The 632.8 nm wavelength low intensity He-Ne laser was used to irradiate on 40 rats which have skin scalded wound with three different laser dose. We observed that: (1) The wound healing process was accelerated by laser irradiation. (2) After laser irradiation for 14 days, the healed-up skin was cut off, the healing process of the new wound was delayed than the groups which also have new wound but without laser irradiation. (3) Both of above appearances were related with the laser dose. In each stage of healing process, the healing speeds were different. Our observation shows that the low intensity He-Ne laser (632.8 nm) irradiation can accelerate the healing process of skin scalded wound in rats, but it can delay the healing process of new open cutting wound which was made after the laser irradiation, especially when using little dose laser. Thus, it must be noted that new wound should be avoid before the healing process completed.

It was found that porphyrin could photo-decompose and serum protein could absorb the fluorescence emitted from porphyrin. The serum fluorescence was analyzed by optical waveguide technology and necessary sample volume was decreased from 1 ml to 0.05 ml and good signal-noise ratio was got.

The optical property of dermal cuticle was investigated for the purpose of in-vivo photo therapy with low power laser. Both of the laser spectra and fluorescence spectra demonstrated that light absorption mainly result from the keratin and melanin. Transmission of dermal cuticle was 15% in the wavelength range of 590 - 792 nm. It was possible for in- vivo phototherapy by using of low power laser.

The S. flexnesi, which have high drug-resistance especially in Cm, Sm, Tc, SD, were irradiated by Ar⁺ laser at 488 nm and semiconductor laser at 808 nm. The experiment results have shown that both Ar⁺ laser and semiconductor laser with power density of 1.7 w/cm² and irradiation dose of 2000 J/cm² can conduce to the bacterial lethality and increase the mutation rates of the bacterial drug-sensitivity, and 'Colony Count' method have the superiority over the 'Inhibacteria Ring' method. At the mean time it further indicate that the high power semiconductor laser would play an important role in the sciences of laser biological medicine. But the effect of the near infrared semiconductor laser is far lower than that of Ar⁺ laser of shorter wavelength at the same irradiation dose. It is clear that the output and irradiation dose of near infrared semiconductor laser shall be increased in order to get the same rates of the bacterial lethality and the drug-sensitivity mutation as Ar⁺ laser's.

PDT-induced HeLa cells apoptosis was evidenced by morphological changes, DNA fragmentation and decrease of mitochondria dehydrogenase activity. Apoptosis was associated with the formation of IP₃ of photosensitized cells and rapid release of Ca²⁺ from intracellular pools. Vitamin E, which was added before irradiation, could significantly protect cells against cell death, indicating that reactive oxygen species (ROS) play an important role in apoptotic cell death.

To study the effects of the laser on simple obesity (SO), 40 cases of SO patients, which was treated with Semiconductor Laser Acupuncture (SLA), were observed. The treatment Results: the obvious effect were 19 cases (47.5%), the effect 19(47.5%) and no effect 2(5%), so the total effect reached to 95% (P less than 0.01). No any side affection has been observed, and it is suggested that the Laser beam on acupoint can regulate the function of endocrine why the obesity happens.

Because laser is diffusely reflected by the skin as well as scattered and absorbed by the subcutaneous tissue, the lasing intensity which enters into the tissue through the skin is exponentially attenuated with the increase in the depth. Therefore, when the medium-small energy laser is transmitted to the tissue depth through the skin, the lasing intensity is quite finite. However, a lot of diseases occur in the crooked and narrow tube, sinus or deep tissue, for these diseases, it is difficult to get the curative effect by normal laser radiation. As above, we have developed an otolaryngological intracavity therapeutic apparatus of laser diode. Visible GaAlAs laser diode is adopted on this apparatus, its lasing wavelength is 670 nm. The lasing beam is guided into the crooked and narrow tube, sinus or deep tissue, which passes through the optical fiber and the laser pins of different forms and sizes (such as straight, curved and sidelight etc.). Using the fiber-optic connector the laser pins can be changed conveniently. The lasing output power of laser pin can be adjusted from 0 to 20 mW. The lasing intensity may be modulated which changes the rectangular wave form 0 to 1 kHz. Five hundred patients were suffering from 35 kind of otolaryngological diseases were treated in the period of clinical test. The rate of efficiency (cure or improvement) is 89%. Nobody had the side effect or deteriorated. This apparatus has the best curative effect on the inflammation of the mucosa and shallow tissue, such as auris media dropsy, maxillary sinus inflammation, auris external inflammation, chronic laryngitis, otitis media, tinnitus, vertigo, and so on.

