Development of a diagnostic system for osteoarthritis using a photoacoustic measurement method.
OBJECTIVE
We demonstrated that photoacoustic measurement enables viscoelastic characterization of biological tissue. The purpose of this study was to develop a practical photoacoustic measurement system for diagnosis of osteoarthritis (OA) by viscoelastic characterization of articular cartilage.


METHODS
The portable system consists of a commercially available 3rd harmonic Q-switched Nd:YAG laser as a light source and a transducer, which is arranged coaxially with an optical fiber. Cell proliferation tests were performed to study the effect of laser irradiation on chondrocytes. Photoacoustic measurements were performed using enzymatically treated cartilage as a model of OA.


RESULTS
There was no significant damage of chondrocytes caused by laser irradiation (100 microJ/mm2, 5 Hz, 30 shots). The change in relaxation times measured by the photoacoustic measurement had a positive correlation with time of enzymatic treatment, that is, the degree of cartilage degeneration.


CONCLUSIONS
We have developed a noninvasive photoacoustic measurement system designed for arthroscopic use and have demonstrated the applicability of this system to the diagnosis of OA-like cartilage degeneration.
Department of Medical Engineering, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. kobako@ndmc.ac.jp
Miya
M
Ishihara
Masato
M
Sato
Nagatoshi
N
Kaneshiro
Genya
G
Mitani
Shunichi
S
Sato
Joji
J
Mochida
Makoto
M
Kikuchi
D000162:Acoustics / Q000295:instrumentation*; D000818:Animals; D001182:Arthroscopy; D002358:Cartilage, Articular / Q000503:physiopathology* / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D002470:Cell Survival; D019902:Chondrocytes / Q000528:radiation effects; D004548:Elasticity; D005336:Fiber Optic Technology; D007719:Knee Joint; D007834:Lasers; D023421:Models, Animal; D008954:Models, Biological; D055100:Optical Fibers; D020370:Osteoarthritis, Knee / Q000175:diagnosis*; D011817:Rabbits; D014159:Transducers; D014783:Viscosity