Three-dimensional Image Information Research Articles

３次元映像情報メディア技術 誤差拡散法における計算機ホログラムと擬似中間調処理との関係

３次元映像情報メディア技術 誤差拡散法における計算機ホログラムと擬似中間調処理との関係

5485839 Method and apparatus for ultrasonic wave medical treatment using computed tomography

An ultrasonic wave medical treatment in which the position of the focal point of the ultrasonic waves, the temperature in a vicinity of the object to be treated, and the effect of the treatment can be determined easily and accurately. The three-dimensional image information of the object to be treated obtained by a computed tomography device is utilized in locating the focal point. In case of using a nuclear magnetic resonance imaging device as the computed tomography device, the T2 weighted image and the chemical shift data can be used in checking the effect of the treatment and the temperature in a vicinity of the object. The endocavitary probe equipped with temperature and intensity sensors may also be used. The ultrasound tomographic images obtained by the ultrasound tomographic imaging device may also be used in conjunction with the three-dimensional image information. Sequential shifting of the focal point of the ultrasonic waves may be employed to reduce adverse influence due to the cavitation.

The AAPM/RSNA physics tutorial for residents. Physics of SPECT.

Single-photon emission computed tomography (SPECT) provides three-dimensional (3D) image information about the distribution of a radiopharmaceutical injected into the patient for diagnostic purposes. By combining conventional scintigraphic and computed tomographic methods, SPECT images present 3D functional information about the patient in more detail and higher contrast than found in planar scintigrams. A typical SPECT system consists of one or more scintillation cameras that acquire multiple two-dimensional planar projection images around the patient. The projection data are reconstructed into 3D images. The collimator of the scintillation camera has substantial effects on the spatial resolution and detection efficiency of the SPECT system. Physical factors such as photon attenuation and scatter affect the quantitative accuracy and quality of SPECT images, and various methods have been developed to compensate for these image-degrading effects. In myocardial SPECT, an important application of SPECT, recent use of attenuation compensation methods has provided images with reduced artifacts and distortions caused by the non-uniform attenuation in the chest region and by the diaphragmatic and breast attenuation. Attenuation-compensated myocardial SPECT images have the potential to improve clinical diagnosis by reducing the false-positive and false-negative detection of myocardial defects. In the future, further improvement in SPECT images will be realized from the continuous development of new radio-pharmaceuticals for new clinical applications, instrumentation with high spatial resolution and detection efficiency, and image reconstruction algorithms and compensation methods that reduce the image-degrading effects of the collimator-detector, attenuation, and scatter.

Processing of Three-Dimensional Image Information and Its Application to Industry

Processing of Three-Dimensional Image Information and Its Application to Industry

Computer graphics tools for radiation treatment planning

The objective of radiation therapy treatment is to eradicate a cancerous tumor while keeping the damage to nearby healthy organs to a minimum. A variety of tools employing computer graphics exist to aid in the planning and verification of treatments. Three-dimensional (3D) image information available from sources such as computerized tomography (CT) scanners is used to define the sizes, shapes, and spatial locations of the tumor and normal structures in the form of transverse contours. These object definitions are displayed 3D perspective to enable the determination of the best possible directions from which to aim radiation beams at the tumor. The beams may be shaped to match the outline of the tumor, and their intensities may be modified using compensating devices. The results of calculations done to predict the distribution of radiation dose throughout the body due to a given set-up of beams can be displayed to the user in many ways. Dose may be shown in the form of isodose contours overlaid on transverse CT images, or on reconstructed image planes of arbitrary orientation in space. There are also a number of methods of 3D display; dose can be shown on the surface of objects, or in the form of isodose surfaces relative to anatomical structures. Computer-generated beam film images may e used to verify patient set-up and tumor coverage.

On transmission and recovery of three-dimensional image information in optical waveguides*

The paper considers two questions. The first one is: Is it possible to transmit three-dimensional pictorial information through transparent glass (or other dielectric) fibers? We find that due to modal dispersion, pictorial information is invariably “smeared” in transmission. The second question is: Given nature’s reluctance to transmit pictures through fibers, is there anything we can do about it? We suggest that the answer is yes and point to a class of solutions involving nonlinear optical mixing.