A7 546132 五、發明說明（；） (請先閱讀背面之注意事項再填寫本頁) 本發明係關於一種正電子發射斷層（PET，positron emission tomography)照相機或掃描器。 PET掃描器於醫療之領域係眾所週知。此等掃描器係 藉著偵測由注射至人體的放射性物質所發射的放射線而產 生人體之影像。各個掃描器係由放射線偵測器所作成，通 常稱爲閃爍器(scintillator)，其係以一種環形結構而配置繞 於一可移動式的患者手術台。第1圖係顯示一偵測環10與 一患者手術台12之一種典型的配置。各個閃爍器包含一 晶體，且在環上有一關聯配對者位在相對位置。如所揭示 於美國專利第4,843,245號與歐洲專利第0,437,051 B號中 者，諸多習知的照相機係使用Bi4Ge3〇12 (BG0)作爲一閃爍 偵測器。各個閃爍器係連接至一個光電倍增管 (photomultiplier tube)，其係依次連接至讀出（read-out)電子 電路。 於一掃描期間，該患者係位於環狀偵測器之中央的可 移動台上。患者係注射以放射性物質，其係附有一/5+放射 性原子（其具有短的衰減時間），例如:碳-11、氟-18、氧-15 或氮-13。於放射性同位素之原子核的衰減期間，正電子係 放出。當一正電子係發射並且遇到一電子時，碰撞係產生 二個r射線，其具有相同能量(511 KeV)，但係以相反方向 行進。藉著利用直徑對立於該環上之閃爍器而同時偵測所 產生的r射線，係可偵測出崩潰(disintegration)發生之軌跡 。閃爍器晶體係將r射線轉換爲光線之光子(Photon)，其係 傳送至光電倍增管，轉換且放大該等光子爲電氣訊號。此 ___3_ 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 546132 ____B7___ 五、發明說明（> ) (請先閱讀背面之注意事項再填寫本頁) 等電氣訊號係接著由一電腦所處理，以產生於關注區域(例 如:腦部、胸部、肝)之身體的三維影像。 PET掃描之一個優點係具有能力以準確判定放射性核 種(radionuclide)區域化且量化身體中的生理(physiological)處 理。可完成這項工作係因爲由該患者身體發射出於相反方 向行進的二個T光子所致。另一個優點係在於，PET掃描 器係運用類似或相同於人體中所發現者之生物性化合物， 諸如碳、氮、與氧。此係意謂著，PET放射性核種係可被 直接取代成爲由身體所運用之生物性物質。另外，此係意 謂著，PET示蹤劑(tracer)係並非如同用於某些其他掃描器 之藥劑(agent)所爲者僅僅模擬生物性的途徑，，而是PET 示蹤劑係實際跟隨真實的生理與代謝(metabolic)處理。此係 爲有利。反之，其他的核醫學成像技術係需要標示有不常 見於身體中的放射性核種之化合物。此等已修飾的化合物 係僅爲近似於人體中的真實分佈。 因爲固有於PET掃描器之多個優點，於是便會驅使去 改善其性能，藉以提高所掃描的影像之準確度且因此有助 於臨床者(clinician)。欲達成此目的，諸多團體係正於目前 努力以改善該種掃描器之特性。 一個PET照相機之最爲重要的特性係其空間解析度與 靈敏度。習用的PET照相機係可提供於發射光譜之半最大 値的全寬度(FWHM，full width half maximum)之範圍爲 4-6 mm (毫米)的空間解析度。較佳的空間解析度係需要大量之 減小尺寸之閃爍偵測器，且因此需要大量的光偵測器與關 一 4 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 546132 B7 _ ------- 五、發明說明（、） 聯的讀出電子電路。然而，此舉係提高成本。同時，人類 PET儀器使用(例如:於精密的腦成像)之新的要求係需要比 2 mm更好之空間解析度。 對於一 PET掃描器之一重新建構後的影像解析度之組 合式係可爲表示如後： Γ = l.25^(d/2)2 +(0.0022D)2+r2 +b2 此處，Γ係重新建構後的影像解析度(mm FWHM)，d 係偵測器尺寸，D係偵測器陣列直徑，對於一整個身體 PET掃描器通常爲600-800 mm而對於一腦部PET爲250-300 mm (NB包括D，係考量來自正電子衰減之光子非同線 性），r係有效的正電子範圍(從針對18F之0.5 mm到針對 82Rb之4.5 mm)，且b係另外的因數，其係由一擊中點識別 機制所導出(Anger邏輯或者“真(true)”位置靈敏之光偵測 器；即:多個光電倍增器訊號之間的類比値）。假設b對於 一對位置靈敏之光偵測器係爲零，則腦部PET於d=l mm ( 以18F)下，可達到Γ=1 mm解析度。 假設上式係準確，爲了滿足PET照相機之空間解析度 與靈敏度的增大要求，將可認知的是，該種照相機係必須 由具有筒停止功率（stopping power)之長、薄的偵測器所作 成。然而，實行上，此舉係降低在視界之末端處的空間解 析度。此係一個缺點。欲克服此問題而且避免空間解析度 之降級，必須運用一種具有交互作用的深度(DOI，depth of interaction)決定能力之偵測器，即，具有欲決定沿著偵測 器單元(cell)之交互作用座標的能力。欲達成此舉之最爲方 ________5__一 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) · -線 546132A7 546132 V. Description of the invention (;) (Please read the notes on the back before filling this page) The present invention relates to a positron emission tomography (PET) camera or scanner. PET scanners are well known in the medical field. These scanners produce images of the human body by detecting radiation emitted by radioactive substances injected into the human body. Each scanner is made of a radiation detector, often called a scintillator, which is arranged in a ring structure around a movable patient operating table. FIG. 1 shows a typical configuration of a detection ring 10 and a patient operating table 12. Each scintillator contains a crystal, and there is an associated pair on the ring in a relative position. As disclosed in U.S. Patent No. 4,843,245 and European Patent No. 0,437,051 B, many conventional cameras use Bi4Ge3012 (BG0) as a flicker detector. Each scintillator is connected to a photomultiplier tube, which in turn is connected to a read-out electronic circuit. During a scan, the patient was on a movable table in the center of the ring detector. The patient is injected with a radioactive substance attached to a / 5 + radioactive atom (which has a short decay time), such as carbon-11, fluorine-18, oxygen-15, or nitrogen-13. During the decay of the nuclei of radioactive isotopes, positrons are emitted. When a positron system emits and encounters an electron, the collision system generates two r-rays, which have the same energy (511 KeV), but travel in opposite directions. By using a scintillator with a diameter opposite to the ring to detect the generated r-rays at the same time, it is possible to detect the trajectory of disintegration. The scintillator crystal system converts r-rays into photons of light, which are transmitted to a photomultiplier tube, which converts and amplifies these photons into electrical