JPS631048B2 - - Google Patents
Info
- Publication number
- JPS631048B2 JPS631048B2 JP54122064A JP12206479A JPS631048B2 JP S631048 B2 JPS631048 B2 JP S631048B2 JP 54122064 A JP54122064 A JP 54122064A JP 12206479 A JP12206479 A JP 12206479A JP S631048 B2 JPS631048 B2 JP S631048B2
- Authority
- JP
- Japan
- Prior art keywords
- detector
- ray
- radiation
- electrode
- container body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000005855 radiation Effects 0.000 claims description 27
- 238000001514 detection method Methods 0.000 claims description 17
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 claims description 9
- 238000010521 absorption reaction Methods 0.000 description 6
- 230000035945 sensitivity Effects 0.000 description 6
- 238000013480 data collection Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 239000011810 insulating material Substances 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 210000001519 tissue Anatomy 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 210000004872 soft tissue Anatomy 0.000 description 1
- 238000003325 tomography Methods 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Analysing Materials By The Use Of Radiation (AREA)
- Measurement Of Radiation (AREA)
- Apparatus For Radiation Diagnosis (AREA)
Description
【発明の詳細な説明】
本発明はコンピユーテツド・トモグラフイ装置
（以下CT装置と略称する）に使用される放射線検
出器に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation detector used in a computerized tomography device (hereinafter abbreviated as a CT device).
放射線を用いて人体の断層像を撮影する装置と
してCT装置がある。この装置は例えば第１図ａ，
ｂに示す如く偏平な扇状のフアンビームＸ線Fx
をパルス的に曝射するＸ線源１と、このＸ線を検
出する複数の放射線検出セルからなる放射線検出
器２とを被検体Ｐを挾んで対峙させ、且つこれら
Ｘ線源１及び放射線検出器２を前記被検体Ｐを中
心に互いに同方向に同一速度で回転移動させ、被
検体Ｐの断面の種々の方向に対するＸ線吸収デー
タを収集する。そして充分なデータを収集した
後、このデータを電子計算機等で解析し、被検体
断面の個々の位置に対するＸ線吸収率を算出して
その吸収率に応じた階調度で前記被検体断面の画
像を再構成したもので、組成に応じて2000段階に
も及ぶ階調度で分析できるので、軟質組織から硬
質組織に至る迄明確な断層像が得られる。 A CT device is a device that uses radiation to take tomographic images of the human body. For example, this device is shown in FIG.
Flat fan-shaped fan beam X-ray Fx as shown in b
An X-ray source 1 that emits X-rays in a pulsed manner and a radiation detector 2 consisting of a plurality of radiation detection cells that detect the X-rays are placed facing each other with the subject P in between, and these X-ray source 1 and radiation detection The instrument 2 is rotated around the subject P in the same direction and at the same speed to collect X-ray absorption data in various directions of the cross section of the subject P. After collecting sufficient data, this data is analyzed by a computer, etc., the X-ray absorption rate for each position on the cross section of the subject is calculated, and an image of the cross section of the subject is created with a gradation level corresponding to the absorption rate. It is a reconstructed image of the tissue, and can be analyzed in as many as 2,000 gradation levels depending on the composition, so clear tomographic images can be obtained from soft tissues to hard tissues.
ところで、前記放射線検出器２としては、被検
体Ｐの断面を透過したＸ線のエネルギーを電離電
流として検出し、これをＸ線吸収データとして出
力するものが知られている。 Incidentally, as the radiation detector 2, one is known that detects the energy of X-rays transmitted through a cross section of the subject P as an ionizing current and outputs this as X-ray absorption data.
