Interstitial thermotherapy is a new treatment for deep seated brain tumors. To destroy large tissue volumes without adverse effects (vaporization, carbonization) a new laser catheter was developed. The device combines the radiative heating of distant tissue volumes with the conductive cooling of areas close to the optical fiber tip.

Image-guided stereotaxis is an accurate and safe method of directing therapy to target volumes defined in 2D multi-planes or 3D perspectives using computer reconstruction of image data. The major limitations of stereotactic techniques are the lack of intraoperative visualization and the ability to directly monitor the procedures, and changes of intracranial coordinates after decompression of cystic lesions or aspiration of cerebrospinal fluid in the management of intraventricular lesions. Stereotactic neuroendoscopy involves integration of rigid-flexible endoscopy and the Nd-YAG laser in 2D/3D multiplanar image-guided stereotactic procedures. The major advantages of endoscopic laser surgery include being minimally invasive (burrhole or small craniotomy surgery), direct intraoperative visualization, hemostasis, evacuation or resection assessment, and wide exploration of intracranial cavities or ventricles. We used endoscopic laser surgery in the management of 202 patients undergoing biopsy, aspiration, resection, and internal decompression of deep and subcortical intracranial lesions, and for different types of fenestration procedures. Image-guidance combined with endoscopic techniques may offer a safe, accurate alternative to conventional neurosurgical procedures in treating small solid, cystic, intraventricular lesions, and in fenestration procedures.

The use of flexible neuroendoscopic techniques in neurosurgical procedures is routinely performed in the spinal canal and in the intracranial subdural space. Treated entities are syringomyelia, tumors with concomitant syrinxes in spinal cord, cystic legions in the subdural and subarachnoid space in the spinal canal as myelomeningoceles.

A new fiber-optic delivery system for CO₂ radiation has been used to successfully treat non-communicating hydrocephalus. This system consists of a hollow sapphire waveguide employed in the lumen of a stereotactically-guided neuroendoscope. CO₂ gas flows through the bore of the hollow waveguide, creating a path for the laser beam through the cerebrospinal fluid (CSF). This delivery system has the advantages of both visualization and guided CO₂ laser radiation without the same 4.3 mm diameter scope. Several patients with hydrocephalus were treated with this new system. The laser was used to create a passage in the floor of the ventricle to allow the flow of CSF from the ventricles to the sub-arachnoid space. Initial postoperative results demonstrated a relief of the clinical symptoms. Long-term results will indicate if this type of therapy will be superior to the use of implanted silicone shunts. Since CO₂ laser radiation at 10.6 micrometers is strongly absorbed by the water in tissue and CSF, damage to tissue surrounding the lesion with each laser pulse is limited. The accuracy and safety of this technique may prove it to be an advantageous therapy for obstructive hydrocephalus.

Rotating a plane-parallel glass plate in a laser beam can provide precise sub-millimeter beam translation useful for intraoperative localization and laser positioning. Fine control of beam translation by this method can aid in establishing laser-defined planes of a coordinate system used to locate patient anatomy or to align a stereotactic frame. To implement this method, laser dot or line projectors can be equipped with small motor-driven glass plates at or near their output ports. The author assembled an optical system consisting of a six mm thick crown glass plate, a visible diode laser projector and a 40-step stepper motor. This combination of simple and relatively inexpensive elements produces approximately one-half mm increments of beam translation over a five mm adjustment range. Benefits include fine control and freedom from perturbations caused by contact with adjustment thumbscrews. The addition of infrared remote control would allow easy adjustment of positioning lasers in hard-to-access areas of the operating or treatment room.