To study the improvement of the natural killer (NK) cell activity by semiconductor laser acupoint irradiation, rats were used in this experiment and were injected immunosuppressant in their abdomen. The immunoassay was made after the surface irradiation and inner irradiation at Baihui point by semiconductor laser. The NK cell activity is an important index of immunologic function. The results showed that the NK cell activity after laser acupoint irradiation was enhanced. This enhancement is relatively important in the clinical therapy of tumor.

Spectroscopic measurements of the brain activity are discussed in this paper. We introduced a functional near infrared imager which is made of 9 light sources and 4 pairs detectors. Each pair detector has one 850 nm and one 760 nm filtered detector. The light sources are controlled by a computer and the signals from the detectors are filtered, converted and processed by the computer. Functional images of relative changes of blood concentration and deoxygenated hemoglobin in 9 cm by 4 cm detection area are revealed. Since brain function signals afford a contrast due to blood concentration and further oxygenation changes, we focused our studies on brain function by monitoring activity minus rest images.

Therapies for port wine stains including conventional laser irradiation usually cause unacceptable scarring or obtain poor effect. Pulsed dye laser has better approach, but only few patients obtain complete fading after multiple laser treatment. Because port wine stain is a congenital vasculopathy consisting of an abnormal network of capillaries in the upper dermis with an overlying normal epidermis and the researchers found that tumor blood vessels were occluded accompanying the necrosis of the tumor after PDT. It is though to be the effect primarily by thrombus formation in vessels and shut down of the blood supply to the tumor as well as direct tumor cells kill. The author and his colleagues started a series of animal and clinical studies since 1991 about photodynamic therapy for port wine stains and they established the method of PDT for PWS. An experimental study showed that Hpd appeared rapidly within the human vascular endothelial cells in culture fluid. Animal study using chicken combs as PWS models treated by PDT revealed the possibility of selective destruction of the malformative vasculature in PWS. The clinical studies of over 1700 cases proved that PWS can be cured without scar formation by PDT because there is no thermal effect involved. No relapse was found within a maximum follow-up of seven years. The differences and mechanism between the treatments of PDT and conventional lasers are discussed.

In order to study the exterior vascular laser irradiation therapy for replacing the intravascular laser irradiation therapy, we measure the distribution of radiant fluence rate in exterior vascular laser irradiation in vivo and imitative intravascular laser irradiation. The result shows that the average radiant fluence rate of exterior vascular and intravascular is 1.11 and 10.81 respectively, which is ten times between them. In order to get the radiant fluence rate corresponding to the intravascular laser irradiation, we suggest that about 20 mW HeNe laser could be used in exterior vascular laser irradiation therapy, and the laser must irradiate on the vascular perpendicularly. The suitable patient with exposed vascular must be chosen, and the diameter of the irradiated vascular is about 6 mm. Our experiment result, especially the data measured in vivo, will be useful for the research of light transport in human tissue.

Using the Near-Infrared Spectroscopy (NIRS), the noninvasive measurement of cerebral oxygen concentration can be achieved in vivo based on the Lambert-Beer Law. In this paper, we discuss the possibility of studying higher brain functions through combining cerebral oxygen saturation and cerebral function measurement. Event-related experiments are introduced to measure the cerebral phronetal function. Time domain curves show sight differences among these experiment results. However, with the aid of DFT, experiment data of all five human volunteers show the frequency near 20 Hz or 40 Hz is evoked depending on the difficulty of the mental tasks. The results demonstrate the feasibility of cerebral functions study by means of cerebral oxygen saturation measurement analyzed in the frequency domain.