signals. This ___3_ This paper size applies to China National Standard (CNS) A4 specification (210 X 297 mm) A7 546132 ____B7___ 5. Description of the invention (>) (Please read the precautions on the back before filling this page) and other electrical signal systems It is then processed by a computer to generate a three-dimensional image of the body in the area of interest (eg, brain, chest, liver). One advantage of PET scanning is the ability to accurately determine the localization of radionuclide and quantify the physiological processing in the body. This can be done because the patient's body emits two T photons traveling in opposite directions. Another advantage is that the PET scanner uses biological compounds such as carbon, nitrogen, and oxygen that are similar or identical to those found in the human body. This line means that PET radionucleus can be directly replaced by biological substances used by the body. In addition, this means that the PET tracer is not a simulating biological pathway just as the agent used in some other scanners, but the PET tracer actually follows True physiological and metabolic treatment. This system is advantageous. Conversely, other nuclear medicine imaging technologies require compounds labeled with radionuclear species that are not commonly found in the body. These modified compounds are only approximate to the true distribution in the human body. Because of the many advantages inherent in PET scanners, it is driven to improve their performance, thereby increasing the accuracy of the scanned images and thus helping clinicians. To achieve this goal, many mission systems are currently working to improve the characteristics of this type of scanner. The most important characteristics of a PET camera are its spatial resolution and sensitivity. Conventional PET cameras provide spatial resolution in the range of 4-6 mm (mm) at the full width half maximum (FWHM) of the emission spectrum. Better spatial resolution requires a large number of reduced size flicker detectors, and therefore requires a large number of light detectors. This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ) A7 546132 B7 _ ------- V. Description of the invention (,) The combined readout electronic circuit. However, this move raises costs. At the same time, new requirements for the use of human PET instruments (for example, in precision brain imaging) require better spatial resolution than 2 mm. The combination of the reconstructed image resolution of one of the PET scanners can be expressed as follows: Γ = 1.25 ^ (d / 2) 2 + (0.0022D) 2 + r2 + b2 Here, Γ Reconstructed image resolution (mm FWHM), d is the size of the detector, D is the diameter of the detector array, usually 600-800 mm for a whole body PET scanner and 250- for a brain PET 300 mm (NB includes D, taking into account the non-linearity of photons from positron attenuation), r is the effective positron range (from 0.5 mm for 18F to 4.5 mm for 82Rb), and b is another factor, which Derived from a single hit point recognition mechanism (Anger logic or "true" position-sensitive light detectors; that is, analogy between multiple photomultiplier signals). Assuming that b is zero for a pair of position-sensitive photodetectors, the brain PET can achieve a resolution of Γ = 1 mm at d = 1 mm (with 18F). Assuming the above formula is accurate, in order to meet the requirements for increasing the spatial resolution and sensitivity of PET cameras, it will be recognized that this type of camera must be powered by a long, thin detector with a stopping power. Made. In practice, however, this reduces the spatial resolution at the end of the horizon. This is a disadvantage. To overcome this problem and avoid degradation of spatial resolution, a detector with depth of interaction (DOI) determination capability must be used, that is, a detector that has the ability to determine the interaction along the detector cell Ability to act on coordinates. The best way to achieve this is ________5__ 一 This paper size applies Chinese National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page) · -line 546132
