All posts by Sally Hull

Photodynamic Therapy in Honduras

At the end of April 2017, PhD student Ethan LaRochelle and OIM Lab Assistant Kayla Marra traveled to El Rosario, a rural village in the Yoro department of Honduras to take part in a cancer screening project organized by the Norris Cotton Cancer Center in partnership with ACTS Honduras.

Over 300 men ranging in ages 18-96 travelled from 38 surrounding villages to receive cancer screening and education.

In this study, researchers performed daylight photodynamic therapy (PDT) – a technique that the OIM group has researched pre-clinically in the lab – on any pre-cancerous or cancerous skin lesions identified.

Thayer’s researchers took spectral measurements of the sun and determined that it was feasible to deliver an adequate light dose.

The dermatological team, headed by OIM collaborator M. Shane Chapman, MD, Dermatology Section Chief at Dartmouth-Hitchcock Medical Center (shown at right), was pleasantly surprised to find there was a 0% prevalence rate of skin cancer or pre-cancer in the men that were screened.

The next step in this study is to recruit patients at La Liga Contra el Cancer in San Pedro Sula (an urban area that receives a broad patient population) by coordinating with Honduran dermatologists and oncologists.

Thayer’s Jonathan Elliott invited speaker at SNMMI

Jonathan Elliott, PhD, Assistant Professor of Engineering at Dartmouth College, has been invited to speak at the 2017 Annual meeting of the Society of Nuclear Medicine and Molecular Imaging in Denver, CO, on June 14.

Jon Elliott, Ph.D.

Professor Elliott’s presentation is entitled, “Molecular Guided Surgery for Improved Brain Tumor Resection,” part of a session on Intraoperative Detection Devices and Probes.  The session will cover identifying appropriate clinical/investigational applications for fluorescence molecular imaging, adopting emerging biomedical fluorescence imaging technologies to improve accuracy of surgical margins and improve patient outcomes.  Professor Elliott is joined at this session by distinguished colleagues from the Washington University School of Medicine, Stanford University, and Emory University.

Funded by an NIH/NCI K99 “Pathway to Independence” grant, Professor Elliott’s research in the Center for Imaging Medicine at the Thayer School of Engineering focuses on using molecular targeted fluorescence and kinetic imaging to enhance contrast between tumor and normal tissue.

Clinical Cancer Research Cover Image

The May 1, 2017 issue of the publication Clinical Cancer Research features  fluorescence images of ex vivo brain tissue sections acquired by Assistant Professor Jonathan T. Elliott, PhD, of the Thayer School of Engineering.

The cover art (at left) shows images of tissue distribution of novel agent ABY-029 in green, 5-ALA-induced PpIX images in blue, and IRDye 680RD-CX in red. The distribution of these imaging agents in large F98 EGFR-positive tumors represent markers of EGFR expression, protoporphyrin metabolism and perfusion, respectively, which enable optically guided tumor identification.

LaRochelle awarded NSF Fellowship

Thayer PhD student Ethan LaRochelle received a highly-sought fellowship from the National Science Foundation (NSF) Graduate Research Fellowship Program (GRFP).  Ethan’s application was chosen by NSF from more than 13,000 applications submitted this year.  A total of 2,000 fellowships were awarded to a diverse group of students at nearly 450 graduate schools in the U.S.

Since 1952, NSF’s unique GRFP has fostered economic innovation and leadership through support of master’s and doctoral degree students conducting research in STEM fields – science, technology, engineering and mathematics.  NSF selects applications that demonstrate potential to strengthen our nation’s science and engineering enterprise, and aims to help create a globally engaged workforce whose leaders can advance science and engineering (S&E) research and innovation.  NSF Fellows have great opportunities for international research collaboration and professional career development that have led to S&E advancement, global leadership and Nobel laureate honors.

The awardees and honorable mentions for the 2017 NSF Graduate Research Fellowship Program competition have been posted online.

Our heartiest congratulations to Ethan!

NIBIB funds radiotherapy Cherenkov calibration project

Thayer & Geisel researchers are excited to have won a four year NIBIB R01 grant entitled “Optical Cherenkov Calibration for Human Radiation Therapy” that builds upon a fundamental technological discovery made at Dartmouth, and patented into a translational technology, by Professors Pogue, Gladstone and Jarvis along with PhD students Adam Glaser & Rongxiao Zhang.

Researchers in the Medical Physics Program at Dartmouth have used optical imaging of Cherenkov emissions to map the radiation dose deRadiation Therapylivered to tissue. This the first time ever that radiation dose delivered to tissue has been directly imaged with high spatial and temporal resolution.  Their approach represents a complete paradigm change in how radiation therapy is documented and archived for both real time control and quality audits.