There has been considerable interest in the development of frameless stereotaxy based upon scalp mounted fiducials. In practice we have experienced difficulty in relating markers to the image data sets in our series of 25 frameless cases, as well as inaccuracy due to scalp movement and the size of the markers. We have developed an alternative system for accurately and conveniently achieving surgical registration for image-guided neurosurgery based on alignment and matching of patient forehead contours. The system consists of a laser contour digitizer which is used in the operating room to acquire forehead contours, editing software for extracting contours from patient image data sets, and a contour-match algorithm for aligning the two contours and performing data set registration. The contour digitizer is tracked by a camera array which relates its position with respect to light emitting diodes placed on the head clamp. Once registered, surgical instrument can be tracked throughout the procedure. Contours can be extracted from either CT or MRI image datasets. The system has proven to be robust in the laboratory setting. Overall error of registration is 1 - 2 millimeters in routine use. Image to patient registration can therefore be achieved quite easily and accurately, without the need for fixation of external markers to the skull, or manually finding markers on the scalp and image datasets. The system is unobtrusive and imposes little additional effort on the neurosurgeon, broadening the appeal of image-guided surgery.

Stereotactic methodology is employed in a narrow range of neurosurgical procedures due to the difficulty encountered in using mechanical 3D digitizers. To extend the use of stereotaxy to all intracranial surgery, a system employing an infrared optical digitizer to track neurosurgical instruments during intracranial surgery has been developed.

In neurosurgery localization is the process of matching the imaging data generated by an imaging modality such as computed tomography or magnetic resonance imaging with the patient's brain during surgery. This process is done intraoperatively using several methods. Using infrared signals is one of these methods. In this paper we describe a system that uses infrared as a tool to determine a position in three-dimensional space. We also describe a computer-based neurological image data acquisition and correlation system that assists the neurosurgeon with preplanning, simulation, and optimization of the ~mrgical procedures and shows the safest approach to J.esions. We describe localization in laser resection procedures for bot.h contact (NdYAG) and non-contact (C02 ) lasers.

Computer-assisted stereotactic neurological surgery, together with laser instruments, can help neurosurgeons locate and resect deep brain tumor more accurately and more conveniently than traditional techniques. Several successful neurosurgical computer imaging systems already exist, such as Compass and the Neurosurgical Planning System (NSPS-3.0). These systems offer successful software and hardware tools for surgery planning as well as real-time laser instrument guidance.

Abrupt occlusion of a coronary artery is the major cause of morbidity and mortality associated with percutaneous angioplasty. Attempts to reopen occluded vessels are either empirical attempts or guided by angiographic lesion morphology which has inherent limitations in specifically identifying the cause of the occlusion. We performed percutaneous coronary angioscopy in patients with abrupt occlusion to directly visualize the intravascular morphology of abruptly occluded vessels and compared these results with results obtained by angiography.

We used coronary angiography and angioscopy prior and following balloon angioplasty (PTCA) and high speed rotational atherectomy (PTCRA) in order to 1) Assess morphological and surface luminal characteristics of de novo (DN) and restenotic (RS) lesions, 2) Compare surface luminal characteristics following PTCA and PTCRA. 3) Investigate whether lesion morphology helped predict response to therapy; 39 lesions were studied in 38 patients undergoing elective coronary intervention. Angiographic and angioscopic variables were compared by Pearson Chi-square. Angiography pre-intervention was not different in DN and RS lesion. On post intervention angiography, presence of intimal dissection was significantly higher in the PTCA group (p < 0.001). On preintervention angioscopy smooth white lesions differentiated RS from DN lesions (yellow colored lesion) (p < 0.01) while color difference persisted post intervention; smoothness and absence of plaque fracture were device related as noted in the atherectomy group (p < 0001). No other lesion variables noted prc.4ntervention hipcd dfffcrentiatz DN from RS lesions or predict response to catheter therapy. We conclude: 1) angioscopy is superior to angiography in assessing surface luminal characteristics; 2) smooth white lesions characterized RS lesions pre—intervention and color difference persisted after intervention. 3) surface luminal characteristics were very different following PTCRA vs. PTCA with a) angiographically less intimal dissection and b) angioscopically smoother lumen with less plaque fracture following PTCRA.