五、發明說明（心） 便的方式係運用一種多餍的偵測器’而其諸層係爲由具有 不同閃爍性質之材料所作成。因爲§者層具有不同的特性， 當偵測到一 r射線時，便可識別其爲擊中(hlt)之層’故更 爲準確地判定交互作用點° 多種多層的偵測器係習知。舉例而曰，美國專利(us) 第4,843,245號係描述一種多層的閃爍器’其運用相鄰的 BGO與GSO (Gd2Si〇5)晶體。歐洲專利(EP)第0,219,648號係 揭示運用一種三層的閃爍器，其具有一內層之BaF2、一中 層之GSO、與一^外層之BGO。世界專利(W0)弟99/24848號 亦揭示運用一種多層的偵測器，且尤指一種“層式磷光閃 爍體(phoswich)，，偵測器，其中不同的偵測器層係由具有不 同的衰減時間之不同的閃爍器所作成。於世界專利第 99/24848號所述之層式磷光閃爍體(Phoswich)具有二層，各 爲 BGO 與 Lu2Si〇5:Ce (LSO)。 另一種習知的多層式偵測器係運用LS〇與GSO之組合 。於此例中，擊中層之判定係利用脈衝形狀區別而加以進 行。完成此項工作係利用LSO與GSO層之衰減時間常數的 大差異所致。不幸的是，GSO之光電吸收係數爲相較於 LSO者而爲較小許多。此係意謂著，GSO之停止功率係受 到限制，其係使該擊中層之判定增加了某程度的不確定性 〇 於又一種習知的PET，該等閃爍偵測器係由長有不同 的鈽(Ce，cerium)濃度之“快(fast)”與“慢(slow)” LS〇閃 爍器之層所作成。如同關於LSO與GSO偵測器，脈衝形狀 ___6__ 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) 訂： --線_ A7 546132 五、發明說明（s ) 區別係運用以判定該擊中層。然而，此種特定裝置之一個 缺點係在於，“快，，與“慢” LSO之衰減時間常數的差異 係僅約爲10 % (以平均値40奈秒(ns，nanosecond)之4-5 ns) 。因此’其係將難於以任何確定性而判定該擊中層。 習知的PET掃描器除了在空間解析度的限制之外， 在PET掃描器視界的端處亦有空間解析度的一個幾何限制 。此係所謂的徑向延長的失真，其發生在當r軌跡跨過數 個閃爍偵測器時。 [發明槪要] 本發明之一個目的係提出一種用於PET照相機之改良 的閃爍偵測器、以及一種改良的PET照相機。 本發明之種種層面係界定於隨附之申請專利範圍獨立 項。某些較佳的特徵係界定於申請專利範圍依附項。 根據本發明之一個層面，係提出一種正電子發射斷層 (PET)照相機或掃描器，包含:一患者區域；一偵測環，用 於偵測來自該患者區域之相對側的放射線，該環包括指向 該患者區域之複數個閃爍偵測器，當放射線入射於該等閃 爍偵測器上時，該等閃爍偵測器便會發射光線；以及，轉 換機構，其係爲光學耦接至閃爍偵測器，用以將該等閃爍 偵測器所發射的光線轉換爲電氣脈衝，其中該等閃爍偵測 器包含 LuAl〇3:Ce (LuAP)。 該LuAP可包括纟乙(Y，yttrium)以形成LuYAP。銘之量 係可以餾(Lu，lutetium)含量之原子％表示而介於〇%與30% 之間的範圍。 7 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) · -線 A7 546132 五、發明說明（ς) (請先閱讀背面之注意事項再填寫本頁) 較佳而言，該等閃爍偵測器係另外包含LSO。於此例 中’係設置機構用以判定所偵測的放射線是否爲入射於 LuAP或LSO之上。該判定機構係可運作以分析電氣訊號 而判定一脈衝形狀，該脈衝形狀係表示偵測放射線之層。 —種波長分割器(divider)係可設置於各個閃爍偵測器與 關聯的轉換機構之間。該波長分割器與轉換機構最好是相 對於該等閃爍器而偏移，俾使各個波長分割器與各個轉換 機構係跨越(span)二個相鄰的閃爍器。該波長分割器係可包 含一玻璃(glass)爐波器、及/或一干涉(interference)濾波器、 及/或一繞射光柵(diffraction grating)、及/或一稜鏡(prism)、 及/或一繞射性（diffractive)的微光學陣列（micro-optic array) 、及/或一折射性(refractive)的微光學陣列之任何一者或多 者。 較佳而言，轉換機構包含光電倍增管，例如:對位置靈 敏之光電倍增管、或突崩式(avalanche)光電二極體或者ΠΝ 光電二極體。 根據本發明之另一個層面，係提出一種正電子發射斷 層(PET)照相機或掃描器，其包括複數個閃爍偵測器，其中 該等閃爍器包含LuAl〇3:Ce (LuAP)。 該LuAP可包括釔以形成LuYAP。釔之量係可以餾含 量之原子％表示而介於0%與30%之間的範圍。較佳而言， 各個閃爍器具有一層之LS0。 根據本發明之又一個層面，係提出一種運用於PET掃 描器之閃爍器，該種閃爍器包含LuAP。 _____8_ 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 546132 五、發明說明（-) (請先閱讀背面之注意事項再填寫本頁) 該LuAP可包括釔以形成LuYAP。釔之量係可爲介於 餾含量的0%與30%之間的範圍。較佳而言，各個閃爍器更 包括一層之LS〇。 根據本發明之再一個層面，係提出一種正電子發射斷 層照相機或掃描器，其包含:複數個閃爍偵測器，其指向一 患者區域，當放射線入射於該等閃爍偵測器上時，，該等 閃爍偵測器便會發射光線，該等閃爍偵測器係包含二個不 同的閃爍材料層，各發射不同的閃爍光線；以及，轉換機 構，其係爲光學耦接至閃爍偵測器，用以將該等閃爍偵測 器所發射的光線轉換爲電氣脈衝，其中一光學元件係定位 於該等閃爍偵測器與轉換機構之間的一光學路徑中，該光 學元件係使得來自該閃爍偵測器之一層的光線以一種方式 受影響，而來自該閃爍偵測器之另一層的光線以另一種方 式受影響。 此種配置之一個優點係在於，由該等閃爍層之各者所 發射的閃爍光線係以不同方式而受到光學元件存在之影響 ，其意謂著閃爍擊中層係可爲較易於識別。 [圖式簡單說明] 本發明所實施之種種的照相機與閃爍器係將僅僅藉由 舉例且參照伴隨圖式而作說明，其中： 第1圖顯不具有偵測環與患者手術臺的一種典型配置 第2(a)圖係用於一種PET之一第一偵測器的側視圖； 第2(b)圖係於第2(a)圖之箭頭A的前視圖； ^____9_____ 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 546132 五、發明說明（S ) 第3圖顯示其包括LS〇、LuAP與GS〇閃爍器之種種 閃爍特性的圖表； 第4圖係PET掃描器之計算的相對靈敏度對(vs.)晶體 厚度的繪圖，其基於在Er=511 KeV之LS〇、LuAP與GSO 閃爍器； 第5圖顯示對於LSO與LuAP的發射光譜；及 第6圖係用於一種PET之一第二偵測器的方塊圖。 [主要元件符號說明] 10 偵測環 12 患者手術台 14、16 LSO 層 18、20 LuAP 層 22、24 光偵測器 26、28 LSO 層 30、32 LuAP 層 34、36 波長分割器(波長分割元件)(濾波器） 38 > 40 光偵測器 42 > 44 放大器 46 類比至數位轉換器 [較佳實施例詳細說明] 本發明所實施於其中之PET係運用閃爍器，其包含以 鍇(lutetium)爲基的晶體。特定而言，本發明所實施於其中 之閃爍器係運用LuAP或LuYAP。於下文中，該字首語辭 LuAP係將代表LuAP或LuYAP。此材料具有諸多性質，使 _____ίο___ 本紙張尺度適用中國國家標準（CNs)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) .0 i線· 546132 A7 ____ B7___ 五、發明說明（气） 得其可使用作爲一閃爍器。 第2(a)與(b)圖係顯示用於一種PET掃描器之二個閃爍 器，其各者包含一內層之LSO 14、16與一層之LuAP 18、 20。各層之LS〇與LuAP係較佳爲小於20毫米(mm)之厚度 。相鄰於各個LuAP層18、20且光學耦接至其者係一光偵 測器22、24，以供偵測由LSO 14、16或者LuAP 18、20所 發射的光線。光偵測器22、24係可爲任何適合型式者，但 是典型爲包括光電倍增器(photomultiplier)或突崩式光電二 極體。來自光偵測器22、24之訊號係運用讀出電子電路( 未顯示)而作處理。實行上，於第2圖所顯示之複數個閃爍 器與光偵測器係設置爲繞於一患者手術台之環形結構，根 據用於PET掃描器之習用的佈局。運用來自光偵測器的訊 號，所掃描之組織的一影像係可構成。