JPH0348492B2 - - Google Patents
Info
- Publication number
- JPH0348492B2 JPH0348492B2 JP54141124A JP14112479A JPH0348492B2 JP H0348492 B2 JPH0348492 B2 JP H0348492B2 JP 54141124 A JP54141124 A JP 54141124A JP 14112479 A JP14112479 A JP 14112479A JP H0348492 B2 JPH0348492 B2 JP H0348492B2
- Authority
- JP
- Japan
- Prior art keywords
- radiation image
- excitation light
- image information
- general formula
- image conversion
- 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 - Lifetime
Links
- 230000005855 radiation Effects 0.000 claims description 76
- 230000005284 excitation Effects 0.000 claims description 43
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 33
- 238000006243 chemical reaction Methods 0.000 claims description 29
- 229910052771 Terbium Inorganic materials 0.000 claims description 6
- 238000004020 luminiscence type Methods 0.000 claims description 6
- 229910052693 Europium Inorganic materials 0.000 claims description 5
- 229910052791 calcium Inorganic materials 0.000 claims description 5
- 229910052749 magnesium Inorganic materials 0.000 claims description 5
- 229910052712 strontium Inorganic materials 0.000 claims description 5
- 229910052725 zinc Inorganic materials 0.000 claims description 5
- 229910052684 Cerium Inorganic materials 0.000 claims description 3
- 229910052691 Erbium Inorganic materials 0.000 claims description 3
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 3
- 229910052689 Holmium Inorganic materials 0.000 claims description 3
- 229910052779 Neodymium Inorganic materials 0.000 claims description 3
- 229910052775 Thulium Inorganic materials 0.000 claims description 3
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims description 3
- 229910052745 lead Inorganic materials 0.000 claims description 3
- 229910052716 thallium Inorganic materials 0.000 claims description 3
- 229910052727 yttrium Inorganic materials 0.000 claims description 3
- 229910052793 cadmium Inorganic materials 0.000 claims description 2
- 238000000034 method Methods 0.000 claims description 2
- 230000001443 photoexcitation Effects 0.000 claims 1
- 206010036618 Premenstrual syndrome Diseases 0.000 description 12
- 230000007423 decrease Effects 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 150000002910 rare earth metals Chemical class 0.000 description 2
- 230000000638 stimulation Effects 0.000 description 2
- 229920002284 Cellulose triacetate Polymers 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 1
- QKYBEKAEVQPNIN-UHFFFAOYSA-N barium(2+);oxido(oxo)alumane Chemical class [Ba+2].[O-][Al]=O.[O-][Al]=O QKYBEKAEVQPNIN-UHFFFAOYSA-N 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 150000004696 coordination complex Chemical class 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 229910052914 metal silicate Inorganic materials 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
- G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
- G01N23/043—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using fluoroscopic examination, with visual observation or video transmission of fluoroscopic images
Description
【発明の詳細な説明】
本発明は被写体を透過した放射線を吸収した特
定組成の輝尽性螢光体に励起光を照射して、その
時に発光した輝尽光の光量を走査して測定するこ
とにより、輝尽性螢光体に記録されている放射線
画像情報を読み取る読取装置に関するものであ
る。[Detailed Description of the Invention] The present invention involves irradiating excitation light onto a photostimulable phosphor of a specific composition that has absorbed radiation transmitted through an object, and scanning and measuring the amount of photostimulated light emitted at that time. In particular, the present invention relates to a reading device for reading radiation image information recorded on a photostimulable phosphor.
ある種の螢光体は放射線の照射を受けると、吸
収した放射線のエネルギーの一部を蓄積し、この
螢光体に後で特定波長の可視光または赤外線等の
励起光を照射すれば吸収した放射線エネルギーに
比例した量の螢光（輝尽光）を発する（この種の
螢光体を以下「輝尽性螢光体」という）。この輝
尽性螢光体をシート状に成型したパネル（以下
「放射線像変換パネル」という）に人体等の被写
体を透過した放射線を吸収させて該パネルの螢光
体層上に被写体の放射線画像をいつたん蓄積記録
し、その後これをレーザー等の励起光で走査して
その時発光した光を適当な光検出器で読み取り、
この読み取つた画像情報を電気信号に変換してか
ら再び写真フイルムやCRT等の記録媒体に放射
線画線として記録再生するようにした放射線画像
形成装置が知られている（米国特許第3859527
号）。 When a certain type of phosphor is irradiated with radiation, it stores some of the energy of the absorbed radiation, and if this phosphor is later irradiated with excitation light such as visible light or infrared light of a specific wavelength, it can be absorbed. It emits fluorescent light (photostimulable light) in an amount proportional to radiation energy (this type of fluorescent material is hereinafter referred to as a "photostimulable fluorescent material"). A panel (hereinafter referred to as a "radiation image conversion panel") in which this photostimulable phosphor is molded into a sheet form absorbs radiation that has passed through a subject such as a human body, and a radiation image of the subject is printed on the phosphor layer of the panel. is accumulated and recorded, and then scanned with excitation light such as a laser and the light emitted at that time is read with an appropriate photodetector.
