Lixin Chin; Juliana Hamzah; David D. Sampson; Andrea Curatolo; Brendan F. Kennedy

Depth-encoded optical coherence elastography (OCE) enables simultaneous acquisition of two three-dimensional (3D) elastograms from opposite sides of a sample. By the choice of suitable path-length differences in each of two interferometers, the detected carrier frequencies are separated, allowing depth-ranging from each interferometer to be performed simultaneously using a single spectrometer. We demonstrate depth-encoded OCE on a silicone phantom and a freshly excised sample of mouse liver. This technique minimizes the required spectral detection hardware and halves the total scan time. Depth-encoded OCE may expedite clinical translation in time-sensitive applications requiring rapid 3D imaging of multiple tissue surfaces, such as tumor margin assessment in breast-conserving surgery.


Frontiers in Optics | 2015

Quantifying Tissue Stiffness and the Effect of Nonlinearity using Compression Optical Coherence Elastography

Wes M. Allen; Philip Wijesinghe; Kelsey M. Kennedy; Lixin Chin; David D. Sampson; Brendan F. Kennedy

We demonstrate the modification of optical coherence elastography to advance from relative strain images to quantified tissue stiffness on the micro-scale. We highlight the nonlinear dependence of tissue stiffness on the applied load and consider how nonlinearity may help characterise soft tissues.


Journal of Biophotonics | 2018

Optical palpation for the visualization of tumor in human breast tissue

Wes M. Allen; Philip Wijesinghe; Benjamin Dessauvagie; Bruce Latham; Christobel Saunders; Brendan F. Kennedy

Accurate and effective removal of tumor in one operation is an important goal of breast-conserving surgery. However, it is not always achieved. Surgeons often utilize manual palpation to assess the surgical margin and/or the breast cavity. Manual palpation, however, is subjective and has relatively low resolution. Here, we investigate a tactile imaging technique, optical palpation, for the visualization of tumor. Optical palpation generates maps of the stress at the surface of tissue under static preload compression. Stress is evaluated by measuring the deformation of a contacting thin compliant layer with known mechanical properties using optical coherence tomography. In this study, optical palpation is performed on 34 freshly excised human breast specimens. Wide field-of-view (up to ~46 × 46 mm) stress images, optical palpograms, are presented from four representative specimens, demonstrating the capability of optical palpation to visualize tumor. Median stress reported for adipose tissue, 4 kPa, and benign dense tissue, 8 kPa, is significantly lower than for invasive tumor, 60 kPa. In addition, we demonstrate that optical palpation provides contrast consistent with a related optical technique, quantitative micro-elastography. This study demonstrates that optical palpation holds promise for visualization of tumor in breast-conserving surgery.


Proceedings of SPIE | 2017

Dual-scanning optical coherence elastography for rapid imaging of two tissue volumes (Conference Presentation)

Q. Fang; Luke Frewer; Philip Wijesinghe; Juliana Hamzah; Ruth Ganss; Wes M. Allen; David D. Sampson; Andrea Curatolo; Brendan F. Kennedy

In many applications of optical coherence elastography (OCE), it is necessary to rapidly acquire images in vivo, or within intraoperative timeframes, over fields-of-view far greater than can be achieved in one OCT image acquisition. For example, tumour margin assessment in breast cancer requires acquisition over linear dimensions of 4-5 centimetres in under 20 minutes. However, the majority of existing techniques are not compatible with these requirements, which may present a hurdle to the effective translation of OCE. To increase throughput, we have designed and developed an OCE system that simultaneously captures two 3D elastograms from opposite sides of a sample. The optical system comprises two interferometers: a common-path interferometer on one side of the sample and a dual-arm interferometer on the other side. This optical system is combined with scanning mechanisms and compression loading techniques to realize dual-scanning OCE. The optical signals scattered from two volumes are simultaneously detected on a single spectrometer by depth-encoding the interference signal from each interferometer. To demonstrate dual-scanning OCE, we performed measurements on tissue-mimicking phantoms containing rigid inclusions and freshly isolated samples of murine hepatocellular carcinoma, highlighting the use of this technique to visualise 3D tumour stiffness. These findings indicate that our technique holds promise for in vivo and intraoperative applications.


Proceedings of SPIE | 2017

Utilising non-linear elasticity to increase mechanical contrast in quantitative optical coherence elastography (Conference Presentation)

Wes M. Allen; Philip Wijesinghe; Lixin Chin; Juliana Hamzah; Ruth Ganss; David D. Sampson; Brendan F. Kennedy

Compression optical coherence elastography (OCE) enables rapid acquisition with high resolution over fields of view relevant to many clinical applications. Compression OCE typically provides a relative measure of mechanical properties; however, we have recently demonstrated a technique which quantifies stiffness via a compliant layer, termed quantitative OCE. In quantitative OCE, stiffness is reported as a tangent modulus, which is a surrogate for Young’s modulus at a given preload in non-linear elastic material. In biological tissues, which are typically non-linear elastic, values of stiffness reported through quantitative OCE could be over- or under-estimated, and are heavily biased by the arbitrary bulk preload applied to that region. We present a method to measure tissue nonlinearity locally, by preforming compression OCE at multiple preloads ranging from 2% to 40%. We show, through presentation of 2D quantitative elastograms, that compression OCE has the potential to measure the non-linear stiffness in tissue mimicking phantoms and biological tissue. Further, intrinsic mechanical contrast in tissue is dependent upon its preload. By tailoring tissue preload, we demonstrate improved contrast between benign and tumor tissue in a murine liver carcinoma model.


