Laser Raman microprobe, developed mainly in France and the USA during the last decade, consists of a laser light source, an optical microscope, and a Raman spectrometer. The technique has several advantages. One is the ability of nondestructive compound identification. Another is the ease of sample preparation. Yet another is the potential of providing information about molecular structure of micro sample. This review aims at surveying the present status of Laser Raman microprobe method in the medical field and discussing its future prospects.

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In order to evaluate the safety of the noninvasive laser-doppler-velocimeter which authors are trying to develop, this study was designed to investigate histological changes of the arterial tissue following irradiation of low-power He-Ne laser in vivo.
The common carotid arteries of 74 Wistar rats (male, weighing 200g) were exposed and irradiated unilaterally with He-Ne laser (NEC GLG 5700 model, wave length 633nm, power output 27mw, focus diameter 200μm) for 5, 15, 30, 60, 120minutes, respectively, and histological examination of the arterial walls was carried out at 48 hours (acute stage), 1 week (subacute stage), and 4 weeks (chronic stage) after the irradiation.
According to the laser irradiation power, the rats were divided into two groups: the full power (27mW) group (F group) and the half power (27/2 mW) group (H group). Each evaluation consisted of 2 or 3 rats. The contralateral common carotid arteries were treated as the control.
Following results were obtained from this experiment:
1) No change was found in any of the control carotid arteries.
2) Following changes were found in the irradiated carotid arteries of the F group of over 15 min and the H group of 120 min. irradiation.
a) the predominant findings were degeneration and necrosis of the smooth muscle cells of the media in the irradiated site and no change toward recovery was found up to 4 weeks.
b) elastic fibers in the media were relatively well preserved with a slight, increase in size in the chronic stage.
c) it seemed that these pathological changes became more remarkable with the increase of both time and power density of laser irradiation.
From these results the mechanism of the pathological changes of the vessel walls. caused by He-Ne laser irradiation was discussed.

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