JP4474779B2 - X-ray CT system - Google Patents

Description

【００２５】
上記のように重み付けを行って目的スライス＃ｎに隣接するスライスの信号データを目的スライス＃ｎに反映させることでアーティファクト抽出用画像を生成する。これによりアーティファクト抽出用画像におけるアーティファクト成分を含んだ信号成分が最大で２．５倍になる。その一方で（ランダム）ノイズ成分は１／√２．５となる。したがって、隣接スライスを反映させた目的スライス＃ｎのアーティファクト抽出用画像における信号データは、Ｓ／Ｎ比が最大で√２．５倍になる。
【００２６】
ステップＳ３
目的スライス＃ｎを対象にしてアーティファクト除去を施す。
上記の処理によって目的スライス＃ｎのアーティファクト抽出用画像はＳ／Ｎ比が最大で√２．５倍に改善されているので、アーティファクト成分が浮き出しており、十分にアーティファクト成分を除去することが可能となっている。
【００２７】
具体的には、アーティファクト抽出用画像からアーティファクト成分を抽出した後に、上記のようにしてアーティファクト抽出用画像を求めた際に反映させた重み付けを考慮する。つまり、上記の説明では、アーティファクト抽出用画像に元の２．５倍の画像成分が含まれているので、アーティファクト成分をその倍率で除算する。そして、このアーティファクト成分を目的スライス＃ｎから差し引くことにより、目的スライス＃ｎからアーティファクト成分が十分に除去される。
【００２８】
ステップＳ４
上記のようにして十分にアーティファクト成分を除去した目的スライス＃ｎの信号データを対象にしてスライス像の再構成を行う。
【００２９】
ステップＳ５
再構成した目的スライス＃ｎのスライス像をモニタ２１に出力して表示させる。このようにして表示された目的スライス＃ｎのスライス像は、上述した各処理によって高品質の画質となっている。
【００３０】
なお、上記の例では目的スライス＃ｎの前後に隣接する２スライス分の信号データを反映させるようにしたが、１スライス分だけにしてもよく、また３スライス分あるいはそれ以上のスライスを反映させるようにしてもよい。
【００３１】
＜第２実施例＞
上記の実施例では目的スライス＃ｎの前後のスライスを反映させたが、この実施例では、目的スライスよりも時間的に前のスライスだけを反映させる点において異なる。
【００３２】
この実施例について図４を参照して説明する。なお、図４は目的スライス＃ｎの前に位置するスライスだけを反映させる例の説明に供する模式図である。
【００３３】
上述した実施例のようにして関心部位を対象にして複数枚のスライスが撮影され、目的スライス＃ｎまでが撮影されたものとする。
【００３４】
そして、上述したステップＳ２では、例えば、目的スライス＃ｎの前に位置する２スライス分の信号データを目的スライス＃ｎに対して反映させるものとする。つまり、スライス＃ｎ−１，＃ｎ−２の信号データを目的スライス＃ｎに反映させる。
【００３５】
例えば、目的スライス＃ｎの重みを１とした場合には、前のスライスごとに次のような相対的な重み付けを行う。
【００３６】

【００３７】
上記のように重み付けを行って目的スライス＃ｎのアーティファクト抽出用画像を生成することで、目的スライス＃ｎにおけるアーティファクト成分を含んだ信号成分が最大で１．７５倍になる。その一方で（ランダム）ノイズ成分は１／√１．７５となる。したがって、前に位置するスライスを反映させた目的スライス＃ｎのアーティファクト抽出用画像における信号データは、Ｓ／Ｎ比が最大で√１．７５倍になる。
【００３８】
この例によると上述した第１実施例の場合に比べてＳ／Ｎ比の改善度合いが低くなるが、既に収集してあるスライス＃ｎ−１，＃ｎ−２，＃ｎだけを対象にして信号データを反映させるので、目的スライス＃ｎの信号データが収集された時点で処理を行うことができる。したがって、目的スライス＃ｎよりも時間的に後ろに位置するスライスについての信号データの収集を待つ必要がないので、目的スライス＃ｎの撮像が終了した時点で迅速にスライス像の再構成及び表示を行うことができる特徴を有する。
【００３９】
なお、上記の例では目的スライス＃ｎの前に位置する２スライス分の信号データを反映させるようにしたが、１スライス分だけにしてもよく、また３スライス分あるいはそれ以上のスライスを反映させるようにしてもよい。
【００４０】
また、この実施例は、Ｘ線管３とＸ線検出アレイ７の１回転につき薄いスライスを１枚しか収集することができないシングルスライスのＸ線ＣＴ装置において特に有用となる。
【００４１】
＜第３実施例＞
上記各実施例では、スライスの位置関係に応じて信号データを反映させたが、この実施例では関心部位の形状による信号データ強度の相関性をも考慮する。
【００４２】
この実施例について図５を参照して説明する。図５は、スライスの位置に応じて信号データを反映させるとともに、信号強度を考慮する例の説明に供する模式図である。
【００４３】
まず、上記の各実施例で説明したようにして関心部位ＲＯＩを対象にして複数枚のスライスから信号データを収集する。なお、ここでは、関心部位ＲＯＩの形状が図５に示すようなものとして説明する。
【００４４】
次に、目的スライスと隣接するスライスとの位置関係だけでなく、それらの間における信号データの強度の相関性を考慮して隣接するスライスの信号データを目的スライスに反映させる。
【００４５】
なお、各スライスを符号＃１〜＃３で示した場合、関心部位ＲＯＩのボリュームから各スライス＃１〜＃３の信号データ強度の比率が次のようなものであったとして説明する。
【００４６】
スライス＃１ ０．２
スライス＃２ １．０
スライス＃３ １．３
【００４７】
中心に位置しているスライス＃２を目的スライスとした場合には、例えば、次のように信号強度の相関性に基づく係数を求める。
【００４８】
スライスの信号データ ≦ 目的スライスの信号データ である場合
係数 ＝ （スライスの信号データ／目的スライスの信号データ）×基本係数
【００４９】
スライスの信号データ ＞ 目的スライスの信号データ である場合
係数 ＝ （目的スライスの信号データ／スライスの信号データ）×基本係数
【００５０】
ここで、基本係数とは、目的スライスとスライスとの位置関係によって決まる値であり、上述した各実施例に基づいて決定すればよい。
【００５１】
各スライス＃１〜＃３の信号データの比率が上述した値の場合には、各スライスの係数は次のようになる。なお、基本係数はスライス＃１，＃３を０．８とし、目的スライス＃ｎを１．０とする。
【００５２】
スライス＃１の係数 ＝ （０．２／１．０）×０．８ ＝ ０．１６
スライス＃２の係数 ＝ （１．０／１．０）×１．０ ＝ １．０
スライス＃３の係数 ＝ （１．０／１．３）×０．８ ＝ ０．６１５