V. Description of the Invention (Heart) The convenient way is to use a multi-detector 'and its layers are made of materials with different scintillation properties. Because the layers have different characteristics, when an r-ray is detected, it can be identified as the layer that hits (hlt). Therefore, the interaction point can be determined more accurately. . For example, U.S. Patent (US) No. 4,843,245 describes a multi-layered scintillator ' which uses adjacent BGO and GSO (Gd2Si0) crystals. European Patent (EP) No. 0,219,648 discloses the use of a three-layer scintillator having an inner layer of BaF2, a middle layer of GSO, and an outer layer of BGO. World Patent (W0) No. 99/24848 also discloses the use of a multi-layered detector, and in particular a "layered phosphorescent scintillator", a detector in which different detector layers are composed of different layers. Scintillator with different decay time. The layered phosphorescent scintillator (Phoswich) described in World Patent No. 99/24848 has two layers, each of which is BGO and Lu2Si05: Ce (LSO). The known multi-layer detector uses a combination of LS0 and GSO. In this example, the determination of the hit layer is made by using the difference in pulse shape. The completion of this work uses the large attenuation time constant of the LSO and GSO layers. The difference is unfortunately, the photoelectric absorption coefficient of GSO is much smaller than that of LSO. This means that the stopping power of GSO is limited, which increases the determination of the hit layer by some Uncertainty of degree. In another conventional PET, these scintillation detectors are composed of "fast" and "slow" LS with different concentrations of cerium (Ce, cerium). Made at the sensor layer. As for the LSO and GSO detectors, the pulse shape __ _6__ This paper size is in accordance with Chinese National Standard (CNS) A4 (210 X 297 mm) (Please read the notes on the back before filling out this page) Order: --line_ A7 546132 V. Description of invention (s) Difference To determine the hit layer. However, one disadvantage of this particular device is that the difference between the decay time constants of the "fast," and "slow" LSOs is only about 10% (at an average of 奈 40 nanoseconds (ns, nanosecond) of 4-5 ns). Therefore, it will be difficult to determine the hit layer with any certainty. In addition to the limitation of the spatial resolution of the conventional PET scanner, there is also a geometrical limitation of the spatial resolution at the end of the PET scanner's horizon. This is the so-called radial extension distortion that occurs when the r-track crosses several flicker detectors. [Inventive Summary] An object of the present invention is to provide an improved flicker detector for a PET camera, and an improved PET camera. The various aspects of the present invention are defined as separate items within the scope of the accompanying patent application. Certain better features are defined in the scope of the patent application. According to one aspect of the present invention, a positron emission tomography (PET) camera or scanner is provided, including: a patient area; and a detection ring for detecting radiation from the opposite side of the patient area. The ring includes A plurality of scintillation detectors pointing at the patient area, and when radiation is incident on the scintillation detectors, the scintillation detectors emit light; and a conversion mechanism, which is optically coupled to the scintillation detection The detector is used to convert the light emitted by the scintillation detectors into electrical pulses. The scintillation detectors include LuAlO3: Ce (LuAP). The LuAP may include Y (y, tritum) to form LuYAP. The amount of Ming is in the range of 0% to 30%, which can be expressed in atomic% of Lu (lutetium) content. 7 This paper size applies to Chinese National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page) · -A7 546132 V. Description of invention (ς) (Please read the back first Note: Please fill in this page again) Preferably, these flicker detectors include LSO. In this example, a mechanism is used to determine whether the detected radiation is incident on LuAP or LSO. The determination mechanism is operable to analyze an electrical signal to determine a pulse shape, and the pulse shape represents a layer for detecting radiation. A kind of wavelength divider (divider) can be set between each flicker detector and the associated conversion mechanism. The wavelength splitter and the conversion mechanism are preferably offset relative to the scintillators, so that each wavelength splitter and each conversion mechanism span two adjacent