Combining NIRST and BTS

Kelly Michaelsen

While screen-film mammography has been proven to reduce the mortality of the disease, the screening method has its limitations. As Professor Keith Paulsen explains in this video published by the Thayer School of Engineering, doctors often find the images created by mammography difficult to read due to “tissue overlap”—a type of distortion that occurs when a complex, 3D object is rendered as a 2D image:

Approved for use by the FDA in 2011, tomosythesis collects imaging data much like an MRI scan, except that the X-ray generator rotates around the patient and then mathematically reconstructs this data into a 3D model. Currently, MD/PhD student Kelly Michaelsen and Professor Venkataramanan Krishnaswamy are developing a screening system that combines near infrared spectral tomography (NIRST) with the high-resolution 3D structural information of breast tomosythesis (BTS) into a singular breast-cancer detection method. This research is being conducted with both Hologic, Inc—the commercial leader in the development of breast tomosythesis (BTS) technology—and the University of Massachusetts Medical School.

BTS system developed by Hologic, Inc

The first prototype of this imaging system is currently being tested at the Dartmouth Hitchcock Medical Center (DHMC). After calibrating its components on a series of tissue phantoms, Michaelsen and her advisor started conducting pre-clinical imaging trials on patients at DHMC. With the data collected from these trials, the research group identified aspects of the system that could be improved, and began constructing a second-generation prototype of the imaging machine. Once this second-generation prototype is completed, the original machine will be moved to the University of Massachusetts Medical School where researchers will collect clinical data in another series of pre-clinical trials.

“In 2010, the fatality rate for females diagnosed with breast cancer in the US was just over 19 percent,” says Michaelsen. “The combined imaging system that our lab is developing is aimed at decreasing the number of women who go through invasive biopsy procedures. Through improving the early stages of breast cancer detection, we hope to decrease the fatality rate of this disease.”

Diagram of the first-generation prototype designed by Michaelsen and Prof. Krishnaswamy

The research being conducted at all of the institutions involved in this project has been made possible by a funding opportunity provided by the National Institute of Health (NIH) and its National Cancer Institute (NCI) that seeks to develop new in vivo imaging systems. The partnership between Dartmouth, the University of Massachusetts, and Hologic, Inc aims to integrate the two systems into a singular detection method, and to establish the clinical potential of this combined imaging approach.

Details of the components of the first-generation prototype
Tissue phantoms being tested on the machine’s receptor

DCCNE Featured in NH Magazine

On Monday, October 1st, the cancer research conducted by the Dartmouth Center for Cancer Nanotechnology Excellence (DCCNE) was featured on the website of NH Magazine. The article explains a number of non-invasive cancer treatment approaches, including targeted drug delivery.

Micrograph of a Breast Cancer Cell, Dartmouth Medical Magazine

DCCNE is funded by $12.8 million grant from the National Cancer Institute (NCI). Each year, members of the Optics in Medicine Laboratory participate in the center’s educational programs, and conduct interdepartmental research thanks to the funding provided by the NCI.

Prototype Testing in China

Located on the second floor of the Dartmouth Hitchcock Medical Center (DHMC), the Advanced Imaging Center houses several imaging devices used by the Optics in Medicine Laboratory. Currently, graduate student Michael Mastanduno is testing a prototype that combines Magnetic Resonance Imaging (MRI) with Optical Tomography into a singular imaging device. This has the potential to significantly improve the accuracy of non-invasive breast-cancer imaging, leading to better patient care.

El-Ghussein and the system’s computer

This summer, graduate student Fadi El-Ghussein started working on and upgrade to this system’s instrumentation. El-Ghussein’s input enabled the research team to finalize a prototype of this non-invasive imaging machine and to begin testing it on humans in a clinical setting. To expedite the testing process, the research team is moving the imaging system to Xijing Military Hospital in Xi’an, China for two months with Associate Professor Shudong Jiang.

