31 results about "X-Ray Tube Current" patented technology

A dual energy scanning densitometry system for imaging and measuring bone density maintains acceptable flux by adjusting the x-ray current or scan speed according to preceding scan line data. The amount of acceptable flux is maintained within limits modified by information about the region of the body being scanned so that different precisions may be maintained for different body regions. Scan speed and current may be controlled so that scan speed is maximized within the current limits. Essentially continuous flux control can be achieved.

The present invention aims to obtain a tomographic image similar in image quality to a tomographic image obtained by executing a scan at X-ray tube current value set by an X-ray automatic exposure function even when the X-ray tube current value set by the X-ray automatic exposure function are not within a standard range of the X-ray tube current values settable at the X-ray tube (21). X-ray tube current value supplied to the X-ray tube (21) are set by the X-ray automatic exposure function. Thereafter, when the X-ray tube current value set by the X-ray automatic exposure function is not within in the standard range of the X-ray tube current value settable at the X-ray tube, the X-ray tube current value at a portion not within the standard range are changed so as to be within the standard range, and the set value of helical pitch is changed so as to correspond to the ratio between the pre-changed x-ray tube current value and the post-changed X-ray tube current value.

In order to provide an X-ray CT apparatus with little image quality degradation even though a tube current value of the X-ray tube is suppressed, an X-ray CT apparatus of the present invention includes: a system controller that calculates a tube current value of an X-ray tube based on a successive approximation process condition selected from a plurality of successive approximation process conditions and input a scanning condition and / or a reconstruction condition and that performs scanning based on the calculated tube current value of the X-ray tube; and an image reconstruction device that reconstructs a tomographic image of an object, based on the selected successive approximation process condition and the reconstruction condition, from an amount of transmitted X-rays detected by an X-ray detector after being emitted from an X-ray source to the object based on the calculated tube current value of the X-ray tube and being transmitted through the object.

A current feedback circuit in a dental imaging apparatus, which measures the x-ray tube current produced by the x-ray filament. During preheat, when the tube current is sensed to be appropriate for production of a constant rate of electrons, preheat is stopped, and diagnostic radiation emission begins. This circuit eliminates a fixed amount of preheat pulses which contribute unusable radiation during preheat of the filament in prior art systems.

The present invention provides an X-ray CT apparatus capable of obtaining each tomographic image indicative of X-ray tube voltage dependent information of a subject with the optimum image quality by less reduced exposure. The X-ray CT apparatus includes device for setting a plurality of X-ray tube voltages and sets imaging conditions used in the photography using the respective X-ray tube voltages in such a manner that respective image noise of tomographic images photographed at the X-ray tube voltages become substantially identical to one another. The setting of the imaging conditions is the setting of X-ray tube currents. The X-ray tube currents are set based on geometrical characteristic amounts of the subject determined from each scout image in such a manner that the respective image noise of the tomographic images photographed at the plurality of X-ray tube voltages become substantially identical to one another.

The present invention aims to obtain a tomographic image similar in image quality to a tomographic image obtained by executing a scan at X-ray tube current value set by an X-ray automatic exposure function even when the X-ray tube current value set by the X-ray automatic exposure function are not within a standard range of the X-ray tube current values settable at the X-ray tube (21). X-ray tube current value supplied to the X-ray tube (21) are set by the X-ray automatic exposure function. Thereafter, when the X-ray tube current value set by the X-ray automatic exposure function is not within in the standard range of the X-ray tube current value settable at the X-ray tube, the X-ray tube current value at a portion not within the standard range are changed so as to be within the standard range, and the set value of helical pitch is changed so as to correspond to the ratio between the pre-changed x-ray tube current value and the post-changed X-ray tube current value.

A method for determining a tube current profile for the recording of at least one X-ray image of body region of a patient with an X-ray image recording device, a corresponding computer program, a machine-readable data carrier and an X-ray image recording device are disclosed. The method includes acquisition of an image recorded via an optical sensor wherein the image has a field of view including at least the body region of the patient to be depicted by way of an X-ray image; determination of at least one piece of patient-specific, body-related information for the patient from the image; determination of an X-ray attenuation distribution of the patient at least for the body region to be depicted by way of an X-ray image with reference to the at least one piece of patient-specific, body-related information; and determination of the tube current profile with reference to the X-ray attenuation distribution determined.

