JP5126049B2 - Nuclear medicine diagnosis apparatus, morphological tomography diagnosis apparatus, nuclear medicine data calculation processing method, and morphological tomography image calculation processing method - Google Patents

Description

  The present invention relates to a nuclear medicine diagnostic apparatus, a morphological tomography diagnostic apparatus, and a nuclear medicine data calculation processing method for obtaining nuclear medicine data or a morphological tomographic image of a subject based on radiation generated from a subject administered with a radiopharmaceutical. And a morphological tomographic image processing method.

  As the above-described nuclear medicine diagnosis apparatus, that is, an ECT (Emission Computed Tomography) apparatus, a PET (Positron Emission Tomography) apparatus will be described as an example. The PET apparatus detects a plurality of gamma rays generated by annihilation of positrons, that is, positrons, and reconstructs a tomographic image of a subject only when the gamma rays are simultaneously detected by a plurality of detectors. It is configured.

  Specifically, a radiopharmaceutical containing a positron emitting nuclide is administered into a subject, and a 511 KeV pair annihilation gamma ray released from the administered subject consists of a group of a number of detection elements (for example, scintillators). Detect with a detector. And if γ-rays are detected at the same time by two detectors within a certain period of time, they are counted as a pair of annihilation γ-rays, and the point of occurrence of pair annihilation is on the straight line of the detected detector pair Is identified. By accumulating such coincidence information and performing reconstruction processing, a positron emission nuclide distribution image (ie, a tomographic image) is obtained (see, for example, Patent Documents 1 and 2).

  In order to maintain quantitativeness and maintain image quality in nuclear medicine diagnosis, it is essential to absorb and correct the coincidence count information data (also referred to as “emission data”). The absorption of coincidence data in the PET apparatus depends on the path (path) through which the γ-ray passes through the subject, and does not depend on the generation point of γ-ray (positron annihilation generation point). Therefore, usually, an external radiation source that irradiates the same kind of radiation as the radiopharmaceutical (in this case, gamma rays) is used. Then, as the morphological information (also called “transmission data”) based on the γ-rays irradiated from the external radiation source and transmitted through the subject, the reciprocal of the transmittance or the absorption correction value obtained from the absorption coefficient map is used as the emission projection data. Absorption correction can be performed by multiplying by. Recently, a technique has been adopted in which morphological information obtained from an X-ray CT apparatus (PET-CT apparatus) integrated with a PET apparatus instead of an external radiation source is converted into an absorption coefficient map and used for absorption correction. Yes.

  However, when it is difficult to mount an external radiation source, etc., and the inside of the subject can be assumed to be a uniform absorber, the contour of the subject is estimated from the emission data and images, and the inside is a uniform absorber. It is also assumed that absorption correction is performed (see, for example, Non-Patent Document 1).

  On the other hand, in recent years, particularly in the development for high-resolution PET, as a scintillator constituting the detector, the amount of light emission when the scintillator converts radiation to light, the short emission decay time, and the prevention of γ rays A scintillator (LSO, LYSO, LGSO, etc.) containing Lu-176 has come to be used because of a good balance of characteristics such as high performance. Each of these characteristics can be improved in resolution (scintillator downsizing), high count rate characteristics (high-speed event processing), and high sensitivity (high probability of detecting γ rays). It will be the basis that influences.

  However, the element called Lu-176 itself is a radioactive substance, followed by β decay (99.9%, maximum 596 KeV), followed by three gamma decays (300 KeV, 94%, 202 KeV, 78%, 88 KeV, 15%). Since this occurs, there are cases where any plural (two or more) of these radiations are counted simultaneously. This coincidence count cannot be subtracted as an “accidental coincidence count”. However, in PET collection, in order to remove a low energy background such as a scattering component, an energy lower limit threshold (300 to 400 KeV) is usually provided (see, for example, Non-Patent Documents 2 and 3). Then, other than γ-rays (511 KeV) from positrons (ie, radiopharmaceuticals) as detection targets are removed. It has been reported that the self-radioactivity of Lu-176 can be suppressed to an almost negligible level by setting this energy threshold to about 400 KeV. Thus, since the self-radioactivity of Lu-176 can become background noise, suppressing the component has become a main problem in the past.

On the other hand, it is necessary to suppress the self-radioactivity at the time of coincidence counting, but daily check of the detector (including photomultiplier tube (PMT) and electric circuit) using the self-radioactivity. A method for performing the above has also been proposed (see Non-Patent Document 4).
Japanese Patent Laid-Open No. 7-113873 JP 2000-28727 A Koji Kitamura, Ryohiro Ishikawa, Tetsuro Mizuta, Eiji Yoshida, Yasuga Yamatani “Development of Various Data Correction Methods in jPET-D4”, 2005 Next Generation PET Device Development Research Report, p. 47-51 Andrew L. et al; “On the imaging of very weak sources in an LSO PET Scanner”, IEEE MIC 2007, Conf Rec, MO7-5 S Yamamoto et al, “Investigation of single, random, and true counts from natural radioactivity in LSO-based clinical PET”, Ann Nucl Med, vol.19, pp109-114, 2005 Christof Knoess et al, “Development of Daily Quality Check Procedure for the High-Resolution Research Tomograph (HRRT) Using Natural LSO Background Radioactivity”, IEEE Trans. Nucl. Sci., Vol. 49, No. 5, P2074, 2002

  The conventional absorption correction method using an external radiation source or an X-ray CT image as described above is highly accurate and effective. However, when the detector is close to the subject for the purpose of improving sensitivity and spatial resolution, it is not possible to secure a space for mounting a collimated external radiation source or a mechanism for rotating it (radiation source rotation mechanism). There is. In the case of a mammographic PET apparatus applied to a mammogram for breast cancer detection, it is necessary to bring the body (breast) of the subject and the detector as close as possible. In such a case, if the inside of the subject can be regarded as a uniform absorber, absorption correction is performed by extracting the contour of the subject from the emission data or image as described above and regarding the inside as a uniform absorber. The method of doing is taken. However, when the radioactivity accumulation at the edge (edge) of the subject is extremely small, the contour cannot be extracted, and the accuracy of contour extraction deteriorates. In addition, the accuracy of contour extraction may deteriorate even when there is an extreme deviation in the distribution of the edge of the subject. Thus, depending on the accumulation state of the radiopharmaceutical, stable contour information cannot be obtained, and stable absorption correction cannot be performed.

  The present invention has been made in view of such circumstances, and can acquire a morphological tomographic image that can perform stable absorption correction and can be used for data processing / diagnosis for nuclear medicine or grasping of morphological information. It is an object of the present invention to provide a nuclear medicine diagnostic apparatus, a morphological tomography diagnostic apparatus, a nuclear medicine data calculation processing method, and a morphological tomographic image calculation processing method.

In order to achieve such an object, the present invention has the following configuration.
That is, the invention described in claim 1 is a nuclear medicine diagnostic apparatus for obtaining nuclear medicine data of a subject based on radiation generated from the subject administered with a radiopharmaceutical, and simultaneously releases a plurality of radiations. One of the radiation detection means configured to contain an element and one of the radiation emitted by the element in the absence of the subject is counted by the radiation detection means containing the element itself, and the other is detected by another radiation. A blank data collection unit that collects the coincidence data simultaneously counted as blank data by counting with the unit, and one of the radiations emitted by the element in the state where the subject exists includes the element By counting by the radiation detection means itself and counting the other by another radiation detection means, the simultaneous count data that has been simultaneously counted is transmitted. Transmission data collection means for collecting data, and emission data collection for collecting simultaneously counted data as emission data by counting radiation generated from the subject to which the radiopharmaceutical is administered by the radiation detection means Absorption correction data calculating means for obtaining absorption correction data of a subject based on both the blank data collected by the blank data collection means and the transmission data collected by the transmission data collection means , or only transmission data An absorption correction unit that performs absorption correction of the emission data collected by the emission data collection unit using the absorption correction data and finally obtains the absorption-corrected data as the nuclear medicine data. The one in which the features.

[Operation / Effect] According to the first aspect of the present invention, the radiation detecting means comprising the element that simultaneously emits a plurality of radiations is provided. In the absence of the subject, one of the radiations emitted by the element described above is counted by the radiation detection means itself containing the element, and the other is counted by another radiation detection means, thereby simultaneously counting the simultaneous counts. The counting data is collected as blank data by the blank data collecting means. On the other hand, in a state where the subject is present, one of the radiations emitted by the above-described element is counted by the radiation detection means itself containing the element and the other is counted by another radiation detection means, thereby being simultaneously counted. The transmission data collection means collects the coincidence data as transmission data. In addition, by counting the radiation generated from the subject to which the radiopharmaceutical has been administered by the radiation detection means described above, the emission data collection means collects the simultaneously counted coincidence data as emission data. The degree of radiation absorption (including transmission) depending on the presence or absence of the subject based on both the blank data collected by the blank data collection means and the transmission data collected by the transmission data collection means , or only the transmission data. Thus, the absorption correction data calculation means can obtain the absorption correction data of the subject. The absorption correction means performs absorption correction of the emission data collected by the above-described emission data collection means using the absorption correction data, and finally obtains the absorption-corrected data as nuclear medicine data. In this way, background data obtained by self-radioactivity (elements that simultaneously emit a plurality of radiations) typified by Lu-176 is rejected, but the background data is used in reverse. And used for absorption correction data. By using the absorption correction data in this way, it is not necessary to mount an external radiation source or the like more than necessary, the radiation detection means can be brought close to the subject, and the form information obtained from the emission data is used more than necessary. There is no need, and stable absorption correction can be performed.