In order to study the effects of He-Ne laser on the mucosa of middle ear mucosa from 9 patients with chronic otitis media, all of who had slight damp eardrum, were irradiated by low power He-Ne laser ten minutes per day for ten days. Specimen was taken before and after irradiation and observed under scanning electron microscope. It was found that the surface structure of the mucosa was more integral, the arrangement of the epithelial cell was closer together and microvilli arose among the noncilliated cells after irradiation. The inflammatory cell disappeared arid the morphologic structure appeared normal. These data provided the therapeutic evidence for the lower power He-Ne laser irradiation on patients with chronic purulent otitis midia.

This paper study on the light irradiation blood therapy home and abroad, including the intravascular low level laser irradiation therapy (ILLLI) and the ultraviolet blood irradiation therapy (UBI). The treatment method, the indications and mechanism of ILLLI and UBI are discussed. The theory of 'biological resonance' and 'optical trigger' are used to explain the mechanism of ILLLI and UBI. Based on the absorption spectrum of blood, some new suggestions are presented, such as the optimum wavelength irradiation, the ultraviolet laser irradiation and the extravascular laser irradiation.

A real time functional Near-InfraRed Imager (fNIRI) was presented in this paper. We developed a continuous wave (cw) light imaging probe which includes 9 light sources and 4 pairs detectors (each pair has one 850 nm filtered detector and one 760 nm filtered detector). There are 16 measurement sections and total detection area is 9 cm X 4 cm. The detector- source uses 2.5 cm spacing. The light sources are controlled by a computer and the signals from the detectors are converted and processed in real time by the computer. The user-friendly software was programmed with Visual C++ language. Relative changes of oxy-Hb, Hb, and total blood concentration in 16 channels and the corresponding images combined by 16 channels could be displayed in real time on computer. With this cw imaging probe, we have measured motor function in motor cortex area, visual function in occipital area, and cognitive activity in frontal forehead area of the human brain when the subjects are stimulated by moving fingers, viewing a flashing light and doing an analogy test, respectively. The experimental results show that the cw imaging probe can be used for functional images of brain activity, based upon changes of oxygenation and blood volume due to the stimulus.

Low coherence optical tomography (OCT) is a novel technique with high resolution for rapid, noninvasive imaging in living biological tissues. With this technique, a thin 'optical section' within a thick biological specimen can be obtained. Using a combination of the principles of low-coherence interferometry and confocal microscopy, OCT can provide micron-scale tomographic imaging of internal tissue microstructures. In OCT, enhanced optical sectioning performance in biological tissues (highly scattering media) is achieved through high detection sensitivity and high contrast rejection of out-of-focus light. In this paper, basic principle and recent advances in optical coherence tomography are described. The emphasis is to analyze some key problems in OCT setup. Light attenuation and scanning system are studied in detail. A theoretical model for low-coherence optical tomography in highly scattering media (biological tissues) is given. The authors will show that OCT images may be significantly affected by multiple scattering associated with the refractive index inhomogeneities found in scattering media such as biological tissues. At last, a conclusion suggests that OCT is a very promising technique for clinical application because of its simple theory and low cost.

An experimental apparatus is designed to determine the index of refraction of biological tissue using a laser beam and a prism in the familiar to a specular Fresnel reflection method in which the scattering effects are reduced to be disregarded. One of the advantages of the method is its high sensitivity to a small change in refractive index. A flat heater is contacted on the prism and a tiny heat electric couple is hold between a sample and the prism. The refractive indices of several porcine tissues have been measured over a temperature range of 20 to approximately 70 degrees Celsius. The index of refraction keeps stable levels below 36 degrees Celsius and above 60 degrees Celsius, respectively, but increases with an increase in temperature from 36 to 60 degrees Celsius. During a temperature descent after heating, the evolvement of refractive index is determined by the climax of temperature reached. The heating and cooling procedures are irreversible in optical property of tissue. Such results are consistent to the biological observation and can be explained by the cellular response to temperature. A knowledge of these properties is important for tissue optics and laser medicine.