【００５３】
このようにスライス＃３は、スライス＃１に比べて係数が大きくなっており、目的スライス＃２に対する位置関係だけでなく、関心部位ＲＯＩの形状に基づく信号データ強度の相関性が考慮されている。これらの係数を各スライス＃１，＃３に適用して、目的スライス＃２のアーティファクト抽出用画像を対象にしてアーティファクト除去を施すことにより、スライスの位置に応じた相関性に加えて関心部位ＲＯＩのボリュームに基づく信号データ強度についての相関性をも考慮してＳ／Ｎ比が改善される。
【００５４】
この実施例では、関心部位ＲＯＩのボリュームが各スライスで大きく異なっている場合、例えば、脳幹などの場合であっても、信号データ強度の相関をも考慮することによってアーティファクト除去処理で十分にアーティファクト成分を除去可能である。
【００５５】
なお、上記の説明においては、Ｘ線を爆射して信号データを収集する際に天板１を移動させるか固定したままかについては特に説明しなかったが、この発明は固定したままであっても移動しながら収集するスパイラル手法であっても適用可能である。
【００５６】
【発明の効果】
以上の説明から明らかなように、請求項１に記載の発明によれば、目的スライスに隣接する各スライスに対応する信号データを、スライス位置に応じた重み付けにより目的スライスに対する位置に応じて加算してアーティファクト抽出用データを生成し、これから抽出されたアーティファクト成分に基づきアーティファクト除去処理を行うことで目的スライスのＳ／Ｎ比を向上できる。したがって、アーティファクト成分が信号成分に埋もれることがなく、アーティファクト除去処理で目的スライスから十分にアーティファクト成分を除去することができる。したがって、目的スライスを再構成して得られるスライス像の画質を向上することができる。
【００５７】
また、請求項２に記載の発明によれば、既に収集してあるスライスだけを対象にして各スライスの位置に応じて信号データを加算するので、目的スライスの信号データが収集された時点で処理を行うことができる。したがって、目的スライスよりも時間的に後ろに位置するスライスについての信号データの収集を待つ必要がないので、迅速にスライス像の再構成及び表示を行うことができる。
【００５８】
また、請求項３に記載の発明によれば、目的スライスに近いほど相関が強くなるので重み付けを大きくし、目的スライスから離れるほど相関が弱くなるので重み付けを小さくして信号データを加算することにより、アーティファクト抽出用画像のアーティファクト成分を十分に抽出できる。
【００５９】
また、請求項４に記載の発明によれば、関心部位のボリュームがスライスごとに大きく異なっている場合であっても、信号データ強度の相関を考慮することによってアーティファクト除去処理で十分にアーティファクト成分を除去することができる。
【図面の簡単な説明】
【図１】Ｘ線ＣＴ装置の概略構成を示すブロック図である。
【図２】目的スライスの前後のスライスを反映させる例の説明に供する模式図である。
【図３】処理の流れを示したフローチャートである。
【図４】目的スライスの前のスライスだけを反映させる例の説明に供する模式図である。
【図５】信号強度をも考慮する例の説明に供する模式図である。
【符号の説明】
１ … 天板
Ｍ … 被検体
３ … Ｘ線管
７ … Ｘ線検出アレイ
９ … 回動部
１１ … 操作制御部
１３ … 高圧制御部
１５ … ＤＡＳ
１７ … データメモリ
１９ … データ処理部
２１ … モニタ
＃ｎ … 目的スライス[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an X-ray CT apparatus for imaging a slice image based on signal data collected from a region of interest, and more particularly to a technique for obtaining a slice image in which artifact components are suppressed.
[0002]
[Prior art]
Conventionally, in this type of X-ray CT apparatus, an artifact component is extracted based only on signal data of a slice to be imaged, and after removing the component, a slice image is reconstructed from the signal data. It is imaged.
[0003]
[Problems to be solved by the invention]
However, the conventional example having such a configuration has the following problems.
That is, especially when each slice is thin in a multi-slice, the S / N ratio of the signal data in each slice is poor, and thus the artifact component is buried in the noise component. Therefore, there is a problem that even if the artifact removal processing is performed, the artifact component cannot be sufficiently removed. Therefore, when a slice image is reconstructed, the image quality including artifacts is low.
[0004]
Note that when the slice is thin, the S / N ratio of the signal data itself is poor. Therefore, even when the slice image of the signal data itself is reconstructed, the degree of conspicuous artifacts is relatively small. However, when the signal data of slices located before and after the slice are simply added during display processing, the S / N ratio is improved, so that the artifact component buried in the noise component rises due to reconstruction. As a result, artifacts become conspicuous in the slice image.
