JPH0520708B2 - - Google Patents
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- Publication number
- JPH0520708B2 JPH0520708B2 JP29567086A JP29567086A JPH0520708B2 JP H0520708 B2 JPH0520708 B2 JP H0520708B2 JP 29567086 A JP29567086 A JP 29567086A JP 29567086 A JP29567086 A JP 29567086A JP H0520708 B2 JPH0520708 B2 JP H0520708B2
- Authority
- JP
- Japan
- Prior art keywords
- output
- timing signal
- event
- detection circuit
- signal
- 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 - Fee Related
Links
- 238000001514 detection method Methods 0.000 claims description 18
- 230000005855 radiation Effects 0.000 claims description 16
- 238000000034 method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 238000004020 luminiscence type Methods 0.000 description 1
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- Measurement Of Radiation (AREA)
- Nuclear Medicine (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は放射線入射位置検出回路に係わり、特
に真の単一発光事象が発生したときのみタイミン
グ信号とアドレス信号の両方を出力することので
きる放射線入射位置検出回路に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a radiation incident position detection circuit, and in particular is capable of outputting both a timing signal and an address signal only when a true single light emission event occurs. This invention relates to a radiation incident position detection circuit.
一般にポジトロンCTにおいては、検出器を環
状に配置し、検出器内の発光体の同時発光事象を
観測している。この同時発光事象の判定において
は、回路数の省略のために、検出器をいくつかの
グループに分け、各グループ同士の同時発光事象
を観測する方法がとられている。１つのグループ
からは発光事象情報、即ちタイミング信号と、発
光した検出器を同定する情報、即ちアドレス信号
とが出力される。グループ内での同時発光が生じ
た場合は、誤情報を生ずることとなるので、信号
の出力を棄却しなければならないが、このグルー
プ内の同時発光事象の判定にはパリテイチエツカ
を用いる方式がとられていた。
Generally, in positron CT, detectors are arranged in a ring, and simultaneous light emission events of light emitters within the detectors are observed. In determining this simultaneous light emission event, in order to reduce the number of circuits, a method is used in which the detectors are divided into several groups and the simultaneous light emission event between each group is observed. One group outputs light emission event information, ie, a timing signal, and information identifying the detector that emitted light, ie, an address signal. If simultaneous light emission occurs within a group, erroneous information will be generated, so the output of the signal must be rejected, but a method that uses a parity checker is used to determine simultaneous light emission events within a group. was.
しかしながら、パリテイチエツカを用いる方式
では同時発光事象が偶数か奇数かの判定しかして
おらず、例えば同時に三つ事象が発生した場合に
は、あたかも単一事象であるかの如く処理してし
まうという問題が生じる。また、タイミング信号
とアドレス信号を別経路から取り出す回路構成の
ものにおいては、タイミング信号は複数の検出器
の出力の和から取り出されるために、例えばグル
ープ内の二つの検出器で棄却すべき小さな発光が
それぞれ同時に生じた時に、アドレス情報が無い
のにタイミング信号が出力されてしまうという場
合が起こり、このことは、またタイミング信号取
り出し系とアドレス信号取り出し系における信号
弁別のためのスレツシヨールドレベルが異つて設
定されることによつても生ずる。
However, the method using parity checker only determines whether simultaneous light emission events are even or odd, and there is a problem that, for example, when three events occur at the same time, they are processed as if they were a single event. arise. In addition, in circuit configurations in which the timing signal and address signal are extracted from separate routes, the timing signal is extracted from the sum of the outputs of multiple detectors, so for example, small emitted light that should be rejected by two detectors in a group. When these occur at the same time, a timing signal may be output even though there is no address information. This also causes the threshold level for signal discrimination in the timing signal extraction system and address signal extraction system to be It also occurs when the values are set differently.