Optical coherence microcopy (OCM) is a new method for optical and near-infrared imaging of biological tissues. This method is based on the detection of least-back-scattering light that maintain coherence and has thus spend shortest time that its path-length difference (Delta) L falling within the coherence length L_c of the low-coherence source. This paper points out that there are also a special part of multiple scattering light which has the sufficient small part length differences (Delta) L falling within the coherence L_c. The effects of this part of multiple scattering light can be divided into two categories. One is nonlinear effects and the other is speckle effects.

It is to investigate molecule interactions between antigen and antibody with ellipsometric imaging technique and demonstrate some features and possibilities offered by applications of the technique. Molecule interaction is an important interest for molecule biologist and immunologist. They have used some established methods such as immunofluorescence, radioimmunoassay and surface plasma resonance, etc. to study the molecule interaction. At the same time, experimentalists hope to use some updated technique with more direct visual results. Ellipsometric imaging is non-destructive and exhibits a high sensitivity to phase transitions with thin layers. It is capable of imaging local variations in the optical properties such as thickness due to the presence of different surface concentration of molecule or different deposited molecules. If a molecular mono-layer (such as antigen) with bio-activity were deposited on a surface to form a sensing surface and then incubated in a solution with other molecules (such as antibody), a variation of the layer thickness when the molecules on the sensing surface reacted with the others in the solution could be observed with ellipsometric imaging. Every point on the surface was measured at the same time with a high sensitivity to distinguish the variation between mono- layer and molecular complexes. Ellipsometric imaging is based on conventional ellipsometry with charge coupled device (CCD) as detector and images are caught with computer with image processing technique. It has advantages of high sensitivity to thickness variation (resolution in the order of angstrom), big field of view (in square centimeter), high sampling speed (a picture taken within one second), and high lateral resolution (in the order of micrometer). Here it has just shown one application in study of antigen-antibody interaction, and it is possible to observe molecule interaction process with an in-situ technique.

At the optical processing domain, the three-dimension reconstruction of information is an important problem of research. At the last few years, the laser confocal scanning microscope (LCSM) system was researched and has been used successfully as advanced optical instrument in the biological and medical research range. This paper primarily research the 3-D image reconstruction of the cell using its 2-D section image formed by the laser confocal scanning microscopy. First, the paper rests on the LCSM system characteristic of forming image to analyze the image noise and remove it. Then we extract the information of 2-D section image edge, and we use these informations to reconstruct the 3-D image of cell surface by method of B-Spline.

Utilizing the ultra-fast laser or superluminescence diode (SLD) as the light source, optical coherence tomography (OCT) is a new tomographic imaging technique. It has great applying foreground in many fields such as medicine, biology, material and so on. We founded an OCT system and applied it in biological imaging successfully. Furthermore, we found a potential great application for this technique in measuring the inner structure of bedded samples such as paint films. The experiment in OCT has made prompt development, while only a little work has been done on the theoretical analysis. Some experimental results, thus, can't be explained clearly. In this paper, we use the Monte-Carlo simulation method to analyze OCT image. The differences between single scattered (or least scattered) light and multiply scattered light and its influence to the quality of OCT image are discussed in detail. To show an example, our simulating calculation object is a conduit immersing in a high scattering medium that can be regarded as the approximation of blood vessel. After programming and calculating we get the theoretical result as the form of pseudo color image. The images of conduit immersing in the high scattering medium are clearly seen. Comparing with the experimental imaging of vein they are accordant basically. All above prove the Monte-Carlo simulation method correct and effective in theoretical research of OCT. Many significant results, which are very helpful for experimental research, are draw through this method.

