JP2006087540A - Medical image diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PET/CT system capable of properly setting a range where X-ray CT inspection is done based on the result of PET diagnosis. <P>SOLUTION: A medical image diagnostic apparatus equipped with a PET section, an X-ray CT section, and a bed section for mounting a subject has an image data generating section 31 generating a plurality kinds of images such as a PET image, an SUV image, and a transmission image based on the data acquired by the PET section, and an inspection range setting section 34 capable of displaying the plurality of kinds of images generated by the image data generating section 31 as images for setting an inspection range and making an operator set the range to be inspected by the X-ray CT section on the images for setting the inspection range. The images for setting the inspection range can be displayed in a plurality of volume displaying configurations by the inspection range setting section. Further, the apparatus is equipped with a setting range confirmation means displaying the inspection range set by the inspection range setting section 32 as an axial (a body axis) tomogram. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a medical diagnostic imaging apparatus (hereinafter, referred to as “PET”) capable of performing PET (Positron Emission Tomography) inspection and X-ray CT (Computed Tomography) inspection using a common bed. (Referred to as PET / CT system as appropriate).

In PET diagnosis, a drug labeled with a positron-emitting nuclide (hereinafter referred to as a radiopharmaceutical) is administered to a subject, and the radiation released from the radiopharmaceutical to the outside of the subject is detected. Physiological and biochemical information in the living body is captured by taking a biodistribution image. If a drug that easily accumulates in cancer cells such as ¹⁸ F-FDG (fluoro-deoxy-glucose) is used as the radiopharmaceutical, the size and shape of the cancer lesion can be known from this distribution image, and early detection of cancer Can be useful. The types of images generated in PET diagnosis include a PET image that shows the degree of drug accumulation in terms of the luminance value of the image, and an SUV (Standardized Uptake Value) that is generated based on the PET image and represents canceration There are SUV images composed of values. Furthermore, as an image processing form for generating and displaying each image from the volume data collected by photographing (in the present invention, this is called a volume display form), an arbitrary cross section is extracted from the volume data to obtain a tomographic image. MPR (Multi Planar Reconstruction) display that displays an image, MIP (Maximum Intensity Projection) display that displays an image in which the maximum pixel is projected in an arbitrary direction using the volume data, etc. The doctor makes various diagnoses using these images.

  However, since PET is used to image biological function information, it has less anatomical positional information than X-ray CT or MRI (Magnetic Resonance Imaging), which forms morphological information. In addition, since the spatial resolution is also inferior, there is a drawback in that it is impossible to accurately diagnose where in the body tissue a region with a high radiopharmaceutical distribution in the image is obtained only by an image obtained by PET.

  Therefore, in recent years, a PET / CT system that can inspect PET and X-ray CT using a common bed has been developed, and PET images taken on the same cross section of the same subject using this system. And X-ray CT images are superimposed on each other to diagnose the exact localization in a living body at a site with a high possibility of canceration (Patent Document 1).

  In the PET / CT system, there is a diagnostic method in which the entire body of the subject is first imaged by the PET unit to identify a region with a high possibility of canceration, and then only that region is imaged by the X-ray CT unit. This is possible, and exposure by X-ray CT can be minimized. In this case, the SUV image obtained by PET is observed, and only when an area that is highly suspected to be a cancer lesion is found, the examination range is set using the SUV image and X-ray CT imaging is performed. Is called.

Japanese Unexamined Patent Publication No. 7-20245

However, at this time, there is a problem that it is difficult to determine an appropriate range only from the low-resolution SUV image because the anatomical division of the target organ is poor.
Therefore, the problem to be solved by the present invention is to provide a PET / CT system capable of appropriately setting a region for performing X-ray CT examination based on the result of PET diagnosis.

The medical image diagnostic apparatus according to the present invention made to solve the above problems is a medical image diagnostic apparatus including a PET unit, an X-ray CT unit, and a bed unit for placing a subject.
a) image generation means for generating a plurality of types of images based on the data acquired by the PET unit;
b) A plurality of types of images generated by the image generation means can be displayed as an inspection range setting image, and the operator can set a range to be inspected by the X-ray CT unit on the inspection range setting image. X-ray CT examination range setting means,
It is characterized by providing.

  Further, the medical image diagnostic apparatus according to the present invention further includes setting range confirmation means for displaying the examination range set by the X-ray CT examination range setting means as an axial (body axis) sectional image. Is desirable.