scintillators. The wavelength splitter may include a glass furnace, and / or an interference filter, and / or a diffraction grating, and / or a prism, and Any one or more of a diffractive micro-optic array and / or a refractive micro-optic array. Preferably, the conversion mechanism includes a photomultiplier tube, such as a position-sensitive photomultiplier tube, or an avalanche photodiode or a ΠN photodiode. According to another aspect of the present invention, a positron emission tomography (PET) camera or scanner is proposed, which includes a plurality of scintillation detectors, wherein the scintillators include LuAlO3: Ce (LuAP). The LuAP may include yttrium to form LuYAP. The amount of yttrium is in the range of 0% to 30%, which can be expressed in atomic% of the distillation content. Preferably, each scintillator has a layer of LSO. According to another aspect of the present invention, a scintillator for a PET scanner is proposed. The scintillator includes LuAP. _____8_ This paper size is in accordance with Chinese National Standard (CNS) A4 (210 X 297 mm) A7 546132 5. Description of the invention (-) (Please read the notes on the back before filling this page) The LuAP can include yttrium to form LuYAP . The amount of yttrium may range from 0% to 30% by weight. Preferably, each scintillator further includes a layer of LS0. According to yet another aspect of the present invention, a positron emission tomography camera or scanner is proposed, which includes: a plurality of scintillation detectors which are directed to a patient area, and when radiation is incident on the scintillation detectors, The scintillation detectors emit light. The scintillation detectors include two different scintillation material layers, each emitting a different scintillation light; and a conversion mechanism, which is optically coupled to the scintillation detectors. To convert the light emitted by the scintillation detectors into electrical pulses. An optical element is positioned in an optical path between the scintillation detectors and the conversion mechanism. Light from one layer of the flicker detector is affected in one way and light from the other layer of the flicker detector is affected in another way. One advantage of this configuration is that the scintillation light emitted by each of the scintillation layers is affected by the presence of optical elements in different ways, which means that the flicker hitting layer system can be more easily identified. [Brief description of the drawings] The various cameras and scintillators implemented in the present invention will be described only by way of example and with reference to the accompanying drawings. Among them: Figure 1 shows a typical example without a detection ring and a patient operating table. Figure 2 (a) is a side view of one of the first detectors of PET; Figure 2 (b) is a front view of arrow A in Figure 2 (a); ^ ____ 9_____ This paper size applies China National Standard (CNS) A4 specification (210 X 297 mm) A7 546132 V. Description of the invention (S) Figure 3 shows a chart of flicker characteristics including LS〇, LuAP and GS〇 scintillators; Figure 4 shows A plot of the calculated relative sensitivity of a PET scanner versus (vs.) crystal thickness based on LS0, LuAP, and GSO scintillators at Er = 511 KeV; Figure 5 shows the emission spectra for LSO and LuAP; and Figure 6 The figure is a block diagram for one of the second detectors of a PET. [Description of main component symbols] 10 Detection ring 12 Patient operating table 14, 16 LSO layer 18, 20 LuAP layer 22, 24 Light detector 26, 28 LSO layer 30, 32 LuAP layer 34, 36 Wavelength splitter (wavelength division (Element) (filter) 38 > 40 photodetector 42 > 44 amplifier 46 analog-to-digital converter [detailed description of preferred embodiment] The PET in which the present invention is implemented is a scintillator, which includes: (lutetium) -based crystal. In particular, the scintillator in which the present invention is implemented uses LuAP or LuYAP. In the following, the prefix LuAP will stand for LuAP or LuYAP. This material has many properties that make _____ ίο ___ This paper size