JP2007093376A - Method and apparatus for detecting radiation position - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable emission intensity of each scintillator crystal to be detected by using light-sensitive elements whose number is less than that of scintillator crystals, by overcoming the limit of detectability due to existence of non-sensitive regions inherent in the light-sensitive elements. <P>SOLUTION: A radiation detector includes: a polyhedral scintillator block composed of a plurality of scintillators arranged thereon; and the light-sensitive elements for receiving light emitted from the scintillators caused by incidence of radiation through the scintillators where optical coupling is carried out. In a method for detecting a radiation position, which employs the radiation detector and detects a position of a light-emitting scintillator and energy of absorbed radiation, two or more groups of light-sensitive elements each having the non-sensitive region in at least one surface and coupling optically with different scintillators, are disposed at both edges of a channel passing through the plurality of scintillators, and reflectivity and transmissivity of light at border and peripheral planes of respective scintillators are adjusted, thereby controlling respective groups of light-sensitive elements in allocation of light-receiving amount. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radiation position detection method and apparatus, and more particularly to a scintillator block in which a plurality of scintillators are arranged, which is suitable for use in medical equipment and radiation measuring instruments using nuclear medicine imaging such as PET, and radiation incident. The present invention relates to a radiation position detection method and apparatus for detecting the position of emitted scintillator and the energy of absorbed radiation in a radiation detector including a light receiving element that receives light emitted from the scintillator through an opposing scintillator.

  Certain substances have the property of emitting fluorescence when irradiated with radiation. These substances are called scintillators and are widely used as radiation sensors. In order for the scintillator to produce fluorescence, it needs to receive energy by interaction with radiation. Since high-energy photons such as positron annihilation gamma rays have a high ability to transmit substances, a scintillator crystal having a thickness of 2 cm or more may be installed in the traveling direction of gamma rays in order to detect them efficiently.

  On the other hand, in the field of nuclear medicine imaging, the length of each side of the scintillator crystal is preferably short for the purpose of specifying the incident direction of radiation and increasing the resolution of the image. As a technique for solving this contradiction, a technique has been developed for securing a thickness by stacking a plurality of small scintillator crystals. In this case, high energy photons may pass through a crystal and give energy only to the crystal behind it. In this method, a technique for accurately detecting the emitted crystal is indispensable.

  Usually, the radiation detector is composed of a scintillator crystal element and a light receiving element, and the crystal element that has emitted light can be identified by calculating the position based on the light emission amount of the crystal element measured by the light receiving element.

  Two-dimensional detection of radiation is generally performed by position calculation of a detector signal in a gamma camera or the like. Several methods have been proposed for three-dimensional detection, but the most common is, for example, as described in Patent Document 1, crystal elements having different scintillation waveforms are stacked in the depth direction, This is a method of obtaining depth information by specifying the type of crystal. However, in this method, it is necessary to devise a method to make up for the difference in the performance of a plurality of types of crystals used.

  In Patent Document 1, the space between the scintillator cells is filled with air, light reflecting material (metal foil, polymer film, inorganic powder), light transmitting material (silicone oil, transparent adhesive), etc., and the optical surface for each scintillator cell It also describes that the total amount of light received by the light receiving element is made uniform by optimizing the combination of conditions (mirror surface or rough surface) and a light reflecting material and a light transmitting material.

  On the other hand, as three-dimensional detection in a crystal arrangement in which crystal elements of the same kind and the same size are stacked, in Patent Documents 2 and 3, as shown in FIG. A light path 130 that reaches the light receiving elements 111 and 112 at both ends is formed, and the scintillator determines how many times the emitted light passes through the boundary surfaces 120 to 126 of the scintillator cells 101 to 106 before reaching the light receiving elements 111 and 112. The scintillator cells that emit light are specified by the output ratio of the light receiving elements 111 and 112 so as to be different for each of the cells 101 to 106, and, as shown in FIG. To the boundary surface of ˜316, if necessary, the reflection sheet 331 of the entire area, the reflection sheet 332 of about half the area, about 1/4 of the reflection sheet By inserting the reflective sheet 333 of the product or silicone oil and identifying the incident position from the output ratio to the light receiving elements 321 to 324 as shown in FIG. 3, not only in the vertical and horizontal directions but also in the height direction, γ rays It is described that the radiation incident position is detected three-dimensionally by identifying which scintillator cell is incident.