A radiation image forming apparatus is known that converts the read image information into electrical signals and then records and reproduces them as radiation images on a recording medium such as photographic film or CRT (U.S. Pat. No. 3,859,527).
issue).
上述の放射線画像形成装置においては放射線像
変換パネルの螢光体層上を、スポツト状の励起光
で走査して該パネルに蓄積記録されている放射線
画像情報を該励起光のスポツト径に相当する大き
さの画素に分解して時系列化して輝尽光として取
り出し、これを例えば光電子増倍管（以下「P.
M.T.」と略称する）、ホトダイオード等の光検出
器で受光して電気的信号に変換し、CRTや光走
査装置に送り、ここで各画素からの画像情報を合
成して、被写体の放射線画像を再生するのである
が、この時、放射線像変換パネルから放出された
輝尽光を受光するに際して、前記光検出器として
P.M.T.を使用した場合、その出力信号としては
該輝尽光の光子信号数の時間平均値に対応する
量、即ち時間平均の直流電流値として検出し、こ
れを高増幅度の直流増幅器で増幅し、輝尽光強度
に比例した電圧に変換し、この電圧を更にＡ−Ｄ
変換器によつてデジタル化し、これを一旦磁気テ
ープ等の記憶装置に記憶させておいて、必要に応
じて逆にＤ−Ａ変換し、再生装置に入力して放射
線像を再生することが一般に行なわれている。 In the above-mentioned radiation image forming apparatus, the phosphor layer of the radiation image conversion panel is scanned with spot-shaped excitation light, and the radiation image information stored and recorded on the panel is converted to the radiation image information corresponding to the spot diameter of the excitation light. The photomultiplier tube (hereinafter referred to as "P.
(abbreviated as "MT"), the light is received by a photodetector such as a photodiode, converted into an electrical signal, and sent to a CRT or optical scanning device, where the image information from each pixel is combined to create a radiation image of the subject. At this time, when receiving the stimulated light emitted from the radiation image conversion panel, the photodetector
When a PMT is used, the output signal is detected as a time-averaged DC current value corresponding to the time-averaged number of photon signals of the stimulated light, and this is amplified with a high-amplification DC amplifier. , convert it into a voltage proportional to the photostimulated light intensity, and further convert this voltage into A-D
Generally, the radiographic image is digitized by a converter, stored in a storage device such as a magnetic tape, and converted back to D-A if necessary, and then input to a reproduction device to reproduce the radiographic image. It is being done.
しかしながら上述の放射線画像情報読取装置に
おいては、放射線像変換パネルに記録された放射
線画像情報の読み取り時間を短縮させるために励
起光の走査速度を出来るだけ早めることが要請さ
れ、また得られた放射線画像の鮮鋭度を高めるた
めに励起光スポツト径を出来るだけ小さくし、か
つ励起光が放射線像変換パネルの螢光体層に照射
された時、励起光が螢光体層内で拡散しないよう
に螢光体層を出来るだけ薄くしたり、螢光体層を
着色剤で着色したりすることが要請される。とこ
ろがP.M.T.の出力信号を入力光子信号数の時間
平均値に対応した光電流値として測定するいわゆ
る直流増幅回路を設けた従来の放射線画像情報読
取装置の場合、放射線像変換パネルからの輝尽光
を時間平均の直流電流値として検出しているた
め、P.M.T.の暗電流等のノイズもこの中に含ま
れる結果、励起光のスポツト径を小さくしたり、
励起光の走査速度を早めたり、放射線像変換パネ
ルの螢光体層を薄くすると、各画素毎の発光量が
著しく減少して輝尽光による光電流とP.M.T.の
暗電流との識別が困難となり、光量子の統計的変
動成分が大きくなるため、Ｓ／Ｎ比が低下する
上、励起光の走査速度を余り早くすると各画素毎
の光情報に対し充分に追随できなくなる。また、
逆に増幅器の応答を早くするために帯域幅の広い
増幅器を使用すると増幅率が低下してやはりＳ／
Ｎ比が低下するので微小光の測定が困難となり、
放射線像変換パネルの螢光体層の厚みは余り薄く
できない上、励起光の走査時間が短縮できないと
いう欠点を有していた。 However, in the above-mentioned radiation image information reading device, in order to shorten the reading time of the radiation image information recorded on the radiation image conversion panel, it is required to increase the scanning speed of the excitation light as much as possible. The diameter of the excitation light spot is made as small as possible in order to increase the sharpness of the image, and when the excitation light is irradiated onto the phosphor layer of the radiation image conversion panel, the phosphor layer is made so that the excitation light does not diffuse within the phosphor layer. It is required to make the phosphor layer as thin as possible or to color the phosphor layer with a coloring agent. However, in the case of a conventional radiation image information reading device equipped with a so-called DC amplifier circuit that measures the output signal of the PMT as a photocurrent value corresponding to the time average value of the number of input photon signals, the stimulated light from the radiation image conversion panel is Since it is detected as a time-averaged DC current value, noise such as PMT dark current is included in this value, so it is necessary to reduce the spot diameter of the excitation light.
