Measurements of Breast Tissue Optical Properties (LBS)
At Beckman Laser Institute, University of California, Irvine, we have developed diagnostic device call frequency-domain photon migration(FDPM).
We have continued to develop Frequency-Domain Photon Migration (FDPM) as a non-invasive optical technique to characterize breast tissue. A simple, rapid, hand-held optical screening device which will yield low resolution tissue functional information that complements and enhances the detailed structural information obtained from x-ray mammography. The functional information obtained from the optical screening device should allow for distinguishing between healthy and diseased tissue by providing a description of the tissue cellular state. Most non-optical imaging technologies measure static physical structure rather than cellular state, so that while images may reflect anatomical details, they reveal nothing about the functionality of the tissue.
The diagnostic tools are based on FDPM and utilize anomalies in the transmission of diffusing near infra-red (NIR) light for the rapid detection of oxygenated and deoxygenated hemoglobin, NIR-absorbing drug levels, blood volume changes, and scattering properties in tissues.
The long-term work is expected to lead to a compact, portable, low-resolution, functional imaging instrument. Before any optical imaging technology is developed; however, it is essential for low resolution functional information provided by optical techniques to be correlated with high-resolution structural information given by x-ray mammography. The functional information deduced from the measured tissue optical properties will include tissue water content, oxy- and deoxyhemoglobin concentration, blood volume, and tissue scattering properties.
The wavelength-dependence of tissue scattering determined by NIR Frequency-Domain Photon Migration (FDPM) is related to the size of the biological scatterer. The slope of the linear wavelength-dependence of scattering, termed the 'scatter power' can indicate the relative amounts of collagen or fat in the breast tissue . Thus the tissue composition measured by the scatter power should correlate with mammographic density. Secondly, the physiological parameters quantified by NIR FDPM will provide insight into the functional and physiological basis of mammographic density. In addition, because NIR FDPM is quantitative it can provide the consistent methodology for measuring mammographic density that is currently lacking.
|Study Design:||Observational Model: Case-Only
Time Perspective: Prospective
|Official Title:||Measurements of Breast Tissue Optical Properties|
- Measurements of Breast Tissue Optical Properties [ Time Frame: up to 12 months ] [ Designated as safety issue: No ]
|Study Start Date:||December 1995|
|Estimated Study Completion Date:||July 2015|
|Estimated Primary Completion Date:||July 2015 (Final data collection date for primary outcome measure)|
Device: Diffuse Optical Spectroscopy
Non-invasive measurements of breast tissue optical properties will be performed on the skin surface using a specially designed FDPM measurement probe which is similar in shape to an ultrasound probe. The FDPM probe is embedded with optic fibers set at a fixed separation. The FDPM probe will be placed on different areas of the breast including areas suspected to have disease and areas appearing to be normal. The diseased location will be identified by clinical palpation. Some mild tissue compression will be performed within comfort tolerance of the patient during the application of the FDPM probe.
When the probe is in position, the laser will be activated and a measurement will be taken. Each measurement will require about 30-60 seconds to record the data and calculate optical properties. The probe will then be turned off and moved to a new position for further measurements. The process will be repeated until an adequate number of measurements are performed (about 10-20). The whole process should take about 30 to 90 minutes.
Anticipate Risk and Benefit;
The optical scan is not expected to cause any pain, burning, or discomfort during or after the exam. There may be risks, however, that are currently unforeseeable. During all measurements, the laser will be turned on only when needed. Although not required for safety, subjects may wear protective eye goggles if requested.
There is no therapeutic benefit to the subject, especially none that might influence the indication for the diagnostic procedure as indicated. However, information obtained may lead to a new form of non-invasive imaging for the early detection of breast cancer.
|United States, California|
|Beckman Laser Institute University of California Irvine|
|Irvine, California, United States, 92612|
|Chao Family Comprehensive Cancer Center University of California Irvine|
|Orange, California, United States, 92868|
|Principal Investigator:||Bruce J Tromberg, Ph.D||Beckman Laser Institute|