An X-ray CT apparatus includes: an X-ray source which emits X-rays while rotating around a subject; a compensation filter which adjusts at least one of the output distribution and the spectral distribution of the X-rays emitted from the X-ray source to the subject; an X-ray detector which is disposed opposite to the X-ray source with the subject interposed therebetween, rotates together with the X-ray source, and detects the amount of X-rays transmitted through the compensation filter and the subject; an image operation unit which reconstructs a tomographic image of the subject on the basis of the detected amount of X-rays; a display unit which displays the tomographic image; a control unit which controls each of the constituent components; and a compensation unit which compensates for deterioration of image quality, which is based on the amount of displacement between the rotation center of the X-ray source and a desired position of the subject, by changing an X-ray tube current modulation pattern indicating a time-series change of emission of the X-rays and / or by moving the position of the subject.

An X-ray CT apparatus is provided with an X-ray tube current modulation pattern calculation means that calculates an X-ray tube current modulation pattern based on a 3-dimensional model of an object calculated based on a scanogram image of the object, start-up shape acquisition means that acquires a start-up shape of CT values of a predetermined region of the object or CT value time differences after injecting contrast agent into the object, time contrast curve prediction means that predicts a time contrast curve indicative of a time sequential change of contrast in a diagnostic portion of the object at each slice position at a scan time based on the acquired start-up shape of the CT values or CT value time differences, object 3-dimensional model modification means that modifies a 3-dimensional model of the object based on the predicted time contrast curve, and X-ray tube electric current modulation pattern modification means that modifies the X-ray tube electric current modulation pattern based on the modified 3-dimensional model of the object.

This invention is provided to determine a tube current at the imaging of the heart by an X-ray CT apparatus in such a manner that image noise becomes constant. Upon determining a tube current of an X-ray tube at the time that the heart is imaged by an X-ray CT apparatus, the tube current is determined based on an index related to image's noise and a BMI of a subject. The noise is at a central portion of an ascending main artery. Determining the tube current is conducted using a function with the BNI as a variable. The function is given in the form of a polynomial equation of the BMI. Each coefficient of the polynomial equation is a function of the index.

An X-ray CT apparatus is provided with an X-ray tube current modulation pattern calculation means that calculates an X-ray tube current modulation pattern based on a 3-dimensional model of an object calculated based on a scanogram image of the object, start-up shape acquisition means that acquires a start-up shape of CT values of a predetermined region of the object or CT value time differences after injecting contrast agent into the object, time contrast curve prediction means that predicts a time contrast curve indicative of a time sequential change of contrast in a diagnostic portion of the object at each slice position at a scan time based on the acquired start-up shape of the CT values or CT value time differences, object 3-dimensional model modification means that modifies a 3-dimensional model of the object based on the predicted time contrast curve, and X-ray tube electric current modulation pattern modification means that modifies the X-ray tube electric current modulation pattern based on the modified 3-dimensional model of the object.

In a method for controlling the modulation of the tube current of an X-ray tube in the production of images using computed tomography, a single topogram of the examination subject is obtained and an orthogonal attenuation value is calculated therefrom, also making use of geometrical information associated with the position of the table on which the examination subject is disposed. In a subsequently-obtained computed tomography scan, the tube current is controlled using the orthogonal patient attenuation.

A method for performing reference normalization for an image created by an imaging system. The imaging system includes a radiation detector array with a right and left edge. The method includes receiving a projection dataset created by the imaging system in response to a varying x-ray tube current. The projection dataset includes a view and predicted fluxes are calculated for the set of reference channels within the view. A right set of reference channels are located proximate at the right edge of the detector array and a left set of reference channels are located proximate to the left edge of the detector array. The method also includes calculating average actual fluxes for the sets of reference channels. Based on the predicted reference fluxes and the average fluxes, a reference correction value for the view is determined. The correction value is applied for the reference correction of the view.

Approaches for acquiring CT image data corresponding to a full scan, but at a reduced dose are disclosed. In one implementation, X-ray tube current modulation is employed to reduce the effective dose. In other implementations, acquisition of sparse views, z-collimation, and two-rotation acquisition protocols may be employed to achieve a reduced dose relative to a full-scan acquisition protocol.

A method for performing reference normalization for an image created by an imaging system. The imaging system includes a radiation detector array with a right and left edge. The method includes receiving a projection dataset created by the imaging system in response to a varying x-ray tube current. The projection dataset includes a view and predicted fluxes are calculated for the set of reference channels within the view. A right set of reference channels are located proximate at the right edge of the detector array and a left set of reference channels are located proximate to the left edge of the detector array. The method also includes calculating average actual fluxes for the sets of reference channels. Based on the predicted reference fluxes and the average fluxes, a reference correction value for the view is determined. The correction value is applied for the reference correction of the view.