When the scanning speed of excitation light is increased or the phosphor layer of the radiation image conversion panel is made thinner, the amount of light emitted by each pixel decreases significantly, making it difficult to distinguish between the photocurrent due to stimulated light and the dark current of PMT. Since the statistical fluctuation component of the light quantum becomes large, the S/N ratio decreases, and if the scanning speed of the excitation light is made too fast, it becomes impossible to sufficiently follow the optical information of each pixel. Also,
Conversely, if an amplifier with a wide bandwidth is used to speed up the amplifier response, the amplification factor will decrease and the S/
As the N ratio decreases, it becomes difficult to measure small amounts of light.
The thickness of the phosphor layer of the radiation image conversion panel cannot be made very thin, and the scanning time of the excitation light cannot be shortened.
本発明は上記欠点に鑑みてなされたものであ
り、輝尽性螢光体を螢光膜とする放射線像変換パ
ネルを用いた放射線画像情報読取装置において放
射線画像読取時間を短縮して、しかもＳ／Ｎ比の
向上した、高鮮鋭度の放射線画像が得られる放射
線画像情報読取装置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-mentioned drawbacks, and it is possible to shorten the radiation image reading time in a radiation image information reading device using a radiation image conversion panel having a stimulable phosphor as a fluorescent film, and to reduce the It is an object of the present invention to provide a radiation image information reading device that can obtain radiation images with high sharpness and improved /N ratio.
本発明の放射線画像情報読取装置は、下記の特
定組成の輝尽性螢光体からなる放射線像変換パネ
ルに励起光を照射する励起光源と、上記放射線像
変換パネルから放出された輝尽発光光を検出する
光電子増倍管と、該光電子増倍管の陽極で生じた
電流パルスを増幅する交流増幅器と、該交流増幅
器の出力パルスの中から上記光電子増倍管の暗電
流並びに雑音に対応する電流パルスを除去して上
記輝尽発光光に対応する光電流パルスのみを出力
するデイスクリミネーターと、上記光電流パルス
を計数するパルスカウンターと、このパルスカウ
ンターからのデジタル信号を一旦記憶する記憶装
置とを有し、上記放射線像変換パネルに被写体を
透過した放射線を吸収せしめ、しかる後に該パネ
ルを上記励起光源から発する励起光で走査してこ
れに蓄積されている放射線画像情報を輝尽発光光
として放出させ、この輝尽発光光の光子パルス信
号に対応して上記光電子増倍管の陽極に発生する
陽極電流パルスを直接計数して上記放射線画像情
報をデジタル信号として取り出すことを特徴とす
る。 The radiation image information reading device of the present invention includes an excitation light source that irradiates excitation light to a radiation image conversion panel made of a photostimulable phosphor having the following specific composition, and stimulated luminescence light emitted from the radiation image conversion panel. an AC amplifier that amplifies the current pulse generated at the anode of the photomultiplier tube; and a photomultiplier tube that detects the dark current and noise of the photomultiplier tube from among the output pulses of the AC amplifier. a discriminator that removes current pulses and outputs only photocurrent pulses corresponding to the stimulated luminescent light; a pulse counter that counts the photocurrent pulses; and a storage device that temporarily stores digital signals from the pulse counter. The radiation image conversion panel absorbs the radiation transmitted through the subject, and then the panel is scanned with excitation light emitted from the excitation light source to convert the radiation image information stored therein into stimulated luminescence light. The radiation image information is extracted as a digital signal by directly counting the anode current pulse generated at the anode of the photomultiplier tube in response to the photon pulse signal of the stimulated luminescent light.