即ち、このＸ線吸収データの収集に当つては電
離箱を構成する各放射線検出セルとＸ線源１とを
結ぶ直線（これを「Ｘ線パス」と称する）上を透
過して来たＸ線のエネルギーを電離電流として検
出してこれを所定の時間積分し、この積分値を所
定数の放電回路にて放電してその放電時間に対応
する値をＸ線吸収データとする。一つの角度位置
（方向）からの扇状のＸ線パスに対するデータ収
集が全て終ると次の角度位置に対するＸ線パスの
データ収集に移行するが、この間に前回のＸ線投
影による電離電流や積分値の放電等が完全に消
滅、終了していなければ次のデータ収集に誤差と
なつて表われてくる。即ち、Ｘ線ビームの曝射の
繰り返し周期は一般に放射線検出器のこれら回復
時間によつて制限を受けることになる。これは断
層像１画面当りのデータ収集時間（即ち撮影時
間）に大きな影響を及ぼす要因であり、撮影時間
の短縮を求められる今日、できる限りこれを短縮
しなければならない。また再構成画像の分解能は
放射線検出器のもつ感度、分解能で定まるため、
優れたCT装置とするには速い回復時間、高感度、
高分解能の放射線検出器を使用しなければならな
い。優れた高分解能、感度を得るためには、各放
射線検出セルを構成する電極板が放射線検出セル
の全長に亘つて互いに近接し、且つ一様に配設さ
れることが望ましい。又、高密度分解能、空間分
解能を得るためには各放射線検出セルの間隔を極
力狭くし、収集データを細分化しなければなら
ず、検出セル全体を多チヤンネル化することが必
要である。一般に、上記のような多チヤンネル検
出器に用いられる電極板は一様な厚さ（0.1〜0.2
mm程度）の矩形状のモリブデン板、或いはタング
ステン板のような重金属が使用される。そして、
その両端を所定のピツチ（0.6〜1.2mm程度）で溝
が切られている絶縁物（ガラスエポキシ板、セラ
ミツク等）のサポートに挿入することにより多チ
ヤンネル検出器が構成される。 That is, when collecting this X-ray absorption data, the X-rays that have passed through the straight line (this is called the "X-ray path") connecting each radiation detection cell that makes up the ionization chamber and the X-ray source 1 are The energy of the line is detected as an ionization current, which is integrated over a predetermined period of time, and this integrated value is discharged in a predetermined number of discharge circuits, and the value corresponding to the discharge time is used as X-ray absorption data. When all data collection for the fan-shaped X-ray path from one angular position (direction) is completed, data collection for the X-ray path for the next angular position is completed, but during this time, the ionizing current and integral value from the previous X-ray projection are If the discharge, etc. is not completely extinguished or terminated, it will appear as an error in the next data collection. That is, the repetition period of X-ray beam exposure is generally limited by the recovery time of the radiation detector. This is a factor that greatly affects the data collection time (ie, imaging time) per tomographic image, and in today's world where there is a demand for shortening imaging time, this must be shortened as much as possible. In addition, the resolution of the reconstructed image is determined by the sensitivity and resolution of the radiation detector, so
A good CT device requires fast recovery time, high sensitivity,
High-resolution radiation detectors must be used. In order to obtain excellent high resolution and sensitivity, it is desirable that the electrode plates constituting each radiation detection cell be disposed close to each other and uniformly over the entire length of the radiation detection cell. Furthermore, in order to obtain high-density resolution and spatial resolution, it is necessary to make the interval between each radiation detection cell as narrow as possible, to subdivide the collected data, and to make the entire detection cell multichannel. Generally, the electrode plates used in multi-channel detectors such as those mentioned above have a uniform thickness (0.1~0.2
Heavy metals such as rectangular molybdenum plates or tungsten plates are used. and,
A multichannel detector is constructed by inserting both ends of the detector into a support made of an insulating material (glass epoxy board, ceramic, etc.) with grooves cut at a predetermined pitch (approximately 0.6 to 1.2 mm).