  Moreover, when collecting blank data using the radiation detection means comprised including self-radioactivity (the element which discharge | releases several radiation simultaneously), the morphological tomography diagnostic apparatus in this invention is as follows. A configuration may be adopted.

  That is, the invention according to claim 2 is a morphological tomography diagnostic apparatus for obtaining a morphological tomographic image of a subject based on radiation generated from the subject to which a radiopharmaceutical is administered, and simultaneously emits a plurality of radiations. One of the radiation detection means configured to contain an element and one of the radiation emitted by the element in the absence of the subject is counted by the radiation detection means containing the element itself, and the other is detected by another radiation. A blank data collection unit that collects the coincidence data simultaneously counted as blank data by counting with the unit, and one of the radiations emitted by the element in the state where the subject exists includes the element By counting by the radiation detection means itself and counting the other by another radiation detection means, the coincidence count data simultaneously counted is transmitted. Transmission data collecting means for collecting data as transmission data; fluoroscopic image obtaining means for obtaining a fluoroscopic image of a subject based on the blank data collected by the blank data collecting means and the transmission data collected by the transmission data collecting means; Morphological tomographic image acquisition means for reconstructing the fluoroscopic image and acquiring the morphological tomographic image of the subject is provided.

  [Operation / Effect] According to the second aspect of the present invention, the radiation detecting means comprising the element that simultaneously emits a plurality of radiations is provided. In the absence of the subject, one of the radiations emitted by the element described above is counted by the radiation detection means itself containing the element, and the other is counted by another radiation detection means, thereby simultaneously counting the simultaneous counts. The counting data is collected as blank data by the blank data collecting means. On the other hand, in a state where the subject is present, one of the radiations emitted by the above-described element is counted by the radiation detection means itself containing the element and the other is counted by another radiation detection means, thereby being simultaneously counted. The transmission data collection means collects the coincidence data as transmission data. Based on the blank data collected by the blank data collection means described above and the transmission data collected by the transmission data collection means described above, the degree of radiation absorption (including transmission) depending on the presence or absence of the subject is known, and the subject is seen through. The fluoroscopic image acquisition means can acquire the image. Then, the perspective image is reconstructed to obtain a morphological tomographic image. In this way, background data obtained by self-radioactivity (elements that simultaneously emit a plurality of radiations) typified by Lu-176 is rejected, but the background data is used in reverse. Thus, a morphological tomographic image that can be used for data processing / diagnosis for nuclear medicine or grasping of morphological information can be acquired.

The invention according to claim 17 is a nuclear medicine data arithmetic processing method for performing arithmetic processing on nuclear medicine data of a subject based on radiation generated from a subject administered with a radiopharmaceutical, (1) In the absence of the subject, the radiation detection means itself comprising an element that simultaneously emits a plurality of radiations counts one of the radiations emitted by the element and the other as another A step of collecting coincidence data simultaneously counted as blank data by counting with a radiation detection means; and (2) one of the radiations emitted by the element in the state where the subject is present. In addition to counting by the radiation detection means itself including the other, and counting the other by another radiation detection means, the simultaneously counted simultaneous count data is collected as transmission data And (3) collecting simultaneously generated count data as emission data by counting radiation generated from the subject to which the radiopharmaceutical has been administered by the radiation detection means, and (4) A step of obtaining the absorption correction data of the subject based on both the blank data and the transmission data or only the transmission data , and (5) a step of performing absorption correction of the emission data using the absorption correction data. The calculation process of the steps (1) to (5) for finally obtaining the absorption-corrected data as the nuclear medicine data is performed.

[Operation / Effect] According to the invention described in claim 17, radiation detection means itself configured to include an element that simultaneously emits a plurality of radiations in the absence of a subject is emitted by the above-described elements. By counting one of the radiations and counting the other by another radiation detection means, the simultaneously counted coincidence data is collected as blank data in the step (1). On the other hand, in a state where the subject is present, one of the radiations emitted by the above-described element is counted by the radiation detection means itself containing the element and the other is counted by another radiation detection means, thereby being simultaneously counted. The coincidence data is collected as transmission data in the step (2). Further, by counting the radiation generated from the subject to which the radiopharmaceutical has been administered by the above-described radiation detection means, the coincidence count data is collected as emission data in the step (3). Based on both the blank data and the transmission data described above , or the transmission data alone , the degree of radiation absorption (including transmission) depending on the presence or absence of the subject can be determined. It can be obtained. Using the absorption correction data, in step (5), the emission data is subjected to absorption correction, and the absorption-corrected data is finally obtained as nuclear medicine data. The arithmetic processing in the steps (1) to (5) is performed on nuclear medicine data. As described above, by using the background data obtained by the elements that simultaneously emit a plurality of radiations and using the data as absorption correction data, stable absorption correction can be performed.

  When blank data is collected using radiation detecting means configured to include self-radioactivity (elements that simultaneously emit a plurality of radiations), the morphological tomographic image calculation processing method according to the present invention is as follows. A simple configuration may be adopted.

  That is, the invention according to claim 18 is a morphological tomographic image processing method for performing arithmetic processing on a morphological tomographic image of a subject based on radiation generated from a subject to which a radiopharmaceutical is administered. In a state where there is no subject, the radiation detection means itself including an element that simultaneously emits a plurality of radiations counts one of the radiations emitted by the element and the other by another radiation detection means. A step of collecting coincidence data simultaneously counted by counting as blank data, and (2) radiation detection including one of the radiations emitted by the element in a state where the subject is present. By counting by the means itself and counting the other by another radiation detecting means, the coincidence count data simultaneously counted is collected as transmission data. And (6) obtaining a fluoroscopic image of the subject based on the blank data and the transmission data, and reconstructing the obtained fluoroscopic image of the subject to obtain the morphological tomographic image ( It is characterized by performing the arithmetic processing of steps 1), (2), and (6).

  [Operation / Effect] According to the invention described in claim 18, the radiation detecting means itself including an element that simultaneously emits a plurality of radiations in the absence of a subject is emitted by the element described above. By counting one of the radiations and counting the other by another radiation detection means, the simultaneously counted coincidence data is collected as blank data in the step (1). On the other hand, in a state where the subject is present, one of the radiations emitted by the above-described element is counted by the radiation detection means itself containing the element and the other is counted by another radiation detection means, thereby being simultaneously counted. The coincidence data is collected as transmission data in the step (2). Based on the blank data and the transmission data described above, the degree of radiation absorption (including transmission) depending on the presence or absence of the subject can be known, and a fluoroscopic image of the subject can be acquired in the step (6). Then, the perspective image is reconstructed to obtain a morphological tomographic image. The arithmetic processing of the steps (1), (2), and (6) is performed. In this way, background data obtained from elements that simultaneously emit multiple radiations is used in reverse to obtain morphological tomographic images that can be used for data processing / diagnosis for nuclear medicine or grasping morphological information. Can do.

In the above-described invention, as a specific example of obtaining the absorption correction data based on both the blank data and the transmission data , or only the transmission data, the contour of the subject is extracted only from the transmission data and the absorption coefficient map of the subject is extracted. To obtain absorption correction data (the invention according to claims 3 and 19), or to extract an object contour from transmission data and blank data to create an absorption coefficient map of the object. Obtaining absorption correction data is mentioned (inventions according to claims 4 and 20). Of course, as another specific example, the absorption correction data may be obtained by obtaining the reciprocal of the transmittance of the subject obtained from the ratio of the transmission data and the blank data without creating the above-described absorption coefficient map. It is possible (the invention according to claims 10 and 26).

  Further, in an example of obtaining the absorption correction data by extracting the contour of the subject from the transmission data and the blank data and creating the absorption coefficient map of the subject (inventions according to claims 4 and 20), specifically, Extracts the contour of the subject from the ratio between the transmission data and the blank data or the difference between the transmission data and the blank data (inventions according to claims 5 and 21).

  In an example in which the absorption correction data is obtained by extracting the contour of the subject from only the transmission data and creating the absorption coefficient map of the subject (the inventions according to claims 3 and 19), the absorption coefficient map is uniform inside. It may be a map (invention according to claims 6 and 22) regarded as a simple absorber, and the absorption coefficient map is a map where the inside is regarded as an absorber composed of a plurality of absorption coefficient segments. (Inventions described in claims 7 and 23). In the case of the latter map (Claims 7 and 23), the contour of the subject and the internal shape information on which the above-described absorption coefficient segment is based are extracted from transmission data alone.

  Similarly, the absorption coefficient can be obtained even in an example in which the absorption correction data is obtained by extracting the contour of the subject from the transmission data and the blank data and creating the absorption coefficient map of the subject (inventions according to claims 4 and 20). The map may be a map in which the inside is regarded as a uniform absorber (the invention according to claims 6 and 22), and the absorption coefficient map is an absorber composed of a plurality of absorption coefficient segments. It may be an assumed map (the inventions according to claims 8 and 24). In the case of the latter map (the inventions described in claims 8 and 24), the contour of the subject and the internal shape information on which the above-described absorption coefficient segment is based are extracted from the transmission data and the blank data.

  Thus, in the case of the latter map (the invention described in claims 7, 8, 23, and 24), a more accurate absorption coefficient map can be created in accordance with the actual subject, Accurate absorption correction can be performed.

  Further, the absorption coefficient map is not limited to a single one, and it is only necessary to improve the accuracy of contour extraction in combination with a conventional contour extraction method. For example, the contour of the subject may be extracted using emission data in addition to the transmission data and the blank data described above (the inventions according to claims 9 and 25).

