[OPTICAL REVIEW Vol. 7, No. 4 (2000) 353-357]

Nanosecond Time-Gated Spectroscopy of Laser-Ablation Plume of Human Hair to Detect Calcium for Potential Diagnoses

Masato OHMI,1 Mitsuo NAKAMURA,1,* Shigeto MORIMOTO2 and Masamitsu HARUNA1

1School of Allied Health Sciences, Faculty of Medicine, Osaka University, 1-7, Yamada-Oka, Suita, Osaka, 565-0871 Japan, 2Department of Geriatric Medicine, Graduate School of Medicine, Osaka University, 2-2, Yamada-Oka, Suita, Osaka, 565-0871 Japan

(Received March 2, 2000; Accepted May 1, 2000)

We demonstrate the nanosecond time-gated spectroscopy of plume luminescence in UV laser ablation of human hair. Clear and sharp peaks of calcium ion (Ca+) appear in the spectrum although the Ca content is only 0.1% in human hair. Highly sensitive detection of Ca is thus possible. In the experiment, the peak intensity of Ca+ was measured for human hair samples of female subjects over a wide range of age, and compared to the bone mineral density of the lumbar vertebrae of the subjects themselves. Our experimental results suggest that this specific spectroscopy has the potential for novel diagnoses including monitoring of daily Ca intake and a screening diagnosis of osteoporosis. The spectroscopic system and time transition of plume-luminescence spectra are also described.

Key words : tissue laser ablation, plume luminescence, time-gated spectroscopy, calcium detection, optical diagnosis