第２図は多チヤンネル放射線検出器の一例を示
す斜視図であり、図中３は電極群その他を保持す
る円弧状箱形の本体、４はこの本体開口部を閉塞
する蓋である。これら本体３及び蓋４は内部に充
填される例えばXe（キセノン）ガス等の高圧ガス
に対して充分な強度及び気密を保持できるように
してある。この放射線検出器はフアンビームＸ線
Fxの広がり角θに対応して、その入射面側壁３
ａの一部３ｂを他の部分より肉薄としてＸ線エネ
ルギーが内部の電極群に充分に到達するようにし
てある。第３図は第２図のＡ−Ａ線矢視断面図で
あり、３ｃは電極群を配置するための空洞であ
る。 FIG. 2 is a perspective view showing an example of a multi-channel radiation detector. In the figure, 3 is an arcuate box-shaped main body for holding an electrode group and the like, and 4 is a lid that closes the opening of this main body. The main body 3 and the lid 4 are designed to maintain sufficient strength and airtightness against the high pressure gas such as Xe (xenon) gas filled inside. This radiation detector is a fan beam X-ray
Corresponding to the spread angle θ of Fx, the side wall 3 of the incident surface
A portion 3b of a is made thinner than other portions so that X-ray energy can sufficiently reach the internal electrode group. FIG. 3 is a sectional view taken along the line A--A in FIG. 2, and 3c is a cavity for arranging the electrode group.
第４図は信号電極或いはバイアス電極として用
いられる電極板５を示すもので、例えばタングス
テン或いはモリブデンのような重金属からなる方
形の極めて薄い導電性板体の一部に突部即ちタブ
５ａを形成している。タブ５ａは信号電極板とし
て用いるときには電離電流の取出し口として、バ
イアス電極板として用いるときには高圧印加部と
しての役割をになつている。この電極板５を上述
した本体３の空洞部３ｃに交互に信号電極及び高
圧電極として順次挿入配置していく。即ち、電極
板５は、極めて微小間隔毎に支持部材としての絶
縁物質からなるサポートの表面に形成されている
支持溝に信号電極板、バイアス電極板が交互に挿
入され、しかる後に前記検出器本体３の空洞３ｃ
に第５図の如く組み込まれる。６は前記電極板を
支持する電極サポート、７は信号電流を取り出し
て検出器外部の信号処理システムに供給するため
の信号電極板と蓋４に埋め込まれたターミナル８
とを結ぶリード線である。 FIG. 4 shows an electrode plate 5 used as a signal electrode or a bias electrode. For example, a protrusion or tab 5a is formed on a part of a rectangular, extremely thin conductive plate made of heavy metal such as tungsten or molybdenum. ing. The tab 5a serves as an ionizing current outlet when used as a signal electrode plate, and as a high voltage application portion when used as a bias electrode plate. The electrode plates 5 are sequentially inserted and arranged alternately into the cavity 3c of the main body 3 as signal electrodes and high voltage electrodes. That is, in the electrode plate 5, the signal electrode plate and the bias electrode plate are alternately inserted into support grooves formed on the surface of a support made of an insulating material as a support member at extremely minute intervals, and then the detector main body is inserted. 3 cavity 3c
It is incorporated in as shown in Fig. 5. 6 is an electrode support that supports the electrode plate; 7 is a signal electrode plate for extracting a signal current and supplying it to a signal processing system outside the detector; and a terminal 8 embedded in the lid 4;
This is the lead wire that connects the
第６図は第５図をＸ線入射方向から見た図であ
り、９は一枚おきに電極サポート６に挿入された
バイアス電極に高圧を印加するためのリード線で
ある。 FIG. 6 is a view of FIG. 5 viewed from the X-ray incident direction, and 9 is a lead wire for applying high voltage to the bias electrodes inserted into the electrode support 6 every other electrode.
