CCNY, MEMORIAL SLOAN-KETTERING SCIENTISTS USE NEAR-INFRARED LASER LIGHT TO DETECT CANCEROUS BREAST TISSUE
Development Could Lead to Noninvasive Diagnosis Techniques
NEW YORK, January 3, 2006 – A team of scientists from The City College of New York (CCNY) and Memorial Sloan-Kettering Cancer Center has successfully used near-infrared laser light to differentiate between cancerous and non-cancerous human breast tissue. The development could eventually lead to noninvasive techniques for detecting and diagnosing breast cancer.
The findings were published in the October 2005 edition of Technology in Cancer Research & Treatment. The research team consists of: Robert R. Alfano, Ph.D., Distinguished Professor of Science and Engineering at CCNY; Dr. Swapan K. Gayen, Ph.D., Associate Professor of Physics at CCNY; Mohammed Alrubaiee, a CCNY graduate student, and Jason A. Koutcher, M.D., Ph.D., Chief of Imaging and Spectroscopic Physics Service at Memorial Sloan-Kettering.
“Near-infrared imaging is a non-invasive technique has several advantages over mammography,” said Professor Gayen. “It has the potential to diagnose cancer whereas mammography can only detect a tumor but not specify whether it is benign or malignant.”
Under current protocols, when a mammography shows the presence of a tumor, patients are sent for biopsies in order to extract a tissue sample for diagnosis. In 80 percent of those cases, cancer is not found, he noted.
Also, mammography is less effective at detecting tumors in women with an abundance of dense glandular tissue in the breast, he added. More research is necessary to determine whether optical imaging can overcome this problem.
“Laser light’s salient features, such as spectral brightness, monochromaticity, polarization, coherence and wavelength tunability, make it a promising technology for non-invasive and minimally invasive cancer detection and diagnosis,” said Professor Alfano, who heads the Institute for Ultrafast Spectroscopy and Lasers (IUSL) at CCNY, which has been a pioneer in developing such techniques. “We are searching for the key wavelengths and time zones to detect cancer.”
Other cancer-related investigations conducted by the IUSL include noninvasive techniques for detection of prostate cancer tumors and skin cancer as well as a “photonic pill” that would transmit signals from inside the body after being swallowed by a patient.
The breast cancer researchers used a technique known as time gating to capture images produced by three different groups of photons after they passed through ex vivo (non-living) samples of cancerous and normal breast tissue. Photons – tiny, ultra-fast bursts of light emitted by a laser – scatter in different directions as they pass scattering medium, such as breast tissue.
The photons that take the most direct routes, called ballistic components, produce different kinds of images than “snake” and diffuse components, which take more circuitous paths. The images produced by the ballistic and early snake slices of transmitted light highlighted tumors while those produced by the late snake and diffuse components accentuated normal tissue.
The time-resolved imaging experiment involved use of 120 femtosecond, 1 KHz repetition-rate, 800 nanometer light pulses generated by a Ti:sapphire laser, to illuminate the tissue samples, and a 80 picosecond resolution ultrafast gated intensified camera system to record two-dimensional time-sliced images. A femtosecond is 10-15 of a second, a picosecond is 10-12 of second and a nanometer is one-billionth of a meter.
For spectroscopic imaging, the researchers illuminated the samples with near-infrared light from a Cr:Forsterite laser tunable between the 1220-1300 nm wavelength range. There was higher light transmission through the cancerous tissue than the normal tissue. Even more interestingly, the ratio of light transmitted through the cancerous tissue to that transmitted through normal tissue changed with the wavelength. “This wavelength-dependent transmission has the potential to provide diagnostic information,” noted Professor Alfano.
Over the coming year, the research team plans to conduct further testing, optimizing the inverse-reconstruction approach to obtain a three-dimensional image of a ‘model breast’ approximating the size of an average female breast, according to Professor Gayen. He adds that the team hopes to begin in vivo (live) tests by 2007 that, if successful, could eventually lead to commercial development.
The project was conducted under a grant from the U.S. Army Medical Research and Materiel Command’s Breast Cancer Research Program.
About The City College of New York
For over 158 years, The City College of New York has provided low-cost high-quality education for New Yorkers in a wide variety of disciplines. Over 12,200 students pursue undergraduate and graduate degrees in the College of Liberal Arts and Science, the School of Architecture, the School of Education, the School of Engineering, the Center for Worker Education and the Sophie Davis School of Biomedical Education.