[0005]
The present invention has been made in view of such circumstances, and by performing the artifact removal processing after improving the S / N ratio, the artifact component of the target slice can be sufficiently removed and the slice image can be reduced. An object of the present invention is to provide an X-ray CT apparatus capable of improving image quality.
[0006]
[Means for Solving the Problems]
In order to achieve such an object, the present invention has the following configuration.
That is, according to the first aspect of the present invention, in an X-ray CT apparatus that images a slice image based on signal data collected from a region of interest, the slice to be imaged is a target slice, and each slice adjacent to the target slice is used. a signal data corresponding to the scan, adds the signal data object slice to generate artifacts extracted data by weighting according to the slice location, extracting the artifact component from the artifact extraction data, object based on the artifact component Image processing means is provided for performing slice image reconstruction processing on a target slice after performing artifact removal processing on the slice.
[0007]
Further, the invention according to claim 2, in X-ray CT apparatus according to claim 1, wherein the image processing means includes a feature that you added only signal data of a slice that is already collected on the purpose slices To do.
[0008]
According to a third aspect of the present invention, in the X-ray CT apparatus according to the first or second aspect, the image processing means reduces the weight as the position of each adjacent slice moves away from the target slice. the signal data of the slice in which characterized that you added to the object slice.
[0009]
According to a fourth aspect of the present invention, in the X-ray CT apparatus according to the first or second aspect, the image processing means further provides a correlation between the intensity of the signal data of the target slice and the signal data of each slice. in view is the signal data of each slice in which characterized that you added to the object slice.
[0010]
[Action]
The operation of the first aspect of the invention is as follows.
That is, the signal data corresponding to each slice adjacent to the object slice, since there is a strong correlation in response to the position for the objective-slice artifact extracted data by adding the signal data of each slice by weighted according to the slice location Is generated. Based on the artifact component extracted from the artifact extraction data, a process for removing the artifact component from the target slice is performed to improve the S / N ratio of the target slice.