ところで、CT装置におけるＸ線焦点と検出器
セル間の相対配置は非常に厳密な正確さが要求さ
れ、これが充分されない場合にはスノーリング等
のアーチフアクトとなり画質に悪影響を及ぼすこ
とになる。即ち、これは例え検出器容器内の各検
出セルが一様に配設されていたとしても容器その
ものがＸ線焦点に対し規定通りに取り付けられて
いない場合には顕著に表われる現象である。又、
逆にＸ線焦点と検出器容器は規定通り配設されて
いるが、容器内部の各検出セルが一様に配設され
ていない場合にも上記現象が生ずるものであり、
更に上記両者が競合して発生することもある。 By the way, the relative positioning between the X-ray focal point and the detector cell in a CT apparatus requires very strict accuracy, and if this is not achieved, artifacts such as snow rings will occur, which will adversely affect image quality. That is, even if the detection cells in the detector container are uniformly arranged, this phenomenon is noticeable if the container itself is not attached to the X-ray focal point in a specified manner. or,
Conversely, although the X-ray focal point and detector container are arranged as specified, the above phenomenon also occurs when the detection cells inside the container are not arranged uniformly.
Furthermore, the above two may conflict with each other.
以上のことを図面を参照して更に詳細に説明す
る。第７図はＸ線焦点と検出セル群の理想的配置
を示すものであり、セル群５の先端後端はＸ線焦
点からｒ、r′なる同心円上にあり、かつ各セル間
の角度θ1は全て一様になつている。しかるに実際
には製造上のバラツキによりセル群は第８図に示
すように同心円上に並ばず、又角度がθ2だけずれ
ることもある。又、内部セル群の配置は正常であ
るにも拘わらず検出器容器３の初期設定ミスによ
り第９図に示すようにＸ線焦点とセルとの位置関
係がずれてしまうことがある。ここで電極板の厚
さやチヤンネルピツチ等の精度を５〜10μ程度に
抑えることができれば前記位置ずれによつてアー
チフアクトが生ずるのを防止することができるわ
けであるが、そのような高精度の検出器を製造す
ることは現在技術ではとても無理である。従つ
て、検出器取付の際のＸ線焦点との相対位置の位
置決め精度を向上させることにより、前記諸問題
を回避する以外に方法はないわけである。 The above will be explained in more detail with reference to the drawings. FIG. 7 shows the ideal arrangement of the X-ray focal point and the detection cell group, in which the front and rear ends of the cell group 5 are on concentric circles r and r' from the X-ray focal point, and the angle θ between each cell is 1 are all uniform. However, in reality, due to manufacturing variations, the cell groups may not be lined up concentrically as shown in FIG. 8, or may be deviated by an angle of θ 2 . Furthermore, even though the arrangement of the internal cell group is normal, due to an error in the initial setting of the detector container 3, the positional relationship between the X-ray focus and the cells may shift as shown in FIG. 9. If the accuracy of the electrode plate thickness, channel pitch, etc. can be suppressed to about 5 to 10 μm, it is possible to prevent artifacts from occurring due to the positional deviation. It is impossible to manufacture such vessels with current technology. Therefore, there is no other way than to avoid the above-mentioned problems by improving the positioning accuracy of the relative position to the X-ray focal point when installing the detector.
本発明は前記事情に鑑みてなされたものであ
り、検出器自体に、Ｘ線焦点に対する相対位置を
補正するための微調整装置を取り付け、その調整
により各検出セルの製造上の個々のバラツキや検
出器容器自体のＸ線焦点に対する設定誤差を極力
小さくし、画質上に生ずるアーチフアクトを減少
させることを可能にした放射線検出器を提供する
ことを目的とするものである。 The present invention has been made in view of the above circumstances, and includes a fine adjustment device attached to the detector itself for correcting the position relative to the X-ray focal point, and the adjustment eliminates individual manufacturing variations of each detection cell. It is an object of the present invention to provide a radiation detector that can minimize setting errors for the X-ray focus of the detector container itself and reduce artifacts that occur in image quality.
以下実施例により本発明を具体的に説明する。 The present invention will be specifically explained below using Examples.