  Note that the transmission data collection in the step (2) and the emission data collection in the step (3) may be performed separately or simultaneously.

  In the former case, the coincidence data simultaneously counted in the step (2) and the coincidence data simultaneously counted in the step (3) are different from each other (claims 11 and 27). Invention). In the latter case, the coincidence data simultaneously counted in the step (2) and the coincidence data simultaneously counted in the step (3) are data acquired by one photographing, (2 The transmission data collection in the step (3) and the emission data collection in the step (3) may be separated into the coincidence data for transmission data collection and the coincidence data for emission data collection. , 28).

  As a specific separation method, when the radiation is counted, the data acquired by one imaging may be separated based on the energy from the radiation (the invention according to claims 13 and 29), or the radiation. Based on the time difference information at the time of simultaneous counting, the data acquired by one imaging may be separated (invention according to claims 14 and 30), or radiation detection comprising the above-mentioned elements When combining the means and the radiation detection means configured without including the above-described elements, the data acquired by one imaging is obtained based on the spatial information obtained by the radiation detection means of these combinations. They may be separated (inventions according to claims 15 and 31).

  In the case where the data acquired by one photographing is separated based on the spatial information (the inventions according to claims 15 and 31), specifically, the following is performed. That is, the radiation detection means configured to include the elements described above and the radiation detection means configured to not include the elements described above are arranged in a ring shape so as to surround the body axis of the subject. Among the LOR (Line Of Response), which is a line connecting two simultaneously counted radiation detection means, by simultaneously counting the radiation while rotating the ring-type radiation detection mechanism around the body axis of the subject, Transmission data based on radiation emitted from radiation detecting means configured to contain the above-described elements and LOR relating to radiation detecting means configured to include the above-mentioned elements, and radiation generated from the subject to which the radiopharmaceutical was administered In addition to collecting spatial information mixed with emission data based on the above, the radiation detection hand constructed without including the above-mentioned elements in the LOR Radiopharmaceutical A LOR collects spatial information only emission data based on the radiation generated from a subject being administered about only. Then, by subtracting the spatial information of only the collected emission data from the spatial information in which the collected emission data and transmission data are mixed, the radiation is detected while rotating the ring-type radiation detection mechanism around the body axis of the subject. It is possible to separate the data acquired in one photographing that simultaneously counts (the inventions according to claims 16 and 32).

  According to the nuclear medicine diagnosis apparatus, the morphological tomography diagnosis apparatus, the nuclear medicine data calculation processing method, and the morphological tomography image calculation processing method according to the present invention, the background data obtained by the elements that simultaneously emit a plurality of radiations are reversed. By utilizing this for absorption correction data, stable absorption correction can be performed. Further, by using the background data in reverse, a morphological tomographic image that can be used for data processing / diagnosis for nuclear medicine or grasping of morphological information can be acquired.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a side view and block diagram of a mammo PET (Positron Emission Tomography) apparatus according to the first embodiment, and FIG. 2 is a block diagram and detection around a detector plate used in the mammo PET apparatus according to the first embodiment. FIG. 3 is a schematic side view showing a specific configuration of the radiation detector in the detector plate, and FIG. 4 is a diagram showing each aspect of the scintillator constituting the radiation detector. In the present embodiment 1, including later-described embodiments 2 and 3, a PET apparatus will be described as an example of a nuclear medicine diagnosis apparatus. In the first embodiment, a mammographic PET apparatus applied to a mammogram for detecting breast cancer will be described as an example.

  As shown in the block diagrams of FIGS. 1 and 2A, the mammo PET apparatus according to the first embodiment includes a detector unit 1, a support mechanism 2, a controller 3, an input unit 4, an output unit 5, and a coincidence counting circuit. 6, a projection data calculation unit 7, a blank data collection unit 8, a transmission data collection unit 9, an absorption correction data calculation unit 10, an absorption correction unit 11, a reconstruction unit 12, and a memory unit 13. The detector unit 1 includes two detector plates 1A and 1B that face each other with the subject M interposed therebetween. As shown in the schematic diagram of FIG. 2B, each detector plate 1A, 1B is configured by arranging a plurality of radiation detectors 1a in parallel with the notches 1C. The radiation detector 1a corresponds to the radiation detection means in this invention.

  As shown in FIG. 3, the radiation detector 1 a includes a scintillator block 21 configured by combining a plurality of scintillators as detection elements, a light guide 22 optically coupled to the scintillator block 3 a, and an optical device connected to the light guide 22. And a photomultiplier tube (PMT) 23 coupled thereto. Each scintillator in the scintillator block 21 detects γ-rays by emitting light by the incident γ-rays and converting it into light. The radiation detector 1a detects not only γ rays but also β rays.

  In the present embodiment 1, including later-described embodiments 2 and 3, each scintillator is configured to include an element that simultaneously emits a plurality of radiations (including β rays as well as γ rays). In the present specification, “... comprising an element” means that, for example, as shown in FIG. 4A, each scintillator 21A (see the hatched area in the upper right diagonal line in FIG. FIG. 4B shows a case where it is composed of a self-radioactivity represented by 176 or the like (an element that simultaneously emits a plurality of radiations) or a substance to which self-radioactivity is added (for example, GSO containing Lu). As described above, the scintillator 21B is made of a material that is not self-radiating, such as GSO, and is a scintillator in which a thin film tape made of self-radiation or a material to which self-radiation is added is attached to the scintillator 21B. 21C (see hatching in the upper right oblique line in the figure), or a coating agent made of self-radiation or a substance to which self-radiation is added is a scintillator 21B (in the figure But also the case of the scintillator 21C applied to see the top right hatched).

  When the radiation detector 1a (see FIGS. 2 (b) and 3) is configured by a scintillator configured to include such self-radioactivity (elements that simultaneously emit a plurality of radiations), as described above, β Following the decay (99.9%, up to 596 KeV), three gamma decays (300 KeV, 94%, 202 KeV, 78%, 88 KeV, 15%) occur simultaneously. As a result, any plural (two or more) of these radiations are emitted from the scintillator, and one of them is detected and counted by the radiation detector 1a (which has emitted the radiation). At the same time, the other radiation detector 1a (that is, the radiation detector 1a not emitting the radiation) is detected and counted. When the emitted radiation is β-rays, it is detected by the emitted scintillator itself, a nearby scintillator or a nearby radiation detector. When the emitted radiation is γ rays, the radiation is detected and counted by the radiation detector 1a having the emitted scintillator itself or another radiation detector 1a (including neighboring radiation detectors).

  Hereinafter, γ rays will be described. As described above, γ rays are emitted by the scintillator and converted into light. The light guide 22 guides the light converted by the scintillator block 21 to the photomultiplier tube 23. The photomultiplier tube 23 photoelectrically converts the light guided by the light guide 22 and outputs it as an electrical signal, which is sent to the coincidence circuit 6 as shown in FIGS.

  Next, returning to the description of FIG. 1, the support mechanism 2 supports the detector plates 1A and 1B facing each other with the body (for example, the breast) of the subject M interposed therebetween, so that the detector plates 1A and 1B are It is configured to face each other. The controller 3 comprehensively controls each part constituting the mammo PET apparatus according to the first embodiment. The controller 3 includes a central processing unit (CPU).

  The input unit 4 sends data and commands input by the operator to the controller 3. The input unit 4 includes a pointing device represented by a mouse, a keyboard, a joystick, a trackball, a touch panel, and the like. The output unit 5 includes a display unit represented by a monitor, a printer, and the like.

  The memory unit 13 is composed of a storage medium represented by ROM (Read-only Memory), RAM (Random-Access Memory), and the like. In the first embodiment, the projection data obtained by the projection data calculation unit 7, the tomographic image reconstructed by the reconstruction unit 12, the blank data collected by the blank data collection unit 8, and the transmission data collection unit 9 The collected transmission data, the absorption correction data obtained by the absorption correction data calculation unit 7, the projection data corrected by the absorption correction unit 11, and the like are written and stored in the RAM, and read from the RAM as necessary. . The ROM stores in advance programs for performing various types of nuclear medicine diagnosis, and the controller 3 executes the programs to perform nuclear medicine diagnosis according to the programs.

  The projection data calculation unit 7, the blank data collection unit 8, the transmission data collection unit 9, the absorption correction data calculation unit 10, the absorption correction unit 11, and the reconstruction unit 12 are storage media represented by the above-described memory unit 13, for example. This is realized by the controller 3 executing a program stored in the ROM or a command input by a pointing device represented by the input unit 4 or the like.

  The scintillator block 21 (see FIG. 2 (a)) converts γ-rays generated from the subject M to which a radiopharmaceutical, that is, a radioisotope (RI) is administered, into light, and the converted light is amplified by photoelectrons. The double tube 23 (see FIG. 2A) performs photoelectric conversion and outputs an electrical signal. The electric signal is sent to the coincidence counting circuit 6 as image information (pixel).

  Specifically, when a radiopharmaceutical is administered to the subject M, two γ rays are generated due to the disappearance of the positron of the positron emission type RI. The coincidence counting circuit 6 checks the position of the scintillator block 21 (see FIG. 2A) and the incident timing of the γ-ray, and the two scintillator blocks 21 that are opposed to each other with the subject M in between are γ-rays. The image information sent in is determined to be appropriate data only when. When γ rays are incident only on one of the scintillator blocks 21, the coincidence counting circuit 6 treats the image information sent at that time as noise instead of γ rays generated by the disappearance of the positron. Dismiss.

