Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session H23: Physics in Medicine: Imaging, Therapy, and Disruptions on the HorizonFocus
|
Hide Abstracts |
Sponsoring Units: GMED Chair: Thomas Bortfeld, Harvard Medical School Room: BCEC 158 |
Tuesday, March 5, 2019 2:30PM - 3:06PM |
H23.00001: Magnetic Resonance Relaxometry and Macromolecular Mapping: An Inverse Problem Framework, with Applications to Alzheimer's Disease and Osteoarthritis Invited Speaker: Richard G Spencer Quantification of changes in the macromolecular constituents of tissue is a major theme in biomedical magnetic resonance (MR). In many cases, constituents can only be distinguished through their differing water transverse relaxation times, instead of by frequency differences as is more familiar in MR spectroscopy. However, this requires implementation of multiexponential transverse relaxation analysis (METRA), a special case of the inverse Laplace transform, a notoriously ill-posed and unstable inverse problem. Our work in this area combines basic science studies with methodologies that carry immediate translational potential. We will discuss METRA as a means to quantify the myelin water fraction (MWF) of total brain water as a marker for myelin, a critical element of signal transmission within the central nervous system, in the mathematical setting of a linear inverse problem. In addition, we have stabilized MWF estimates using a rapid steady-state MR pulse sequence through Bayesian analysis of the corresponding non-linear inverse problem. With this, we provide the first report of myelination deficits using direct MWF measurements in subjects with mild cognitive impairment and Alzheimer's disease. We have implemented similar methods to map cartilage proteoglycan, the macromolecule most vulnerable to loss in osteoarthritis, obtaining results indicating the potential for improved detection of this condition. Finally, we describe extensions of METRA to higher dimensional experiments, with two or more independent time variables. We discuss the stability of parameter estimates from these experiments, as well as correlation experiments providing insight into chemical exchange between macromolecular constituents. All of these studies are directed toward the clinical goal of improving the ability of MR to diagnose pathology and monitor disease progression, and to define therapeutic targets for treatment. |
Tuesday, March 5, 2019 3:06PM - 3:18PM |
H23.00002: Fractional Anisotropy by DTI in Patients with Myotonic Distrophy Type I Margarita Lopez, Rosalinda Díaz, Carlos Hernández, Jonhatan Magaña, Juan Fernández Myotonic Distrophy Type I (DM1) is a neurodegenerative and hereditary disorder; its more typical symptoms are muscle weakness and hypotonia, which may lead to several complications like respiratory failure and cardiac arrest. The aim of this study is to find biomarkers that help us to characterize the evolution of this disorder related to white matter. In the present work 74 volunteer participants (37 DM1 patients and 37 healthy control subjects) were matched by age, gender and level education, then underwent an MRI session in a 3T Philips Ingenia |
Tuesday, March 5, 2019 3:18PM - 3:30PM |
H23.00003: Stability of Parameter Estimates from Multiexponential Decay in MR Relaxometry and Related Experiments in One, Two, and Three Dimensions Richard G Spencer, Mustapha M Bouhrara Analysis of one-dimensional (1D) multiexponential decay has remained a topic of active research for over 200 years. This attests to the ubiquity of such signals as well as the difficulty in deriving parameters of the underlying monoexponential decays. However, we have shown in the context of nuclear magnetic resonance (NMR) relaxometry that parameter estimates derived from two-dimensional (2D) exponential decays, with two distinct time variables, exhibit substantially greater accuracy than those obtained from analysis of 1D data with a single time variable [1]. Here, we present statistical underpinnings of this remarkable fact and indicate applications in 2D NMR relaxometry and related experiments. These may be constructed, for example, as T1-T2 experiments correlating longitudinal (T1) and transverse (T2) relaxation times or as T2-diffusion (T2-D) correlation experiments. These results are readily generalizable to higher dimensions and may provide a means of circumventing conventional limits on multiexponential parameter estimation. |
Tuesday, March 5, 2019 3:30PM - 3:42PM |
H23.00004: Mote-carlo simulation to reduce sensor dimension of EEG neurofeedback device Prasanta Pal, Daniel L. Theisen, Michael Datko, Remko V Lutterveld, Alexandra Roy, Judson brewer Neuro-feedback (NF) training using EEG device is finding wide acceptance for treatment of ADHD, epilepsy, anxiety, dyslexia, schizophrenia etc. In realistic clinical practice, high quality delivery of NF signal is possible only with high sensor density devices. Unfortunately, these are often cost-prohibitive, time consuming and unmanageable due to large number of sensors. So, reduction of sensor dimension without compromising the quality of the signal is an important clinical problem. |
