Abstract: In order to execute a high-resolution reconstructible distance-driven back projection process and to generate a high-resolution tomographic image, an X-ray CT apparatus 1 determines the presence/absence of opposing data corresponding to each piece of target data on the basis of scanning conditions, and calculates a phase range where opposing data is present (Step 21). The X-ray CT apparatus 1 performs high-resolution conversion of a zero-insertion method on a phase range where opposing data is present, and performs high-resolution conversion using a data interpolation method on a phase range where no opposing data is present, thereby creating double sampled high-resolution projection data, and calculates a view weight (Step 22). The X-ray CT apparatus 1 performs a distance-driven high-resolution back projection process using high-resolution projection data and generates a reconstructed image (Step 23).

Abstract: In order to provide an image processing device and the like making it possible to generate a target image in which edges of a structure are upheld and from which streaking artifacts are removed, a computation device determines a shape of a non-linear function on the basis of feature amounts of an original image and a smoothed image (S101). Next, the computation device calculates a condition coefficient of the original image and the smoothed image by using the non-linear function for which the shape was determined in S101 (S102). Next, the computation device uses the condition coefficients calculated in S102 to calculate a weighting coefficient for each of the pixels of the original image and the smoothed image (S103). Next, the computation device adds weighting to the original image and the smoothed image to generate the target image (S104).

Abstract: With respect to projection data covering a plurality of sites, in order to create a medical image in which a uniform noise reduction effect is achieved for all sites within the projection data, an arithmetic device (5) determines one or more of proper subsets on the basis of scanning conditions and reconstruction conditions (step 2). Next, the arithmetic device (5) calculates a penalty-term weight for each proper subset on the basis of a detector output weight corresponding to a set element contained in the proper subset (step 3). Then, the arithmetic unit (5) performs an iterative approximation by using the penalty-term weight for each proper subset (step 4).

Abstract: To provide an image reconstruction device capable of creating an image with image quality matching the operator's request when a cross-sectional image is reconstructed through a repeated calculation, the image reconstruction device which performs a repeated calculation on the basis of a difference between calculated projection data and measured projection data, the calculated projection data being obtained by performing a forward projection calculation on a reconstructed image which is reconstructed based on the measured projection data, includes an input section to which an image quality parameter which is considered to be important by an operator is input, a weight calculation section that calculates a weighting coefficient on the basis of the image quality parameter, and a repeated calculation section that performs a repeated calculation on the basis of a value obtained by weighting and adding a pixel value obtained in the previous iteration to a pixel value obtained from now using the weighting coefficien

Abstract: An X-ray CT apparatus is provided that generates a three-dimensional cross-section model from scanogram projection data of an examinee. An operator inputs a site of interest, an assumed displacement amount of the site and a desired image quality index value. A scan planning unit calculates an X-ray attenuation index from the three-dimensional cross-section model, and corrects the calculated X-ray attenuation index on the basis of the input site of interest, assumed displacement amount and image quality index value. The scan planning unit further determines a tube current modulating pattern (irradiation X-ray dose modulating pattern) on the basis of the corrected X-ray attenuation index. When scanning is executed, an X-ray tube is controlled according to the determined irradiation X-ray dose modulating pattern, and controlled so as to obtain an optimum X-ray dose.

Abstract: 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

Abstract: In order to provide a CT image forming method that can reduce an artifact caused by an image reconstructing method, and an X-ray CT apparatus using the same, an X-ray CT image forming method according to the invention is characterized in that an artifact component caused by the image reconstructing method of the projection data is obtained by calculation; the determined artifact component is subtracted from the projection data to create corrected projection data containing an inverted artifact component, and image reconstruction is executed on the corrected projection data to obtain a reconstructed image from which the artifact is reduced. The inverted artifact component is obtained as differential between the projection data and re-projection data obtained by inversely projecting a reconstructed image which is obtained by reconstructing the projection data concerned.

Abstract: In order to execute a high-resolution reconstructible distance-driven back projection process and to generate a high-resolution tomographic image, an X-ray CT apparatus 1 determines the presence/absence of opposing data corresponding to each piece of target data on the basis of scanning conditions, and calculates a phase range where opposing data is present (Step 21). The X-ray CT apparatus 1 performs high-resolution conversion of a zero-insertion method on a phase range where opposing data is present, and performs high-resolution conversion using a data interpolation method on a phase range where no opposing data is present, thereby creating double sampled high-resolution projection data, and calculates a view weight (Step 22). The X-ray CT apparatus 1 performs a distance-driven high-resolution back projection process using high-resolution projection data and generates a reconstructed image (Step 23).

Abstract: In order to provide an X-ray CT apparatus and the like that reconstruct an image using an iterative approximation method which ensures stable convergence and can be executed at high speed, a computation device 5 of an X-ray CT apparatus 1 calculates matrices A, B, D, R, and R? on the basis of the scanning conditions input through an input device 6 (step 1). Then, the computation device 5 calculates each element of a matrix I??(SBTDA+?SR) (step 2). Then, the computation device 5 calculates the operator norm ?I??(SBTDA+?SR)? of the matrix I??(SBTDA+?SR) (step 3). Then, the computation device 5 determines a relaxation coefficient ? such that a predetermined conditional expression is satisfied (step 4).