第１０図及び第１１図は本発明に係る放射線検
出器の一実施例を示す説明図である。図中１４は
略円筒形状を有する架台であり、その一部に放射
線検出器２が取付けられる。尚、この架台１４の
検出器取付部に対向する面には図示しないＸ線源
が取付けられる。前記放射線検出器２は、検出器
容器本体３と、検出器蓋４とからなり、内部に検
出器セル群（図示せず）が収納されている。そし
て、検出器容器本体３は、その背壁部に固着され
た軸１８を介して架台１４内に埋め込まれた摺動
可能な軸受（例えばボール軸受）１３に取付けら
れて、微小角度だけ回転することが可能に構成さ
れている。尚、この軸１８は検出器容器本体３の
中心部であつて稍上方に位置して設けられてい
る。検出器容器本体３の両側タブ部３ａ，３ａに
は上下に配設された円弧状の２個の長孔１７ａ，
１７ｂと１７ｃ，１７ｄが対称的に配設されてお
り、下方タブ部３ｂの中央部には他の円弧状の長
孔１７ｅが設けられている。そして、それら各長
孔１７ａ〜１７ｅに対応する位置の架台１４の表
面にはネジ穴が設けられており、ネジ１２ａ〜１
２ｅにより検出器容器本体３をネジ止めできるよ
うになつている。又、検出器容器本体３の両側タ
ブ部３ａ，３ａの背面には、架台１４に設けられ
た位置決めピン１５ａ，１５ｂに嵌合するガイド
用の円弧状の長溝１６ａ，１６ｂが対設されてお
り、位置決めの際の便宜が図れるようになつてい
る。ところで、前記検出器容器本体３に設けられ
た長孔１７ａ〜１７ｅのうち、側部タブ部３ａに
設けられた長孔１７ｂ，１７ｃは軸１８を中心と
する第１の円の同一周面に沿つて設けられ、他の
長孔１７ａ，１７ｃは前記第１の円よりも僅かに
径の小さな円の同一円周面に沿つて設けられ、タ
ブ部３ｂに設けられた長孔１７ｅは小径円ｄの円
周上に沿つて設けられている。又、ガイド孔１６
ａ，１６ｂは前記第２の円よりも僅かに径の小さ
な円ｅの周面に沿つて設けられている。このよう
にして検出器２が中心軸１８を中心として微小回
動できるようになる。尚、架台１４における検出
器２の配置される部分下部にはネジガイド部１９
ａ，１９ｂが対設されており、このネジガイド部
を介して調整ネジ１１ａ，１１ｂの先端が検出器
容器本体３の底部側面に当接されるようになつて
いる。 FIGS. 10 and 11 are explanatory diagrams showing one embodiment of the radiation detector according to the present invention. In the figure, reference numeral 14 denotes a pedestal having a substantially cylindrical shape, and the radiation detector 2 is attached to a part of the pedestal. Note that an X-ray source (not shown) is attached to the surface of the pedestal 14 facing the detector attachment portion. The radiation detector 2 consists of a detector container body 3 and a detector lid 4, and a detector cell group (not shown) is housed inside. The detector container body 3 is attached to a slidable bearing (for example, a ball bearing) 13 embedded in the pedestal 14 via a shaft 18 fixed to the back wall thereof, and rotates by a minute angle. It is configured to be possible. Note that this shaft 18 is located at the center of the detector container body 3 and located slightly above. Two arc-shaped elongated holes 17a are arranged vertically in the tab parts 3a, 3a on both sides of the detector container body 3.
17b, 17c, and 17d are arranged symmetrically, and another arcuate long hole 17e is provided in the center of the lower tab portion 3b. Screw holes are provided on the surface of the pedestal 14 at positions corresponding to the long holes 17a to 17e.
2e allows the detector container main body 3 to be screwed. Further, on the back surfaces of both side tab portions 3a, 3a of the detector container body 3, arc-shaped long grooves 16a, 16b for guides that fit into positioning pins 15a, 15b provided on the pedestal 14 are provided oppositely. , for convenience in positioning. By the way, among the elongated holes 17a to 17e provided in the detector container body 3, the elongated holes 17b and 17c provided in the side tab portion 3a are located on the same peripheral surface of a first circle centered on the axis 18. The other elongated holes 17a and 17c are provided along the same circumferential surface of a circle with a slightly smaller diameter than the first circle, and the elongated hole 17e provided in the tab portion 3b is provided along the same circumferential surface of a circle with a slightly smaller diameter than the first circle. It is provided along the circumference of d. Also, the guide hole 16
a and 16b are provided along the circumferential surface of a circle e having a slightly smaller diameter than the second circle. In this way, the detector 2 can be slightly rotated about the central axis 18. Note that a screw guide portion 19 is provided at the lower part of the mount 14 where the detector 2 is placed.
a and 19b are arranged opposite each other, and the tips of the adjustment screws 11a and 11b are brought into contact with the bottom side surface of the detector container body 3 via the screw guide portions.