下記一般式（）〜（）で表わされる蛍光体
群、即ち、
一般式（Ba1-xMx〓）FX：yＡ …（）
（但しM〓はMg、Ca，Sr，ZnおよびCdのうち
の少なくとも１つを、ＸはCl，BrおよびＩのう
ちの少なくとも１つを、ＡはEu，Tb，Ce，Tm，
Dy，Pr，Ho，Nd，Yb及びErのうちの少なくと
も１つを、ｘ及びｙは０ｘ0.6及び０ｙ
0.2なる条件を満たす数字を表わす）、
一般式LnOX：ZA …（）
（但しLnはLa，Ｙ，Gd及びLuの少なくとも
１つを、ＸはCl及び／又はBrを、ＡはCe及び／
又はTbを、Ｚは０＜Ｚ＜0.1を満足する数字を表
わす）、
一般式BaO・mAl2O3：Eu …（）
（但し0.8ｍ10なる条件を満たす数字を表
わす）および
一般式M′O・nSiO2：A′ …（）
（但しM′はMg，Ca，Sr，Zn又はBa，A′は
Ce，Tb，Eu，Tm，Pb，Tl，Bi，Mnの内の少
なくとも１つ、0.5ｎ2.5なる条件を満たす数
字を表わす）
から選ばれる少なくとも１種。 The group of phosphors represented by the following general formulas () to (), that is, the general formula ( Ba 1-x M X is at least one of Cl, Br and I, A is Eu, Tb, Ce, Tm,
At least one of Dy, Pr, Ho, Nd, Yb and Er, x and y are 0x0.6 and 0y
0.2), general formula LnOX:ZA...() (However, Ln represents at least one of La, Y, Gd and Lu, X represents Cl and/or Br, and A represents Ce and/or
or Tb, Z represents a number satisfying 0<Z<0.1), general formula BaO・mAl 2 O 3 :Eu...() (however, represents a number satisfying the condition of 0.8m10), and general formula M'O・nSiO 2 :A′ …() (However, M′ is Mg, Ca, Sr, Zn or Ba, A′ is
At least one of Ce, Tb, Eu, Tm, Pb, Tl, Bi, Mn, representing a number satisfying the condition 0.5n2.5).
本発明の放射線画像情報読取装置は、特に輝尽
発光輝度の高い上記特定組成の輝尽性螢光体から
なる放射線像変換パネルを用いると共に輝尽発光
光の光子の数を直接計数してデジタル信号とする
ものであるから、P.M.T.の出力信号を直流増幅
回路を通してアナログ信号として取り出してから
Ａ−Ｄ変換器によりデジタル信号に変換した場合
に比べ、感度を大幅に向上させることができる。
したがつて、放射線像変換パネルの螢光体層を薄
くし、かつ、励起光のスポツト径を小さくしても
十分なＳ／Ｎ比が得られるため、より鮮鋭度の高
い画像が得られる。更に本発明の放射線画像情報
読取装置によると、励起光の走査速度を従来のも
のより早めても同様に鮮鋭度の高い画像が得られ
る。 The radiation image information reading device of the present invention uses a radiation image conversion panel made of a photostimulable phosphor having the above-mentioned specific composition that has particularly high photostimulated luminance, and directly counts the number of photons of stimulated luminescence light to digitalize it. Since it is a signal, the sensitivity can be significantly improved compared to the case where the output signal of the PMT is extracted as an analog signal through a DC amplifier circuit and then converted into a digital signal by an AD converter.
Therefore, even if the phosphor layer of the radiation image conversion panel is made thinner and the spot diameter of the excitation light is made smaller, a sufficient S/N ratio can be obtained, and an image with higher sharpness can be obtained. Further, according to the radiation image information reading device of the present invention, an image with high sharpness can be obtained even if the scanning speed of the excitation light is made faster than that of the conventional device.
以下、本発明を、その実施態様に基いて詳細に
説明する。 Hereinafter, the present invention will be explained in detail based on its embodiments.
第１図は本発明の放射線画像情報読取装置の一
例を示したもので放射線画像が蓄積記録された放
射線像変換パネル１１を回転自在なドラム１０に
装着し、この上に励起光源１２から励起光を照射
する。励起光はハーフミラー１３を透過して放射
線像変換パネル１１に入射する。励起光源として
はレーザー光を用いるのが好ましいがタングステ
ンランプを用いピンホールを通して光束をしぼ
り、レンズで集光したスポツト状の光を放射線像
変換パネル１１に入射させても良い。励起光のス
ポツト径は小さい程、得られる放射線画像の解像
力を高めることができるがレーザー光を用いた場
合でも50μφ以下まで絞ることは困難なため、50
〜100μφとするのが好ましい。励起光の波長は用
いられる輝尽性螢光体によつて変わるが操作性、
励起効率等を考慮すると600〜700nmの波長の光
源が望ましい。上記の励起光源１２で放射線像変
換パネル１１の螢光体層を照射し、ドラム１０を
回転させながらドラムの回転軸に平行な方向へ励
起光を走査してゆく。この励起光で励起された螢
光体は蓄積されているエネルギーを輝尽光として
放出する。この輝尽による発光光はハーフミラー
１３で反射され、レンズ１４によつて、励起光等
の反射光をカツトするフイルター１５を透過して
P.M.T.16に集められ、電気信号に変換される。 FIG. 1 shows an example of the radiation image information reading device of the present invention, in which a radiation image conversion panel 11 on which radiation images are stored and recorded is mounted on a rotatable drum 10, and an excitation light source 12 is applied onto the radiation image conversion panel 11. irradiate. The excitation light passes through the half mirror 13 and enters the radiation image conversion panel 11 . Although it is preferable to use a laser beam as the excitation light source, it is also possible to use a tungsten lamp, narrow the light beam through a pinhole, and make the spot-shaped light focused by a lens incident on the radiation image conversion panel 11. The smaller the spot diameter of the excitation light, the higher the resolution of the obtained radiographic image, but even when using a laser beam, it is difficult to narrow down the spot diameter to less than 50 μφ.