  Patent Documents 1 to 3 are based on the condition that there is no insensitive region of the light receiving element. However, Patent Documents 4 to 7 describe a crystal element arranged outside the sensitivity effective region of the light receiving element using a light guide. It is described that the light emission of is led to the sensitivity effective region.

JP 2004-132930 A Japanese Patent No. 3597979 (FIGS. 1, 9, and 13) JP-A-11-142524 IEEE Transaction on Nuclear Vol.33 No.1 (February 1986) pp460-463 IEEE Transaction on Nuclear Vol.45 No.6 (December 1998) pp3000−3006 IEEE Transaction on Nuclear Vol.46 No.3 (June 1999) pp542-545 IEEE Transaction on Nuclear Vol.50 No.3 (June 2003) pp367-372

  To achieve high sensitivity of the device, it is ideal to arrange the light receiving elements without gaps corresponding to the scintillator crystal. However, considering the cost effectiveness, the number of light receiving elements is reduced and the existence of the insensitive area of the light receiving elements is overcome. Technology to do this is required.

  Note that the use of a light guide is not preferable because it often causes the detector configuration to be complicated and the crystal discrimination ability to deteriorate due to an increase in signal fluctuation accompanying light loss.

  Also, the method of adjusting the area of the reflection sheet is difficult to detect three-dimensionally with the same crystal.

  In addition, the present invention was made to solve the above-mentioned conventional problems, overcomes the limit of detection capability due to the presence of the insensitive region unique to the light receiving element, and uses each light receiving element having a smaller number than the scintillator crystal, It is an object to make it possible to detect the emission intensity of a scintillator crystal.

  The present invention is a radiation detector including a scintillator block composed of a polyhedron in which a plurality of scintillators are arranged, and a light receiving element that receives light emitted from the scintillator by incidence of radiation through a scintillator that is optically bonded, and the position and absorption of the emitted scintillator. A radiation position detection method for detecting the energy of emitted radiation, wherein two or more groups of light receiving elements optically joined to different scintillators and having a dead area in at least one plane are at both ends of a path passing through the plurality of scintillators By adjusting the reflectance and transmittance of light on the boundary surface and outer peripheral surface of each scintillator, the peak position of the emission intensity distribution of each scintillator crystal incident on the light receiving element is shifted, for example, to solve the above problem It is a thing.

  Further, at least two groups of the light receiving elements are provided by optically joining predetermined scintillators to the outer surfaces of the scintillator blocks in different directions.

  Further, at least two groups of the light receiving elements are each provided by optically joining a predetermined scintillator on the outer surface in the same direction of the scintillator block.

  Further, the scintillator to which at least one group of the light receiving elements is optically bonded includes a scintillator positioned in contact with one side of the scintillator block.

  The scintillator positioned in contact with one side of the scintillator block is positioned at a corner of the scintillator block.

  In addition, light receiving elements are arranged at both corners of one side of a rectangular surface, and both light receiving elements are optically joined to at least two or more scintillators extending along the side in a direction perpendicular to the one side. Is.

  Further, light emitted from the scintillator passes through the non-light receiving scintillator surface and enters the light receiving elements via a one-stroke path connecting the two groups of light receiving elements.

  Further, the reflectance and transmittance of light on the boundary surface and outer peripheral surface of the scintillator are adjusted by using at least one of a light reflecting material, an air layer, optical grease, a transparent adhesive, and a crystal surface state. It is a thing.

  Here, the polymer as the light reflecting material is, for example, an ESR film manufactured by Sumitomo 3M, the optical grease is, for example, silicon oil KF96H (1 million CS) manufactured by Shin-Etsu Chemical, and the transparent adhesive is, for example, Shin-Etsu Chemical. One-component RTV rubber KE420 manufactured by the company can be used.

  The present invention is also a radiation position detecting device for detecting the position of the emitted scintillator and the energy of the absorbed radiation, and includes a scintillator block in which a plurality of scintillators are arranged, and light emission of the scintillator by incidence of radiation. Radiation including two or more groups of light receiving elements each having a non-sensitive area in one plane provided at both ends of a path passing through a plurality of scintillators for receiving light through opposing scintillators with a non-light receiving scintillator surface interposed therebetween. Reflector / transmittance for adjusting the distribution of the amount of light received by each group of the light receiving elements by adjusting the reflectance and transmittance of light disposed on the boundary surface and outer peripheral surface of the detector and each crystal element. The problem is solved by providing the adjusting means.

