Surface Imaging Applications Research Articles

Evaluating a modified delay-multiply-and-sum reconstruction algorithm to improve detection of osteochondritis dissecans

Osteochondritis dissecans (OCD) is a focal joint defect that is prevalent among youth athletes. With the application of medical ultrasound, OCD of the humeral capitellum could be detected earlier and prevent surgery. In this work, we tested a modified Delay-Multiply-and-Sum (DMAS) reconstruction algorithm to evaluate how it affects medical ultrasound’s ability to detect OCD. Starting with the DMAS reconstruction algorithm described by Matrone et al. (2015), we modified the implementation of filtering and envelope detection steps. Delay-and-Sum (DAS), DMAS, and modified DMAS algorithms were tested on phantom and cadaveric models of capitellar OCD. The DMAS and modified DMAS images were histogram matched to the DAS image for quantitative comparison. By taking several profiles across the images of the artificial OCD lesions, we compared the lesion contrast and bone surface clarity produced by each algorithm. We found that the unmodified DMAS algorithm showed little improvement over the DAS algorithm, particularly after histogram matching. The modified DMAS algorithm showed a much greater improvement in the detection of OCD lesions compared to the DMAS algorithm. This modified DMAS algorithm could be used for other bone surface imaging applications. Future work includes evaluating these algorithms in vivo with patients diagnosed with OCD.

Facilitated tip-enhanced Raman scattering by focused gap-plasmon hybridization

Tip-enhanced Raman scattering (TERS) spectroscopy is a nondestructive and label-free molecular detection approach that provides high sensitivity and nanoscale spatial resolution. Therefore, it has been used in a wide array of applications. We demonstrate a gap-plasmon hybridization facilitated by a bottom-illuminated TERS configuration. The gap-plasmon hybridization effect is first performed with the finite-difference time-domain method to optimize the parameters, and experiments are then conducted to calibrate the performance. The results demonstrate an enhancement factor of 1157 and a spatial resolution of 13.5 nm. The proposed configuration shows great potential in related surface imaging applications in various fields of research.

Synthesis of Fluorescent Boron Difluoride Complexes of 3-Acyl-4-hydroxy­coumarins

A series of boron difluoride–3-acyl-4-hydroxycoumarin complexes were synthesized in good yields in three steps starting from 4-hydroxycoumarins. The boron complexes showed strong luminescence­ in the green–yellow region and are compatible with surface imaging applications.

MO‐F‐500‐01: Clinical Applications of Surface Imaging

Non‐invasive 3D surface matching systems have become clinically available for patient positioning and tracking throughout treatment. This session will focus on the current clinical applications of surface imaging, specifically for breast radiotherapy and cranial radiosurgery. First, acceptance and commissioning of surface imaging systems will be reviewed. Next, workflows and resulting data will be presented for the use of surface imaging to position patients receiving whole‐breast irradiation. Additionally, workflows and data describing the use of surface imaging to track patients during breath‐hold breast cancer treatments and frameless radiosurgery will also be described. The session outline is: a. An overview of commissioning and acceptance testing of surface imaging systems, including incorporation of routine QA into current clinical practice for a comprehensive IGRT program b. The use of surface imaging for daily positioning of patients receiving whole‐breast radiotherapy c. Surface imaging applications for breath‐hold treatment of left‐sided breast cancer patients d. Surface imaging applications for frameless cranial radiosurgery.Learning Objectives:1. Learn to incorporate QA for surface imaging into current QA procedures for IGRT.2. Understand the advantages and limitations of surface imaging for clinical use in breast radiotherapy and cranial radiosurgery.3. Learn about the potential use of surface imaging for real‐time motion tracking.Jan‐Jakob Sonke's research is sponsored by Elekta Corporation.Elekta Corporation sponsors research by Jan‐Jakob Sonke.

Vibroacoustography for the assessment of total hip arthroplasty

OBJECTIVES:This paper proposes imaging with 3-dimensional vibroacoustography for postoperatively assessing the uncovered cup area after total hip arthroplasty as a quantitative criterion to evaluate implant fixation.METHODS:A phantom with a bone-like structure covered by a tissue-mimicking material was used to simulate a total hip arthroplasty case. Vibroacoustography images of the uncovered cup region were generated using a two-element confocal ultrasound transducer and a hydrophone inside a water tank. Topological correction based on the geometry of the implant was performed to generate a 3-dimensional representation of the vibroacoustography image and to accurately evaluate the surface. The 3-dimensional area obtained by the vibroacoustography approach was compared to the area evaluated by a 3-dimensional motion capture system.RESULTS:The vibroacoustography technique provided high-resolution, high-contrast, and speckle-free images with less sensitivity to the beam incidence. Using a 3-dimensional-topology correction of the image, we accurately estimated the uncovered area of the implant with a relative error of 8.1% in comparison with the motion capture system measurements.CONCLUSION:Measurement of the cup coverage after total hip arthroplasty has not been well established; however, the covered surface area of the acetabular component is one of the most important prognostic factors. The preliminary results of this study show that vibroacoustography is a 3-dimensional approach that can be used to postoperatively evaluate total hip arthroplasty. The favorable results also provide an impetus for exploring vibroacoustography in other bone or implant surface imaging applications.

Synthesis of fluorescent coumarin triazolylglycosides

A series of coumarin triazolylglycosides were synthesized in good yields using copper-mediated 1,3-dipolar cycloaddition reactions of carbohydrate azides and 4-alkynyl-substituted coumarins. Several of the products show strong luminescence in the 490–560nm region and are compatible with surface imaging applications.

A uniplanar three-axis gradient set for in vivo magnetic resonance microscopy

We present an optimized uniplanar magnetic resonance gradient design specifically tailored for MR imaging applications in developmental biology and histology. Uniplanar gradient designs sacrifice gradient uniformity for high gradient efficiency and slew rate, and are attractive for surface imaging applications where open access from one side of the sample is required. However, decreasing the size of the uniplanar gradient set presents several unique engineering challenges, particularly for heat dissipation and thermal insulation of the sample from gradient heating. We demonstrate a new three-axis, target-field optimized uniplanar gradient coil design that combines efficient cooling and insulation to significantly reduce sample heating at sample-gradient distances of less than 5mm. The instrument is designed for microscopy in horizontal bore magnets. Empirical gradient current efficiencies in the prototype coils lie between 3.75G/cm/A and 4.5G/cm/A with current and heating-limited maximum gradient strengths between 235G/cm and 450G/cm at a 2% duty cycle. The uniplanar gradient prototype is demonstrated with non-linearity corrections for both high-resolution structural imaging of tissue slices and for long time-course imaging of live, developing amphibian embryos in a horizontal bore 7T magnet.

Integrated Silylation and Dry Development of Resist for sub-0.15.MU.m Top Surface Imaging Applications.

Integrated Silylation and Dry Development of Resist for sub-0.15.MU.m Top Surface Imaging Applications.