[0011]
Further, according to the invention described in claim 2, among the slices adjacent to the object slice, Runode be added signal data in response to only the slices have already been collected to the subject position of each slice, object Processing can be performed when signal data of the slice is collected.
[0012]
Further, according to the invention described in claim 3, by increasing the weighting the correlation closer to the purpose slice becomes stronger, it is summed signal data by reducing the weighting because the correlation farther from the target slice becomes weak.
[0013]
According to the fourth aspect of the present invention, when the volume of the region of interest is greatly different for each slice, the intensity of the signal data changes abruptly between the slices. Although it may not be sufficiently improved S / N ratio when you sum signal data in accordance with only the position of each slice for purposes slices in this state, such a disadvantage by further considering the correlation of the signal data strength Can be eliminated.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to one embodiment of the present invention.
[0015]
The top plate 1 is used to place the subject M and is made of a material that transmits X-rays. Above the top plate 1, an X-ray tube 3 that is attached to an inner periphery of a gantry (not shown) and emits an X-ray fan beam (shown by a dotted line in the drawing) is disposed. In addition, an X-ray detection array 7 in which a large number of X-ray detection elements 5 are arranged in an arc shape is provided at a position opposite to the X-ray tube 3 with the top plate 1 interposed therebetween. The X-ray tube 3 and the X-ray detection array 7 are rotated around the body axis Z of the subject M by the rotating unit 9 while maintaining the opposed arrangement state.
[0016]
The rotation unit 9 is controlled via the operation control unit 11. The operation control unit 11 also controls the high-pressure control unit 13 that adjusts the X-ray intensity of the X-ray tube 3 and the like. X-rays that have received explosive X-rays from the X-ray tube 3 and transmitted through the subject M are detected by the X-ray detection array 7 and then collected by a DAS (data collection unit) 15.
[0017]
The data memory 17 stores the signals collected by the DAS 15 as signal data associated with different explosion angles. When the data collection and storage are completed, the data processing unit 19 generates an artifact extraction image by reflecting the signal data of the adjacent slice with respect to the target slice that is a target of displaying the slice image, and from this, the artifact component To extract artifacts from the target slice. Next, the slice image is displayed on the monitor 21 after the target slice is reconstructed.
[0018]
The method of reflecting the slice signal data in the data processing unit 19 described above includes the following forms.
[0019]
<First embodiment>
FIG. 2 is a schematic diagram for explaining an example in which slices before and after the target slice are reflected, and FIG. 3 is a flowchart showing the processing flow.
[0020]
It is assumed that a plurality of slices are imaged for a region of interest by the X-ray CT apparatus having the above configuration, and each slice is positioned as shown in FIG. Here, the slice to be imaged is set as the target slice #n, and the slices positioned before (collected earlier) are set as codes # n-1, # n-2, and # n-3, and thereafter Positioned slices are denoted by codes # n + 1, # n + 2, and # n + 3.
[0021]
Step S1
First, as described above, the X-ray tube 3 and the X-ray detection array 7 are rotated around the body axis Z of the subject M by the rotating unit 9 while being opposed to each other. As a result, signal data of a plurality of slices for the region of interest are collected and sequentially stored in the data memory 17.
[0022]
Step S2
The signal data of the adjacent slice is reflected with respect to the target slice #n.
For example, when the signal data of two slices positioned before and after the target slice #n are reflected in the target slice #n, the slices # n−1 and # n−2 adjacent to the target slice #n at the previous position. Then, the signal data of the adjacent slices # n + 1 and # n + 2 at the rear position are reflected.
[0023]
Specifically, the closer the slice to the target slice #n, the stronger the correlation, so that the weighting is increased, and the correlation is weaker as the distance increases. For example, when the weight of the target slice #n is 1, the following relative weighting is performed for each of the preceding and succeeding slices.
[0024]

[0025]
The artifact extraction image is generated by weighting as described above and reflecting the signal data of the slice adjacent to the target slice #n to the target slice #n. As a result, the signal component including the artifact component in the artifact extraction image becomes 2.5 times as much as possible. On the other hand, the (random) noise component is 1 / √2.5. Therefore, the signal data in the artifact extraction image of the target slice #n reflecting the adjacent slice has a maximum S / N ratio of √2.5.
[0026]
Step S3
Artifact removal is performed on the target slice #n.
As a result of the above processing, the artifact extraction image of the target slice #n has been improved to a maximum S / N ratio of √2.5 times, so that the artifact component is raised and the artifact component can be sufficiently removed. It has become.