With the expanding array of therapies available for coronary intervention, the invasive cardiologist has many choices for treating a specific lesion in an individual patient. Certain types of lesions might respond more effectively with stents, particularly the rigid Palmax- Schatz device. Thrombus and dissection immediately following stent placement are associated with early occlusion, and the interventionist must be able to assess their presence pre- and post-stenting. Angiography is deficient in quantifying minimal disease and in defining lesion architecture and composition, as well as the plaque rupture and thrombosis associated with unstable angina. It is also imprecise in detecting dissection and thrombus. Intravascular ultrasound (IVUS) provides high-resolution images that delineate irregularities and other structures inside the lumen and within the vessel wall and surrounding tissues. Like angiography, IVUS has limited specificity for thrombus differentiation. Angioscopy is superior to angiography and IVUS in detecting thrombus and dissection. Angioscopy allows the clinician to assess the appearance of stent struts after deployment and at follow-up. This may aid in reducing acute complications as well as restenosis. Follow-up angioscopy of stents to detect thrombus or exposed struts may guide therapy in a patient who has clinical symptoms of restenosis.

Worldwide clinical Experience with Percutaneous Coronary Angioscopy using the Baxter ImageCath^TM system has exceeded 3000 procedures since first introduced in July 1991. In spite of extensive investigation into a broad range of applications, a proven clinical indication has yet to be defined, thus restraining the technology from general clinical use. Although coronary angioscopy has provided unique insight into coronary artery disease, the inherent qualitative nature of angioscopic data has limited the scope and breadth of the findings. Indeed, a study of experienced investigators has shown that consistent inter-observer agreement is limited to the presence of thrombus or dissection. Various methods of image quantification attempt to overcome the limitations inherent in angioscopic data. Current research in the areas of direct lumenal measurement, computerized color analysis, and spectroscopy promise to provide reliable image interpretation and possible correlation of image content to clinical syndrome.

To assess the ability of intravascular ultrasound (IVUS) imaging to identify morphologic predictors of restenosis after percutaneous transluminal coronary angioplasty, we studied 30 patients undergoing single vessel angioplasty. Our results indicate that IVUS appears to provide useful information that may identify patients at risk for restenosis immediately after angioplasty and may help determine the effectiveness of interventional techniques aimed at reducing plaque burden.

Current intravascular ultrasound imaging technology is able to determine the extent and distribution of pathologic processes within the vessel wall, but is not highly sensitive in discriminating between certain types of tissue. `Tissue characterization' refers to a set of computer-based techniques that utilize features of the ultrasound signal beyond basic amplitude to help define the composition of the tissue of interest. This technique involves quantitative analysis of the ultrasound signals reflected from tissue before these signals pass through the processing steps in the ultrasound instrument.

Dental x-ray systems are at this time the best method to locate carious lesions but it is difficult to detect them when they are small. Light imaging systems in the past have shown to be more sensitive than x-ray system to carious lesions but one has difficulty in determining the characteristics of these lesions especially when they are small. We developed a new light imaging technique which makes it much easier to determine the size and depth of lesions on most areas of the teeth even though still modifications on the present setup will be necessary to detect them as easily also on occlusal surfaces. This technique is based on a raster scan of the teeth with narrow collimated light beams. The investigation shows that even the area of small incipient lesions (< 0.1 mm²) can be measured and their depth estimated.

Investigations of new transillumination techniques have created a need for detailed transmission studies of teeth and tissues. Recent results have shown that light imaging of extracted teeth can identify small (1 mm² cross-section) caries in teeth by raster scanning using helium-neon laser light and a post collimated in-line detector. Preliminary frequency (wavelength) dependent transmission studies have been carried out from the visible to the near infrared spectral regions on the dentin of a slice of an extracted tooth 1.85 mm thick. These preliminary results show that in the region from 5,000 to 20,000 cm^-1 the dentin of an extracted, healthy, human tooth has a transmission of between 2.5 and 5.5 percent, indicating that the total attenuation coefficient is between 16 and 19.5 cm^-1.