It is preferable to set it to 100μφ. The wavelength of the excitation light varies depending on the photostimulable phosphor used, but the operability and
Considering excitation efficiency, etc., a light source with a wavelength of 600 to 700 nm is desirable. The phosphor layer of the radiation image conversion panel 11 is irradiated with the excitation light source 12, and the excitation light is scanned in a direction parallel to the rotation axis of the drum while rotating the drum 10. The phosphor excited by this excitation light releases the stored energy as photostimulated light. The emitted light due to this stimulation is reflected by the half mirror 13, and transmitted through the filter 15 that cuts reflected light such as excitation light by the lens 14.
It is collected by PMT16 and converted into an electrical signal.
第２図は本発明の放射線画像情報読取装置のブ
ロツクダイアグラムを示したものであるが、上述
のごとく放射線画像情報が記録された放射線像変
換パネル１１から放射された輝尽による発光光
は、P.M.T.16に入射し、P.M.T.16からはその光
子信号に対応した光電流パルスが出力される。こ
の時、P.M.T.の陽極で生じた光電流パルスはそ
の振幅に関して一定の分布を持つており、特にP.
M.T.自体での暗電流に帰因する電流パルスとは、
その振幅が異なつているのでこれらP.M.T.の暗
電流も含んだP.M.T.からの出力信号は交流増幅
器１７を通して増幅した後、デイスクリミネータ
ー１８を通して振幅の大小によつてP.M.T.の暗
電流等のノイズを除去した後、純粋の光電流パル
スのみを取り出し、パルスカウンター１９に導い
て更に表示装置２０に入力するか、ここで得られ
たデジタル信号を一旦記憶装置２１に入力し、磁
気テープ等の記録媒体に記録した後、必要に応じ
て再びＤ−Ａ変換し、写真フイルム露光装置に入
力し、写真フイルム上に放射線画像を再生した
り、CRT等の再生装置に入力して再生画像を得
る。なお放射線画像情報の読み取りに要する時間
は短いほどより好ましいのであるが、銀塩を利用
した放射線写真システムにおいて汎用の撮影済み
フイルムの自動現像機の場合、速いもので90秒を
要していることを考慮すると、本発明の放射線画
像情報読取装置においても少なくとも90秒以内で
読取を完了することが望ましいが、例えば40cm×
40cmの放射線像変換パネルに記録された画像情報
を90秒で読み取る場合、励起光のスポツト径を
50μφとしたとき、6.7×107個に分解した画素を90
秒で走査することになるので、１画素当りの走査
時間は約1.3μsecとなる。従つてこれに追随させ
るためには約1MHzの速いパルスを検出しなけれ
ばならないため、前記の交流増幅器としてはその
帯域増幅が１ないし10MHzの広帯域幅を有する増
幅器を用いる。このように広帯域幅の増幅器を用
いることによつて励起光の走査速度を上げても空
間周波数の高い画像情報をも忠実に伝達すること
ができ、最終的に、従来の直流増幅法によるより
も鮮鋭度の高い画像が得られる。 FIG. 2 shows a block diagram of the radiation image information reading device of the present invention. As mentioned above, the emitted light due to stimulation emitted from the radiation image conversion panel 11 on which radiation image information is recorded is PMT16. The PMT 16 outputs a photocurrent pulse corresponding to the photon signal. At this time, the photocurrent pulse generated at the anode of the PMT has a certain distribution in terms of its amplitude, especially the P.
The current pulse resulting from the dark current in the MT itself is
Since the amplitudes are different, the output signals from the PMTs, including the dark currents of these PMTs, are amplified through an AC amplifier 17 and then passed through a discriminator 18 to remove noise such as the dark currents of the PMTs depending on the magnitude of the amplitude. After that, only the pure photocurrent pulse is taken out, guided to the pulse counter 19 and further inputted to the display device 20, or the digital signal obtained here is once inputted to the storage device 21 and recorded on a recording medium such as a magnetic tape. After that, if necessary, the data is DA-converted again and inputted into a photographic film exposure device to reproduce the radiation image on the photographic film, or inputted into a reproducing device such as a CRT to obtain a reproduced image. The shorter the time required to read radiation image information, the better; however, in the case of a general-purpose automatic developing machine for photographed film in a radiographic system using silver salts, it takes 90 seconds at the fastest. Considering this, it is desirable that the radiation image information reading device of the present invention completes reading within at least 90 seconds.