A lattice random walk model based on walkers wandering on discrete lattice of scattering space by discrete spatial and temporal step is presented. The discrete Green's function for infinite homogeneous turbid medium deduced by inductive method from the lattice random walk model is used with the method of images to describe the photon density distribution in two dimensional semi-infinite and finite slab homogenous turbid media such as tissue. The scattering matrix and linking matrix of the lattice random walk are obtained to describe the scattering and absorption processes in homogeneous and inhomogeneous turbid media. All the results obey the principle of causality.

The application of image fusion in biomedical image analysis has led to a new concept about the nature of disease and to new diagnostic capabilities. However, the algorithm research of fusion is still an open research topic because the algorithm is often changed with different original images, different detectors and different research objects. This paper focuses on comparison of four image fusion algorithms based on wavelet transform to select the suitable methods for biomedical image fusion. The algorithms include: (1) weighted algorithm, (2) maximum selection algorithm, (3) stressing one image and (4) logic OR algorithm. For the sake of selecting the suitable image fusion methods for biomedical images, we propose six quantitative performance measure criterion linked with the characters of the biomedical image: standard deviation ((sigma) ), peak signal-to-noise ratio (PSNR), mean deviation ((Delta) (mu) ), the difference in entropy ((Delta) H), coefficient of correlation between the fusion image and ideal image (Correlation) and the difference in contrast between the fusion image and ideal image ((Delta) Contrast). Using the four algorithms to process biomedical images, such as fluorescence image and the corresponding transmission image, the visual investigation and the six quantitative performance measure criterion indicate that the weighted algorithm is the most suitable method for biomedical images among the four algorithms.

A phase modulation optical system was introduced to localize an object in a highly scattering medium. A good sensitivity of this system has been achieved. Liquid and solid brain models have been constructed and utilized to determine the optimum system configuration. Two different detection geometry, remission and transmission, have been tested on brain models. These two geometry scan different area of the brain model and both have a good detectability in the detection area. A 6 mm (or even smaller) absorber can be detected and the absorber position can be localized through a significant change in relative phase.

We present an analytical perturbation analysis for studying the imaging characteristics of photon diffusion imaging in highly scattering media such as human tissues. The photon source, the optical properties of the sample, and measurement system are all considered as parts of the whole imaging system. A concise relation between the internal structure and the detected signal was derived. We also proved that photon diffusion imaging possess the property of linear shift invariance. The image formation mechanism of such measurements as functional imaging or tumor early diagnosis is illustrated from the point of linear shift invariant system view.

In this paper, an optical fiber spectrometer is used to measure the properties of absorption of p-BLM at visible range. The formation and collapse of p-BLM has been observed. According to the ration of decreasing in the light intensity transmitted through p-BLM at a certain wavelength, the average lifetime of p-BLM can be estimated.

In this paper, a simple color correction method for the color reproduction of image obtained by angioscope is reported. We present the method to obtain the matrices theoretically and experimentally respectively. For the angioscope system, we suggest two matrices: an average color correction matrix A and a blood vessel color correction matrix A'. Using the two matrices, the images of several color samples captured by angioscope are processed, and their reproduced colors are evaluated. With this method, the discrimination ability of angioscope will be improved dramatically.

There are many reports about the study for highly focused laser-beam gradient forces exerted on dielectric microspheres to date. But the force values calculated theoretically are commonly larger than the actual and effective forces measured in experiment, which indicates that there is a sort of system errors between theory and experiment. In this paper a focusing characteristic study of laser beam affected by the astigmation of slide glass is presented using geometrical-optics method. And it is pointed out that the affection is one of the main factors causing system error mentioned above.

A photon count image system has been developed to obtain the ultra-weak bioluminescence image. The photon images of some plant, animal and human hand have been detected. The biophoton image is different from usual image. In this paper three characteristics of biophoton image are analyzed. On the basis of these characteristics the detected probability and detected limit of photon count image system, detected limit of biophoton image have been discussed. These researches provide scientific basis for experiments design and photon image processing.