Various designs of the kinestatic charge detector (KCD) have used a Frisch Grid--a planar, meshed electrode sandwiched between the detector's anode and cathode. The grid shields the cathode from effects of drifting ions until they reach the region between the cathode and the grid. Including the grid, however, has made detector design difficult because of electric field non-uniformities and microphonics. Recent studies have shown that the KCD may not need a grid. `Self-gridding,' an effect which produces the same results, occurs when the ratio of cathode's collector width to the drift gap is sufficiently small. The greater this ratio, the more self-gridding takes place. The process of signal formation has been analyzed for the self- gridding geometry using Excel^TM (Microsoft Corporation, Redmond, WA). Detector response to microcalcifications has been simulated by small, drifting volumes with a steep dip in ion count; low-contrast lesions by larger volumes with a shallow dip in ion count. Both of these typical breast lesions can be detected with self-gridding geometry. This geometry will soon be tested in an experiment for validity as a detector design.

We have investigated possible clinical applications of a Kinestatic Charge Detector (KCD) for dual-energy x-ray imaging. The KCD is a good candidate as a detector for dual-energy radiography, because it is a digital detector with a high detective quantum efficiency, good spatial resolution and good scatter rejection. Computer simulations have been performed to design and optimize dual-energy KCDs for specific clinical applications. The clinical applications that have been investigated for dual-energy KCD imaging are chest radiography, mammography and osteoporosis. Experimental data have also been taken with a small research dual-energy KCD.

A method utilizing digital dual-energy subtraction X-ray radiography for measuring calcium densities localized to the cortical and cancellous regions of bone cross sections is described. The method is being used to study calcium loss in femurs of two differently treated groups of rats. In each experimental cohort, one group of rats is restrained from weightbearing on hind limbs by suspension from a tail harness. The other (control) group is allowed normal weightbearing on all limbs. The densitometry data for each rat leg consists of six X-ray projection images acquired at roughly equal angles about the bone axis by an intensifying screen/CCD camera imaging system. Images of bone cross sections are reconstructed by application of a maximum entropy algorithm constrained by the six projection images. The observed density data are further discriminated into cortical, cancellous and external regions on the basis of reference levels found on image density histograms.

A technique is developed to measure the x-ray source intensity profile of a medical accelerator using its built-in collimators, and two reconstruction techniques are investigated.

In this paper, modulation transfer function and image noise measurements are presented for Kinestatic Charge Detectors employing high-pressure Kr gas doped with NH₃ and CO₂. Kr improves spatial resolution over Xe because, at equal x-ray mean free path, it has both reduced fluorescence reabsorption and reduced electron range. NH₃ eliminates mobility dispersion (disparate ionic mobilities from multiple charge carriers) caused by gas impurities. CO₂ reduces electron attachment and thus ion-ion recombination because it lowers the electron temperature, thereby increasing electron drift velocity via the Ramsauer effect.

The aim of this study was to develop a diagnostic and evaluation system for analyzing 3D spaces defined by digitized cross-sectional US images of coronaries to quantify the vasomotion in relation to the morphology of arterial wall. Sequences of echographic images were obtained to have ordered stacks of 2D frames recorded on a VHS videotape. For each image, an automatic lumen edge segmentation is performed, then 3D reconstruction is obtained to evaluate time-dependent lumen and vessel wall modifications. Directly on 3D volumes, dynamic phenomena can be evidenced and quantitative analysis can be performed (e.g., area/hemidiameter variations, projections, sections, `carving', etc.).

The aim of our experimental and clinical studies was to investigate the suitability of Color- Coded Duplex Sonography (CCDS) for on-line monitoring of the Laser-Induced Thermotherapy procedures. Both the changes in the CCDS imaging during irradiation as well as the thresholds at which a `color bruit' occurs were investigated. Furthermore we have evaluated the correlation between the B-scan imaging of the damaged area and the size of coagulation in pathology measurements.

We are investigating the performance of a digital photoelectronic imaging system assembled in our laboratory. The primary radiological image is converted to a visible image by a Gd₂O₂S:Tb fluorescent screen optically coupled to a microchannel plate intensified CCD camera. The imaging system includes a motorized zoom lens, with a nominal zoom range of 6, for changing the imaging field size from 12.0 X 10.7 mm² to 63 X 56 mm². Video images are digitized by a real-time frame grabber, integrated with a personal computer for image processing and analysis by using specially developed computer software. The Modulation Transfer Functions of the system have been determined for various zoom factors. A spatial resolution limit of 7.5 lp/mm and of 2.5 lp/mm has been obtained for the maximum and the minimum optical zoom factor, respectively. For large zoom factors the resolution limit is due to the intrinsic resolution of the fluorescent screen.