When reading image information recorded on a 40cm radiation image conversion panel in 90 seconds, the spot diameter of the excitation light should be
When 50μφ, the pixels divided into 6.7×10 7 are 90
Since scanning is performed in seconds, the scanning time per pixel is approximately 1.3 μsec. Therefore, in order to follow this, it is necessary to detect a fast pulse of about 1 MHz, and therefore, as the AC amplifier, an amplifier having a wide bandwidth of 1 to 10 MHz is used. In this way, by using a wide-bandwidth amplifier, image information with high spatial frequencies can be transmitted with high fidelity even when the scanning speed of the excitation light is increased, and ultimately, it is possible to transmit image information with high spatial frequency more faithfully than with conventional DC amplification methods. Images with high sharpness can be obtained.
本発明の放射線像変換パネル１１は第３図に示
したごとく例えばポリエチレンテレフタレートフ
イルム、三酢酸セルロース等の支持体１上に平均
粒子径が10μのBaFCl：Fu螢光体をニトロセルロ
ース等を用いて塗布し、乾燥膜厚が50〜100μの
螢光体層２を形成したものである。輝尽性螢光体
としてはBaFCl：Eu蛍光体の外に、一般式
（Ba1-xMx〓）FX：yＡ（但しM〓はMg，Ca，Sr，
ZnおよびCdのうちの少なくとも１つを、ＸはCl，
BrおよびＩのうちの少なくとも１つを、ＡはEu，
Tb，Ce，Tm，Dy，Pr，Ho，Nd，Yb及びEr
のうちの少なくとも１つを、ｘ及びｙは０ｘ
0.6及び０ｙ0.2なる条件を満たす数字を表わ
す）で表わされる希土類付活二価金属の複合ハロ
ゲン化物蛍光体、一般式LnOX：ZA（但しLnは
La，Ｙ，Gd及びLuの少なくとも１つを、ＸはCl
及び／又はBrを、ＡはCe及び／又はTbを、Ｚは
０＜Ｚ＜0.1を満足する数字を表わす）で表わさ
れるCe及び／又はTb付活希土類オキシハライド
蛍光体、一般式BaO・mAl2O3：Eu（但し0.8ｍ
10なる条件を満たす数字を表わす）で表わされ
るEu付活アルミン酸バリウム系蛍光体及び一般
式M′O・nSiO2：A′（但しM′はMg，Ca，Sr，Zn
又はBa、A′はCe，Tb，Eu，Tm，Pb，Tl，Bi，
Mnの内の少なくとも１つ、0.5ｎ2.5なる条
件を満たす数字を表わす）で表わされる二価金属
珪塩蛍光体の少なくとも１種が用いられる。 As shown in FIG. 3, the radiation image storage panel 11 of the present invention is constructed by using nitrocellulose or the like to coat BaFCl:Fu phosphor with an average particle size of 10μ on a support 1 such as polyethylene terephthalate film or cellulose triacetate. A phosphor layer 2 having a dry film thickness of 50 to 100 .mu.m is formed. In addition to BaFCl:Eu phosphor, stimulable phosphors include the general formula (Ba 1-x M x 〓) FX: y A (where M 〓 is Mg, Ca, Sr,
at least one of Zn and Cd, X is Cl,
at least one of Br and I, A is Eu,
Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb and Er
x and y are 0x
0.6 and 0y0.2) is a rare earth-activated divalent metal complex halide phosphor with the general formula LnOX:ZA (however, Ln is
at least one of La, Y, Gd and Lu, X is Cl
and/or Br, A represents Ce and/or Tb, and Z represents a number satisfying 0<Z<0.1), a Ce and/or Tb activated rare earth oxyhalide phosphor, general formula BaO・mAl 2 O 3 :Eu (however, 0.8m
Eu-activated barium aluminate phosphor represented by the number satisfying the condition 10) and the general formula M′O・nSiO 2 :A′ (where M′ is Mg, Ca, Sr, Zn
Or Ba, A′ is Ce, Tb, Eu, Tm, Pb, Tl, Bi,
At least one type of divalent metal silicate phosphor represented by Mn (representing a number satisfying the condition of 0.5n2.5) is used.
放射線像変換パネルに記録された放射線画像情
報を励起光で走査して、光検出器としてP.M.T.
を用いる放射線画像情報読取装置において、
BaFCl：Fu螢光体を螢光膜とする40cm×40cmの
大きさの放射線像変換パネルを用い、スポツト径
50μφのHe−Neレーザーを励起光源として使用し
た場合、最終的に得られる放射線画像情報を例え
ば写真フイルム上に再生させてその画質を従来の
ものと本発明のものについて比較した。光検出器
からの出力信号を直流増幅する従来の装置によれ
ば、前記放射線像変換器の螢光膜の膜厚を薄くし
ていくと、得られる画像の鮮鋭度は良くなる傾向
にあるものの、膜厚が150μ以下になるとＳ／Ｎ
比が悪くなるため鮮鋭度の向上する割合が次第に
小さくなつた。また螢光膜の膜厚を150μとし、
励起光の走査時間を５分から1.5分に短縮した場
合、いずれも放射線画像の鮮鋭度が低下したが、
P.M.T.からの出力信号を光電流パルスとして計
測する本発明の装置によれば螢光膜の膜厚を
200μから80μに変えた場合、得られた放射線画像
の鮮鋭度は向上した。また励起光の走査時間を５
分から1.5分に短縮しても画質はほとんど変化し
なかつた。更に放射線像変換パネルの螢光体層の
膜厚を100μとし、励起光の走査時間を1.5分に設
定して放射線画像情報を読み取つた場合、従来の
装置によれば励起光のスポツト径を100μφから
50μφに変えるとＳ／Ｎ比が低下し、得られる画
像は極めて不鮮明となつたが本発明の装置によれ
ばスポツト径を100μφから50μφに変えることによ
つて画像の解像度が向上した。 PMT is used as a photodetector by scanning the radiation image information recorded on the radiation image conversion panel with excitation light.