  Here, the group of light receiving elements of “two or more light receiving elements” is, for example, a PMT in the case of a 256 channel flat panel position sensitive photomultiplier tube (256 channel position discriminating photomultiplier tube (PMT): H9500 manufactured by Hamamatsu Photonics). Although there are 256 light receiving parts, if 4 × 4 light receiving elements face one scintillator, the 16 light beams constitute one group.

  Hereinafter, the principle of the present invention will be described.

  FIG. 4 shows the principle of two-dimensional detection that is the principle of the present invention. Consider a detector in which 1 × 2 array of scintillation crystals a and b are installed on two independent light receiving elements 12A and 12B. For simplicity, it is assumed that the crystal arrangement is covered with a highly reflective material 16 having a reflectivity of 100%, and all light emitted when detecting radiation (γ rays) enters the light receiving element 12A or 12B. The positional relationship between the crystal element a and the light receiving element A is referred to as being disposed opposite to each other.

  As shown in the upper part of FIG. 4 (A), when the crystal elements a and b are partitioned by a highly reflective material 18 having a reflectance of 100%, no light is emitted to the adjacent crystal when detected by either crystal. The output is only from the light receiving element directly below the detection crystal. Therefore, the histogram in which the horizontal axis indicates the result of the calculation of the center of gravity of the output (B−A) / (A + B) is as shown in the lower part of FIG. The detection crystal is specified by looking at which distribution it belongs to on such a histogram.

  On the other hand, as shown in the upper part of FIG. 4B, when the crystal elements a and b are separated by a low-reflecting material 20 having a reflectance of 50% and a transmittance of 50%, the light emitted from the detection crystal is also emitted to the adjacent crystal. Since it spreads, a weak output is generated from the adjacent light receiving element, and the histograms approach each other as shown in the lower part of FIG. Here, the low reflective material refers to a non-absorbing partially transmissive reflective material.

  In addition, as shown in the upper part of FIG. 4C, when the reflecting material between the crystal elements a and b is removed and the air layer 22 is extracted, the spread of light to the next crystal increases, but the refraction of the crystal and air Due to the difference in rate and the characteristics of the surface state of the crystal, the output of the light receiving element directly below the light emitting crystal is slightly increased. As a result, the histogram is as shown in the lower part of FIG.

  FIG. 5 shows the case where the reflectors 18 and 20 or the air layer 22 having different optical characteristics are inserted into the 8 × 8 two-dimensional crystal array 14 straddling two pairs of light receiving elements 24A to D and 24E to 24H. It is an example of an effect. One light receiving element has a size corresponding to two crystals in the vertical and horizontal directions, and the bottoms of two crystals at both ends are in contact with the light receiving element. Crystal identification is performed on a two-dimensional position histogram which is a result of expanding the histogram of FIG. 4 two-dimensionally and calculating the position. As shown in FIGS. 4B and 4C, light is emitted to a plurality of light receiving elements. When the light is devised so as to reach, as shown in FIG. 5 (C), the distance between the distributions increases as the reflectance of the inserted reflector increases, and the air layer becomes narrower. Thus, the position of the two-dimensional position histogram distribution can be manipulated by devising the optical characteristics in the crystal array 14.

  In the radiation detector, if the distribution on the two-dimensional position histogram corresponding to each crystal element does not overlap each other, the detection crystal can be specified. As described above, using materials with different reflection and transmission characteristics, taking advantage of the characteristics of the surface state of the crystal to control the light spread within the crystal array, the position of the distribution appearing in the two-dimensional position histogram is optimal for crystal identification can do.

  In the present invention, the above-described method is applied to specify a crystal in between that is not in contact with the sensitivity effective region of the light receiving element. Crystal identification becomes more difficult as the ratio between the distance between the sensitivity effective regions and the crystal size increases. In addition, it is more difficult to identify crystals in a three-dimensional array. However, when the present invention is used, as shown in FIGS. 6A and 6B, even if the upper crystal array 15 is superimposed on the lower crystal array 14, each crystal as shown in FIG. Can be identified.