Time-gated attenuation of plane-parallel light propagation through tissue is discussed by using Monte Carlo method. The result shows that the energy attenuation is approximately exponential.

We have obtained and investigated the laser Surface-Enhanced Raman Scattering (SERS) spectrum of Leptospiral Glycolipoproteim (GLP). The SERS spectrum of GLP offers the structural information of the molecules and provides the evidence that the functionality of the molecules are preserved on the Ag surface. The SERS spectrum and its Ordinary Raman Scattering (ORS) spectrum of GLP show their correlations. In the ORS spectrum, the intense AmI at 1651 cm^-1 and weak AmIII at 1283 cm^-1 show that GLP has a predominantly (alpha) -helix secondary structure. The Raman line at 542 cm^-1 indicates that the molecules of GLP has trans-gauch-trans configuration of the C-C-S-S-C-C linkage. In the SERS spectrum, the low-frequency band at 239 cm^-1 is attributed to the metal-molecule vibration, indicating chemisorption of the molecules of GLP on Ag surface. The bands belong to (delta) (COO^-) at 620, 683 cm^-1, the band belongs to (upsilon) _s(C-COO^-) at 921 cm^-1, belongs to (upsilon) (C-N), (upsilon) _s(COO^-) and (delta) (NH₂) at 1158, 1366 and 1648 cm^-1. It suggests that the molecules of GLP were adsorbed on Ag surface through both carboxylate groups and amino groups. The Raman enhancement of GLP has a short-range mechanism. The laser SERS spectrum enhancement factor of GLP is about 3 X 10².

This paper discusses a design of optical transfer system used in carbon-dioxide laser therapeutic machine. The design of this system is according to the requirement of the therapeutic machine. The therapeutic machine requires the movement of laser transfer system is similar to the movement of human beings arms, which possesses 7 rotating hinges. We use optical hinges, which is composed of 45 degree mirrors. Because the carbon-dioxide laser mode is not good, light beam diameter at focus and divergence angle dissemination are big, we use a collecting lens at the transfer system output part in order to make the light beam diameter at focus in 0.2 to approximately 0.3 mm. For whole system the focus off-axis error is less than 0.5 mm, the transfer power consumption is smaller than 10%. The system can move in three dimension space freely and satisfies the therapeutic machine requirement.

A new type of UV/VIS liquid-core optical fiber long lightpath absorption system, which was designed as an accessory and spectrum range was extended to UV with minimum wavelength 220 micrometer to compatible with conventional UV/VIS spectrophotometer, was described with high assembling precision RSD 1.4% and absorption 1 to approximately 700 cm for choice. The coupling between source light radiation and liquid-core optical fiber was tested and optimum condition was obtained. The samples introduction was presented and UV transmission spectra of optical fiber was detected. The system was applied to detect elements Cd(II), Pd(II), F^-1, Cr(VI), Cu(II), Fe(II), Ti(IV), Pt(II) and medicines Carbamazipine and Vitamin E by using of 105 cm long LCOF, and sensitivities were 42 to approximately 158 times as much as those by 1 cm conventional cell in length, detection limits (3(sigma) ) 0.14 to approximately 17 ng/ml, relative errors less than 11.2%, and recoveries 94 to approximately 102%.

Electronic system composition principle of CO₂ laser therapy instrument with 30 to approximately 40 w is introduced in this paper. Problems such as design of a harmonic oscillation type high voltage switch power supply, excess current protection and excess voltage protection as well as a single chip microprocessor interface etc. are studied.

This paper discusses a light transfer system of therapeutic machine using carbon-dioxide laser. This system is based on imitating human being arm motion principle, consists of optical cardans mainly and can move in three-D space freely. Through it carbon-dioxide laser (which wavelength is 10.6 micrometer) is reflected, focused or diverged and transferred to the different therapeutic part of body to realize the purpose of cutting operation, gasification, cauterization and irradiation. This system includes an indicating system using He-Ne laser, by which carbon-dioxide laser can arrive therapeutic part accurately. This system possesses some advantages e.g. an accurate transfer, large moving range, small power consumption, high power density and easy operation. At present the occupancy in home market of this kind laser transfer system products is over 95%. Some products have been exported to other countries.