In a radiation image information reading device using
Using a radiation image conversion panel measuring 40cm x 40cm with BaFCl:Fu phosphor as the fluorescent film, the spot diameter
When a 50 μΦ He--Ne laser was used as an excitation light source, the finally obtained radiation image information was reproduced on, for example, a photographic film, and the image quality was compared between the conventional one and the one of the present invention. According to the conventional device that amplifies the output signal from the photodetector with direct current, the sharpness of the obtained image tends to improve as the thickness of the phosphor film of the radiation image converter becomes thinner. , S/N decreases when the film thickness becomes 150μ or less.
As the ratio worsened, the rate of improvement in sharpness gradually decreased. In addition, the thickness of the fluorescent film is 150μ,
When the excitation light scanning time was shortened from 5 minutes to 1.5 minutes, the sharpness of the radiation images decreased in both cases.
According to the device of the present invention, which measures the output signal from the PMT as a photocurrent pulse, the film thickness of the fluorescent film can be measured.
When changing from 200μ to 80μ, the sharpness of the obtained radiographic images improved. Also, the scanning time of the excitation light is 5
Even when the time was shortened from minutes to 1.5 minutes, there was almost no change in image quality. Furthermore, if the thickness of the phosphor layer of the radiation image conversion panel is 100μ, and the scanning time of the excitation light is set to 1.5 minutes to read the radiation image information, the spot diameter of the excitation light is 100μφ with the conventional device. from
When the spot diameter was changed from 100 .mu..phi. to 50 .mu..phi., the S/N ratio decreased and the obtained image became extremely unclear, but according to the apparatus of the present invention, the resolution of the image was improved by changing the spot diameter from 100 .mu..phi. to 50 .mu..phi.
このように本発明の放射線画像情報読取装置に
よれば従従来の装置に比べＳ／Ｎ比が向上し、放
射線像変換パネルの螢光体層の膜厚を薄くした
り、励起光のスポツト径を小さくしたり、励起光
の走査時間を短くしても鮮明な画像が得られ、従
つて、従来の装置に比べ短時間で高鮮鋭度な放射
線画像を得ることができる。 As described above, according to the radiation image information reading device of the present invention, the S/N ratio is improved compared to conventional devices. A clear image can be obtained even if the beam size is made small or the scanning time of the excitation light is shortened. Therefore, a radiographic image with high sharpness can be obtained in a shorter time than with conventional apparatuses.
第１図はドラム走査式の放射線画像情報読取装
置を示す正面図、第２図は本発明の実施例による
放射線画像情報読取装置のブロツクダイアグラ
ム、第３図は本発明に使用する放射線像変換パネ
ルの断面図である。
１…支持体、２…輝尽性螢光体層、１０…回転
ドラム、１１…放射線像変換パネル、１２…励起
光源、１３…ハーフミラー、１４…集光レンズ、
１５…フイルター、１６…光電子増倍管。
FIG. 1 is a front view showing a drum scanning type radiation image information reading device, FIG. 2 is a block diagram of a radiation image information reading device according to an embodiment of the present invention, and FIG. 3 is a radiation image conversion panel used in the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Support, 2... Stimulable phosphor layer, 10... Rotating drum, 11... Radiation image conversion panel, 12... Excitation light source, 13... Half mirror, 14... Condensing lens,
15... Filter, 16... Photomultiplier tube.