  Consider a simple radiation detector having a 2 × 2 × 2 three-dimensional crystal in which 2 × 2 two-dimensional crystals are stacked in two stages. Here, as shown in the upper part of FIG. 7 (A) or (B), the two-dimensional crystals (arrays) 32 and 34 in which the interface is air and the high reflective material 16 is wound around so that light does not leak outside. Are stacked in two stages, and the light receiving elements 12A and 12B are arranged at two crystal positions of the four crystals on the bottom surface thereof, the result of the center of gravity calculation of the outputs A and B of the light receiving elements 12A and 12B ( Histograms of (B−A) / (A + B) are as shown in the lower part of FIGS. 7A and 7B, respectively. As shown in the upper part of FIG. 7A, the light receiving elements 12A and 12B are arranged on one side. When arranged, the outputs of the crystal elements a and e, the crystal elements b and f, the crystal elements d and h, and the crystal elements c and g cannot be distinguished from each other as shown in the lower stage. 7B, when the light receiving elements 12A and 12B are arranged at diagonal positions, the crystal elements a and e, the crystal elements b, c, f and g, The outputs of the crystal elements d and h overlap and cannot be distinguished.

  On the other hand, as shown in the upper part of FIGS. 8A, 8B, and 8C, since it has transmission characteristics, it has a lower reflectance than the high reflector 16, for example, a reflectance of 50% and a transmittance of 50%. When the low reflection material 20 is inserted into the interface as appropriate, the output distribution of each crystal element is separated as shown in the lower stage, and the output of the pair of light receiving elements 12A and 12B causes all the crystal elements a to g to be separated. The output can be identified.

  The same applies to the case where the 1 × 3 one-dimensional crystal arrays 42 and 44 are stacked in two stages to form a 1 × 3 × 2 two-dimensional solid crystal as shown in FIG.

  The present invention has been made based on such knowledge.

  According to the present invention, it is possible to overcome the limitation of the detection capability due to the presence of the insensitive region unique to the light receiving element, and to achieve the desired detector performance with a smaller number of light receiving elements than the crystal element, and the ratio of cost to effect In addition, the signal processing circuit can be simplified and the apparatus can be operated stably. Furthermore, since it is not necessary to change the length and area of the reflecting material in each crystal element, the detector structure is simple and easy to make, and can withstand mass production essential to the apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 10, the radiation detector 50 of the present embodiment is similar to that shown in FIG. 6, each crystal of the two-dimensional crystal arrays 14 and 15 including 16 × 8 × 8 crystal elements of the same kind and the same size. A 100% high-reflecting material 18, 50% low-reflecting material 20 and an air layer 22 are appropriately interposed between the elements, and the top and side surfaces are 100% high-reflecting material so that light does not leak outside. 16, the lower layer crystal array 14 and the upper layer crystal array 15 are overlapped to form two stages, and four pairs of light receiving elements 24 </ b> A to 24 </ b> D and 24 </ b> E to 24 </ b> H are arranged on both sides on the lower side.

For example, an avalanche photodiode or a photomultiplier tube (PMT) can be used as the light receiving elements 24A to 24H.
As shown in FIG. 11, the outputs of the light receiving elements 24A to 24H are input to the position calculating unit 54 via the readout circuit 52, where the position calculation of the light receiving element outputs A to H is performed, for example, according to the following equation.

x = {4/4 (A + E) +3/4 (B + F) +2/4 (C + G)
+1/4 (D + H)} / (A + B +... + H) (1)
y = {4/4 (E + F + G + H) +1/4 (A + B + C + D)}
/(A+B+...+H) (2)

  The position calculation result by the position calculation unit 54 is displayed on the display unit 56 as a two-dimensional position histogram. In the figure, reference numeral 48 denotes a power source.

  In this embodiment, crystal elements of the same type and the same size are used, so the configuration is simple and no problem arises due to the difference in crystal performance. Note that different types and sizes of crystal elements may be used in combination. Further, the crystal arrangement is not limited to two stages, and may be one stage (two-dimensional) or three or more stages.

  In the present embodiment, since the light guide is not used, the detector configuration is not complicated by the insertion of the light guide, and the crystal discrimination ability is not deteriorated due to an increase in signal fluctuation accompanying light loss. Note that the light guide can be used as long as it does not cause a problem.

  Furthermore, the number and arrangement positions of the light receiving elements are not limited to the above embodiment, and various arrangements can be made as illustrated in FIGS. 12A to 12F, and they may be in the central portion instead of the periphery. . Moreover, as shown in FIG. 13, it may be arranged on the side surface instead of the bottom surface of the crystal, or may be arranged for each layer. Further, the combination of the light receiving elements is not limited to the two groups of 1: 1, and may be a combination of 1: n or m: n as three or more groups. The number of paths between the light receiving elements is not limited to one, and a plurality of paths may be limited between the light receiving elements.