“Due to our remote location in the Upper Valley, we’re only able to image a small number of patients each year,” explains Mastanduno. “However, in Xi’an, our team will be able to test the imaging machine on two patients a day. Hopefully, the images gathered by our team in the Xi’an clinical tests will provide the data necessary to have the efficacy of the technology fully evaluated by 2012.

Details of the components built by El-Ghussein

The instrumentation built by El-Ghussein enables the imaging machine to deliver optical light to the MRI scanner, and then to collect this data from either a tissue phantom, or a patient. While the components used by El-Ghussein to build this device are commonplace in clinical imaging systems, this machine is unique in that it allows both the MRI scanner and the machine’s optical components to independently collect data, and then feeds this information into a computer where it is mathematically reconstructed into a detailed 3D model.

“The instruments that I’ve developed over the last few months use both Photo Multiplier Tubes (PMT) and Photo Diodes (PD) to collect the data from the machine’s fiber-optic components. This data is then mathematically reconstructed into a tissue model, and is then combined with the magnetic data gathered through the MRI scan,” explains El-Ghussein. “I’m very happy with the data that our lab has collected so far in Upper Valley, and both Mike and I look forward to traveling to China to conduct clinical trials at the Xijing Military Hospital.”

Mastanduno and the system’s breast coil

To enable the imaging system to simultaneously collect MRI and tomographic data, Mastanduno engineered the machine’s cradle so that its optical fibers connect directly with the patient’s skin. Housed beneath the MRI’s breast coil, this cradle guides the fiber optic cables to the patient’s breast, and once each cable is firmly connected with the organ’s surface, the machine starts to collect imaging data.

“The great thing about this machine is that that it’s entirely non-invasive,” says Mastanduno. “While the patient might feel a slight compression as the optical cables connect with her breast or a warming sensation as the MRI machine gathers magnetic data, our lab’s imaging systems do not rely upon surgical procedures to collect data.”

Tomographic Imaging

Tomographic imaging creates three-dimensional models of breast cancer that supplement the information provided by mammograms, a breast cancer screening method commonly used in hospitals. Currently, the Optics in Medicine Laboratory is researching a number of methods to improve these imaging techniques, and is developing medical devices that integrate tomographic imaging with other tumor-modeling techniques.

This July, Professor Keith Paulsen acquired both 2D and 3D microwave tomographic images of calcaneus bones in two patients. This study, which was conducted with seven other medical researchers, compared the data gathered through microwave tomographic imaging against x-ray density measurements. The team observed a good correlation between the data gathered from the two imaging systems. The study represents the first clinical examples of microwave images taken of the calcaneus, as well as some of the first successful 3D tomographic images taken of a human anatomic site in a clinical setting.

Published by the Dartmouth Hitchcock Medical Center earlier this month, Dr. Steven Poplack explains the benefits of tomosythesis mammography in this video. Though Dr. Poplack is not directly affiliated with the Optics in Medicine Lab, his explanation of tomosythesis mammography relates to the research conducted by Professor Paulsen.

First-Year Student, Yan Zhao

The Optics and Medicine Laboratory would like to welcome its newest graduate student, Yan Zhao, to Hanover. Originally from Xuchang, China, Yan received his bachelors degree in engineering from Xian Jiaotong University. While at Jiaotong, Yan published a paper titled “Polarization dressings of four-wave mixing process in a V-type three-level atomic system” in Optics Communications. Published with a number of other students, this paper examines the interplay of four coexisting four-wave mixing (FWM) signals and focuses on how these waves act in atomic systems.

This is Yan’s first time coming to the United States. After landing in New York, Yan traveled to Hanover via coach, and started moving into his new office in Thayer. So far, he finds New Hampshire “amazing and interesting” and looks forward to meeting other incoming graduate students.

At Dartmouth, Classes Officially started on Monday, September 10th

Outside the lab Yan plays tennis and badminton, and enjoys reading science fiction novels.

Welcome to the lab, Yan!