A new method of 3D multi-spot surface profiling for patient's positioning is presented in this paper. In the approach, an encoded pattern structured light is used to project onto the target to be positioned, which is typically part of the patient surface. A single camera is used to image the projected light beams and the range data from camera to the target points can be extracted from the image of the deformed pattern. Because the light pattern is encoded, the correspondence between the projected beams and imaged beams is easily determined and, hence, the range data can be calculated quickly. The 3D sensing method here is based on the active light illumination triangulation. A detail description of the method is given, including system configuration, algorithms for solving the correspondence problem, reconstruction of the point's 3D position, calibration and experimental results, etc. One of the features of the system is extremely simplicity in hardware. And there is no movement part in the system. The encoded grid beam pattern makes it possible to solve the problem of the correspondence between the illuminated spots on the patient and their image points on the image plane. Also, the 3D reconstructed coordinates can be obtained from only one picture frame captured and the time consuming for computer is reasonably reduced.

T-cell contact with antigen-presenting cells (APC) initiates an activation cascade which includes an increase in T-cell intracellular calcium [(Ca²⁺)_i] and leads to T-cell proliferation and differentiation. Although T-cell/APC physical contact is required for an immune response, little is known about the patterns of cellular interaction and their relation to activation. We have combined fluorescence spectroscopy and imaging with optical manipulation to investigate the contact requirements for T-cell activation, using optical tweezers to control the orientation of T- cell/APC pairs and fluorescence microscopy to measure the subsequent (Ca²⁺)_i response, detected as an emission shift from the combination of fura-red and oregon- green, two cytoplasmic (Ca²⁺) indicators. APCs or beads coated with antibodies to the T-cell receptor (TCR) are trapped with a near-infrared titanium-sapphire laser and placed at different locations along the T-cell, which has a polarized appearance defined by the shape and direction of crawling (2-5 micrometers /min). T cells contacted with antigen- presenting cells or antibody-coated beads entered a dynamic and reproducible program in the first 10 - 20 mins, including (Ca²⁺)_i increase, changes in shape and motility, engulfment, and stable contact. T cells presented with antigen at the leading edge had a higher probability of responding (85%) and a shorter latency of response (50 secs) than those contacting APCs or beads with their trailing end (APCs: 30%, 150 secs; beads: 6%, 300 secs). Alterations in antibody density, quantified by FACS analysis, and bead size were used to determine the spatial requirements for T cell activation and the minimum number of receptors which must be engaged in order to transmit a positive signal. Preliminary data show that T cell responses [response percentage, latency and (Ca²⁺)_i pattern] depend on both antibody density and bead size.

Recently, much efforts and progress have been made in using steady state, time-domain and frequency-domain NIR technique to obtain tissue optical properties. We have developed a novel PMS system which can efficiently eliminate the phase-amplitude cross-talk along with a new algorithm to calculate (mu) _a and (mu) _s' of strong scattering media we measured. The PMS system consists of two master oscillators separated by a frequency at 25 khz. The two laser diodes (780 and 816 nm) are time shared by a small mirror excited by a 60 Hz chopper so that the phase detector can alternatively detects the response of the object in two wavelength. The output from phase meter is selected by an electronic switch, then filtered, amplified and sent to a computer. In order to eliminate phase-amplitude cross-talk, we designed a dynode feedback control circuit. Its purpose is to keep the amplitude signal from PMT to be constant so that the amplitude has less contribute to the phase shift. At the same time, phase output is corrected using a linear compensation circuit to eliminate the phase shift caused by the high voltage change. The optical bench tests showed the phase-amplitude cross-talk has been reduced to be very small. We did a series model experiments including ink, Introlipid and blood model to test the system. The results show very reasonable (mu) _a and (mu) _s' based on photon diffusion equations and algorithm. Next work is to apply it in clinic and measure the hemoglobin saturation change in tissues.