The optically coupled CCD x-ray imaging system is a cascaded multistage imaging chain. Its design considerations and performance evaluation rely heavily on the analysis of signal-to- noise ratio. In this study, theoretically models of related characteristics are derived. The results of quantitative analysis are also presented.

The use of fractal statistics for characterizing and synthesizing medical imagery has in recent time been demonstrated as feasible. Traditionally, global fractal dimensions based on morphological coverings were used to quantify the texture of sampled data sets. This texture could be used to describe the second order statistics in 2D Magnetic Resonance Imaging, or microscopic images. With the realization of the benefits of fractal analysis has come a need for faster and more efficient computational algorithms. ROSETA (Range Over Standard Deviation, Experimental Trend Analysis) is an algorithm which yields substantial computational performance improvements by calculating entropy-based fractal statistics instead of morphological geometric statistics. ROSETA may be used as a robust general purpose analytical tool and several examples of its implementation are described. A simple variation of this algorithm is also presented which facilitates manual calculation using a calculator. This simple fixed point calculation may be used to analyze blood pressure, temperature, and heart rates as select discrete time samples with very few total points.

It is very important to locate the tumor for a patient, who has cancer in his brain. If he only gets X-CT or MRI pictures, the doctor does not know the size, shape location of the tumor and the relation between the tumor and other organs. This paper presents the formation of stereo images of cancer. On the basis of color code and color 3D reconstruction. The stereo images of tumor, brain and encephalic truncus are formed. The stereo image of cancer can be round on X, Y, Z-coordinates to show the shape from different directions. In order to show the location of tumor, stereo image of tumor and encephalic truncus are provided on different angles. The cross section pictures are also offered to indicate the relation of brain, tumor and encephalic truncus on cross sections. In this paper the calculating of areas, volume and the space between cancer and the side of the brain are also described.

Voltage-sensitive dyes have been used to optically monitor cardiac transmembrane potential for almost twenty years. This method now permits mapping of cardiac activation and recovery with spatial resolution that is unattainable by conventional mapping techniques. Despite the growing use and potential advantages of optical mapping with voltage-sensitive dyes, little information is available regarding optical action potential signal characteristics. Thus, no accepted standards for recording optical action potentials exists (e.g., sampling rates, analog filtering requirements). This paper will review some of the unique characteristics of optically recorded cardiac action potentials.

High resolution movies of transmembrane electrical activity in thin (0.5 mm) slices of sheep epicardial muscle were recorded by optical imaging with voltage-sensitive dyes and a CCD video camera. Activity was monitored at approximately 65,000 picture elements per 2 cm² tissue for several seconds at a 16 msec sampling rate. Simple image processing operations permitted visualization and analysis of the optical signal, while isochrome maps depicted complex patterns of propagation. Maps of action potential duration and regional intermittent conduction block showed that even these small preparations may exhibit considerable spatial heterogeneity. Self-sustaining reentrant activity in the form of spiral waves was consistently initiated and observed either drifting across the tissue or anchored to small heterogeneities. The current limitations of video optical mappings are a low signal-to- noise ratio and low temporal resolution. The advantages include high spatial resolution and direct correlation of electrical activity with anatomy. Video optical mapping permits the analysis of the electrophysiological properties of any region of the preparation during both regular stimulation and reentrant activation, providing a useful tool for studying cardiac arrhythmias.

Recent theoretical models predict specific spatial distribution of cardiac transmembrane potentials (V_m) around and between the stimulating electrodes during electrical stimulation or defibrillation. Therefore it is desirable to measure the coupling between applied current and V_m during and following the time span of the stimulus pulse. Confounding electrical artifacts can be circumvented through the use of optical recordings.