Tuesday, March 5, 2019 3:42PM - 3:54PM |
H23.00005: Plasmonic Halos Towards Molecular Sensing of Target Biomarkers Luke D'Imperio, Juan M. Merlo, Chaobin Yang, Yitzi M Calm, Megi Maci, Michael J Burns, Timothy Connolly, Thomas C Chiles, Michael J Naughton Diagnostic tools e.g., those used in the biomedical field, have greatly benefited from taking advantage of the properties of plasmonic phenomena in micro- and nano-scale thin films and structures [1]. Here, we discuss the considerations involved in the design and fabrication of a previously reported plasmonic microstructure towards the goal of sensitive detection of disease biomarkers [2]. We show current fabrication results and motivate relevant processes, parameters and materials therein. We describe our measurement setup and provide comparison to a commercially available system, particularly to motivate how our device can extend existing detection tools to point-of-care applications. We introduce preliminary device responses and our approaches to current obstacles of the project. |
Tuesday, March 5, 2019 3:54PM - 4:06PM |
H23.00006: Analytical solutions of radiative transfer equation for analysis of medical hyperspectral images Matija Milanic, Jošt Stergar, Luka Rogelj, Rok Dolenec, Martin Horvat Hyperspectral imaging (HIS) is an optical technique providing both spectral and spatial information in one measurement. A big challenge in the medical HIS (diagnostics and surgery) is effective processing of a huge amount of data and extraction of relevant parameters. |
Tuesday, March 5, 2019 4:06PM - 4:18PM |
H23.00007: EVALUATING GOLD NANOPARTICLES FOR ENHANCEMENT OF RADIATION AND PHOTODYNAMIC THERAPY EFFICACY IN 3D TUMOR MODELS Ljubica Petrovic This study uses a 3D cell culture approach to study the impact of gold nanoparticles (GNP) uptake and localization on radiation dose enhancement, as well as on combined photodynamic (PDT)/photothermal treatment (PTT). The use of 3D cell cultures reveals that GNP resides in the extracellular matrix (ECM) for surprisingly long durations after initial delivery and prior to localization in tumor nodules, an effect which, as it will be shown here, has a big impact on the treatment outcomes for nanoparticle-aided therapy. |
Tuesday, March 5, 2019 4:18PM - 4:30PM |
H23.00008: MRI-guided focal proton radiation therapy for locally advanced prostate cancer Maryam Moteabbed, Mukesh Harisinghani, Jason A Efstathiou, Hsiao-Ming Lu We investigate the dosimetric efficacy and clinical implications of proton radiation therapy of prostate cancer with dose microboost to the MRI-defined dominant intraprostatic lesions (DIL). |
Tuesday, March 5, 2019 4:30PM - 4:42PM |
H23.00009: Radiation cabinet to study the effect of Low-dose radiation on cells Bishwambhar Sengupta, Donald Medlin, Xiaoran Zheng, Endre Takacs
|
Tuesday, March 5, 2019 4:42PM - 4:54PM |
H23.00010: A new entropic algorithm to measure of the impact of magnetic field on dose distribution: application to MRI-guided radiotherapy Jean-Luc Feugeas Purpose - The integration of magnetic resonance imaging, providing an efficient soft-tissue contrast opens real perspective for a better radiotherapy-based treatment. However, the magnetic fields will modify the localization of radiation dose always induced by charged particles. The fast development of these new facilities is one of the recent challenges for the next generation of treatment planning softwares. |
Tuesday, March 5, 2019 4:54PM - 5:06PM |
H23.00011: A Vector-Space Representation of Cytoskeletal Drug Mechanisms for Intracellular Doppler Spectroscopy Zhe Li, John Turek, David Nolte Biodynamic imaging is sensitive to intracellular transport and has been successfully used to profile drug effects in 3-D cell culture. We report the use of biodynamic imaging to provide phenotypic profiles of cytoskeletal drugs that have a wide range of mechanisms of action (MoA). These profiles serve as “fingerprints” of the drug MoA and can be queried by machine learning clustering algorithms. In this study, 7 cytoskeletal drugs are used, including cytochalasins and latrunculin that inhibit the polymerization of actin, jasplakinolide that enhances actin polymerization, colchicine and nocodazole that inhibit microtubule polymerization, and taxanes that stabilize microtubules. In contrast, blebbistatin is a molecular motor inhibitor that inhibits ATPase activity. Biodynamic imaging is sensitive to subtle changes in intracellular motion, and drugs that affect the cytoskeleton are particularly strong inducers of biodynamic fingerprints. Biodynamic imaging uses short-coherence digital holography to profile cytoskeletal drug responses of 3D cultured tumor spheroids. Drug responses and their relations are examined in a high-dimensional space spanned by vectors of biomarkers and related with their mechanism of actions and targeted cytoskeletal components. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700