  In the case of the radiation detector 1a having the scintillator block 21 configured to include the self-radioactivity described above, the scintillator block 21 configured to include the self-radioactivity in addition to the γ rays from the radiopharmaceutical described above. The γ rays emitted from the radiation are also incident on the scintillator block 21 of the radiation detector 1a. The coincidence counting circuit 6 also treats such γ rays as “simultaneous counting data” when they are simultaneously incident on the two scintillator blocks 21 located opposite to each other across the subject M. The data obtained by this self-radiation (that is, the data counted by the coincidence circuit 6 when the γ-rays emitted from the scintillator block 21 configured to include the self-radiation enter) is background data. However, this background data is also used in the first embodiment including the second and third embodiments described later.

  The coincidence circuit 6 sends a component from the radiopharmaceutical among the detected γ-rays to the projection data calculation unit 7. Of the detected γ-rays, the self-radioactivity component is sent to the transmission data collection unit 9. Further, among the detected γ-rays, data obtained by self-radiation in the absence of the subject is sent to the blank data collection unit 8. The projection data calculation unit 7 obtains the image information sent from the coincidence counting circuit 6 as projection data, and sends the projection data to the absorption correction unit 11. The projection data obtained by the projection data calculation unit 7 is also called “emission data”. The projection data calculation unit 7 corresponds to the emission data collection means in this invention.

  The blank data collection unit 8 collects data obtained by self-radiation in the absence of a subject as blank data. The transmission data collection unit 9 collects data obtained by self-radiation in the presence of the subject as transmission data. The blank data collected by the blank data collection unit 8 and the transmission data collected by the transmission data collection unit 9 are sent to the absorption correction data calculation unit 10. The blank data collection unit 8 corresponds to the blank data collection unit in the present invention, and the transmission data collection unit 9 corresponds to the transmission data collection unit in the present invention.

  Based on the blank data collected by the blank data collection unit 8 and the transmission data collected by the transmission data collection unit 9, the absorption correction data calculation unit 10 obtains the absorption correction data of the subject M. In Example 1, including Example 2 described later, the absorption correction data is obtained by extracting the contour of the subject M from the ratio of the transmission data and the blank data and creating the absorption coefficient map of the subject M. . The absorption correction data obtained in this way is sent to the absorption correction unit 11. The absorption correction data obtained by the absorption correction data calculation unit 10 is applied to the projection data obtained by the projection data calculation unit 7 to correct the projection data in consideration of the absorption of γ rays in the body of the subject M. . The absorption-corrected projection data is sent to the reconstruction unit 12. The absorption correction data calculation unit 10 corresponds to the absorption correction data calculation unit in the present invention, and the absorption correction unit 11 corresponds to the absorption correction unit in the present invention.

  The corrected projection data is sent to the reconstruction unit 12. The reconstruction unit 12 reconstructs the projection data to obtain a tomographic image taking into account the absorption of γ rays in the body of the subject M. Thus, by providing the absorption correction unit 11 and the reconstruction unit 12, the projection data is corrected based on the absorption correction data, and the tomographic image is corrected. The corrected tomographic image is sent to the output unit 5 and the memory unit 13 through the controller 3.

  Next, an arithmetic processing method for each data will be described with reference to FIGS. FIG. 5 is a flowchart illustrating a flow of a series of nuclear medicine diagnosis including the arithmetic processing method according to the first embodiment, and FIG. 6 is a graph schematically illustrating an absorption coefficient with respect to energy of γ rays. In the first embodiment, for the distinction between γ rays from the radionuclide administered to the subject M and γ rays generated from the scintillator, a “discriminating method with photon energy” described later will be described as an example.

(Step S1) Blank data collection In a state where there is no subject and a plurality of radiation detectors 1a having scintillator blocks 21 configured to include self-radiation are arranged, the energy lower limit value is set to 200 KeV, for example. Self-radioactive gamma rays (307 KeV, 202 KeV, 88 KeV) emitted from the scintillator block 21 can be efficiently collected. The γ-rays emitted from the scintillator block 21 configured to include self-radioactivity over a predetermined time (for example, 10 hours) are counted. At this time, one of the emitted γ rays is counted by the radiation detector 1a itself having the scintillator block 21 (that is, the emitted scintillator) including self-radiation, and the other is counted as another radiation. The detector 1a counts. By counting in this way, the coincidence data simultaneously counted by the coincidence circuit 6 is not γ-rays from the radiopharmaceutical, but background data obtained by self-radioactivity in the absence of the subject. The blank data collection unit 8 collects blank data. This step S1 corresponds to the step (1) in the present invention.

(Step S2) Transmission Data Collection Next, in a state where the subject M is present, a plurality of radiation detectors 1a each having the scintillator block 21 configured to include the self-radioactivity are arranged, and the self-radioactivity over a predetermined time. The γ-rays emitted from the scintillator block 21 including the above are counted. At this time, in the first embodiment, by setting the energy lower limit value to, for example, 200 KeV, self-radioactive γ rays (307 KeV, 202 KeV, 88 KeV) emitted from the scintillator block 21 can be efficiently collected. The self-radioactive γ-ray counts one of the emitted γ-rays or the β-ray by the radiation detector 1a itself having a scintillator block 21 (that is, the emitted scintillator) including the self-radioactivity. At the same time, the radiation detector 1a counts another γ-ray transmitted through the subject M and reaching the other radiation detector 1a. By counting in this way, the transmission data collection unit 9 determines that the coincidence data simultaneously counted by the coincidence circuit 6 is background data obtained by self-radiation in the presence of the subject M. Collect as data. This step S2 corresponds to the step (2) in the present invention. It is desirable that no radioactive substance is administered to the subject M. However, even in the administered state, data with a high contribution of background components due to self-radiation can be obtained by optimizing the energy width. Can do.

(Step S3) Emission Data Collection Emission data collection is performed by simultaneously counting γ rays emitted from the subject M. Since the energy of γ rays is 511 keV, it is collected with an energy width that covers this energy range. Transmission data collection, that is, it is performed simultaneously or independently with step S2. The order does not matter from either. Therefore, step S3 may be performed after step S2, step S3 may be performed before step S2, or step S3 may be performed simultaneously or independently in parallel with step S2.

  Similarly to step S2, a state in which a plurality of radiation detectors 1a each having a scintillator block 21 configured to include self-radioactivity are administered by administering a radiopharmaceutical to the subject M in a state where the subject M is present. Count with. By setting the energy threshold to 400 keV, γ rays (background data) from self-radioactivity can be suppressed to a level that can be almost ignored. By counting in this way, the projection data calculation unit 7 collects the coincidence data simultaneously counted by the coincidence circuit 6 as emission data on the assumption that the coincidence data is γ rays from the radiopharmaceutical. This step S3 corresponds to the step (3) in the present invention.

(Step S4) Count ratio sinogram The ratio of the blank data (B) collected by the blank data collection unit 8 in step S1 and the transmission data (T) collected by the transmission data collection unit 9 in step S2 is developed into a sinogram. The absorption correction data calculation unit 10 obtains the values. Specifically, blank data (B) is divided by transmission data (T) for each pixel on the sinogram.

(Step S5) Contour Cynogram The sinogram developed and divided into sinograms in this way can stably obtain contour information at the edge (edge) of the subject M without depending on the radiopharmaceutical accumulation state. (Contour sinogram).

(Step S6) Extraction of Contour Image This contour sinogram is developed into projection data other than the sinogram (the same dimension as the projection data obtained by the projection data calculation unit 7), and the absorption correction data calculation unit 10 reads the contour of the subject M. Extract images.

(Step S7) Creation of Absorption Coefficient Map Since the value obtained by dividing the blank data (B) by the transmission data (T) is the transmittance of the subject M, the absorption correction data calculation unit is obtained by logarithmically reconstructing the image. 10 creates an absorption coefficient map. In step S7, the absorption coefficient map is created by regarding the inside as a uniform absorber.

  In step S7, the blank data and transmission data, which are the basis of the absorption coefficient map, are based on γ rays of energy such as 307 KeV, so the absorption coefficient map is also data for 307 KeV γ rays. An outline may be extracted from the absorption coefficient map at 307 KeV, a theoretical absorption coefficient for 511 keV γ rays may be assigned and absorption correction may be performed in step S 8 described later, or the emission data to be subjected to absorption correction may be simultaneously counted at 511 KeV Since it is data, the absorption coefficient map may be converted from 307 KeV to 511 KeV accordingly. For example, as shown in FIG. 6, a graph of an absorption coefficient μ (for example, an absorption coefficient of water) with respect to γ-ray energy E or a lookup table showing a correspondence relationship between γ-ray energy and absorption coefficient is prepared in advance. Then, referring to the graph or lookup table, convert the absorption coefficient at 307 KeV to the absorption coefficient at 511 KeV and then create the absorption coefficient map at 511 KeV, and then the absorption coefficient at 511 KeV Absorption correction may be performed in step S8 described later using the map. Steps S4 to S7 correspond to the step (4) in the present invention.

  The step of obtaining the absorption correction data, that is, steps S4 to S7, is performed simultaneously with or independently of the emission data collection, that is, step S3. The order does not matter from either. Therefore, steps S4 to S7 may be performed after step S3, steps S4 to S7 may be performed before step S3, or steps S4 to S7 may be performed simultaneously or independently in parallel with step S3. Good.