[0027]
Specifically, after the artifact component is extracted from the artifact extraction image, the weight reflected when the artifact extraction image is obtained as described above is considered. In other words, in the above description, since the artifact extraction image includes the original image component of 2.5 times, the artifact component is divided by the magnification. Then, by subtracting this artifact component from the target slice #n, the artifact component is sufficiently removed from the target slice #n.
[0028]
Step S4
The slice image is reconstructed with respect to the signal data of the target slice #n from which the artifact component has been sufficiently removed as described above.
[0029]
Step S5
The slice image of the reconstructed target slice #n is output to the monitor 21 and displayed. The slice image of the target slice #n displayed in this way has high quality image quality by the above-described processes.
[0030]
In the above example, the signal data for two adjacent slices before and after the target slice #n is reflected. However, only one slice may be reflected, or three slices or more may be reflected. You may do it.
[0031]
<Second embodiment>
In the above embodiment, the slices before and after the target slice #n are reflected, but this embodiment is different in that only the slice preceding the target slice is reflected in time.
[0032]
This embodiment will be described with reference to FIG. FIG. 4 is a schematic diagram for explaining an example in which only the slice located before the target slice #n is reflected.
[0033]
Assume that a plurality of slices are imaged for the region of interest as in the above-described embodiment, and up to the target slice #n.
[0034]
In step S2 described above, for example, signal data for two slices positioned before the target slice #n is reflected on the target slice #n. That is, the signal data of slices # n-1 and # n-2 are reflected in the target slice #n.
[0035]
For example, when the weight of the target slice #n is 1, the following relative weighting is performed for each previous slice.
[0036]

[0037]
By performing the weighting as described above to generate the artifact extraction image of the target slice #n, the signal component including the artifact component in the target slice #n becomes 1.75 times at the maximum. On the other hand, the (random) noise component is 1 / √1.75. Therefore, the signal data in the artifact extraction image of the target slice #n reflecting the previous slice has a maximum S / N ratio of √1.75 times.
[0038]
According to this example, the degree of improvement in the S / N ratio is lower than in the case of the first embodiment described above, but only slices # n-1, # n-2, #n that have already been collected are targeted. Since the signal data is reflected, the processing can be performed when the signal data of the target slice #n is collected. Therefore, there is no need to wait for signal data collection for a slice located behind the target slice #n, so that the slice image can be quickly reconstructed and displayed when imaging of the target slice #n is completed. It has features that can be done.
[0039]
In the above example, the signal data for two slices positioned before the target slice #n is reflected. However, only one slice may be reflected, or three slices or more slices are reflected. You may do it.
[0040]
This embodiment is particularly useful in a single slice X-ray CT apparatus that can collect only one thin slice per rotation of the X-ray tube 3 and the X-ray detection array 7.
[0041]
<Third embodiment>
In each of the above embodiments, the signal data is reflected according to the positional relationship of the slices. However, in this embodiment, the correlation of the signal data intensity depending on the shape of the region of interest is also considered.
[0042]
This embodiment will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining an example in which signal data is reflected in accordance with the position of a slice and signal strength is taken into consideration.
[0043]
First, as described in each of the above embodiments, signal data is collected from a plurality of slices for the region of interest ROI. Here, description will be made assuming that the shape of the region of interest ROI is as shown in FIG.
[0044]
Next, not only the positional relationship between the target slice and the adjacent slice, but also the signal data of the adjacent slice is reflected in the target slice in consideration of the correlation of the intensity of the signal data between them.
[0045]
In addition, when each slice is denoted by reference numerals # 1 to # 3, it is assumed that the ratio of the signal data intensity of each slice # 1 to # 3 from the volume of the region of interest ROI is as follows.
[0046]
Slice # 1 0.2
Slice # 2 1.0
Slice # 3 1.3
[0047]
When the slice # 2 located at the center is the target slice, for example, a coefficient based on the correlation of the signal strength is obtained as follows.
[0048]
When the signal data of the slice is equal to or less than the signal data of the target slice, coefficient = (slice signal data / target slice signal data) × basic coefficient
If the signal data of the slice> the signal data of the target slice, coefficient = (target slice signal data / slice signal data) x basic coefficient
Here, the basic coefficient is a value determined by the positional relationship between the target slice and the slice, and may be determined based on the above-described embodiments.