Claims (1)
体群から選ばれる少なくとも一種である輝尽性蛍
光体からなる放射線像変換パネルに励起光を照射
する励起光源と、上記放射線像変換パネルから放
出された輝尽発光光を検出する光電子増倍管と、
該光電子増倍管の陽極で生じた電流パルスを増幅
する交流増幅器と、該交流増幅器の出力パルスの
中から上記光電子増倍管の暗電流並びに雑音に対
応する電流パルスを除去して上記輝尽発光光に対
応する光電流パルスのみを出力するデイスクリミ
ネーターと、上記光電流パルスを計数するパルス
カウンターと、このパルスカウンターからのデジ
タル信号を一旦記憶する記憶装置とを有し、上記
放射線像変換パネルに被写体を透過した放射線を
吸収せしめ、しかる後に該パネルを上記励起光源
から発する励起光で走査してこれに蓄積されてい
る放射線画像情報を輝尽発光光として放出させ、
この輝尽発光光の光子パルス信号に対応して上記
光電子増倍管の陽極に発生する陽極電流パルスを
直接計数して上記放射線画像情報をデジタル信号
として取り出すことを特徴とする放射線画像情報
読取装置。 一般式（Ba1-xMx〓）FX：yＡ …（） （但しMnはMg，Ca，Sr，ZnおよびCdのうち
の少なくとも１つを、ＸはCl，BrおよびＩのう
ちの少なくとも１つを、ＡはEu，Tb，Ce，Tm，
Dy，Pr，Ho，Nd，Yb及びErのうちの少なくと
も１つを、ｘ及びｙは０ｘ0.6及び０ｙ
0.2なる条件を満たす数字を表わす）、 一般式LnOX：ZA …（） （但しLnはLa，Ｙ，Gd及びLuの少なくとも
１つを、ＸはCl及び／又はBrを、ＡはCe及び／
又はTbを、Ｚは０＜Ｚ＜0.1を満足する数字を表
わす）、 一般式BaO・mAl2O3：Eu …（） （但し0.8ｍ10なる条件を満たす数字を表
わす）および 一般式M′O・nSiO2：A′ …（） （但しM′はMg，Ca，Sr，Zn又はBa、A′は
Ce，Tb，Eu，Tm，Pb，Tl，Bi，Mnの内の少
なくとも１つ、0.5ｎ2.5なる条件を満たす数
字を表わす）。[Scope of Claims] 1. An excitation light source that irradiates excitation light onto a radiation image conversion panel made of at least one stimulable phosphor selected from the group of phosphors represented by the following general formulas () to (); a photomultiplier tube that detects stimulated luminescence light emitted from a radiation image conversion panel;
an AC amplifier that amplifies the current pulse generated at the anode of the photomultiplier; and an AC amplifier that removes the current pulse corresponding to the dark current and noise of the photomultiplier from the output pulse of the AC amplifier to perform the photoexcitation. It has a discriminator that outputs only photocurrent pulses corresponding to the emitted light, a pulse counter that counts the photocurrent pulses, and a storage device that temporarily stores digital signals from the pulse counter, and the radiation image conversion method includes: causing a panel to absorb the radiation transmitted through the object, and then scanning the panel with excitation light emitted from the excitation light source to emit the radiation image information stored therein as stimulated luminescence light;
A radiation image information reading device characterized in that the anode current pulse generated at the anode of the photomultiplier tube in response to the photon pulse signal of the stimulated luminescence light is directly counted to extract the radiation image information as a digital signal. . General formula (Ba 1-x M x 〓)FX: y A...() (However, M n is at least one of Mg, Ca, Sr, Zn, and Cd, and X is at least one of Cl, Br, and I. At least one, A is Eu, Tb, Ce, Tm,
At least one of Dy, Pr, Ho, Nd, Yb and Er, x and y are 0x0.6 and 0y
0.2), general formula LnOX:ZA...() (However, Ln represents at least one of La, Y, Gd and Lu, X represents Cl and/or Br, and A represents Ce and/or
or Tb, Z represents a number satisfying 0<Z<0.1), general formula BaO・mAl 2 O 3 :Eu...() (however, represents a number satisfying the condition of 0.8m10), and general formula M'O・nSiO 2 :A′...() (However, M′ is Mg, Ca, Sr, Zn or Ba, A′ is
At least one of Ce, Tb, Eu, Tm, Pb, Tl, Bi, Mn, a number satisfying the condition 0.5n2.5).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14112479A JPS5664651A (en) | 1979-10-31 | 1979-10-31 | Radiation image information read system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14112479A JPS5664651A (en) | 1979-10-31 | 1979-10-31 | Radiation image information read system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5664651A JPS5664651A (en) | 1981-06-01 |
| JPH0348492B2 true JPH0348492B2 (en) | 1991-07-24 |
Family
ID=15284713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14112479A Granted JPS5664651A (en) | 1979-10-31 | 1979-10-31 | Radiation image information read system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5664651A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4857734A (en) * | 1986-04-21 | 1989-08-15 | Siemens Aktiengesellschaft | Read system for a luminescent image storage screen in an x-ray diagnostics installation |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3859527A (en) * | 1973-01-02 | 1975-01-07 | Eastman Kodak Co | Apparatus and method for producing images corresponding to patterns of high energy radiation |
-
1979
- 1979-10-31 JP JP14112479A patent/JPS5664651A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3859527A (en) * | 1973-01-02 | 1975-01-07 | Eastman Kodak Co | Apparatus and method for producing images corresponding to patterns of high energy radiation |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5664651A (en) | 1981-06-01 |
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