  In summary, when step S3 (step (3)) is performed after step S2 (step (2)), (A) after step S3 (step (3)), (B) After step S2 (step (2)) and before step S3 (step (3)) or (C) step S3 (step (3)) simultaneously or independently, steps S4 to S7 (Step (4)) is performed. In addition, when Step S3 (Step (3)) is performed before or in parallel with Step S2 (Step (2)) or before Step S2 (Step (2)), Step S2 ((( After step 2), steps S4 to S7 (step (4)) are performed.

(Step S8) Absorption Correction / Reconstruction Using the absorption correction data (absorption coefficient map in the first embodiment) obtained by the absorption correction data calculation unit 10 in steps S4 to S7, the projection data calculation unit 7 in step S3. Perform absorption correction of the obtained emission data. Reconstruction unit 12 reconstructs the absorption-corrected projection data (that is, emission data), and finally obtains the tomographic image as nuclear medicine data. At the time of absorption correction, processing other than absorption correction normally used, such as normalization processing and scattering correction, may be performed together. This step S8 corresponds to the step (5) in the present invention.

  The mammographic PET apparatus according to the first embodiment having the above-described configuration includes the radiation detector 1a configured to include an element (self-radioactivity, for example, Lu-176) that simultaneously emits a plurality of radiations. By counting one of the γ-rays emitted by the above-described element with the radiation detector 1a itself containing the element and counting the other with another radiation detector 1a in the absence of the subject, simultaneous counting is performed. In step S1, the blank data collection unit 8 collects the coincidence count data as blank data. On the other hand, in the state where the subject M is present, one of the γ-rays emitted by the element described above is counted by the radiation detector 1a containing the element and the other is counted by another radiation detector 1a. In step S2, the transmission data collecting unit 9 collects the coincidence data thus counted as transmission data. Further, by counting the γ-rays generated from the subject M to which the radiopharmaceutical is administered by the radiation detector 1a described above, the projection data calculation unit 7 collects the coincidence count data as emission data in step S3. To do.

  Based on the blank data collected by the blank data collection unit 8 in step S1 described above and the transmission data collected by the transmission data collection unit 9 in step S2 described above, the degree of γ-ray absorption (transmission) due to the presence or absence of the subject M The absorption correction data calculation unit 10 can obtain the absorption correction data of the subject M (the absorption coefficient map in the first embodiment) in steps S4 to S7. In step S8, the absorption correction unit 11 performs the absorption correction of the emission data collected by the projection data calculation unit 7 using the absorption correction data (the absorption coefficient map in the first embodiment), and the absorption-corrected data. (In the first embodiment, a tomographic image) is finally obtained as nuclear medicine data. The arithmetic processing of steps S1 to S8 is performed on nuclear medicine data.

  In this way, background data obtained by self-radioactivity (elements that simultaneously emit a plurality of radiations) typified by Lu-176 is rejected, but the background data is used in reverse. And used for absorption correction data. By providing the absorption correction data in this way, it is not necessary to mount an external radiation source or the like more than necessary, and the radiation detection means represented by the radiation detector 1a can be brought close to the subject M, and obtained from the emission data. Therefore, it is not necessary to use unnecessary form information more than necessary, and stable absorption correction can be performed.

  In the first embodiment, as a specific example for obtaining the absorption correction data based on the blank data and the transmission data, the contour of the subject M is extracted from the ratio (T / B) between the transmission data and the blank data. Absorption correction data is obtained by creating an M absorption coefficient map. In the first embodiment, the absorption coefficient map is a map in which the inside is regarded as a uniform absorber.

  In the first embodiment, transmission data collection in step S2 and emission data collection in step S3 are performed separately. That is, transmission data collection in the step (2) and emission data collection in the step (3) in the present invention are performed separately. In the case of the first embodiment, the coincidence count data simultaneously counted in the step (2) and the coincidence count data simultaneously counted in the step (3) are different from each other.

  Further, in the first embodiment, since the absorption correction can be performed without providing an external radiation source, the radiation detector 1a can be brought close to the subject M, and an apparatus like a mammo PET apparatus can be used. There is also an effect that the device sensitivity can be improved by downsizing. Since an external radiation source is not used, it is not necessary to purchase or replace the radiation source, and the running cost and maintenance cost can be reduced.

Next, Embodiment 2 of the present invention will be described with reference to the drawings.
FIG. 7 is a side view and block diagram of a PET (Positron Emission Tomography) apparatus according to the second embodiment, and FIG. 8 is a schematic view of a ring-type radiation detection mechanism used in the PET apparatus according to the second embodiment. In the second embodiment, as in the first embodiment, a PET apparatus will be described as an example of a nuclear medicine diagnosis apparatus. In the second embodiment, a PET apparatus provided with a ring-type radiation detection mechanism 1D that has a structure excluding an external radiation source and is as close to the subject M as possible to achieve miniaturization will be described as an example. .

  As shown in FIG. 7, the PET apparatus according to the second embodiment includes a controller 3, an input unit 4, an output unit 5, a coincidence circuit 6, a projection data calculation unit 7, and blank data collection similar to those in the first embodiment. A unit 8, a transmission data collection unit 9, an absorption correction data calculation unit 10, an absorption correction unit 11, a reconstruction unit 12, and a memory unit 13 are provided. Except for the coincidence circuit 6, the above-described components included in the PET apparatus are the same as those in the above-described first embodiment, and thus the description thereof is omitted. In the second embodiment, the PET apparatus includes a ring-type radiation detection mechanism 1D instead of the detector unit 1 of the first embodiment, and a rotation drive mechanism that rotates the ring-type radiation detection mechanism 1D around the body axis of the subject M. 14. The ring type radiation detection mechanism 1D corresponds to the ring type radiation detection mechanism in the present invention, and the rotation drive mechanism 14 corresponds to the rotation drive mechanism in the present invention.

  As shown in FIG. 8, the ring-type radiation detection mechanism 1D is configured by arranging a plurality of radiation detectors 1a in a ring shape so as to surround the body axis of the subject M. The ring-type radiation detection mechanism 1D only needs to include at least a radiation detector 1a configured to include an element (self-radioactivity, for example, Lu-176) that simultaneously emits a plurality of radiations. For example, as shown in FIG. 8A, all the radiation detectors 1a configured to include self-radioactivity (see the hatched area in the upper right diagonal line in the figure) may be provided, or FIG. As shown, the radiation detector 1a configured to include self-radioactivity (see the hatching in the upper right diagonal line in the figure) includes only a part of the radiation and is composed of a substance that is not self-radioactive such as GSO. You may provide the detector 1a. The structure shown in FIG. 8B is useful when separating data acquired by one image capturing based on spatial information described later. The specific configuration of the radiation detector 1a is the same as that shown in FIG. The radiation detector 1a corresponds to the radiation detection means in this invention.

  In a normal nuclear medicine diagnosis, there is a case where the measurement (collection) is started after a sufficient amount of time has elapsed until the administered drug is distributed in the body of the subject M and sufficiently distributed. Therefore, it is preferable to collect transmission data for absorption correction in a post-administration transmission performed in a stable distribution state. Therefore, it is more preferable to perform transmission data collection and normal emission data collection at the same time in view of time reduction. Therefore, in the second embodiment, the coincidence data simultaneously counted in the step (2) and the coincidence data simultaneously counted in the step (3) in the present invention are data acquired by one photographing. In order to collect transmission data in the process (2) and emission data in the process (3), it is separated into coincidence data for transmission data collection and coincidence data for emission data collection. .

  Therefore, in the second embodiment, the coincidence counting circuit 6 separates the coincidence counting data simultaneously counted in the state where the subject M is present into transmission data collection and emission data collection. A specific separation method will be described later. The rotation drive mechanism 14 is configured by a motor or the like (not shown).

  Next, an arithmetic processing method for each data will be described with reference to FIGS. FIG. 9 is a flowchart showing a flow of a series of nuclear medicine diagnosis including the arithmetic processing method according to the second embodiment, FIG. 10 is a schematic diagram for explaining separation by energy, and FIG. 11 is a time difference. FIG. 12 is a schematic diagram for explaining separation in space. FIG. 12 is a schematic diagram for explaining separation in space.

(Step S1) Blank Data Collection Since step S1 is the same as that in the first embodiment, description thereof is omitted. This step S1 corresponds to the step (1) in the present invention.

(Step T2) Transmission Data / Emission Data Collection In a state where the subject M is present, a radiopharmaceutical is administered to the subject M, and the radiation detector 1a having the scintillator block 21 configured to include self-radiation is provided. In a state where a plurality of γ-rays are arranged, γ rays emitted from the scintillator block 21 including self-radioactivity are counted. At this time, one of the emitted γ rays is counted by the radiation detector 1a itself having the scintillator block 21 (that is, the emitted scintillator) including self-radiation, and the other is counted as another radiation. The detector 1a counts. By counting in this way, the coincidence data simultaneously counted by the coincidence circuit 6 was obtained by γ-ray data (that is, emission data) from the radiopharmaceutical in the presence of the subject M and self-radioactivity. Transmission data and emission data are collected on the assumption that background data (that is, transmission data) is mixed (denoted as “E + T”). This step T2 corresponds to the steps (2) and (3) in this invention.

(Step T3) Separation As described above, the coincidence data simultaneously counted in the step (2) and the coincidence data simultaneously counted in the step (3) in the present invention are data obtained by one photographing. In order to collect transmission data in the process (2) and emission data in the process (3), a coincidence circuit is provided for the coincidence data for collecting transmission data and the coincidence data for collecting emission data. 6 will be separated. Specific methods of separation include the following methods.