[0051]
When the ratio of the signal data of each slice # 1 to # 3 is the value described above, the coefficient of each slice is as follows. The basic coefficients are 0.8 for slices # 1 and # 3 and 1.0 for target slice #n.
[0052]
Coefficient of slice # 1 = (0.2 / 1.0) × 0.8 = 0.16
Coefficient of slice # 2 = (1.0 / 1.0) × 1.0 = 1.0
Coefficient of slice # 3 = (1.0 / 1.3) × 0.8 = 0.615
[0053]
Thus, slice # 3 has a larger coefficient than slice # 1 and takes into account not only the positional relationship with target slice # 2 but also the correlation of signal data intensity based on the shape of the region of interest ROI. . By applying these coefficients to the slices # 1 and # 3 and performing artifact removal on the artifact extraction image of the target slice # 2, the region of interest ROI in addition to the correlation according to the position of the slice The S / N ratio is improved in consideration of the correlation with respect to the signal data intensity based on the volume.
[0054]
In this embodiment, when the volume of the region of interest ROI is greatly different in each slice, for example, in the case of the brainstem, the artifact component can be sufficiently obtained by the artifact removal processing by considering the correlation of the signal data intensity. Can be removed.
[0055]
In the above description, there is no particular explanation as to whether the top plate 1 is moved or fixed when the signal data is collected by blasting X-rays. However, the present invention remains fixed. Even a spiral method of collecting while moving is applicable.
[0056]
【The invention's effect】
As apparent from the above description, according to the invention described in claim 1, adds the signal data corresponding to each slice adjacent to the object slice, depending on the position for the objective-slice by weighted according to the slice location Thus, the artifact extraction data is generated, and the artifact removal processing is performed based on the artifact component extracted therefrom, whereby the S / N ratio of the target slice can be improved. Therefore, the artifact component is not buried in the signal component, and the artifact component can be sufficiently removed from the target slice by the artifact removal processing. Therefore, the image quality of the slice image obtained by reconstructing the target slice can be improved.
[0057]
Further, according to the invention described in claim 2, Runode be added signal data in accordance with the previously collected and Aru slices only in the target position of each slice, when the signal data of interest slices have been collected Processing can be performed. Therefore, there is no need to wait for signal data collection for a slice located behind the target slice in time, so that the slice image can be quickly reconstructed and displayed.
[0058]
Further, according to the invention described in claim 3, by increasing the weighting the correlation closer to the purpose slice becomes stronger, to add the smaller to the signal data weighting the correlation is weakened with increasing distance from the target slice Rukoto Thus, the artifact component of the artifact extraction image can be sufficiently extracted.
[0059]
According to the fourth aspect of the present invention, even if the volume of the region of interest is greatly different for each slice, the artifact component can be sufficiently removed by the artifact removal processing by considering the correlation of the signal data intensity. Can be removed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an X-ray CT apparatus.
FIG. 2 is a schematic diagram for explaining an example in which slices before and after a target slice are reflected.
FIG. 3 is a flowchart showing a flow of processing.
FIG. 4 is a schematic diagram for explaining an example in which only the slice before the target slice is reflected;
FIG. 5 is a schematic diagram for explaining an example in which signal intensity is also considered.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Top plate M ... Subject 3 ... X-ray tube 7 ... X-ray detection array 9 ... Turning part 11 ... Operation control part 13 ... High-pressure control part 15 ... DAS
17 ... Data memory 19 ... Data processing unit 21 ... Monitor #n ... Target slice

Claims (4)

In X-ray CT apparatus for imaging a slice image based on the signal data collected from the site of interest, a slice to be imaged for the purpose slices, the signal data corresponding to each slice adjacent to the object slice, the slice position by adding the signal data object slice to generate artifacts extracted data by corresponding weighting, extract the artifact component from the artifact extraction data, from performing artifact removal process for the target slices based on the artifact component An X-ray CT apparatus comprising image processing means for performing slice image reconstruction processing on a target slice. In X-ray CT apparatus according to claim 1, wherein the image processing means, X-ray CT apparatus characterized that you added to the object slice only signal data slices have already been collected. In X-ray CT apparatus according to claim 1 or 2, wherein the image processing means, the position of each slice adjacent to decrease the weight increasing distance from the target slice, you add the signal data of each slice in the object slice An X-ray CT apparatus characterized by that. 3. The X-ray CT apparatus according to claim 1, wherein the image processing unit further considers the correlation of the intensity between the signal data of the target slice and the signal data of each slice, and outputs the signal data of each slice. X-ray CT apparatus characterized that you added to the slice.

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