  As the plurality of types of images that can be displayed as the inspection range setting image, any image can be used as long as it is an image created based on data acquired by the PET unit. It is desirable to use a transmission image or the like. In addition, for the inspection range setting, an image created based on data acquired by such a PET unit and an image created based on data acquired by other modalities (imaging techniques) are superimposed. You may make it usable as an image. Examples of the other modalities include, but are not limited to, X-ray CT and MRI. Further, it is desirable that such an inspection range setting image can be displayed in a plurality of volume display forms such as MPR display and MIP display.

In the present invention, when setting the range of the X-ray CT examination based on the result of the PET diagnosis, instead of using only the SUV image as in the past, the display is switched to a plurality of types of images that can be displayed such as a PET image and a transmission image. This makes it easy to recognize the area to be inspected by X-ray CT, and makes it possible to set an appropriate area. Further, as the inspection range setting image, an image obtained by superimposing an image obtained by PET inspection and an image taken by another modality can be used, or the inspection range setting image can be displayed in a plurality of volume display forms. By doing so, the target site can be grasped more accurately and easily.
Further, if the set inspection range can be displayed as an axial (body axis) cross-sectional image, the range can be confirmed during the setting operation, and a more reliable range setting can be performed.

  Hereinafter, the best mode for carrying out the present invention will be described based on examples.

[Example]
FIG. 1 is a schematic configuration diagram of a PET / CT system according to the present embodiment, and FIG. 2 is a block diagram illustrating a configuration of a main part of the PET / CT system according to the present embodiment. The PET / CT system according to this embodiment includes an X-ray CT gantry 10, a PET gantry 20, a console 30, and a bed unit 40. The X-ray CT gantry 10 includes a tunnel portion 11 for allowing the subject 50 to pass through in the center, and around the tunnel portion 11, an X-ray tube 12, an X-ray detector 13, and the X-ray tube. A rotation mechanism (not shown) for rotating the sphere 12 and the X-ray detector 13 along the periphery of the tunnel portion 11 is provided. The PET gantry 20 also includes a tunnel portion 21 for allowing the subject 50 to pass therethrough in the center, and a large number of emission data radiation detectors 22 arranged in a ring shape around the tunnel portion 21 and a transmission A data radiation detector 23 and a radiation source 24 are provided. The bed unit 40 includes a top plate 41 on which the subject 50 is placed. By moving the top plate 41, the subject is placed in the tunnel units 11 and 21 of the X-ray CT gantry 10 and the PET gantry 20. 50 can be passed.

  In the PET examination, a part of the radiation emitted from the medicine administered to the subject 50 is absorbed by the body tissue. Therefore, in the PET / CT system of this embodiment, the radiation emitted from the subject body is used. Data obtained by detecting with the emission data radiation detector 22 (emission data) and obtained by detecting with the transmission data radiation detector 24 the radiation emitted from the radiation source 24 and transmitted through the body tissue. Two types of data (transmission data) are measured, emission data is absorbed and corrected using the transmission data, and a PET image and an SUV image are generated based on the corrected data.

  The X-ray detector 13 provided in the X-ray gantry 10 and the electrical signals output from the emission data radiation detector 22 and the transmission data radiation detector 23 provided in the PET gantry 20 are provided in the console 30. Sent to the image data generation unit 31 and converted into image data such as PET image data, SUV image data, and X-ray CT image data. The display processing unit 32 performs processing for displaying an image on the monitor 33 based on the image data generated by the image data generation unit 31. The inspection range setting unit 34 causes the operator to set an arbitrary range on the image obtained by PET, and determines the set range as a range for performing the X-ray CT inspection. In addition, the console 30 is provided with a control unit 35 for controlling the entire PET / CT system, and an input unit 36 including a pointing device such as a mouse, a keyboard, and the like.

  Hereinafter, in the PET / CT system of the present embodiment, a procedure will be described in which a PET examination is first performed, and only a part suspected of being cancerous is further subjected to an X-ray CT examination.

When a PET examination by the PET gantry 20 is performed on the subject 50 to which the radiopharmaceutical has been administered in advance, and emission data and transmission data relating to the subject 50 are acquired, the image data generation unit 31 is based on these data. Thus, PET image data, SUV image data, transmission image data, and the like are generated and displayed on the monitor 33.
When the operator observes the image displayed on the monitor 33 and finds a part that needs to perform an X-ray CT scan, the operator performs a predetermined operation on the input unit 36 to display FIG. An X-ray CT examination range setting screen 60 as shown in FIG. On the sagittal frame 61, the coronal frame 62, and the axial frame 63 provided on the setting screen 60, the images obtained by the above-described PET inspection as the inspection range setting images are respectively sagittal (sagittal) cross section and coronal (coronal). ) Displayed in cross section, axial (body axis) cross section. As the types of images displayed as the inspection range setting image, SUV images, PET images, transmission images, and the like can be used, and inspection is performed by operating an image change button (not shown) provided on the operation frame 65. The type of image displayed as the range setting image can be switched as appropriate. Furthermore, by operating a volume display form change button (not shown) provided on the operation frame 65, the volume display forms (MPR display, MIP display, etc.) of these images can be switched as appropriate.