Abstract: In order to provide a technique of obtaining an image having high diagnosability without degrading the operability in an X-ray CT apparatus that suppresses the amount of exposure of an object by controlling the amount of radiation by setting a target image SD and determining the imaging conditions (tube current) satisfying the target image SD, there is provided an X-ray CT apparatus that controls the amount of radiation according to the size of an object in consideration of the contrast by simply inputting one image quality level as a reference of the image quality level that the operator desires. The input image quality level is set as a target image SD when scanning an object having a standard size with a standard tube voltage.

Abstract: There is provided a medical image processing device that enables high-precision identification of the type of a biomedical tissue and display of an identification degree with respect to medical image information in multi-energy imaging. The medical image processing device acquires tissue information (statistic amount information such as average CT value, standard deviation of CT values, etc., display color, etc.) of a biomedical tissue every energy intensity of the multi-energy imaging. The medical image processing device creates an identification map for identifying the type of the biomedical tissue on the basis of the statistic amount information, and further creates an identification probability map for determining the identification degree of the biomedical tissue on the basis of the statistic amount information and the identification map.

Abstract: In order to provide a reconstruction computing device, a reconstruction computing method, and an X-ray CT apparatus capable of improving the image quality while reducing the amount of computation when reconstructing an X-ray CT image using an iterative method, a reconstruction computing device divides an initial image 50 reconstructed using an analytical method such as an FBP method into a bed region 51, an object region 52, and the other air region 53, sets reconstruction conditions including at least convergence conditions and a pixel size for each of the divided regions, updates estimation images by performing an iterative process, and fixes estimation images or forward projection data of a subset satisfying the convergence conditions until other subsets satisfy the convergence conditions.

Abstract: There are provided an X-ray CT scan simulator and an X-ray CT apparatus in which a lesion postulated by an operator can be displayed on a simulation image and a high-precision simulation containing a postulation of occurrence of a new lesion can be performed. They comprise an image storing device for storing a reference image, a target noise value setting device for setting a target noise value of a desired image, a simulated lesion setting device for setting a condition for a simulated lesion postulated by the operator, a simulation image generating device for generating a simulation image containing a simulated lesion by using the reference image on the basis of the set target noise value and the condition for the simulated lesion, and an image display device for displaying the simulation image containing the simulated lesion.

Abstract: Provided is an X-ray CT apparatus which can perform CT scan of multi-energy scanning at a high speed and can obtain an image having an excellent substance distinguishing ability. The X-ray CT apparatus includes: means to continuously perform a first CT scanning using a first X-ray energy and a second CT scanning using a second X-ray energy without interrupting CT scan; means to transit the X-ray energy emitted from the X-ray during a transition period TR including an end of the first CT scanning and a beginning of the second CT scanning from the first X-ray energy to the second X-ray energy; and means to compensate the scan data in the transition period by the opposing data in the residual scan period so as to reconstruct an image.

Abstract: 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 modifi

Abstract: 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

Abstract: An X-ray CT apparatus comprising: a scanner unit for rotating one or more X-ray sources for applying X-ray beams having different energy spectra to an object, and detectors disposed opposed to the X-ray sources for detecting transmitted X-ray data on the object, around the object while applying X-rays, reconstructing means for reconstructing a tomogram of the object by acquiring transmitted X-ray data on the object including the two or more different energy spectra by using the scanner, and display means for displaying the reconstructed tomogram; the X-ray CT apparatus further comprising input means for inputting information on an identification tissue of the object to be identified and a separate tissue to be separated from the identification tissue from the tomogram and scanning condition determining means for determining the scanning condition for identifying the identification tissue from the tomogram. With this, an optimum scanning condition of a multi-energy X-ray CT apparatus can be determined.

Abstract: In order to provide a CT image forming method that can reduce an artifact caused by an image reconstructing method, and an X-ray CT apparatus using the same, an X-ray CT image forming method according to the invention is characterized in that an artifact component caused by the image reconstructing method of the projection data is obtained by calculation; the determined artifact component is subtracted from the projection data to create corrected projection data containing an inverted artifact component, and image reconstruction is executed on the corrected projection data to obtain a reconstructed image from which the artifact is reduced. The inverted artifact component is obtained as differential between the projection data and re-projection data obtained by inversely projecting a reconstructed image which is obtained by reconstructing the projection data concerned.

Abstract: An image processing method comprises: an inputting step of inputting image data which is obtained by imaging a subject for a predetermined period of time with a medical imaging apparatus and is arranged in time series; an extracting along the time axis step of extracting pixels which satisfy a predetermined condition along the time axis from all the pixels arranged in time series for each pixel coordinate position with respect to each pixel in the image data; and a constructing step of constructing a two-dimensional or three-dimensional image based on the pixels extracted along the time axis in the extracting along the time axis step.

Abstract: An X-ray CT apparatus acquires a scanogram of an object to be examined, generates an ellipse model having an X-ray attenuation coefficient equivalent to that of water and approximated to a tomographic image of the obtained imaged portion from the feature quantity of the projection value profile, determines whether or not the generated elliptic model is adequate as a model of the imaged portion from another feature quantity with respect to the projection value profile, generates a corrected elliptic model according to yet another feature quantity with respect to the projection value profile if the elliptic model is determined to be inadequate, and controls the modulation of the tube current in an X-ray source so that a predetermined target SD value is maintained in any scanning position when a tomographic image is reconstructed according to X-rays transmitted through the object by using the elliptic model or the corrected elliptic model.