Professor Pogue remarked, “From a practical standpoint, using optical technology to image Cherenkov emissions is significantly simpler than most dosimetry tools currently available to clinicians. The challenge is to maintain quantitative accuracy in order to be competitive in documenting the dose delivered to tissue.”

Through pilot studies of breast cancer patients undergoing radiotherapy, the grant project will advance methods to correct for tissue curvature and tissue optical properties, two of the most dominant factors that alter the linear relationship between dose and Cherenkov emission. Researchers will focus on reducing errors in alignment of patients for daily treatments by using Cherenkov imaging to verify the combined on-patient delivery of the beam, using vascular patterns of the breast that are visible in treatment beam images.  The team will also explore the similarity of Cherenkov intensity to thermoluminescent diode measurement, to determine if this solution is more accurate and easier to implement.

This study is being conducted in partnership with leading companies that are advancing the methods for patient surface scanning, tissue optical property imaging and Cherenkov imaging system development, ensuring that the discoveries made can be translated into a commercial venture.

The team is actively looking to recruit researchers in Medical Physics or Electrical Engineering to work on this project, and expects to use this funding to support several Thayer PhD students in the coming years.

Dartmouth presents at SPIE Photonics West

In January 2017, researchers from the Thayer School of Engineering made more than 20 technical presentations at workshops during Photonics West, the “world’s largest photonics technologies event.” The conference is hosted by SPIE, the international society for optics and photonics, and is held each year in San Francisco. It draws about 20,000 attendees to 4,800 workshops in three conference tracks: Biomedical Optics and Biophotonics, Laser Sources and Lasers for Manufacturing, and Optoelectronic Materials and Devices.  Here’s the rundown:

  • Jaime Bravo – “In vivo optical properties of human brain tissue.”
  • Mackenzie Carlson – “Structured light scatteroscopy through a rigid endoscope provides unique real-time contrast based on tissue ultrastructure.”  Mackenzie and Bo McClatchy – “High spatial frequency RGB modulated imaging in comparison to cross-polarized imaging.”
  • Scott Davis – “Diffuse optical tomography for in vivo 3D vascular imaging of a murine bone graft model.”
  • Ana Luiza Ribeiro de Souza – “Comparison of doses delivered in daylight versus regular light delivery in ALA-PDT in the treatment of skin cancer.”
  • Eric Henderson, MD, of DHMC, presented his invited paper, “Novel applications of near-infrared fluorescence imaging in
    orthopedic surgery.”
  • Shudong Jiang and Yan Zhao – “Breast cancer detection using non-contrast T2-weighted-MRI imaging guided near infrared spectroscopy tomography” and “A portable, 12-wavelength parallel near-infrared spectral tomography (NIRST) system for efficient characterization of breast cancer during neoadjuvant chemotherapy.”
  • Ethan Larochelle – “In vivo wide-field multispectral dosimeter for use in ALA-PpIX based photodynamic therapy.”
  • Bo McClatchy – “Sub-diffusive spatial frequency domain imaging provides widefield visualization and quantification of light scattering as an endogenous biomarker for morphological change in tissue.”  Bo and Chad Kanick – “Label-free hyperspectral dark-field microscopy for quantitative scattering imaging of tissue-mimicking phantoms” and “Combined multispectral spatial frequency domain imaging and computed tomography system for intraoperative breast tumor margin assessment.”
  • Mike Nieskoski – “Quantification of localized total tissue pressure and extracellular matrix components as related to vascular patency and verteporfin uptake within pancreatic cancer.”
  • Brian Pogue chaired a three day conference, Molecular-Guided Surgery, for the third year with Sylvain Gioux, Universite de Strasbourg (France).  The conference wrapped up with a panel discussion that Brian moderated, regarding new devices for molecularly-guided surgery.  Brian also made two technical presentations on Cherenkov-excited luminescence and Cherenkov-excited imaging.
  • Keith Paulsen presented an invited paper entitled, “Technological advances on fluorescence-guided neurosurgery.”
  • Kim Samkoe – “Quantitative imaging of intracellular signaling for personalized pancreatic cancer therapy in an in ovo avatar” and “Evaluation of semi-automated method for coregistering fresh tissue fluorescence images with histopathology slides for preclinical evaluation of molecular guided surgery agents.”
  • Thayer researchers presented these posters:
    • Jason Gunn – “Pre-clinical development and safety testing of GMP produced ABY-029,
      fluorescent anti-EGFR affibody, for use in surgical resection.”
    • Kayla Marra – “Pre-clinical evaluation of fluorescent ABY-029 in 3 mouse sarcoma models, to assess enhanced contrast in fluorescence guided surgery relative to fluorescent perfusion contrast.”
    • “Review of fluorescence guided surgery systems: identification of key performance capabilities beyond ICG imaging.”
    • “Dexamethasone enhances 5-ALA/PpIX contrast but degrades ABY-029 contrast at glioma margins during fluorescence guided resection.”