Using a multiple-site optical recording system and a voltage-sensitive merocyanine-rhodanine dye, we have been able to monitor, for the first time, spontaneous electrical activity in pre- fused cardiac primordia in 6- and early 7-somite chick embryos.

Optical recording uses a voltage-sensitive dye to transduce transmembrane cellular potential into a fluorescence, absorption or birefringence signal. Optical recording is useful for studying cardiac electrophysiology because it (1) is a non-contact method which spares fragile preparations mechanical damage, (2) can achieve sub-cellular spatial resolution, (3) allows acquisition of large numbers of simultaneous readings, and (4) is immune to artifacts produced by electrical shocks.

An important effect of electrical stimulation on myocardial tissue is the change in the transmembrane voltage induced during the stimulation pulse. This initial effect then activates transmembrane voltage-dependent ion channels and can produce a propagated action potential after the pulse. Fluorescence mapping with transmembrane voltage-sensitive dye has been used to measure the direction of the initial change in transmembrane voltage-sensitive during a stimulation pulse and the magnitude of the change relative to the action potential amplitude.

In this paper, a new method of 3D reconstruction for medical image processing is presented. In this method, the organic 3D image is reconstructed using several CT photographs. Because the transparent techniques are used, not only the organic surface but also the size and shape inside the organs can be observed and measured. Compared with the 3D reconstruction method for medical image before, this method has more advantages such as higher simulating precision and very convenient for measurement. It expresses through the application on actual medical images that the organic position and its area and volume can be measured and calculated precisely using the 3D reconstruction method presented in this paper. It is very useful for analyzing and researching organic pathological changes and making correct decision of diagnosis. The 3D reconstruction method presented in this paper is a good method for medical image processing.

In current clinic, pictures of B-supersonic, X-ray, X-CT and MRI are applicated widely. All of these are 2D pictures. The 3D information is blended. The blended information always leads doctors astray. If images are processed, mistakes will be reduced. In this paper the processing methods of 2D images are described. Examples of clinical applications are given. The acquiring methods of 3D information from 2D images are explained. The stereo image of liver and cancer is shown. The calculating ways of areas and volumes of liver and cancer are provided.

Automation of the Pap-smear cervical screening method is highly desirable as it relieves tedium for the human operators, reduces cost and should increase accuracy and provide repeatability. We present here the design for a high-throughput optoelectronic system which forms the first stage of a two stage system to automate pap-smear screening. We use a mathematical morphological technique called the hit-or-miss transform to identify the suspicious areas on a pap-smear slide. This algorithm is implemented using a VanderLugt architecture and a time-sequential ANDing smart pixel array.

In this paper, a technique extracting the misalignment information in topographical measurement of the corneal curvature is presented. First, automatic focus is introduced to guarantee system alignment in the direction of the optical axis. Secondly, movement invariant is used to establish the centralized images of a set of rings in the image plane. Therefore, misalignment in the image plane is compensated by adjusting parameters of the optical system.

The main goal of this paper is to present a new approach based on computer-aided phase microscope Airyscan for submicron biological structures dynamic investigation. In our experiments micelial cell walls were used as the object with well known submicron structure. Two types of cilia beating specimens and cytoplasm movement inside the onion cell were chosen for dynamic processes registering. This paper peruses mainly methodological goals for demonstration of the new method possibilities.

Most current systems for the investigation of biological motion are pointwise rather than full field techniques. The aim of this research is to achieve a full field semi-quantitative measure of motion. Systems being looked at range from linearly moving mechanical objects to movement within biological systems. The methods described can be used to detect in-plane and out-of-plane motion, and are based on the first order spatial statistics of time-integrated speckle patterns, especially speckle contrast. In addition to a photographic investigation of time integrated speckle, a digital processing technique has been developed. This computational technique is designed to produce a contrast map relating to the motion in the target field, with the advantage of working in quasi-real time. A digital method of simulating both partially and fully developed speckle patterns has also been studied.