There is provided a radiation tomographic imaging apparatus 100 and a radiation tomographic imaging method 200 which allows the ECG information and the X-ray tube current value to be monitored while obtaining required projection data for the image reconstruction. The radiation tomographic imaging method 200 for forming a tomographic image of a subject by means of the radiation from the radiation source 102 comprises the ECG wave output step S204 for measuring the heartbeat of the heart of the subject to output as the ECG wave signal R; a variable output step S205 for varying the radiation output based on the ECG wave signal; a determining step S209 for determining the tomographic image reconstructed based on the projection data obtained by the radiation output having been varied is good or no good; and a displaying step S210 for displaying the ECG wave signal, the radiation output, and the reconstruction data area for forming a tomographic image if the image is no good.

The invention discloses a CT (Computed Tomography) iterative image reconstruction method, which can be applied to precise sectional image reconstruction in incomplete projection data situations such as low X-ray tube current, under-sampling or limited angle. The method comprises steps of projection-driven iterative calculation, adaptively-determined ordered subset number, adaptive weight, and distance-driven orthographic projection and back projection calculation. A set of all projection data processed by each time of iterative calculation at each projection angle is firstly divided into a plurality of ordered subsets and each subset undergoes the following steps of distance-driven orthographic projection, subtraction with real projection data and weighting, distance-driven back projection and to-be-reconstructed image correction. In the scanning modes of low X-ray tube current, under-sampling or limited angle, a reconstructed image which can fully meet imaging clinical diagnosis demands can be obtained, the method can be self-sufficiently applied to CT imaging aiming at reducing the X-ray radiation dose or can be used for front-end processing of other CT image reconstruction algorithm.

The invention, which belongs to the technical field of the medical image processing, especially relates to an offline-dictionary-sparse-regularization-based CT image reconstruction method in a state of low tube current intensity scanning. A plurality of existing clear CT images of different parts are taken and are used as a sample set, an offline dictionary is trained, and offline-dictionary-based sparse representations of the CT images are used as regularization items; and under the circumstance of low tube current intensity projection, image reconstruction is carried out by using a statistic iterative reconstruction algorithm. The method has the following beneficial effects: the quality of the reconstructed image can be enhanced on the condition of low-X-ray tube current projection; and a clear reconstructed image with structural details kept can be obtained when the radiation dosage is reduced to be 10% of that of the traditional FBP algorithm or even is reduced to be lower than 10%.

The invention relates to a CT image reconstruction method under the condition that CT projection paths are reduced. The CT image reconstruction method comprises the following steps: obtaining a seriesof continuous incomplete projections through scanning in different incomplete projection modes, and obtaining a CT image sequence through reconstruction; performing CT image spatial information datarecovery and image reconstruction by using a deep convolutional neural network; in a network training process, firstly, utilizing a data set of incomplete projection for pre-training a network, then,utilizing a complete data set for carrying out large-scale iterative training on the network, and obtaining an incomplete projection CT spatial information data recovery model; and inputting the realincomplete projection CT image slice into a data recovery model to obtain a high-quality CT reconstructed image. The CT image reconstruction method is reasonable in design, can obtain the high-qualityCT reconstructed image with high contrast, high definition and good detail description, and can greatly improve the reconstruction quality of the incomplete projection CT image under the condition that the X-ray tube current is reduced and the projection path is reduced.

In a method for controlling the modulation of the tube current of an X-ray tube in the production of images using computed tomography, a single topogram of the examination subject is obtained and an orthogonal attenuation value is calculated therefrom, also making use of geometrical information associated with the position of the table on which the examination subject is disposed. In a subsequently-obtained computed tomography scan, the tube current is controlled using the orthogonal patient attenuation.

There is provided a radiation tomographic imaging apparatus and a radiation tomographic imaging method which allows the ECG information and the X-ray tube current value to be monitored while obtaining required projection data for the image reconstruction. The radiation tomographic imaging method for forming a tomographic image of a subject by means of the radiation from the radiation source comprises the ECG wave output step for measuring the heartbeat of the heart of the subject to output as the ECG wave signal; a variable output step for varying the radiation output based on the ECG wave signal; a determining step for determining the tomographic image reconstructed based on the projection data obtained by the radiation output having been varied is good or no good; and a displaying step for displaying the ECG wave signal, the radiation output, and the reconstruction data area for forming a tomographic image if the image is no good.