上記構成の検出器は次のようにして取付けられ
る。先ず、検出器２を架台１４に取付ける際に
は、中心軸１８をボール軸受１３内に挿入すると
共に、ガイド溝１６ａ，１６ｂ内に位置決めピン
１５ａ，１５ｂが挿入されるようにする。そし
て、所定の位置決めをした後各長孔１７ａ〜１７
ｅを介してネジ１２ａ〜１２ｅを締め付け固定す
る。この場合、検出器２は中心軸１８を介して架
台１４上の軸受１３に取付けられるのでＸ線焦点
と検出器２の中心との間の位置決めは極めて容易
に且つ正確に行われる。次に、概略位置決めを行
つた後、実際にＸ線を曝射して検出器から所望の
データを得て、該データを基にして検出セルの感
度のバラツキ状態を判断する。そして、このバラ
ツキを最小とするような最適な位置を見付け出
し、検出器２の位置の微調整を行う。即ち、検出
器容器内の検出セル群（300〜500チヤンネル程
度）は一様にＸ線焦点を中心とする同心円上にあ
り、且つ各セルはＸ線焦点をにらんでいることが
望ましく、それが充足されないと各チヤンネル間
の感度、線量に対する出力のリニアリテイや信号
電流の立上り特性に影響を及ぼし、最終的には画
質上のアーチフアクトを生じさせることになるか
ら、セル間の製造上のバラツキ、検出器の取付け
上の誤差等を最小にするような最適な位置を見付
け出し、調整することが必要となる。この場合、
前記各ネジ１２ａ〜１２ｅ及び調整ネジ１１ａ，
１１ｂの操作により前記調整を簡単に行うことが
できる。即ち、ネジ１２ａ〜１２ｅを緩めた状態
で調整ネジ１１ａ，１１ｂを操作すれば、検出器
２は中心軸１８を中心として、時計方向、反時計
方向に自由に微少回動可能になるため、微調整が
行える。このとき、円弧状の長孔１７ａ〜１７
ｅ、ガイド溝１６ａ，１６ｂ、軸受１３は前記微
少回動を容易にするための機構として作用する。
このようにして位置決めを行なつた後、再び、各
ネジ１２ａ〜１２ｅの締付けを行い検出器２を固
定し、Ｘ線を曝射してデータを収集する。かかる
操作を繰り返すことにより最適な位置決めを行
う。従つて、例えば放射線検出器が前述第８図の
ようにセルの配置が不均衡となつていた場合で
も、そのバラツキに基づく検出感度の低下や線量
の不均衡は最小限に抑えられることになり、又前
述第９図の場合のようなＸ線焦点との間の中心位
置のずれは解消されることになる。 The detector having the above configuration is installed as follows. First, when attaching the detector 2 to the pedestal 14, the center shaft 18 is inserted into the ball bearing 13, and the positioning pins 15a, 15b are inserted into the guide grooves 16a, 16b. After the predetermined positioning, each of the long holes 17a to 17
Tighten and fix the screws 12a to 12e via e. In this case, since the detector 2 is attached to the bearing 13 on the pedestal 14 via the central shaft 18, positioning between the X-ray focal point and the center of the detector 2 can be performed extremely easily and accurately. Next, after roughly positioning, X-rays are actually irradiated to obtain desired data from the detector, and based on the data, the state of variation in sensitivity of the detection cells is determined. Then, the optimal position that minimizes this variation is found, and the position of the detector 2 is finely adjusted. That is, it is desirable that the detection cells (approximately 300 to 500 channels) in the detector container are uniformly located on a concentric circle centered on the X-ray focal point, and that each cell faces the X-ray focal point. If these conditions are not met, it will affect the sensitivity between each channel, the linearity of the output with respect to dose, and the rise characteristics of the signal current, and ultimately cause artifacts in image quality. Therefore, manufacturing variations between cells, It is necessary to find and adjust the optimal position to minimize errors in mounting the detector. in this case,
Each of the screws 12a to 12e and the adjustment screw 11a,
The above adjustment can be easily performed by operating 11b. That is, if the adjusting screws 11a and 11b are operated with the screws 12a to 12e loosened, the detector 2 can be freely slightly rotated clockwise and counterclockwise about the central axis 18. Adjustments can be made. At this time, the arc-shaped long holes 17a to 17
e, the guide grooves 16a, 16b, and the bearing 13 act as a mechanism to facilitate the minute rotation.