本発明は上記問題点を解決するためのもので、
複数個の放射線検出器を１グループとした複数グ
ループからなる放射線入射位置検出回路におい
て、１つのグループ内で真の単一事象が発生した
ときのみ、タイミング信号とアドレス信号の両方
を出力することのできる放射線入射位置検出回路
を提供することを目的とする。 The present invention is intended to solve the above problems,
In a radiation incident position detection circuit consisting of multiple groups of radiation detectors, it is possible to output both a timing signal and an address signal only when a true single event occurs within one group. The purpose of the present invention is to provide a radiation incident position detection circuit that can detect radiation incident positions.
そのために本発明の放射線入射位置検出回路
は、光電子増倍管に発光体を結合させた複数個の
放射線検出器を１グループとした複数グループか
らなる放射線入射位置検出回路において、各グル
ープ内での単一発光事象を判別する単一事象判別
回路と、各検出器出力の加算値が入力されるタイ
ミング信号検出回路と、タイミング信号検出回路
出力と単一事象判別回路出力とが同時に入力され
たときのみタイミング信号を出力するタイミング
信号ゲート回路と、単一事象判別回路出力が加え
られ事象発生の入力信号に対応したアドレス信号
を作成するエンコーダとを備えたことを特徴とす
る。
For this purpose, the radiation incidence position detection circuit of the present invention is a radiation incidence position detection circuit consisting of a plurality of groups each including a plurality of radiation detectors in which a photomultiplier tube is coupled with a light emitter. When a single event discrimination circuit that discriminates a single light emission event, a timing signal detection circuit into which the sum of the outputs of each detector is input, and a timing signal detection circuit output and a single event discrimination circuit output are input at the same time. The present invention is characterized in that it includes a timing signal gate circuit that outputs a single timing signal, and an encoder that is added with the output of a single event discriminator circuit and creates an address signal corresponding to an input signal indicating the occurrence of an event.
（作用）
本発明の放射線入射位置検出回路は、光電子増
倍管に発光体を結合させた複数個の放射線検出器
を１つのグループとし、１つのグループにおける
単一発光事象であることの判定と、発光事象のア
ドレス信号の作成とを同時に行い、単一事象でな
い場合はその出力を出させないようにして、１つ
のグループ内で真の単一事象が発生したときの
み、タイミング信号とアドレス信号の両方を出力
することができる。(Function) The radiation incident position detection circuit of the present invention groups a plurality of radiation detectors each having a photomultiplier coupled with a light emitting body, and detects a single light emission event in one group. , the generation of the address signal for the light emitting event is performed at the same time, and the output is not output unless it is a single event, and the timing signal and address signal are generated only when a true single event occurs within one group. Both can be output.
以下、実施例を図面に基づき説明する。 Examples will be described below based on the drawings.
第１図は本発明の放射線入射位置検出回路の一
実施例を示す図で、タイミング信号とアドレス信
号を別系路から取り出す検出器構成の例である。
図中、１1〜１4はシンチレータ、２1〜２4は光電
子増倍管、３は加算器、４はタイミング信号検出
回路、５1〜５4はエネルギ弁別回路、６は単一事
象判別回路、７1〜７4は反転非反転出力素子、８
１〜８4はアンドゲート、９はオアゲート、１０は
タイミング信号ゲート回路、１１はエンコーダ、
１２，１３はオアゲートである。 FIG. 1 is a diagram showing an embodiment of the radiation incident position detection circuit of the present invention, and is an example of a detector configuration in which a timing signal and an address signal are extracted from separate paths.
In the figure, 1 1 to 1 4 are scintillators, 2 1 to 2 4 are photomultiplier tubes, 3 is an adder, 4 is a timing signal detection circuit, 5 1 to 5 4 are energy discrimination circuits, and 6 is a single event discrimination circuit. circuit, 7 1 to 7 4 are inverting and non-inverting output elements, 8
1 to 8 4 is an AND gate, 9 is an OR gate, 10 is a timing signal gate circuit, 11 is an encoder,
12 and 13 are or gates.