applies to Chinese National Standards (CNs) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page) .0 i-line · 546132 A7 ____ B7___ Fifth, the invention description (qi) can be used as a scintillator. Figures 2 (a) and (b) show two scintillators for a PET scanner, each of which includes an inner layer of LSO 14, 16 and a layer of LuAP 18, 20. The LS0 and LuAP of each layer are preferably less than 20 millimeters (mm) in thickness. Adjacent to each LuAP layer 18, 20 and optically coupled to it is a light detector 22, 24 for detecting light emitted by LSO 14, 16 or LuAP 18, 20. The photodetectors 22 and 24 may be of any suitable type, but typically include a photomultiplier or a burst photodiode. The signals from the photodetectors 22, 24 are processed using readout electronics (not shown). In practice, the plurality of scintillators and light detectors shown in Figure 2 are arranged in a ring structure around a patient's operating table, according to the conventional layout used for PET scanners. Using the signal from the light detector, an image of the scanned tissue can be constructed.
LuAP之運用於第2(a)與⑻圖中的掃描器係提供種種的 裨益。此係因爲LuAP之有利的晶體特性。The application of LuAP to the scanner system in Figures 2 (a) and 提供 provides various benefits. This is because of the favorable crystal properties of LuAP.
LuAP、LS0與GS0之相對的性質係顯示於第3圖之表 格中，可自其看出的是，於511 KeV時之LuAP的光電吸 收係數爲0.31，其係可比得上具有光電吸收係數爲〇.30之 LS0。反之，對於GS0之光電吸收係數爲0.18。此係意謂 著，GS0之有效的停止功率係顯著爲小於LS0或LuAP者 。此外，對於LuAP的衰減常數係針對所發射的光線之60 %而爲11 ns ，而對於LS0係爲40 ns。此係一相當大的差 異。此係有利於第2圖之LSO/LuAP閃爍器，因爲其意謂 著脈衝寬度區別係可運用以準確判定該擊中層。第2圖之 __η____ _ 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) · i線· A7 546132 五、發明說明（…） LS〇/LuAP裝置的又一個優點係在於，LuAP係對於LS〇閃 爍光線爲透明。此係意謂著’由內部LS〇層所發射的光線 係可實質爲無阻礙而通過LuAP至光偵測器。此舉係改善 偵測過程之靈敏度。 於第4圖，其分別運用LuAP、LSO與GSO閃爍器環 之PET掃描器的相對靈敏度係顯示爲晶體厚度之一函數。 所應注意的是，偵測光吸收事件之雙重符合的相對機率係 取作爲PET環靈敏度之一測量。 由第4圖可看出的是，其運用GSO閃爍器之一種PET 掃描器的靈敏度係相較於其運用LuAP閃爍器之一種掃描 器而爲較小許多（比較相词尺寸之掃描器）。因此，第2圖 之雙層LSO/LuAP閃爍器係可作成相較於相同尺寸之習用 的LSO/GSO閃爍器而較爲靈敏。或者是，相同的靈敏度係 可運用一顯著爲較薄的LSO/LuAP閃爍器而得到。此係爲 有利，因爲其意謂著該PET掃描器之整體尺寸係可減小， 如同關聯的成本係可降低。特別而言，對於一種由 LS〇/LuAP所作成之雙層偵測器以及一種由LSO/GSO所作 成之雙層偵測器，當LuAP層係相較於一 GSO層而約爲較 薄1.7倍時，相同階層之靈敏度係可得到。此係意謂著， 由LSO/LuAP所作成之PET掃描器係相較於由LSO/GSO所 作成之一掃描器而具有於視界端處之較佳的空間解析度， 且成本係可能爲較低，因爲所需的晶體之體積係減小。 第5圖係顯示對於LSO與LuAP之各者的發射光譜。 由此可看出的是，LSO光譜具有一最大値爲420 nm，而 -------12___ 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) · -I線· A7 546132 五、發明說明（Π ) (請先閱讀背面之注意事項再填寫本頁)The relative properties of LuAP, LS0, and GS0 are shown in the table in Figure 3. It can be seen that the photoelectric absorption coefficient of LuAP at 511 KeV is 0.31, which is comparable to having a photoelectric absorption coefficient of 0.030 of LS0. In contrast, the photoelectric absorption coefficient for GS0 is 0.18. This means that the effective stopping power of GS0 is significantly smaller than that of LS0 or LuAP. In addition, the attenuation constant for LuAP is 11 ns for 60% of the emitted light, and 40 ns for LS0. This is a considerable difference. This system is advantageous for the LSO / LuAP scintillator in Fig. 2 because it means that the pulse width difference system can be applied to accurately determine the hitting layer. Figure 2 of __η ____ _ This paper size applies to the Chinese National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page) · i-line · A7 546132 V. Description of the invention ( …) Another advantage of the LS〇 / LuAP device is that the LuAP system is transparent to LS〇 flickering light. This means that the light emitted by the internal LSO layer can pass through LuAP to the light detector in a substantially unobstructed manner. This is to improve the sensitivity of the detection process. In Figure 4, the relative sensitivity of a PET scanner using LuAP, LSO, and GSO scintillator rings is shown as a function of crystal thickness. It should be noted that the relative probability of detecting the double coincidence of light absorption events is measured as one of the sensitivity of the PET ring. It can be seen from Figure 4 that the sensitivity of a PET scanner using a GSO scintillator is much smaller than that of a scanner using a LuAP scintillator (compared to the scanner size). Therefore, the