After positioning in this manner, the screws 12a to 12e are tightened again to fix the detector 2, and X-rays are irradiated to collect data. Optimal positioning is achieved by repeating this operation. Therefore, even if, for example, a radiation detector has an unbalanced cell arrangement as shown in Figure 8 above, the reduction in detection sensitivity and dose imbalance due to this variation will be minimized. , and the deviation of the center position between the X-ray focus and the X-ray focus as in the case of FIG. 9 described above is eliminated.
以上詳述した本発明装置によれば、検出器自体
に、Ｘ線焦点に対する相対位置を補正するための
微調整装置を取付け、その調整により各検出セル
の製造上の個々のバラツキや検出器容器自体のＸ
線焦点に対する設定誤差を極力小さくし、画質上
に生ずるアーチフアクトを減少させることが可能
なＸ線検出器を提供することができる。 According to the apparatus of the present invention described in detail above, a fine adjustment device is attached to the detector itself for correcting the relative position with respect to the X of itself
It is possible to provide an X-ray detector that can minimize setting errors for line focus and reduce artifacts that occur in image quality.
第１図ａ，ｂはCT装置の原理を説明するため
の図、第２図は従来の放射線検出器の一例を示す
斜視図、第３図はその断面図、第４図は同例にお
ける電極板の形状を示す図、第５図は同例におけ
る検出器容器とその内部に格納された電極の様子
を示す断面図、第６図は電極板支持状態の一例を
示す断面図、第７図は焦点と検出セル群の理想的
配置図、第８図は検出セル群の配列が乱れている
場合の説明図、第９図は検出器容器自体の配置が
不適当な場合の説明図、第１０図は本発明の一実
施例を示す構成図、第１１図はそのＢ−Ｂ線矢視
断面図である。
１……Ｘ線管、２……放射線検出器、３……検
出器容器本体、４……検出器蓋、１１ａ，１１ｂ
……調整ネジ、１２ａ〜１２ｅ……ネジ、１３…
…軸受、１４……架台、１５ａ，１５ｂ……位置
決めビン、１６ａ，１６ｂ……円弧状ガイド溝、
１７ａ〜１７ｅ……円弧状長孔、１８……中心
軸。
Figures 1a and b are diagrams for explaining the principle of a CT device, Figure 2 is a perspective view showing an example of a conventional radiation detector, Figure 3 is a sectional view thereof, and Figure 4 is an electrode in the same example. A diagram showing the shape of the plate, FIG. 5 is a sectional view showing the detector container and the electrodes stored inside it in the same example, FIG. 6 is a sectional view showing an example of the electrode plate support state, and FIG. 7 8 is an illustration of the ideal arrangement of the focal point and the detection cell group, FIG. 8 is an illustration of the case where the arrangement of the detection cell group is disordered, FIG. 9 is an illustration of the case where the arrangement of the detector container itself is inappropriate, and FIG. FIG. 10 is a configuration diagram showing an embodiment of the present invention, and FIG. 11 is a cross-sectional view taken along the line B--B. 1... X-ray tube, 2... Radiation detector, 3... Detector container body, 4... Detector lid, 11a, 11b
...Adjustment screws, 12a to 12e...Screws, 13...