The spatial distributions of fluence rate (2-D, 3-D) in normal and cancerous human lung tissues in vitro were determined at the 676.4 nm of a Kr⁺ laser by using a small isotropic fiber-optic probe. By comparing the measured fluence distributions with Monte Carlo simulations, the optical properties of human lung tissues at the 676.4 nm were estimated for the first time.

Possibility is experimentally demonstrated of measuring refraction distribution in non-homogeneous translucent objects using Shack-Hartmann sensors. Holographic micro-lens matrix of 13 X 19 lenses with diameter 0.5 mm and focal length 80 mm operating with simple market available CCD array resulted in the sensitivity to wave front measurements corresponding to 0.01 (lambda) .

In this work it has been found that the conventional spin relaxation equations are not valid for the hyperpolarized spins. New longitudinal relaxation equations for the dipole- dipole coupled hyperpolarized spins have been derived. These new equations predict that the longitudinal magnetization relaxation for hyperpolarized spins is, in general, bi- exponential instead single exponential. They also predict that for dipole-dipole coupled hyperpolarized spins the steady state longitudinal magnetization is larger than the thermal equilibrium magnetization. These findings are useful as the base-line information for accurate analysis of the effects of the paramagnetic sources on relaxation of hyperpolarized spins in living body.

Laser-induced fluorescence spectra of normal mucosa and adenocarcinomatous of human colon tissues were investigated using excitation wavelengths of 457.9, 488, 514.5 and 632.8 nm respectively. The characteristic spectral differences between normal and adenocarcinomatous tissues had been observed at the wavelengths greater than 600 nm. In addition, emission intensities at 580 and 720 nm versus laser irradiation time were measured in both normal and abnormal tissues. Non-linear regression fitting of the obtained autofluorescence decay profiles illustrated that the autofluorescence decay followed a double exponential behavior. The evaluation of temporal dynamics of the autofluorescence processes may reveal the different accumulated concentration of endogenous fluorophores between normal and tumor tissues. Furthermore, the fluorescence intensity of the normal and tumor colonic tissues as a function of tissue thickness was also studied. The best fit to the data can yield the effective optical attenuation coefficients of human colon tissues.

Malignant tumors kill hosts almost entirely by tumor invasion to multiple sites including vital organs. These metastases are often difficult to detect and when detected it is usually too late for effective treatment. Therefore, control of metastatic tumors is by far the biggest challenge in cancer treatment. Can the metastases be prevented or eradicated by a treatment of local tumor that can be easily detected and treated? It apparently requires a systemic reaction, usually a tumor- specific immune response. Laser immunotherapy, a novel approach using laser, photosensitizer and immunoadjuvant, has shown the potential to achieve such an immune reaction. This new method was applied in treatment of rat metastatic mammary tumors. The tumor model is DMBA-4, an aggressive tumor that invades different sites through blood vessels and lymphatics. Without treatment, all the tumor-bearing rats died with an average survival time of less than 35 days. Remote metastases were observed in all late-stage tumor-bearing rats. Laser immunotherapy was capable of eradicating treated primary tumors, and more importantly, the metastases at remote sites were also eradicated without direct treatment. The probable mechanism is an induced tumor-specific immune response, and this hypothesis has been supported by several immunoassays. This new therapy may prove to be an effective treatment modality for metastatic tumors by a non-invasive local laser application.

The laser acupuncture equipment using laser diodes of 850, 1300 nm and optical fibers as light needles is presented. The double-frequency modulation of laser beam gives the high efficiency treatment of the low-power laser therapy by the oriental acupuncture method. The laser spot from optical fiber of 50 microns is suitable for the irradiation into special points on body or auricular by the acupuncture treatment schema. The laser intensity in pulse regime of 5 - 40 W/cm² and irradiation time of 5 - 15 minutes are optimum for treatment of neurosis symptoms and pain-relieving.