double-layer LSO / LuAP scintillator in Figure 2 can be made more sensitive than a conventional LSO / GSO scintillator of the same size. Alternatively, the same sensitivity can be obtained using a significantly thinner LSO / LuAP scintillator. This is advantageous because it means that the overall size of the PET scanner can be reduced, just as the associated cost can be reduced. In particular, for a two-layer detector made of LS0 / LuAP and a two-layer detector made of LSO / GSO, the LuAP layer is about 1.7 thinner than a GSO layer At times, the sensitivity of the same class is available. This means that a PET scanner made by LSO / LuAP has a better spatial resolution at the horizon than a scanner made by LSO / GSO, and the cost may be more Low because the required volume of the crystal is reduced. Figure 5 shows the emission spectrum for each of LSO and LuAP. It can be seen that the LSO spectrum has a maximum 値 of 420 nm, and ------- 12___ This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) (Please read first Note on the back, please fill out this page) · -I · A7 546132 V. Description of Invention (Π) (Please read the notes on the back before filling out this page)
LuAP光譜具有一最大値爲378 nm。因此，若由第2圖之光 偵測器所偵測的光線係於378 nm，此係指出LuAP爲擊中 ，然而若所偵測的光線係於420 nm，此係指出LSO爲撃中 。此係意謂著，除了運用脈衝寬度區別，對於第2圖之閃 爍器的發射光譜選擇係可運用以識別擊中層。此舉係可達 成，藉著偵測其到達該光偵測器之光線的“色彩(colour)” 。第6圖係顯示一種偵測器，其係適以偵測光線之色彩。 第6圖係顯示用於一種PET照相機之複數個類似的閃 爍器，其各者係具有一 LS0層26、28與一 LuAP層30、32 。如同前述，各層之LS0 26、28與LuAP 30、32係較佳爲 小於20 mm之厚度。相鄰於該等閃爍器者係複數個波長分 割元件34、36。此等各者係實際爲偏移關於該等閃爍器， 使得其以等量而跨越二個相鄰的閃爍偵測器。相鄰的波長 分割器34與36係具有不同的傳輸係數。此係意謂著，各 個閃爍器之端部係相鄰於二個不同的波長分割器34與36 。波長分割元件34與36係可爲由彩色玻璃濾波器所作成 。於第6圖之實例中，濾波器34係對於分別來自LS0與 LuAP層26與30二者之光線發射爲透明，然而濾波器36 係對於來自LuAP層30之發射爲透明而且對於來自LS〇層 26之發射爲半透明。因此，濾波器34係影響來自該不同 的閃爍層之光線爲相同的程度，而濾波器36係以一種方式 影響來自LuAP層的光線且以另一種方式影響來自LS0層 的光線。 欲偵測來自第6圖之該等閃爍器的閃爍光線，光偵測 ___13 ___ 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 546132 A7 ___ B7___________ 五、發明說明（P ) 器38與40係爲光學耦接至波長分割器34、36 °各個光偵 測器38、40係實際爲偏移關於該等閃爍偵測器’但是實質 爲對齊於其關聯的波長分割器34、36，使得其跨越二個相 鄰的閃爍偵測器。一放大器42、44係耦接至各個光偵測器 38、40，以供放大其輸出。來自放大器42、44之訊號係輸 出至一類比至數位轉換器46，以供處理。處理後的訊號係 運用以構成所掃描的材料之一影像。 欲提出一種PET掃描器，於第6圖所顯不之複數個閃 爍器與光偵測器係根據習用實行而設置爲繞於一患者手術 台之環形結構。 當第6圖之LuAP偵測器30係爲擊中，來自光偵測器 、38與40之電氣脈衝的振幅係相等。此係因爲波長分割器 34與36之各者對於LuAP閃爍光線爲透明。反之，當LS〇 偵測器26係爲擊中，來自光偵測器38之電氣脈衝的振幅 係相較於光偵測器40而爲較高。此係因爲波長分割器34 對於LSO閃爍光線爲透明，然而波長分割器36係對於該 光線而僅爲半透明。因此，藉著比較由該等光偵測器所偵 測之脈衝的振幅，擊中層係可識別。 儘管第6圖之波長分割器34與36包含一玻璃濾波器 ，其係可同樣爲一干涉濾、波器、及/或一繞射光柵、及/或 一稜鏡、及/或一繞射性的微光學陣列、及/或一折射性的 微光學陣列之任何一者或多者。 簡而言之，本發明係針對一種新穎的高靈敏度晶體 (LuAP或LuYAP)之運用，其當應用至一 pet照相機時係提 14 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐) '— " (請先閱讀背面之注意事項再填寫本頁) · —線- 546132 A7 ____B7_____一 五、發明說明（Ο ) 供較大的影像銳利度，歸因於該閃爍偵測器之減小的尺寸 。該種PET係較不昂貴、較爲靈敏並且具有空間解析度之 相當低的角度降級(angulation degradation)，因而允許該偵 測器環之直徑可爲減小，其係依次降低該照相機之整體成 本。再者，於一種雙層結構中，於LSO與LuAP之衰減時 間常數(分別針對所發射的光線之60%而爲40 ns與11 ns) 的大差異係使得脈衝形狀區別成爲一個有用的選項，且允 許有效的擊中層判定。 熟悉此技藝之人士將理解的是，已揭示之配置的變化 係爲可能而並未偏離本發明。是以，特定實施例之說明係 作爲舉例所作成，而非針對限制之目的。對於熟悉此技藝 之人士將爲明確的是，小的修改係可作成而未有對於上述 運作之重大改變。 (請先閱讀背面之注意事項再填寫本頁) --線· — ___15 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐）The LuAP spectrum has a maximum chirp of 378 nm. Therefore, if the light detected by the light detector in Figure 2 is at 378 nm, this indicates that the LuAP is hit, but if the detected light is at 420 nm, this indicates that the LSO is hit. This means that in addition to using the pulse width difference, the emission spectrum selection system for the scintillator in Fig. 2 can be used to identify the hitting layer. This is achieved by detecting the "colour" of the light that reaches the light detector. Figure 6 shows a detector suitable for detecting the color of light. Figure 6 shows a number of similar flashers for a PET camera, each of which has an LSO layer 26, 28 and a LuAP layer 30, 32. As mentioned above, the LS0 26, 28 and LuAP 30, 32 of each layer are preferably less than 20 mm thick. Adjacent to these scintillators are a plurality of wavelength division elements 34,36. Each of these is actually offset with respect to the scintillators so that they span two adjacent scintillation detectors in equal amounts. Adjacent wavelength splitters 34 and 36 have different transmission