Measurement of the Distribution of Optical Properties in Adult Human Muscle

At Beckman Laser Institute, University of California,Irvine. We have developed a diagnostic device use Near-Infrared Tissue Optics as a means to monitor muscle physiology, for example during exercise or in response to external factors such as shock.

The red to near-infrared (NIR) part of the electromagnetic spectrum (600 to 1000 nm) allows photons to penetrate a few centimeters below the surface of the skin. These photons are non-ionizing and do not induce local heating. Quantitative optical spectroscopy in the NIR allows for safe, non-invasive measurements of the concentrations of blood, water, and lipids in tissues.

Diffuse Optical Spectroscopy (DOS) has been in use for clinical studies(UCI HS#1995-563, HS#2002-2306), These studies have clearly shown the enormous sensitivity of DOS to hemodynamic events in tissues. These hemodynamic parameters have been shown to correlate with invasive measures of cardiac output, mean arterial pressure, blood loss, and blood hemoglobin concentration. Thus the DOS signal is more representative of the perfusion of blood and consumption of oxygen in the muscle.

Hypotheses;

The optical properties of muscle vary with age, gender, and muscle fitness level. NIR optical scattering and total hemoglobin concentration are both expected to decrease with age and increase with muscle fitness level.

The application of a two-layer model to the muscle/fat layer system will improve the reliability of DOS measurements over the standard homogenous model.

Changes in optical properties are indicative of response to exercise training

1. Short term changes include increases in hemoglobin and water
2. Long term changes include lesser increases in hemoglobin and tissue scattering

Muscle tissues that display cachexia will display optical properties that are significantly lower than those of muscle tissues in normal subjects.

Cellulite will have a different effect on light transmission than "normal" adipose tissues.

Changes in tissue oxygenation and metabolism can be quantified using DOS during alterations in deep tissue temperature.

Procedure;

Measurement sites for this study will include major muscle groups in the arms, legs and abdomen/back. The optical measurement consists of placing a pen shape probe onto the surface of the body. The optical probe consists of optical fibers and a plastic holder. Total measurement time will be less than 20 minutes.

Anticipate Risk and Benefit;

Near-infrared light does not ionize biological tissue and poses no significant health risk. The measurement is painless, and no discomfort. There are however, risks that are currently unforeseeable.

There are no direct benefits to participants in this protocol. Results from this research will be used to develop devices that would be beneficial to others in sports medicine and critical care medicine.

primary care clinic, community sample

• Muscle Weakness Conditions
• Cachexia
• Hypothermia
• Vascular Occlusion

Inclusion Criteria:

• Male or Female age 18 years and older
• Diagnosed of Cachexic condition
• Diagnosed of Cellulite adult female 18 years and older

Exclusion Criteria:

• Pregnant women
• Taking light sensitive drugs for use in photodynamic therapy