IEEE 2017 NSS/MIC/RTSD ControlCenter

Online Program Overview Session: NCT-WS-01

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Non-Conventional Emission Tomography Techniques and Their Applications in Image-Guided Therapeutics

Session chair: Ling-Jian Meng University of Illinois at Urbana-Champaign; Patrick J. La Riviere
 
Shortcut: NCT-WS-01
Date: Tuesday, October 24, 2017, 13:40
Room: Regency VI
Session type: Workshop

Contents

1:40 pm NCT-WS-01-1

OpET and CPET: New Emission Computed Tomographies for Precision Cancer Therapy (#4334)

H. H. Barrett2, 1, Y. Ding3, L. Caucci2, N. Henscheid4

1 University of Arizona, College of Optical Sciences, Tucson, Arizona, United States of America
2 University of Arizona, Department of Medical Imaging, Tucson, Arizona, United States of America
3 University of Arizona, Dept. of Physics, Tucson, Arizona, United States of America
4 University of Arizona, Program in Applied Mathematics, Tucson, Arizona, United States of America

Content

Emission Computed Tomography (ECT) is three-dimensional imaging of molecules or cells that have been labeled so that they emit light, high-energy photons or charged particles without significant alteration of their biological function.  The familiar forms of ECT are SPECT (Single-Photon Emission Computed Tomography) and PET (Positron Emission Tomography), in which molecules labeled with radionuclides are imaged.  In both cases a detector outside the patient’s body records highly penetrating gamma rays.  In this presentation, we discuss ECT with less-penetrating radiation, specifically visible or infrared photons in OpECT (Optical Emission Computed Tomography), beta particles in BET (Beta Emission Tomography) and alpha particles in αET (AlphET).  BET and αET are forms of CPET (Charged-Particle Emission Tomography). 

CPET and OpET can be performed endoscopically, in rodent window chambers, or on the skin for superficial lesions.  None of these configurations permits rotation of the detector with respect to the object, so only limited-angle tomography is possible, but accurate reconstructions can be obtained if we measure the radiance in the detector plane.  Radiance on a plane is a function of two spatial coordinates, two direction cosines and the energy of a photon or particle.  We will show that the null functions of a CPET or OpET system are very small in magnitude if these five attributes are estimated for each detection event.

The object for ECT is a physiological random process, a random function of spatial position and time.  All statistical properties of a random process are contained in its characteristic functional.  If multiple tracers are used and can be distinguished by their energy attributes, we have a unique tool for studying interacting physiological processes.  If one of those processes is a therapeutic drug and one reflects tumor growth, we can use the joint characteristic functional to estimate the response of the tumor to the drug.

Keywords: charged-particle tomography, optical computed tomography, chemotherapy, characteristic functionals
2:07 pm NCT-WS-01-2

Advances in benchtop x-ray fluorescence computed tomography (XFCT) for quantitative/molecular imaging (#4333)

S. H. Cho1

1 University of Texas, M. D. Anderson Cancer Center, Houston, Texas, United States of America

Content

X-ray fluorescence computed tomography (XFCT) offers unique capabilities for accurate identification and quantification of metals within the imaging objects. As a result, it can be used for quantitative imaging of biological samples and objects, especially in conjunction with metal-based imaging probes. In recent years, benchtop XFCT, which utilizes ordinary polychromatic x-ray sources instead of monochromatic synchrotron x-ray sources, has emerged as a promising molecular imaging modality for preclinical animal studies. This talk will familiarize the audience with the basic principles and various applications of benchtop XFCT. It will also describe the latest research and development efforts to build a fully-functional benchtop XFCT system with transmission CT capability for routine preclinical imaging. Additionally, this talk will discuss about the use of metallic nanoparticles such as gold nanoparticles within the context of preclinical multimodal multiplexed molecular imaging as well as possible human imaging scenarios. Current technical challenges for in vivo translation of benchtop XFCT will also be discussed.

Keywords: x-ray fluorescence computed tomography, quantitative imaging, molecular imaging, preclinical imaging, gold nanoparticles
2:34 pm NCT-WS-01-3

Nanoparticle-mediated X-ray photodynamic therapy for cancer treatment (#4344)

H. Chen1, W. Zhang1, Z. Li2, J. Xie1

1 University of Georgia, Chemistry, Athens, Georgia, United States of America
2 University of North Carolina Chapel Hill, Radiology, Chapel Hill, Georgia, United States of America

Content

Photodynamic therapy (PDT) has shown great promise in cancer treatment but its applications are restrained by the shallow penetration of light (< 1 cm). To address the issue, we have developed a technology called X-ray induced PDT, or X-PDT. As the name tells, X-PDT uses X-ray, which affords great tissue penetration, to trigger a PDT process. The key component of the X-PDT technology is an integrated nanosystem called X-ray nanosensitizer (abbreviated as nanosensitizer), which consists of: 1) a nanoparticle scintillator that converts X-ray photos to visible photons; 2) photosensitizers whose excitation matches the emission of the scintillator nanoparticle; and 3) an appropriate coating that encapsulates the two. Upon X-ray irradiation, the nanoscintillator works as a transducer, producing X-ray excited optical luminescence (XEOL); the visible photons, in turn, activate the photosensitizers, producing reactive oxygen species (ROS), most importantly singlet oxygen (1O2). We have assessed the feasibility of the approach with MC540-SrAl2O4:Eu@SiO2 particles, and more recently, with NC-LiGa5O8:Cr@mSiO2 particles. We show that X-PDT can be activated by X-ray from under thick tissues (>4.5 cm) to efficiently kill cancer cells. More excitingly, our recent research finds that X-PDT is more than a simple derivative of PDT; rather, it is essentially a unique combination of PDT and radiation therapy (RT). The two modalities target different cellular components; the combination overwhelms cellular repairs, leading to synergistic therapy outcomes. These unique features underscore the great potential of X-PDT in clinical translation as a novel therapy methodology.

Keywords: X-ray, photodynamic therapy, radiation therapy, nanoparticles, X-ray fluorescence
3:01 pm NCT-WS-01-4

Title: X-ray luminescence for biomedical imaging and therapy: The long road to the clinic

Title: X-ray luminescence for biomedical imaging and therapy: The long road to the clinic