  Once the tissue suspected of having a cancer lesion is identified by the operator by using an image of the appropriate type and volume display form, the start and end points of the X-ray CT scan range in a predetermined operation, eg, sagittal frame 61 The range of X-ray CT examination is set so that the target part is included by specifying by clicking operation.

  Further, by performing a predetermined operation (for example, clicking an arbitrary point in the set inspection range on the sagittal frame 61), an axial sectional image of the set range can be displayed in the axial frame 63. Therefore, it can be confirmed whether the target organization is included in the setting range. When the operator confirms that the range of the X-ray CT scan is set correctly, sets other inspection conditions in the X-ray CT scan condition setting frame 66, and then performs a predetermined operation on the input unit 36, the control unit An instruction to start an X-ray CT examination is sent from 35 to the X-ray CT gantry 10 and the bed part 40, and the subject 50 is aligned with the tunnel part 11 of the X-ray CT gantry 10, and within the specified range. X-ray CT scan is performed. By superimposing the X-ray CT image obtained in this way with the PET image by a predetermined method, it is possible to accurately determine where in the body tissue the site of high possibility of canceration identified by the PET examination exists. Can be diagnosed.

  In this embodiment, the PET inspection is performed first to obtain the emission data and the transmission data, and the case where the transmission data is used as the data for absorption correction has been described as an example. However, the X-ray CT inspection is performed first. Thus, the obtained data can also be used as absorption correction data for a PET examination to be performed later. Even in such a case, when an X-ray CT scan is performed again on a site having a high suspicion of a cancer lesion after the PET examination, the X-ray CT examination range is set in the same manner as described above. At this time, not only the image obtained by the PET examination as described above as the examination range setting image used for setting the X-ray CT examination range, but also the image obtained by the PET examination and the first X-ray CT examination. It is desirable to be able to use a superposition of the recorded image. Further, as an inspection range setting image, an MR image or the like obtained by superimposing an image obtained by another modality and an image obtained by PET may be used. In this case, data of an image captured with a different modality for the same subject is read into the console using a communication means or a storage medium, and superimposed with an image obtained by the PET examination in the display processing unit, Displayed as an inspection range setting image.

1 is a schematic configuration diagram showing a PET / CT system according to an embodiment of the present invention. The block diagram which shows the structure of the principal part of the PET / CT system which concerns on the Example. The figure which shows the X-ray CT inspection range setting screen of the PET / CT system which concerns on the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... X-ray CT gantry 11, 21 ... Tunnel part 12 ... X-ray tube 13 ... X-ray detector 20 ... PET gantry 22 ... Emission data radiation detector 23 ... Transmission data radiation detector 24 ... Radiation source 30 ... Console 31 ... Image data generation unit 32 ... Display processing unit 33 ... Monitor 34 ... Examination range setting unit 35 ... Control unit 36 ... Input unit 40 ... Bed unit 41 ... Top plate 50 ... Subject 60 ... X-ray CT examination range setting screen

Claims (6)

In a medical diagnostic imaging apparatus comprising a PET unit, an X-ray CT unit, and a bed unit for placing a subject,
a) image generation means for generating a plurality of types of images based on the data acquired by the PET unit;
b) A plurality of types of images generated by the image generation means can be displayed as an inspection range setting image, and the operator can set a range to be inspected by the X-ray CT unit on the inspection range setting image. X-ray CT examination range setting means,
A medical image diagnostic apparatus comprising:   The medical image diagnostic apparatus according to claim 1, wherein the plurality of types of images include a PET image and an SUV image.   The medical image diagnostic apparatus according to claim 1, wherein the plurality of types of images include transmission images.   The plurality of types of images include an image obtained by superimposing an image created based on data obtained by the PET unit and an image created based on data obtained by another modality. The medical image diagnostic apparatus according to claim 1.   The medical image diagnostic apparatus according to claim 1, wherein the X-ray CT examination range setting means can display the examination range setting image in a plurality of volume display forms.   6. The apparatus according to claim 1, further comprising setting range confirmation means for displaying the examination range set by the X-ray CT examination range setting means as an axial (body axis) sectional image. Medical diagnostic imaging device.

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