  Also, the means for adjusting the reflectance is not limited to the reflective material and the air layer with the reflectance of 100% and 50%, but a reflective material other than the reflectance of 100% and 50% is used, or optical grease or a transparent adhesive is used. Thus, the transmittance can be increased, or the surface state of the crystal can be adjusted as a mirror surface by mechanical polishing, a mirror surface by chemical polishing, or a rough surface.

  Note that, as in Compton scattering, when a gamma ray imparts energy to a crystal at a plurality of locations, the plurality of crystals may emit light almost simultaneously. In such an event, an output different from the case where all energy is applied to one crystal is obtained, but the necessity of such a signal depends on the purpose of the measurement, and if it is unnecessary, it is a signal by electronics or software It may be removed by processing.

In the configuration of the above embodiment, as a crystal element, a LYSO crystal (Lu _{2 (1-x)} Y _2x SiO ₅ (x = 0.02) (LYSO) having a mirror surface with a size of 1.46 mm × 1.46 mm × 4.5 mm is used. ), The surface state is a mirror-like (mechanical polishing, manufactured by Proteus, USA) array of 8 × 8 in two layers, and a highly reflective material 18 with reflective and transmissive characteristics as shown in FIG. 14 (ESR manufactured by Sumitomo 3M) Film) and low reflection material 20 (Lumirror 38X20 manufactured by Toray Industries, Inc.) are inserted as shown in FIG. 10, and optical grease (silicon oil KF96H (1 million CS) manufactured by Shin-Etsu Chemical Co., Ltd.) is applied between the layers 14 and 15. Using a 256 channel position-discriminating photomultiplier tube (PS-PMT) with a sampling interval (anode interval) of 3.04 mm as the light receiving element (256 channel flat panel position sensitive photomultiplier tube: H9500 manufactured by Hamamatsu Photonics) region On the PS-PMT, a high-reflection material 16 of the same type as the high-reflection material 18 is laid on the PS-PMT to block light from entering the area. The x8 crystal arrangement two layers are located.

  FIG. 15A shows a two-dimensional position histogram obtained by uniformly irradiating 662 keV γ rays from a Cs ray source (corresponding to the position where “detects the position and energy of the emitted scintillator” in the claims). . In the figure, “upper” is the crystal distribution of the upper layer 15, and “lower” is the crystal distribution of the lower layer 14. The count values are shown in shades. FIG. 15B shows a comparison of the light intensity distribution at the center of each layer of the three-dimensional array and the portion in contact with the light receiving element (corresponding to the energy “detecting the position and energy of the emitted scintillator” in the claims). The ratio of the wave heights of the crystal regions 1, 2, 3, 4 is 1.00: 0.91: 0.61: 0.63, which is high by suppressing the optical loss in the central portion not in contact with the light receiving element. The wave height can be obtained. As a result, energy resolutions of 16.3%, 17.9%, 22.0%, and 19.8% were obtained. From these results, it was confirmed that the image quality of an image that can be imaged when using the apparatus is improved, and crystals of a three-dimensional array that are not in contact with the light receiving element can be identified by the present invention.

  When discriminating crystals of a three-dimensional array installed between light receiving elements having a plurality of light receiving parts as in the embodiment, the light receiving parts are continuously arranged only on both sides of the crystal array. In the structure, it is preferable that two light receiving portions on both sides and a crystal arrangement configuration straddling the light receiving portions be one unit.

  9 and FIG. 16 can also be one unit even on each side of the light receiving section configuration (12A, 12B). In particular, in the case of FIG. 16 where there are many scintillators sandwiched between the light receiving elements 12A and 12B, FIG. Compared to the above, the histograms are duplicated and are difficult to identify. On the other hand, in the two light receiving unit configurations (12A, 12C) (12B, 12D) on each side shown in FIG. 17, the position histogram becomes two-dimensional by a position calculation expression as shown in FIG. Since the distribution of the amount of light received by each group of light receiving elements can be finely adjusted with respect to the direction and the degree of freedom increases, the number of crystals that can be identified can be increased considerably, and the crystal identification ability is doubled. That is, as shown in FIG. 17, in the case of a 2 × 7 row configuration as viewed from the top, if there are two 1 × 7 configurations as shown in FIG. It becomes a one-dimensional line. On the other hand, as shown in FIG. 17, when a set of 2 × 7 is used, the position histogram can be expressed in a two-dimensional plane because the seven directions and the two directions can be distinguished.