(A) Discrimination method based on photon energy Based on the photon energy when γ rays are converted into photons when counting γ rays, the data acquired by the above-described one imaging is discriminated and separated. In the case of collecting data by detecting γ-rays different from photon energy such as Lu-176, two or more types of energy windows (for example, 350 KeV or lower, 400 KeV or higher) are provided as shown in FIG. Thus, even for the subject M after drug administration, emission data (see “Emission” in the figure) for energy windows above 400 KeV and transmission data (“Lu-Coin” in the figure for figures below 350 KeV). And can be collected separately. Note that at 350 KeV or lower, emission data may be mixed as shown in the scattered component in the radiation detector or the dotted line graph in FIG. it is conceivable that.

(B) Discrimination method with time difference information (TOF: Time Of Flight) Based on the time difference information (TOF) when γ rays are counted simultaneously, the data acquired by one imaging described above is discriminated and separated. If the time difference when the annihilation γ-rays are simultaneously counted is accurately measured, the radiation position of the γ-rays (positron annihilation occurrence point) can be obtained from the time difference. A PET apparatus based on this principle is called time difference information (or time of flight) (TOF) type PET. As shown in FIG. 11, the time difference of annihilation γ-rays (annihilation photons) is defined as an absolute value | T1-T2 | of the difference between T1 [sec] and T2 [sec], and the speed of γ-rays (photons) is c [ cm / sec], the distance between the radiation detectors 1a to be simultaneously counted is D [m], and the (time) range determined by the distance between the radiation detectors 1a is Δtmax [sec]. Such a range is represented by D [m] = Δtmax [sec] × c [cm / sec]. The time difference | T1-T2 | of the annihilation photons generated from the subject M falls within such a range (see | T1-T2 | <Δtmax) as shown in FIG. For example). On the other hand, the time difference | T1-T2 | of the annihilation photons generated from the radiation detector 1a (that is, emitted from the self-radioactivity) is always the distance between the radiation detectors 1a as shown in FIG. The determined time difference (Δtmax−Diff ≦ | T1−T2 | ≦ Δtmax + Diff) can be distinguished from the transmission data (see “Lu-Coin”). It is possible to distinguish two types of γ rays by this time difference and occurrence position information. The coincidence coincidence is included in both, but can be removed by a technique such as a delayed coincidence method.

(C) Discrimination method based on spatial information As shown in FIG. 8 (b), the radiation detector 1a configured to include self-radioactivity (see hatching in the upper right oblique line in the figure) and the self-radioactivity are included. Acquired with one imaging described above based on the spatial information obtained by each of the radiation detectors 1a of these combinations when combined with the radiation detectors 1a configured without being configured (for example, configured with GSO) Discriminated and separated data. FIG. 12 shows a line (LOR: Line Of Response) connecting the radiation detectors 1a counted simultaneously in the structure shown in FIG.

  As shown in FIG. 12 (a), in the LOR of the γ-rays emitted from the radiation detector 1a configured to include self-radioactivity (see the hatched area in the upper right diagonal line in the figure), for example, it is attached with the symbol A1. Focusing on the radiation detector 1a, transmission data (T) based on γ rays emitted from self-radioactivity and emission data (R) based on γ rays generated from the subject M are mixed (see “ See E + T). Accordingly, as shown in FIG. 12B, the γ-rays are simultaneously counted while the ring-type radiation detection mechanism 1D is rotated around the body axis of the subject M by the rotation drive mechanism 14 (see FIG. 7). Emission data and transmission data are collected.

  On the other hand, as shown in FIG. 12C, the LOR of γ rays generated from the subject M along the radiation detector 1a configured to include self-radioactivity (see the hatched hatching on the upper right in the figure). If there is, the data obtained from each projection direction does not count the γ-rays emitted from the self-radioactivity (for example, pay attention to the radiation detector 1a attached with the symbol B1), but the transmission data. Not included. Therefore, the data obtained from each projection direction is only emission data (R) (see “E” in the figure). Accordingly, as shown in FIG. 12 (d), the γ-rays are simultaneously counted while the ring-type radiation detection mechanism 1D is rotated around the body axis of the subject M by the rotation drive mechanism 14 (see FIG. 7). Only emission data is collected.

  In the LOR shown in FIGS. 12 (a) and 12 (b), emission data and transmission data are mixed, but only the emission data is collected in the LOR shown in FIGS. 12 (c) and 12 (d). . Therefore, the emission data and the transmission data can be separated by subtracting only the emission data from the mixed data of the emission data and the transmission data.

(Step S4) Count ratio sinogram Since step S4 is the same as that in the first embodiment, the description thereof is omitted.

(Step S5) Contour sinogram Step S5 is the same as that in the first embodiment described above, and a description thereof will be omitted.

(Step S6) Extraction of Contour Image Step S6 is the same as that in the first embodiment described above, and a description thereof will be omitted.

(Step S7) Creation of Absorption Coefficient Map Since step S7 is the same as that in the first embodiment, the description thereof is omitted. Steps S4 to S7 correspond to the step (4) in the present invention.

(Step S8) Absorption Correction / Reconstruction Step S8 is the same as that in the first embodiment, and a description thereof will be omitted. This step S8 corresponds to the step (5) in the present invention.

  According to the PET apparatus according to the second embodiment having the above-described configuration, as in the first embodiment described above, the background data obtained by the elements that simultaneously emit a plurality of radiations are used in reverse to absorb the data. Stable absorption correction can be performed by using the correction data. In the second embodiment, similarly to the first embodiment described above, the absorption correction can be performed without providing an external radiation source. Therefore, the radiation detector 1a can be brought close to the subject M. The device sensitivity can be improved by reducing the size of the device as in the case of a PET device as shown in FIG.

  In the second embodiment, when discriminating by spatial information, the radiation detector 1a configured to include an element (self-radioactivity, for example, Lu-176) that simultaneously emits a plurality of radiations, and self-radioactivity are included. The ring-type radiation detection mechanism 1D configured by arranging the radiation detector 1a without being arranged in a ring shape so as to surround the body axis of the subject M is rotationally driven around the body axis of the subject M. While simultaneously counting radiation, it is emitted from the radiation detector 1a configured to include the above-mentioned self-radioactivity among LOR (Line Of Response) which is a line connecting two radiation detectors 1a counted simultaneously. The transmission data based on the γ-rays and the above-described LOR relating to the radiation detector 1a configured to include the self-radiation, and the emission data based on the γ-rays generated from the subject M are mixed. Collects information and collects spatial information only for the emission data based on γ rays generated from the subject M, which is an LOR of the LOR only for the radiation detector 1a configured without including the self-radioactivity described above. To do. Then, the ring type radiation detection mechanism 1D is rotated around the body axis of the subject M by subtracting the spatial information of only the collected emission data from the spatial information in which the collected emission data and transmission data are mixed. However, it is possible to separate the data acquired by one imaging (transmission data and emission data collection in step T2) that simultaneously counts radiation.

Next, Embodiment 3 of the present invention will be described with reference to the drawings.
FIG. 13 is a side view and block diagram of a mammo PET (Positron Emission Tomography) apparatus according to the third embodiment, and FIG. 14 is a side view and block diagram of a PET (Positron Emission Tomography) apparatus according to the third embodiment. . In the third embodiment, as in the first and second embodiments, a PET apparatus will be described as an example of a morphological tomography diagnostic apparatus. In the third embodiment, a side view and a block diagram applied to the mammo PET apparatus of the first embodiment will be described with reference to FIG. 13, and a side view and a side view applied to a PET apparatus including the ring-type radiation detection mechanism 1D of the second embodiment will be described. A block diagram will be described with reference to FIG.

  The third embodiment is different from the first and second embodiments in that not only the purpose of nuclear medicine diagnosis but also obtaining a morphological tomographic image itself. Except for the projection data calculation unit 7, the above-described components included in the PET apparatus are the same as those in the first and second embodiments, and thus the description thereof is omitted.

  In the third embodiment, the projection data calculation unit 7 acquires a fluoroscopic image of the subject M based on the blank data collected by the blank data collection unit 8 and the transmission data collected by the transmission data collection unit 9. That is, in the third embodiment, the background data obtained by self-radioactivity is used for the fluoroscopic image itself or the morphological tomographic image without being subjected to the absorption correction as in the first and second embodiments. In the third embodiment, the transmittance of the subject M can be obtained as a fluoroscopic image for each pixel from the ratio of transmission data and blank data for each pixel, and the reconstructing unit 12 reconstructs the fluoroscopic image. A morphological tomographic image (absorption coefficient distribution image) of the subject M is acquired. The projection data calculation unit 7 corresponds to the fluoroscopic image acquisition unit in the present invention, and the reconstruction unit 12 corresponds to the morphological tomographic image acquisition unit in the present invention.

  Next, an arithmetic processing method for each data will be described with reference to FIG. FIG. 15 is a flowchart illustrating a flow of a series of morphological tomography diagnosis including the arithmetic processing method according to the third embodiment.

(Step S1) Blank Data Collection Since step S1 is the same as in the first and second embodiments, the description thereof is omitted. This step S1 corresponds to the step (1) in the present invention.

(Step S2) Transmission Data Collection Since step S2 is the same as that in the first embodiment, the description thereof is omitted. This step S2 corresponds to the step (2) in the present invention.

(Step U3) Perspective Image Acquisition From the ratio of the blank data collected by the blank data collection unit 8 in step S1 and the transmission data collected by the transmission data collection unit 9 in step S2, the projection data calculation unit 7 determines for each pixel. The transmittance of the subject M is obtained as a perspective image. This step U3 corresponds to the step (6) in the present invention.