In this paper we present the study on reflection speckles. We have investigated the polarization properties of reflection laser speckles and the relative correlation between speckle patterns of different polarization. If the diffuser is a pure glass it is found that reflection speckles are linear--polarized as that of the incident beam. This state of linear polarization of the speckle field degenerates into a state of average elliptical polarization as the diffuser surface is coated with a layer of flat white paint, as simulated biotissue; the degeneration increases as the thickness of the paint increases. The state of polarization is also a function of the scattering angle, and the maximum linear polarization always occurs at the direction of specular reflection of the average diffuser surface.

An in situ holographic technique, involving the use of a flexible miniaturized endoscope (diameter less than 1 mm) coupled to a CCD camera, to record the hologram, has been developed for medical applications. The hologram is formed, by reflection, on the tip of a multimode fiber bundle (MMB), sampled, and then treated electronically. The image is reconstructed numerically, providing more flexibility to the holographic process. Reconstructed images show the capability of the microendoscopic system to restore 3D informations of the observed scene. The limitations of the holographic approach with the microendoscope have been evaluated and discussed in terms of the resolution limit. In particular, the low frequency sampling of the hologram through the MMB is not a limiting factor for the range of observation distance investigated (4 - 10 mm). A good accordance between the experimental results and the theoretical predictions was found by comparing the cut-off frequency obtained. Our results show that, for the considered observation distances, objects of a few micrometers can be clearly identified. The different sources of noise are analyzed and their influence on the quality of the reconstructed image have been quantified.

During the antlerogenesis and gestation, substantial amounts of mineral compounds are removed from the skeleton and transferred to the growing antler or foetus. We have used holographic nondestructive testing for sorting out biomechanically aberrant radioulnar bones of European moose and radiological methods to study, whether observed aberrations are due to changes of the structure of the long bones (radius). In males, these changes were studied in three phases of antler cycle: antlerless season, antler growing and mature antler. In females, the studies were made with samples of adult individuals in and after gestation period. We studied x-ray diffraction responses of the bones before and after compression up to saturation level. Our results are indicating that compact and spongy part of the bones are giving seasonally different biomechanical responses.

A precise measurement on the surface shape of the denture is proposed and verified by experiments. The new phase unwrapping algorithm is based on the intensity modulation of fringe pattern. The path of phase unwrapping is determined according to the histogram of the intensity modulation, therefore the error is limited, if there is any, to local minimum areas.

An additional digital system has been developed in extension with the transillumination system by Dr. A. O. Wist, which captures images onto film by raster scanning, to decrease scanning time and to acquire, store, and display the scanned results in a personal computer with 256 shades of gray. Since only one scan is required for each image, this method can reduce the scanning time of the previous film system by factor of 10. This technique utilizes software to position the laser and to acquire data. While a tooth is being scanned, the analog to digital converter acquires the output voltage from the receiver and stores on the data on the computer's disk drive where afterwards a software program displays the results in super VGA with 256 gray shades on the monitor. The images are then stored as bit mapped images in either a GIFF or PCX format for printing and portability. Several teeth have been scanned and displayed on a 256 gray scale monitor.

A theoretical and an experimental study in the area of electronic medical imaging devices operating through Kinestatic Charge Detection principles is in progress, aimed at a better understanding of both the macroscopic electric potentials and the charge transfer (exchange) reactions. It will be demonstrated that long range attractive dipolar moment forces associated with low ionization potential polar molecules with a high dipole moment in an inert gas detective medium offer superior imaging performance over the non-polar counterparts with zero electric dipole. The dopant works by introducing a drastic reduction of the ion mobility dispersion. The goal of this study is to implement and develop high resolution imaging detectors with applications in medical detector technology.

The phenomenon of self imaging occurring in a multiple-mode fiber offers a transmission mechanism of 2D images through a single fiber. Potential medical applications of the technique would be the development of disposable single fiber endoscopes or viewing instruments to be used in surgery. In this paper, the theory of coherent light transmission in a multiple-mode waveguide has been described. As a result, a coherently illuminated image will repeat itself periodically while propagating in the waveguide. For the first time in experiment, images have been achieved for a point object transmitted through graded index optical fibers, and the image resolution and the field of view have been obtained. Discussions on problems and improvements are also presented in this paper for the method.