図において、シンチレータ１1〜１4にγ線が入
射するとシンチレーシヨン光を生じ、その光は光
電子増倍管２1〜２4で光電変換されて増巾され
る。光電子増倍管のアノード出力は加算器３で加
算され、タイミング信号検出回路４でタイミング
信号が抽出される。一方、ダイノード信号はエネ
ルギー弁別回路５1〜５4に入力され、波高弁別さ
れて所定レベル以上であれば出力が得られる。こ
うして波高弁別されて得られた検出出力は、単一
事象判別回路６に加えられる。この単一事象判別
回路６は、出力ありを「１」、出力なしを「０」
としたとき、エネルギー弁別回路５1〜５4の出力
が、（１，０，０，０），（０，１，０，０），（０，
０，１，０），（０，０，０，１）のときのみアン
ドゲート８1，８2，８3，８4の出力はそれぞれ
「１」となり、それ以外の場合は「０」となるの
で、シンチレータ１1〜１4のどれか１つがシンチ
レーシヨン光を生じたことを判別し、単一事象発
生時のみ事象発生の入力信号に対応した出力信号
が生ずる。 In the figure, when γ rays are incident on scintillators 1 1 to 1 4 , scintillation light is generated, and the light is photoelectrically converted and amplified by photomultiplier tubes 2 1 to 2 4 . The anode outputs of the photomultiplier tubes are added by an adder 3, and a timing signal is extracted by a timing signal detection circuit 4. On the other hand, the dynode signals are input to energy discrimination circuits 5 1 to 5 4 and subjected to wave height discrimination, and if the signal is at a predetermined level or higher, an output is obtained. The detection output obtained by the pulse height discrimination in this manner is applied to the single event discrimination circuit 6. This single event discrimination circuit 6 indicates "1" if there is an output, and "0" if there is no output.
When the outputs of the energy discrimination circuits 5 1 to 5 4 are (1, 0, 0, 0), (0, 1, 0, 0), (0,
0, 1, 0), (0, 0, 0, 1), the outputs of AND gates 8 1 , 8 2 , 8 3 , 8 4 are respectively "1", and otherwise they are "0". Therefore, it is determined that any one of the scintillators 1 1 to 1 4 has generated scintillation light, and an output signal corresponding to the input signal of event occurrence is generated only when a single event occurs.
次にこの出力は、エンコーダ部１１に加えられ
る。エンコーダ部１１では、単一事象判別回路の
アンドゲート８1〜８4の（１，０，０，０），
（０，１，０，０），（０，０，１，０），（０，０，
０，１）出力に対応して（０，０），（１，０），
（０，１），（１，１）を出力し、検出器アドレス
信号を作成する。そして、オアゲート９の出力と
タイミング信号とのANDをとることにより単一
事象発生時以外でのタイミング信号、即ち誤タイ
ミング信号を出力させないようにする。 This output is then applied to the encoder section 11. In the encoder unit 11, the AND gates 81 to 84 of the single event discrimination circuit (1,0,0,0),
(0,1,0,0),(0,0,1,0),(0,0,
0,1) corresponding to the output (0,0), (1,0),
(0,1), (1,1) are output to create a detector address signal. By ANDing the output of the OR gate 9 and the timing signal, a timing signal other than when a single event occurs, that is, an erroneous timing signal is prevented from being output.
以上の実施例においては、各PMTのアノード
出力信号を加算してタイミング信号を取り出し、
また各PMTのダイノード信号を用いてアドレス
信号を取り出しているが、勿論、各アノード信
号、ダイノード信号どちらか一方を用いて、同様
にタイミング信号、アドレス信号をす取り出すこ
とも可能である。また検出器数は前述のように４
つに限定されるものではなく、これと異なる検出
器数の場合に適用することも勿論可能である。 In the above embodiment, the timing signal is extracted by adding the anode output signals of each PMT,
Further, although the address signal is extracted using the dynode signal of each PMT, it is of course possible to similarly extract the timing signal and address signal using either each anode signal or the dynode signal. Also, the number of detectors is 4 as mentioned above.