(Step U4) Reconstruction The fluoroscopic image (that is, projection data) obtained by the projection data calculation unit 7 in step U3 is reconstructed by the reconstruction unit 12, and the tomographic image is obtained as a morphological tomographic image. Whether to use for absorption correction as in the first and second embodiments is not considered.

  According to the PET apparatus according to the third embodiment having the above-described configuration, the presence or absence of the subject M is determined based on the blank data collected by the blank data collection unit 8 and the transmission data collected by the transmission data collection unit 9. The degree of γ-ray absorption (including transmission) is known, and the projection data calculation unit 7 can acquire a fluoroscopic image of the subject M. Then, the perspective image is reconstructed to obtain a morphological tomographic image. In this way, morphological faults that can be used for data processing / diagnosis for nuclear medicine or grasping morphological information by using background data obtained by elements that emit multiple radiations simultaneously (self-radioactivity) Images can be acquired. The purpose of obtaining this form information is not limited to nuclear medicine diagnosis.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In each of the above-described embodiments, an external radiation source is not provided. However, a radiopharmaceutical and a heterogeneous radiation (X) from the outside of a subject like a PET-CT apparatus including a PET apparatus and an X-ray CT apparatus. In the case of a line CT apparatus, the apparatus may be applied to an apparatus in which an external radiation source is provided on a subject, such as an apparatus that irradiates X-rays) or an apparatus that irradiates the same type of radiation as a radioactive drug from the outside. . The external radiation source here is not only a type that irradiates the same type of radiation as the radiopharmaceutical, but also radiation that is different from the radiopharmaceutical from the outside of the subject, such as an X-ray CT apparatus (in the case of an X-ray CT apparatus). X-ray irradiation type (in the case of an X-ray CT apparatus, X-ray irradiation means) is also included.

  (2) In the first and second embodiments described above, the contour of the subject is extracted from the ratio between the transmission data and the blank data when the contour of the subject is extracted to create the absorption coefficient map of the subject. It is also possible to extract the contour of the subject from the difference between the transmission data and the blank data. It is also possible to extract the contour of the subject from transmission data alone without using blank data. Further, although the absorption coefficient map is single without combining with the conventional contour extraction method, the accuracy of contour extraction may be improved in combination with the conventional contour extraction method. For example, the contour of the subject may be extracted by using emission data in addition to transmission data and blank data. In addition, the emission data is compared with the absorption correction data obtained from the ratio (or difference) between the transmission data and the blank data, and one of the data is selected as more precise data. Absorption correction may be performed using the obtained data.

  (3) In the first and second embodiments described above, the absorption correction data is obtained by extracting the contour of the subject from the ratio between the transmission data and the blank data and creating the absorption coefficient map of the subject. Absorption correction data can be obtained by obtaining the reciprocal of the transmittance of the subject obtained from the ratio of transmission data and blank data without creating an absorption coefficient map.

  (4) In Embodiments 1 and 2 described above, the absorption coefficient map is a map in which the inside is regarded as a uniform absorber, but the absorption coefficient map is an absorber that includes the inside of a plurality of absorption coefficient segments. It may be a map considered. In this case, the contour of the subject and the internal shape information that is the basis of the above-described absorption coefficient segment are extracted from the ratio (or difference) between the transmission data and the blank data. In addition, when extracting the contour of the subject from the transmission data alone and creating the absorption coefficient map of the subject, the contour of the subject and the internal shape information on which the above-described absorption coefficient segment is based are extracted from the transmission data alone. Will do. Thus, in the case of the modification (4), a more accurate absorption coefficient map can be created in accordance with the actual subject, and more accurate absorption correction can be performed.

1 is a side view and block diagram of a mammo PET (Positron Emission Tomography) apparatus according to Embodiment 1. FIG. (A) is a block diagram around the detector plate used in the mammo PET apparatus according to Example 1, and (b) is a schematic diagram of the detector plate. It is a schematic side view which shows the specific structure of the radiation detector in a detector board. (A), (b) is each aspect figure of the scintillator which comprises a radiation detector. 3 is a flowchart showing a flow of a series of nuclear medicine diagnosis including an arithmetic processing method according to the first embodiment. It is the graph which modeled the absorption coefficient with respect to the energy of a gamma ray. 6 is a side view and block diagram of a PET (Positron Emission Tomography) apparatus according to Embodiment 2. FIG. (A), (b) is the schematic of the ring-type radiation detection mechanism used with the PET apparatus which concerns on Example 2. FIG. 10 is a flowchart showing a flow of a series of nuclear medicine diagnoses including an arithmetic processing method according to a second embodiment. It is a schematic diagram with which it uses for description of isolation | separation by energy. (A), (b) is a schematic diagram with which description of separation by time difference is provided. (A)-(d) is a schematic diagram with which it uses for description of isolation | separation in space. It is the side view and block diagram of a mammo PET (Positron Emission Tomography) apparatus concerning Example 3. 6 is a side view and block diagram of a PET (Positron Emission Tomography) apparatus according to Embodiment 3. FIG. 10 is a flowchart showing a flow of a series of morphological tomography diagnosis including an arithmetic processing method according to a third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a ... Radiation detector 7 ... Projection data calculation part 8 ... Blank data collection part 9 ... Transmission data collection part 10 ... Absorption correction data calculation part 11 ... Absorption correction part M ... Subject

Claims (32)