Proceedings of SPIE | 2017

Clinical assessment of human breast cancer margins with wide-field optical coherence micro-elastography (Conference Presentation)

James G. Fujimoto; Joseph A. Izatt; Valery V. Tuchin; Wes M. Allen; Lixin Chin; Philip Wijesinghe; Rodney W. Kirk; Bruce Latham; David D. Sampson; Christobel Saunders; Brendan F. Kennedy

Breast cancer has the second highest mortality rate of all cancers in females. Surgical excision of malignant tissue forms a central component of breast-conserving surgery (BCS) procedures. Incomplete excision of malignant tissue is a major issue in BCS with typically 20 – 30% cases requiring a second surgical procedure due to postoperative detection of tumor in the margin. A major challenge for surgeons during BCS is the lack of effective tools to assess the surgical margin intraoperatively. Such tools would enable the surgeon to more effectively remove all tumor during the initial surgery, hence reducing re-excision rates. We report advances in the development of a new tool, optical coherence micro-elastography, which forms images, known as elastograms, based on mechanical contrast within the tissue. We demonstrate the potential of this technique to increase contrast between malignant tumor and healthy stroma in elastograms over OCT images. We demonstrate a key advance toward clinical translation by conducting wide-field imaging in intraoperative time frames with a wide-field scanning system, acquiring mosaicked elastograms with overall dimensions of ~50 × 50 mm, large enough to image an entire face of most lumpectomy specimens. We describe this wide-field imaging system, and demonstrate its operation by presenting wide-field optical coherence tomography images and elastograms of a tissue mimicking silicone phantom and a number of representative freshly excised human breast specimens. Our results demonstrate the feasibility of scanning large areas of lumpectomies, which is an important step towards practical intraoperative margin assessment.


Proceedings of SPIE | 2016

Towards intraoperative assessment of tumor margins in breast surgery using optical coherence elastography(Conference Presentation)

Brendan F. Kennedy; Philip Wijesinghe; Wes M. Allen; Lixin Chin; Bruce Latham; Christobel Saunders; David D. Sampson

Surgical excision of tumor is a critical factor in the management of breast cancer. The most common surgical procedure is breast-conserving surgery. The surgeon’s goal is to remove the tumor and a rim of healthy tissue surrounding the tumor: the surgical margin. A major issue in breast-conserving surgery is the absence of a reliable tool to guide the surgeon in intraoperatively assessing the margin. A number of techniques have been proposed; however, the re-excision rate remains high and has been reported to be in the range 30-60%. New tools are needed to address this issue. Optical coherence elastography (OCE) shows promise as a tool for intraoperative tumor margin assessment in breast-conserving surgery. Further advances towards clinical translation are limited by long scan times and small fields of view. In particular, scanning over sufficient areas to assess the entire margin in an intraoperative timeframe has not been shown to be feasible. Here, we present a protocol allowing ~75% of the surgical margins to be assessed within 30 minutes. To achieve this, we have incorporated a 65 mm-diameter (internal), wide-aperture annular piezoelectric transducer, allowing the entire surface of the excised tumor mass to be automatically imaged in an OCT mosaic comprised of 10 × 10 mm tiles. As OCT is effective in identifying adipose tissue, our protocol uses the wide-field OCT to selectively guide subsequent local OCE scanning to regions of solid tissue which often present low contrast in OCT images. We present promising examples from freshly excised human breast tissue.


Proceedings of SPIE | 2016

Compression optical coherence elastography for improved diagnosis of disease(Conference Presentation)

Brendan F. Kennedy; Philip Wijesinghe; Lixin Chin; Andrea Curatolo; Shaghayegh Es'haghian; Wes M. Allen; Luke Frewer; Arash Arabshahi; Karol Karnowski; David D. Sampson

Optical coherence elastography (OCE) is emerging as a potentially useful tool in the identification of a number of diseases. In our group, we are developing OCE techniques based on compressive loading. Typically, these techniques employ a quasi-static mechanical load introduced by uniaxially compressing a sample with a rigid plate. The resulting deformation of the sample is measured using phase-sensitive detection and the local axial strain is estimated from the slope of displacement over a finite depth in the sample, providing qualitative mechanical contrast. In this talk, an overview of our work will be given and some of the outstanding challenges described. Our group’s work in OCE can broadly be divided into four streams, each of which will be described in detail in the talk: system development; techniques; quantification; and applications. • System development: The phase-sensitive OCE method we have developed will be described, as well as a high resolution optical coherence microscopy-based elastography system suitable for imaging cellular-scale mechanical properties. • Techniques: In addition to presenting techniques to estimate strain, our approaches to imaging tissue viscoelasticity and nonlinearity will be described. A technique to segment elastograms based on strain heterogeneity will be presented. • Quantification: Methods under development to quantify tissue stiffness in compression OCE will be described. This work is enabled by optical palpation and solutions to the forward and inverse elasticity problems. • Applications: Three applications areas will be described: intraoperative assessment of tumour margins, mapping stiffness in tumour biology and assessing the stiffness of cardiovascular tissue in an animal model.

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Lixin Chin

University of Western Australia

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David D. Sampson

University of Western Australia

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Philip Wijesinghe

University of Western Australia

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Christobel Saunders

University of Western Australia

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Andrea Curatolo

University of Western Australia

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Juliana Hamzah

University of Western Australia

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Q. Fang

University of Western Australia

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Kelsey M. Kennedy

University of Western Australia

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Rodney W. Kirk

University of Western Australia

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