The present invention is not limited to this, and it is of course possible to apply the number of detectors to a different number.
以上のように本発明によれば、光電子増倍管に
発光体を結合させた複数個の放射線検出器を１つ
のグループとし、１つのグループ内で生じた単一
発光事象であることの判定と、発光事象のアドレ
ス信号の作成とを同時に行い、単一発光事象でな
い場合はその出力を出させないようにして、１つ
のグループ内の真の単一事象が発生したときの
み、タイミング信号とアドレス信号の両方を出力
することが可能となり、ポジトロンCT等の検出
器からの誤情報を無くすことができ、その結果断
層像のノイズを減らすことが可能となる。
As described above, according to the present invention, a plurality of radiation detectors each having a photomultiplier tube coupled to a luminescent material are grouped into one group, and a single luminescence event occurring within one group can be determined. , the generation of the address signal for the light emitting event is performed at the same time, and the output is not output unless it is a single light emitting event, and the timing signal and address signal are generated only when a true single event in one group occurs. This makes it possible to output both, eliminating false information from detectors such as positron CT, and as a result, reducing noise in tomographic images.
第１図は本発明による放射線入射位置検出回路
の一実施例を示す図である。
１1〜１4…シンチレータ、２1〜２4…光電子増
倍管、３…加算器、４…タイミング信号検出回
路、５1〜５4…エネルギ弁別回路、６…単一事象
判別回路、７1〜７4…反転非反転出力素子、８1
〜８4…アンドゲート、９…オアゲート、１０…
タイミング信号ゲート回路、１１…エンコーダ、
１２，１３…オアゲート。
FIG. 1 is a diagram showing an embodiment of a radiation incident position detection circuit according to the present invention. 1 1 - 1 4 ... scintillator, 2 1 - 2 4 ... photomultiplier tube, 3 ... adder, 4 ... timing signal detection circuit, 5 1 - 5 4 ... energy discrimination circuit, 6 ... single event discrimination circuit, 7 1 to 7 4 ...Inverting non-inverting output element, 8 1
~8 4 ...and gate, 9...or gate, 10...
timing signal gate circuit, 11...encoder,
12, 13...or gate.
Claims (1)
放射線検出器を１グループとした複数グループか
らなる放射線入射位置検出回路において、各グル
ープ内での単一発光事象を判別する単一事象判別
回路と、各検出器出力の加算値が入力されるタイ
ミング信号検出回路と、タイミング信号検出回路
出力と単一事象判別回路出力とが同時に入力され
たときのみタイミング信号を出力するタイミング
信号ゲート回路と、単一事象判別回路出力が加え
られ、事象発生の入力信号に対応したアドレス信
号を作成するエンコーダとを備えたことを特徴と
する放射線入射位置検出回路。1 Single-event discrimination that discriminates a single light-emission event within each group in a radiation incident position detection circuit consisting of multiple groups of radiation detectors each having a photomultiplier tube coupled to a light-emitting body a timing signal detection circuit to which a sum value of each detector output is input; and a timing signal gate circuit to output a timing signal only when the timing signal detection circuit output and the single event discriminating circuit output are input simultaneously. , and an encoder to which a single event discrimination circuit output is added and creates an address signal corresponding to an input signal of event occurrence.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29567086A JPS63148185A (en) | 1986-12-11 | 1986-12-11 | Detecting circuit for radiation incidence position |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29567086A JPS63148185A (en) | 1986-12-11 | 1986-12-11 | Detecting circuit for radiation incidence position |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63148185A JPS63148185A (en) | 1988-06-21 |
| JPH0520708B2 true JPH0520708B2 (en) | 1993-03-22 |
Family
ID=17823663
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29567086A Granted JPS63148185A (en) | 1986-12-11 | 1986-12-11 | Detecting circuit for radiation incidence position |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63148185A (en) |
-
1986
- 1986-12-11 JP JP29567086A patent/JPS63148185A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63148185A (en) | 1988-06-21 |
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