A nuclear medicine diagnostic apparatus for obtaining nuclear medical data of a subject based on radiation generated from a subject to which a radiopharmaceutical has been administered, comprising: a radiation detecting means comprising an element that simultaneously emits a plurality of radiations; In the absence of the analyte, one of the radiations emitted by the element is counted by the radiation detection means itself containing the element and the other is counted by another radiation detection means, thereby being simultaneously counted. The blank data collection means for collecting coincidence data as blank data, and the radiation detection means containing the element itself counts one of the radiation emitted by the element in a state where the subject is present, and the other is separated. Transmitter that collects coincidence count data as transmission data by counting with radiation detection means Data collection means, emission data collection means for collecting simultaneously counted data as emission data by counting radiation generated from the subject to which the radiopharmaceutical has been administered by the radiation detection means, and the blank Absorption correction data calculation means for obtaining the absorption correction data of the subject based on both the blank data collected by the data collection means and the transmission data collected by the transmission data collection means , or only the transmission data , and the absorption correction data A nuclear medicine comprising: an absorption correction means for performing an absorption correction of the emission data collected by the emission data collection means by using the apparatus and finally obtaining the absorption corrected data as the nuclear medicine data Diagnostic device.   A morphological tomography diagnostic apparatus for obtaining a morphological tomographic image of a subject based on radiation generated from a subject to which a radiopharmaceutical is administered, the radiation detecting means comprising an element that simultaneously emits a plurality of radiations; In the absence of the analyte, one of the radiations emitted by the element is counted by the radiation detection means itself containing the element and the other is counted by another radiation detection means, thereby being simultaneously counted. The blank data collection means for collecting coincidence data as blank data, and the radiation detection means containing the element itself counts one of the radiation emitted by the element in a state where the subject is present, and the other is separated. This is a transformer that collects coincidence count data as transmission data. A radiographic image acquisition means, a fluoroscopic image acquisition means for acquiring a fluoroscopic image of the subject based on the blank data collected by the blank data collection means and the transmission data collected by the transmission data collection means, and the fluoroscopic image again. A morphological tomography diagnostic apparatus comprising: a morphological tomographic image acquisition unit configured to acquire a morphological tomographic image of a subject.   2. The nuclear medicine diagnostic apparatus according to claim 1, wherein the absorption correction data calculation means extracts the absorption correction data by extracting an outline of the subject from only the transmission data and creating an absorption coefficient map of the subject. A nuclear medicine diagnostic apparatus characterized by being sought.   2. The nuclear medicine diagnosis apparatus according to claim 1, wherein the absorption correction data calculation means extracts the contour of the subject from the transmission data and the blank data to create an absorption coefficient map of the subject. A nuclear medicine diagnostic apparatus characterized by obtaining absorption correction data.   5. The nuclear medicine diagnosis apparatus according to claim 4, wherein the absorption correction data calculation means extracts the contour of the subject from a ratio between the transmission data and the blank data or a difference between the transmission data and the blank data. A nuclear medicine diagnostic apparatus characterized by:   The nuclear medicine diagnosis apparatus according to any one of claims 3 to 5, wherein the absorption coefficient map is a map in which the inside is regarded as a uniform absorber.   4. The nuclear medicine diagnosis apparatus according to claim 3, wherein the absorption coefficient map is a map in which the inside is regarded as an absorber composed of a plurality of absorption coefficient segments, and the absorption correction data calculation means is configured to transmit only the transmission data. A nuclear medicine diagnosis apparatus that extracts outline information of the subject and internal shape information that is a basis of the absorption coefficient segment.   The nuclear medicine diagnosis apparatus according to claim 4 or 5, wherein the absorption coefficient map is a map in which an interior is regarded as an absorber composed of a plurality of absorption coefficient segments, and the absorption correction data calculation means includes: A nuclear medicine diagnosis apparatus, wherein the outline of the subject and the internal shape information that is the basis of the absorption coefficient segment are extracted from the transmission data and the blank data.   9. The nuclear medicine diagnosis apparatus according to claim 4, wherein the absorption correction data calculation means uses emission data in addition to the transmission data and the blank data. Then, the nuclear medicine diagnostic apparatus is characterized in that the absorption correction data is obtained by extracting the contour of the subject and creating an absorption coefficient map of the subject.   2. The nuclear medicine diagnosis apparatus according to claim 1, wherein the absorption correction data calculation means obtains the absorption correction data by obtaining an inverse of the transmittance of the subject obtained from a ratio between the transmission data and the blank data. A nuclear medicine diagnostic apparatus characterized by being sought.   11. The nuclear medicine diagnostic apparatus according to claim 1, wherein the simultaneous counting data simultaneously counted by the transmission data collecting means and the simultaneous counting simultaneously counted by the emission data collecting means. Data is different from each other.   11. The nuclear medicine diagnostic apparatus according to claim 1, wherein the simultaneous counting data simultaneously counted by the transmission data collecting means and the simultaneous counting simultaneously counted by the emission data collecting means. Data is data acquired by one imaging, and is used for the transmission data collection by the transmission data collection means and the coincidence count data for collecting transmission data for the collection of the emission data by the emission data collection means. And a nuclear medicine diagnostic apparatus characterized in that it is separated into coincidence counting data for emission data collection.   13. The nuclear medicine diagnostic apparatus according to claim 12, wherein when the radiation is counted, the data acquired by the one imaging is separated based on energy from the radiation.   The nuclear medicine diagnosis apparatus according to claim 12 or 13, wherein data acquired by the one imaging is separated based on time difference information when the radiation is simultaneously counted. apparatus.   The nuclear medicine diagnosis apparatus according to any one of claims 12 to 14, wherein the radiation detection unit configured to include the element and the radiation detection unit configured to not include the element are combined. Furthermore, the nuclear medicine diagnostic apparatus characterized by separating the data acquired by said one imaging | photography based on the spatial information each obtained by the radiation detection means of these combinations.   16. The nuclear medicine diagnostic apparatus according to claim 15, wherein the radiation detection means configured to include the element and the radiation detection means configured to not include the element surround the body axis of the subject. A ring-type radiation detection mechanism arranged in a ring shape, and a rotation drive mechanism that rotationally drives the ring-type radiation detection mechanism around the body axis of the subject. By simultaneously counting radiation while rotating the radiation detection mechanism around the body axis of the subject, the element is included in the LOR that is a line connecting the two radiation detection means that are simultaneously counted. The LOR relating to the radiation detection means configured to include the transmission data based on the radiation emitted from the radiation detection means and the element, and the radioactive Collecting the spatial information mixed with the emission data based on the radiation generated from the subject to which the agent is administered, and the LOR relating only to the radiation detection means configured not including the element of the LOR Collecting the spatial information of only the emission data based on the radiation generated from the subject administered with the radiopharmaceutical, and collecting the collected emission data from the spatial information in which the collected emission data and transmission data are mixed By subtracting the spatial information of only the data, the data acquired in the one imaging that separates the radiation while simultaneously rotating the ring-type radiation detection mechanism around the body axis of the subject is separated by the rotation drive mechanism. A nuclear medicine diagnostic apparatus characterized by: A nuclear medicine data arithmetic processing method for performing arithmetic processing on nuclear medicine data of a subject based on radiation generated from a subject administered with a radiopharmaceutical, (1) in the absence of the subject, The radiation detection means itself configured to include an element that emits a plurality of radiations at the same time counts one of the radiation emitted by the element and the other by another radiation detection means, thereby simultaneously counting. Collecting the coincidence count data as blank data, and (2) counting one of the radiations emitted by the element by the radiation detection means itself containing the element while the subject is present and the other Collecting the coincidence count data as transmission data by counting with another radiation detection means, and (3) administering the radiopharmaceutical. And the radiation generated from the subject by counting in the radiation detecting means, and acquiring the coincidence count data coincidence as emission data, (4) both the blank data and the transmission data or transmission data, a step of obtaining the absorption correction data of the object based only on, (5) a step of performing an absorption correction of the emission data using the absorption correction data, the absorption correction data as said nuclear medicine data A nuclear medicine data calculation processing method characterized by performing calculation processing of the steps (1) to (5) to be finally obtained.   In a morphological tomographic image processing method for performing arithmetic processing on a morphological tomographic image of a subject based on radiation generated from a subject to which a radiopharmaceutical is administered, (1) in the absence of the subject, a plurality of radiation Simultaneously counted simultaneously by counting one of the radiation emitted by the element and counting the other with another radiation detecting means by the radiation detecting means itself configured to include the element to be emitted simultaneously. A step of collecting data as blank data; (2) in a state where the subject is present, one of the radiation emitted by the element is counted by the radiation detection means itself containing the element, and the other is counted as another radiation. A step of collecting coincidence count data simultaneously counted as transmission data by counting with a detection means; (6) the blank data and the previous Obtaining a fluoroscopic image of the subject based on transmission data, and reconstructing the fluoroscopic image of the acquired subject to obtain the morphological tomographic image of (1), (2), (6) A morphological tomographic image calculation processing method characterized by performing calculation processing of a process.   18. The nuclear medicine data operation processing method according to claim 17, wherein, in the step (4), the absorption is performed by extracting an outline of the subject from only the transmission data and creating an absorption coefficient map of the subject. A data processing method for nuclear medicine characterized by obtaining correction data.   18. The nuclear medicine data operation processing method according to claim 17, wherein in the step (4), an outline of the subject is extracted from the transmission data and the blank data to create an absorption coefficient map of the subject. Thus, the absorption correction data is obtained.   21. The nuclear medicine data processing method according to claim 20, wherein in the step (4), the ratio of the transmission data to the blank data or the difference between the transmission data and the blank data A nuclear medicine data calculation method characterized by extracting a contour.   The nuclear medicine data calculation processing method according to any one of claims 19 to 21, wherein the absorption coefficient map is a map in which the inside is regarded as a uniform absorber. Processing method.   The nuclear medicine data calculation processing method according to claim 19, wherein the absorption coefficient map is a map in which an interior is regarded as an absorber composed of a plurality of absorption coefficient segments, and in the step (4), A nuclear medicine data calculation processing method, wherein the outline of the subject and the internal shape information that is the basis of the absorption coefficient segment are extracted from only transmission data.   In the nuclear medicine data calculation processing method according to claim 20 or claim 21, the absorption coefficient map is a map in which the inside is regarded as an absorber composed of a plurality of absorption coefficient segments, In the process, a nuclear medicine data calculation processing method is characterized in that, from the transmission data and the blank data, the contour of the subject and internal shape information that is the basis of the absorption coefficient segment are extracted.   25. The nuclear medicine data operation processing method according to claim 20, claim 21, or claim 24, wherein, in the step (4), in addition to the transmission data and the blank data, an emission is performed. A nuclear medicine data calculation processing method, wherein the absorption correction data is obtained by extracting the contour of the subject using data and creating an absorption coefficient map of the subject.   18. The nuclear medicine data operation processing method according to claim 17, wherein in the step (4), the absorption is performed by obtaining an inverse of the transmittance of the subject obtained from a ratio between the transmission data and the blank data. A data processing method for nuclear medicine characterized by obtaining correction data.   27. The nuclear medicine data operation processing method according to any one of claims 17 and 19 to 26, wherein the coincidence data simultaneously counted in the step (2) and the simultaneous count in the step (3) A nuclear medicine data calculation method, wherein the counted coincidence data is data different from each other.   27. The nuclear medicine data operation processing method according to any one of claims 17 and 19 to 26, wherein the coincidence data simultaneously counted in the step (2) and the simultaneous count in the step (3) The counted coincidence data is data acquired by one photographing, and transmission data is collected for the transmission data collection in the step (2) and the emission data collection in the step (3). A data processing method for nuclear medicine, characterized in that it is separated into coincidence data for data collection and coincidence data for emission data collection.   29. The nuclear medicine data operation processing method according to claim 28, wherein when the radiation is counted, the data acquired in the one imaging is separated based on energy from the radiation. Data calculation processing method.   30. The data processing method for nuclear medicine according to claim 28 or 29, wherein data acquired by the one imaging is separated based on time difference information when simultaneously counting the radiation. Data calculation processing method for nuclear medicine.   The nuclear medicine data operation processing method according to any one of claims 28 to 30, wherein the radiation detection means configured to include the element and the radiation detection means configured to not include the element. A data processing method for nuclear medicine characterized in that, when combined, data obtained by the one imaging is separated based on spatial information respectively obtained by the radiation detection means of these combinations.   32. The nuclear medicine data operation processing method according to claim 31, wherein the radiation detection means configured to include the element and the radiation detection means configured to not include the element include a body axis of the subject. By simultaneously counting radiation while rotating a ring-type radiation detection mechanism, which is arranged in a ring shape so as to surround the circumference, around the body axis of the subject, the two radiation detection means simultaneously counted are connected. Among the LORs that are lines, the LOR relating to the transmission data based on the radiation emitted from the radiation detection means configured to include the element and the radiation detection means configured to include the element, wherein the radiopharmaceutical is Collecting the spatial information mixed with the emission data based on the radiation generated from the administered subject, Collecting the spatial information of only the emission data based on the radiation generated from the subject to which the radiopharmaceutical is administered, the LOR relating only to the radiation detection means configured not including the element, While rotating the ring-type radiation detection mechanism around the body axis of the subject by subtracting the spatial information of only the collected emission data from the spatial information in which the collected emission data and transmission data are mixed A data processing method for nuclear medicine data, wherein the data acquired in the one imaging for simultaneously counting radiation is separated.

Images