... Bearing, 14 ... Frame, 15a, 15b ... Positioning pin, 16a, 16b ... Arc-shaped guide groove,
17a-17e...Circular long hole, 18...Central axis.
Claims (1)
複数の放射線検出セルが並設されると共に、放射
線源からの扇形状放射線を検出し得るように配設
される放射線検出器において、前記容器本体の中
心部に回動軸を設けると共に、前記容器本体の他
の部分に回動調整部材を配置することにより架台
への取付けの際の回動微調整を可能にしたことを
特徴とする放射線検出器。1. A radiation detector in which a plurality of radiation detection cells are arranged in parallel along the longitudinal direction inside an arcuate box-shaped container main body and arranged so as to be able to detect fan-shaped radiation from a radiation source. A radiation source characterized in that a rotation axis is provided in the center of the container body, and a rotation adjustment member is arranged in other parts of the container body, thereby making it possible to finely adjust the rotation when mounting on a pedestal. Detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12206479A JPS5645640A (en) | 1979-09-25 | 1979-09-25 | Radioactive ray detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12206479A JPS5645640A (en) | 1979-09-25 | 1979-09-25 | Radioactive ray detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5645640A JPS5645640A (en) | 1981-04-25 |
| JPS631048B2 true JPS631048B2 (en) | 1988-01-11 |
Family
ID=14826726
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12206479A Granted JPS5645640A (en) | 1979-09-25 | 1979-09-25 | Radioactive ray detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5645640A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015182493A1 (en) * | 2014-05-26 | 2015-12-03 | 株式会社 日立メディコ | X-ray ct apparatus |
-
1979
- 1979-09-25 JP JP12206479A patent/JPS5645640A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015182493A1 (en) * | 2014-05-26 | 2015-12-03 | 株式会社 日立メディコ | X-ray ct apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5645640A (en) | 1981-04-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20040057556A1 (en) | Method and apparatus for alignment of anti-scatter grids for computed tomography detector arrays | |
| US6370218B1 (en) | Methods and systems for determining x-ray beam position in multi-slice computed tomography scanners | |
| US7564940B2 (en) | Radiation mask for two dimensional CT detector | |
| US5583903A (en) | Computed tomography apparatus | |
| JP3381223B2 (en) | Electronically enhanced X-ray detector | |
| US6652143B2 (en) | Method and apparatus for measuring the position, shape, size and intensity distribution of the effective focal spot of an x-ray tube | |
| KR100271904B1 (en) | Pre-calibration device and method of X-ray tube focus | |
| US5125012A (en) | Computer tomography apparatus | |
| JPS63501735A (en) | Improved X-ray attenuation method and device | |
| JPH05192324A (en) | Computerized tomographic device having fan beam position controlling and correcting function | |
| GB1602521A (en) | Arrangement for producing an image of a body section using gamma or x-radiation | |
| Gottschalk et al. | SPECT resolution and uniformity improvements by noncircular orbit | |
| US6898269B2 (en) | Methods and apparatus for x-ray images | |
| JPH09224929A (en) | Twin-beam ct scanner | |
| GB2049237A (en) | Device for determining local absorption differences in an object | |
| JP6307268B2 (en) | Collimator for use in CT system | |
| US6169778B1 (en) | Computed tomography device | |
| JPS631048B2 (en) | ||
| US20020165686A1 (en) | Method for correcting calibration values in a calibration table of a computed tomography apparatus | |
| US4476390A (en) | Radiation detector having radiation source position detecting means | |
| US4457009A (en) | Device for determining local absorption differences in an object | |
| US5303459A (en) | Method for manufacturing precisely focused collimator | |
| US4881251A (en) | Computed tomograph apparatus | |
| US7101078B1 (en) | Methods and systems for imaging system radiation source alignment | |
| JPH11244275A (en) | X-ray ct scanner |