An X-ray CT apparatus includes: an X-ray source which emits X-rays while rotating around a subject; a compensation filter which adjusts at least one of the output distribution and the spectral distribution of the X-rays emitted from the X-ray source to the subject; an X-ray detector which is disposed opposite to the X-ray source with the subject interposed therebetween, rotates together with the X-ray source, and detects the amount of X-rays transmitted through the compensation filter and the subject; an image operation unit which reconstructs a tomographic image of the subject on the basis of the detected amount of X-rays; a display unit which displays the tomographic image; a control unit which controls each of the constituent components; and a compensation unit which compensates for deterioration of image quality, which is based on the amount of displacement between the rotation center of the X-ray source and a desired position of the subject, by changing an X-ray tube current modulation pattern indicating a time-series change of emission of the X-rays and / or by moving the position of the subject.

Methods and systems are provided for controlling an x-ray imaging system. In one embodiment, a method for an x-ray imaging system, includes acquiring, with the x-ray imaging system, a plurality of images as an x-ray tube current of the x-ray imaging system is ramping from a predefined x-ray tube current to an updated x-ray tube current, the updated x-ray tube current determined based on an estimated patient thickness estimated from a prior image acquired with the x-ray imaging system while the x-ray tube current is at the predefined x-ray tube current, combining the plurality of images into a final image, and outputting the final image for display via a display device.

The present invention relates to an apparatus for determining an effective energy spectrum of an X-ray tube. It is described to provide (210) a temporally varying acceleration voltage of an X-ray tubefor a time period. A temporally varying X-ray tube current is also provided (220) for the time period. At least one product of the temporally varying X-ray tube current and a time interval is determined (230). An effective energy spectrum of the X-ray tube is determined (250) as a function of the at least one product of the temporally varying X-ray tube current and the time interval and as a function of the voltage of the X-ray tube.

This invention is provided to determine a tube current at the imaging of the heart by an X-ray CT apparatus in such a manner that image noise becomes constant. Upon determining a tube current of an X-ray tube at the time that the heart is imaged by an X-ray CT apparatus, the tube current is determined based on an index related to image's noise and a BMI of a subject. The noise is at a central portion of an ascending main artery. Determining the tube current is conducted using a function with the BNI as a variable. The function is given in the form of a polynomial equation of the BMI. Each coefficient of the polynomial equation is a function of the index.

The present invention relates to an apparatus for determining an effective energy spectrum of an X-ray tube. It is described to provide (210) a temporally varying acceleration voltage of an X-ray tube for a time period. A temporally varying X-ray tube current is also provided (220) for the time period. At least one product of the temporally varying X-ray tube current and a time interval is determined (230). An effective energy spectrum of the X-ray tube processing the X-ray tube is determined (250) as a function of the at least one product of the temporally varying X-ray tube current and the time interval and as a function of the voltage of the X-ray tube.

A computed tomography (CT) system includes a rotatable gantry having an opening to receive an object to be scanned, a high-voltage generator, an x-ray tube positioned on the gantry to generate x-rays through the opening, a pixelated detector positioned on the gantry to receive the x-rays, and a computer. The computer is programmed to obtain a scout image of the object, calculate an equivalent diameter of a water cylinder based on the scout image over a length of the scout image, calculate a major axis and a minor axis for an equivalent ellipse over the length, calculate, based on a noise index and based on the equivalent diameter as the function of the length, an mA modulation as a function of the length, and obtain image data of the object by modulating an mA applied to the x-ray tube based on the calculated mA modulation.

The invention belongs to the technical field of industrial X ray machines, and particularly relates to a wireless integrated X ray flaw detector. The wireless integrated X ray flaw detector comprisesa controller and a generator, wherein the controller is a PDA (Personal Digital Assistant) which controls the generator by a PLC (Programmable Logic Controller) control system through a touch screen;the generator comprises a shell constructed by detachably connecting a cover plate I, a pipe barrel I, a device board, a pipe barrel II, a pipe barrel III, a pipe barrel IV and a cover plate II in sequence; through holes of unified sizes are uniformly formed in the upper part of the barrel wall of the pipe barrel I to dissipate heat; a circuit control board, a power supply and a wireless transceiver are detachably connected in the pipe barrel I; the circuit control board is used for controlling a centrifugal fan and the primary stage of a fly-back transformer, and detecting current of a pressure sensor, a temperature sensor, a temperature relay and an X ray tube; the wireless transceiver is used for receiving and transmitting a signal of the controller. The wireless integrated X ray detection machine disclosed by the invention has the advantages of high efficiency, high heat dissipation speed, insusceptibility to interference, adjustable parameters, portability and the like.