coefficients. This means that the ends of each scintillator are adjacent to two different wavelength splitters 34 and 36. The wavelength division elements 34 and 36 may be made of a colored glass filter. In the example in FIG. 6, the filter 34 is transparent to the light emission from both the LS0 and LuAP layers 26 and 30, while the filter 36 is transparent to the emission from the LuAP layer 30 and to the LS0 layer. The emission of 26 is translucent. Therefore, the filter 34 affects the light from the different scintillation layers to the same degree, and the filter 36 affects the light from the LuAP layer in one way and the light from the LS0 layer in another way. To detect the flickering light from the scintillators in Figure 6, light detection ___13 ___ This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 546132 A7 ___ B7___________ 5. Description of the invention ( P) The detectors 38 and 40 are optically coupled to the wavelength splitter 34 and 36 °. Each of the light detectors 38 and 40 is actually offset with respect to the flicker detectors, but is substantially aligned with its associated wavelength division. Detectors 34, 36 such that they span two adjacent scintillation detectors. An amplifier 42, 44 is coupled to each of the light detectors 38, 40 for amplifying its output. The signals from the amplifiers 42, 44 are output to an analog-to-digital converter 46 for processing. The processed signal is used to form an image of the scanned material. To propose a PET scanner, the plurality of flickers and light detectors shown in Fig. 6 are arranged in a ring structure around a patient's operating table according to customary practices. When the LuAP detector 30 of FIG. 6 is hit, the amplitudes of the electrical pulses from the photodetectors 38 and 40 are equal. This is because each of the wavelength splitters 34 and 36 is transparent to the LuAP flickering light. Conversely, when the LS0 detector 26 is hit, the amplitude of the electrical pulse from the photodetector 38 is higher than that of the photodetector 40. This is because the wavelength splitter 34 is transparent to the LSO flickering light, while the wavelength splitter 36 is only translucent to the light. Therefore, by comparing the amplitudes of the pulses detected by these light detectors, the stratum is recognizable. Although the wavelength splitters 34 and 36 of FIG. 6 include a glass filter, they may also be an interference filter, a wave filter, and / or a diffraction grating, and / or a chirp, and / or a diffraction Any one or more of a micro-optical array that is flexible and / or a micro-optical array that is refractive. In short, the present invention is directed to the application of a novel high-sensitivity crystal (LuAP or LuYAP). When applied to a pet camera, the paper size is 14 and the Chinese national standard (CNS) A4 specification (210 X 297) is applicable. (Mm) '— " (Please read the precautions on the back before filling in this page) · —line-546132 A7 ____B7_____15. Description of the invention (Ο) Provides greater image sharpness due to the flicker detection Reduced size of the measuring device. This type of PET is less expensive, more sensitive, and has a relatively low angular degradation of spatial resolution, thus allowing the diameter of the detector ring to be reduced, which in turn reduces the overall cost of the camera . Furthermore, in a two-layer structure, the large difference between the decay time constants of LSO and LuAP (40 ns and 11 ns respectively for 60% of the emitted light) makes the pulse shape distinction a useful option, And allows effective hit layer determination. Those skilled in the art will understand that variations in the configurations disclosed are possible without departing from the invention. Therefore, the description of specific embodiments is made as an example, not for the purpose of limitation. It will be clear to those skilled in the art that small modifications can be made without major changes to the operations described above. (Please read the precautions on the back before filling this page) --line · — ___15 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)