Sectional drawing for demonstrating the detection principle of the radiation incident position three-dimensional detector described in patent document 2 Same perspective view The figure showing the image which similarly shows the correspondence of each point and the scintillator cell of a three-dimensional detector (A) Cross section of crystal and (B) Histogram showing the spread of light emitted from the detection crystal for explaining the principle of the present invention (A) Plan view (B) Side view and (C) Two-dimensional position histogram of the same two-dimensional array crystal (A) Plan view (B) Side view and (C) Two-dimensional position histogram of the same three-dimensional array crystal Perspective view and histogram for explaining problems when a single reflector is used in a 2 × 2 × 2 three-dimensional array crystal Similarly, a perspective view and a histogram when the reflecting material is adjusted according to the present invention Similarly perspective view and histogram in the case of a 1 × 3 × 2 solid crystal The disassembled perspective view which shows the structure of embodiment of the radiation detector concerning this invention. Similarly, a block diagram showing a signal processing circuit Plan view showing a modification of light receiving element arrangement A perspective view and a histogram showing another modification example The figure which shows the (A) reflection characteristic and (B) transmission characteristic of the reflecting material used in the Example of this invention. The figure which shows the measurement result of the wave height distribution of the part which touches the (A) two-dimensional position histogram in the said Example, and the (B) three-dimensional array center and a light receiving element. Similarly perspective view and histogram in the case of 1 × 7 × 2 solid crystal A perspective view and a histogram in the case of a 2 × 7 × 2 solid crystal

Explanation of symbols

12A, 12B, 24A-24H ... light receiving element 14 ... lower layer crystal arrangement 15 ... upper layer crystal arrangement 16,18 ... high reflection material 20 ... low reflection material 22 ... air layer 50 ... radiation detector 52 ... output readout circuit 54 ... position calculation 56: Display unit

Claims (9)

A radiation detector including a scintillator block composed of a polyhedron in which a plurality of scintillators are arranged, and a light receiving element that receives light emitted from the scintillator by the incidence of radiation through a scintillator that is optically bonded. The position of the emitted scintillator and the absorbed radiation A radiation position detection method for detecting energy, comprising:
Two or more light-receiving elements that are optically bonded to different scintillators and have at least one insensitive area are provided at both ends of a path that passes through the plurality of scintillators.
A radiation position detection method, comprising: adjusting a distribution of received light amount of each group of the light receiving elements by adjusting a reflectance and a transmittance of light on a boundary surface and an outer peripheral surface of each scintillator.   The radiation position detection method according to claim 1, wherein at least two groups of the light receiving elements are optically joined to predetermined scintillators on outer surfaces of the scintillator blocks in different directions.   A radiation position detecting method, wherein at least two groups of the light receiving elements are each optically bonded to a predetermined scintillator on an outer surface in the same direction of the scintillator block.   4. The radiation position detection method according to claim 1, wherein the scintillator to which at least one group of the light receiving elements is optically bonded includes a scintillator positioned in contact with one side of the scintillator block.   The radiation position detection method according to claim 4, wherein a scintillator positioned in contact with one side of the scintillator block is positioned at a corner of the scintillator block.   Each of the light receiving elements is disposed at both corners of one side of a rectangular surface, and both the light receiving elements are optically joined to at least two or more scintillators extending along the side in a direction perpendicular to the one side. The radiation position detection method according to claim 1.   7. The light emitted from the scintillator is incident on both light receiving elements through a one-stroke path connecting the two groups of light receiving elements through the non-light receiving scintillator surface. Radiation position detection method.   The light reflectance and transmittance of the boundary surface and the outer peripheral surface of the scintillator are adjusted using at least one of a light reflecting material, an air layer, optical grease, a transparent adhesive, and a crystal surface state. The radiation position detection method according to claim 1. A radiation position detection device for detecting the position of emitted scintillator and the energy of absorbed radiation,
A scintillator block in which a plurality of scintillators are arranged, and a scintillator block that receives light emitted from the scintillator due to the incidence of radiation through opposite scintillators, provided at both ends of a path that passes through the plurality of scintillators, with a non-light-receiving scintillator surface in between A radiation detector including two or more groups of light receiving elements having insensitive areas in one plane;
Reflection / transmittance adjusting means for adjusting the reflectance and transmittance of light disposed on the boundary surface and the outer peripheral surface of each crystal element to adjust the distribution of the amount of light received by each group of the light receiving elements,
A radiation position detection apparatus comprising: