245 results about "Helical scan" patented technology

An endoscope system has an optical fiber configured to transmit illumination light emitted from a light source to the tip portion of a scope; a scanner configured to spirally scan a target area with illumination light by vibrating the tip portion of said optical fiber; and an image generator configured to generate image data from image-pixel signals obtained from the light reflected from the target area. Then, the scanner scans the illumination light in a circular motion midway through a spiral scanning procedure.

A display stand for displaying an article of merchandise includes a base defining an outer periphery and means for dispensing and collecting a helical cable attached to the article of merchandise. The means for dispensing and collecting supports and guides the helical cable along the outer periphery of the base between a retracted length and an extracted length. The dispensing and collecting means may include at least one wheel disposed on the outer periphery of the base. The dispensing and collecting means may include at least one roller disposed on the outer periphery of the base. The dispensing and collecting means may include a low-friction surface disposed on the outer periphery of the base. The dispensing and collecting means may include a scalloped surface disposed on the outer periphery of the base. The display stand may further include a collection tube for delivering the helical cable to the article.

A CT scanner according to the present invention is particularly useful for scanning the spine and extremities, such as knees, and ankles, especially while the patient is in an upright position. The CT scanner generally includes a source and detector that are rotatable about a generally upright axis. The source and detector are also moved along the upright axis during rotation to perform a helical scan. The source and detector are mounted to an inner ring, which is rotatably mounted within an outer ring. The outer ring is fixedly mounted to a carriage that is movable along an upright rail.

A CT scanner according to the present invention is particularly adapted for scanning the extremities of a patient. The CT scanner includes an x-ray source and x-ray detector mounted for rotation and translation along an axis parallel to a table for supporting the patient's extremity. The source and detector are mounted opposite one another on an inner circumference of an inner ring. The inner ring is rotatable about the axis within an outer ring mounted on at least one carriage. The carriage is movable parallel to the axis. During scanning, the inner ring rotates within the outer ring while the rings and carriage move along the axis, thereby producing a helical scan of the extremity.

A scout image of a subject is displayed. An operator designates at least one range in a body-axis direction, of the scout image. Further, the operator graphically inputs or key-inputs and sets imaging condition parameters such as a helical pitch, a noise index and the like for a shuttle mode helical scan with being made independent every ranges. Thus, conditions such as helical pitch and noise index for the shuttle mode helical scan can efficiently and intelligibly be set independently for each region or organ, and hence the control/optimization of imaging conditions is enabled.

Systems and methods are provided for acquiring and reconstructing projection data using a computed tomography (CT) system having stationary distributed X-ray sources and detector arrays. In one embodiment, a non-sequential activation of X-ray source locations on an annular source is employed to acquire projection data. In another embodiment, a distributed source is tilted relative to an axis of the scanner to acquire the projection data. In a further embodiment, a plurality of X-ray source locations on an annular source are activated such that the aggregated signals correspond to two or more sets of spatially interleaved helical scan data.

An apparatus and method for scanning an object with a helical CT scanner, the method comprising: acquiring an amount of data corresponding to the object that is scanned by the CT scanner, wherein the amount of data is generated by an x-ray source that projects a fan beam of x-rays toward a detector array on an opposite side of a gantry of the CT scanner, the fan beam being generated at multiple x-ray source positions as the x-ray source is rotated about the object as the object passes through an opening in the gantry disposed about a conveyor for moving the object through the opening; monitoring a position of the conveyor as the object passes through the opening in the gantry; determining if the conveyor has been stationary for more than one rotation of the gantry and discarding redundant data after one rotation, optionally turning off the x-ray tube if the conveyor has been stationary for more than one gantry rotation, and if so preventing the conveyor from moving again until the tube is turned on and is stable, inputting the position of the conveyor at each x-ray source position into a reconstruction algorithm; and presenting an image of the object.

A collimator control method for an X-ray CT apparatus includes changing an aperture of the collimator according to a position of a helical scan on the body axis of the subject in the progress of the helical scan.

Some configurations of the present invention thus provide a method for producing images of an object. The method includes dynamically helically scanning an object on a moving table utilizing a scanning imaging system. During the scan, projection views of the object are acquired and stored together with corresponding table locations. A plane for reconstruction of an image of the object is selected. The stored table locations are used to determine geometric variables applicable to the stored projection views; and the stored projection views are filtered and backprojected utilizing the geometrical variables to reconstruct an image of the object at the reconstruction plane.

A scan control method for an X-ray CT apparatus wherein a subject with a contrast agent injected therein is helically scanned with an X-ray beam and image reconstruction is performed based on projection data obtained through an X-ray detector. The method includes controlling a velocity of a helical scan following motion of the contrast agent in the subject.

The invention relates to a computed tomography (CT) iteration reconstruction method for an asymmetrical detector. The CT iteration reconstruction method is characterized by comprising the following steps of: performing air correction, nonlinear correction, crosstalk correction, defocus correction and calibration correction on raw data acquired by a computed tomography scanner to obtain projection data; judging whether the projection data is CT scan data or helical scan data, and if the projection data is the CT scan data, grouping the CT scan data; calculating a projection weight to obtain a weight matrix; performing ordered subset expectation maximization (OSEM) iteration orthographic and back projection according to the weight matrix; judging whether iteration ending conditions are met, if so, ending the iteration orthographic and back projection to obtain an initial CT image; and performing postprocessing on the initial CT image to obtain the reconstructed CT image. By the method, the iteration back projection reconstruction is carried out by directly using incomplete projection data, artifact can be relived, noise level difference caused by data inconsistency due to interpolation is inhibited, and the CT iteration reconstruction method is mainly suitable for less-than-four-row CT detectors.

One embodiment of the present invention is a method for imaging an object with a computed tomographic (CT) imaging system that includes steps of helically scanning the object with a multi-slice CT imaging system to acquire attenuation measurements of the object, the measurements including more than two conjugate samples for estimation of a projection at a plane of reconstruction of the object; and filtering and backprojecting the attenuation measurements of the object, including the more than two conjugate samples, to reconstruct at least one image slice of the object. An improved sampling pattern and better use of the attenuation samples obtained during a scan is thus provided.

The present invention provides a multi plate screw press sludge dewatering machine and a helical shaft thereof. The multi plate screw press sludge dewatering machine includes fixed rings, movable rings, the helical shaft, a sludge inlet tank and a sludge discharging tank; the helical shaft adopts a variable diameter variable pitch helical shaft, a lead angle arrangement sequence of a helical blade of the whole helical shaft is gradual reduction from the sludge discharging tank to the sludge inlet tank, and the lead angle arrangement sequence is gradually reduced from 16°-22° to 6°-14°; a pitch of the helical shaft is gradually increased along a direction from the sludge inlet tank to the sludge discharging tank; a diameter of a shaft body of the helical shaft is gradually increased along with a direction of the sludge discharging tank from a ⅓ position of a shaft length; and blockage prevention plates are arranged on two sides of the bottom of the helical blade. The helical shaft in the present invention is specially designed, so that the pitch is more reasonable, a helical angle is gentler, frictional resistance when sludge passes through the helical shaft may be effectively reduced, and phenomena of shaft blockage and shaft sticking of the sludge may be reduced.

A scanning electron beam computed tomographic system eliminates axial offset between target and detector by disposing the target, collimator, and detector such that active portions of the target and detector are always diametrically opposite each other. This result is achieved by providing a helical target, collimator, and detector, or by providing planar target, collimator, and detector components that are inclined relative to the vertical axis such that active portions of the target and detector are always diametrically opposite each other. Either configuration eliminates cone beam error and the necessity to correct for same. Further, the system can provide multi-slice scanning of an object that is in constant motion at a critical velocity, without having to interpolate data. Conventional helical scanning may still be undertaken. Detector elements can be disposed axially to improve signal/noise ratio and to produce a cone beam cancellation effect.

An X-ray computer tomography apparatus includes an X-ray tube, an X-ray detector, a data collection apparatus that collects X-ray signals from the X-ray detector repeatedly, a shutter mechanism that is arranged between the X-ray tube and a subject in order to convert an X-ray into a pulse-like X-ray and is constituted such that a ratio of a shutter open period and a shutter close period is variable, a restructuring unit that restructures image data on the basis of the collected X-ray signals, and a control unit that controls the shutter mechanism in order to change the ratio of a shutter open period and a shutter close period during a helical scan.

An object of the present invention is to utilize a distance, which is linearly moved for acceleration or deceleration, out of an overall distance linearly moved during a helical scan for the purpose of image reconstruction. Projection data is acquired even during acceleration or deceleration of linear movement made for a helical scan. The acquired projection data is utilized for image reconstruction. Moreover, during the acceleration of linear movement, while a tube current is being increased, projection data is acquired. During the deceleration of linear movement, while the tube current is being decreased, projection data is acquired.

The invention relates to a helical scanning common path interference type endoscopic frequency-swept optical coherence tomography (OCT) real-time imaging method and a helical scanning common path interference type endoscopic frequency-swept OCT real-time imaging system. A light splitter and a reference lens are arranged in a probe, so that the whole system is formed into a common path interference structure, a micromotor mounted in the probe is used for carrying out the smooth helical scanning of a focused illuminating light beam, and the frequency-swept OCT technology which does not require mechanical scanning movement along the depth direction of a sample is adopted to achieve the purpose of fast imaging; and finally, a series of digital signal processing is carried out on the acquired interference signals to obtain the three-dimensional image of the detected sample. The invention is characterized in that: the system is not sensitive to various interferences, the probe is plug-and-play, three-dimensional imaging is real-time, image distortion is little, and the omission of pathological changes is reduced.