CN111375144B

CN111375144B - Tomographic and image-guided radiation therapy apparatus

Info

Publication number: CN111375144B
Application number: CN201811653870.3A
Authority: CN
Inventors: 高河伟; 陈志强; 张丽; 邢宇翔
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2018-12-29
Filing date: 2018-12-29
Publication date: 2021-03-05
Anticipated expiration: 2038-12-29
Also published as: CN111375144A

Abstract

A tomographic and image-guided radiation therapy apparatus comprising a high energy radiation source; a first detector and a second detector, the second detector comprising PET detectors and a CT-type detector positioned between the PET detectors; placing at least one kilovolt KV ray source for medical diagnosis on the first detector, the inner side of the first detector or the outer side of the first detector, wherein the kilovolt KV ray source is used for generating KV rays; the second detector receives the KV ray and carries out KVCT imaging; the first detector and the second detector are also used for receiving gamma rays emitted by the object and carrying out PET imaging; the high-energy ray source generates high-energy rays for carrying out radiotherapy on an object; KVCT imaging and/or PET imaging for assisting and/or guiding radiation therapy of an object. The invention adopts the CT type detector and the PET detector at the same time, thereby improving the detection sensitivity of the device, improving the spatial resolution of KVCT imaging and reducing scattering artifacts.

Description

Tomographic and image-guided radiation therapy apparatus

Technical Field

The invention relates to the field of medical imaging and radiotherapy guiding, in particular to a tomography and image-guided radiotherapy device.

Background

Radiation Therapy (Radiation Therapy) is one of the major current modalities for treating malignant tumors. In radiotherapy, Image Guidance (Image Guidance) is one of the key means to ensure high precision treatment. The radiotherapy guiding is that before or during the treatment of the patient, the accurate body position information of the patient is acquired by using a medical image means, so that the treatment errors caused by the movement of organs such as the body placement, the heartbeat, the respiration and the like of the patient are reduced, and the precision of radiotherapy is improved or ensured. Currently, the most common radiotherapy treatment is the use of Megavolt (MV) grade high energy X-rays, and the most common radiotherapy treatment guidance is Kilovolt (KV) X-ray based Computed Tomography (CT). In recent years, radiotherapy based on Magnetic Resonance Imaging (MRI) guidance has also been developed successfully and applied clinically. At the same time, scientists and engineers are also actively developing new radiotherapy modalities based on Positron Emission Tomography (PET) guidance.

PET is a functional imaging that can obtain biological information from the human body. In PET imaging, gamma photons generated by positron annihilation have the potential to directly reflect the real-time location information of a tumor in a patient. The real-time tumor position information has great significance for high-precision tumor treatment. Movement of organs during treatment of patients has been a major challenge in radiation therapy. Therefore, the radiotherapy apparatus guided by PET has a strong clinical application potential, and is one of the hot spots and difficulties in research in academia and industry at present. In PET-guided radiotherapy apparatus, PET alone cannot give accurate body contour information of a patient lying on a treatment couch, due to the physical mechanism of PET imaging. Meanwhile, PET generally requires attenuation correction or the like using CT images. Thus, similar to PET/CT in medical diagnostics, in PET-guided radiotherapy devices, a CT is often required to "assist" the PET imaging.

In summary, CT imaging plays a significant role in radiotherapy systems. Currently, there are two main modes of CT subsystems: kilovolt CT (kvct) and megavolt CT. Among them, megavoltage CT is usually a medical linear accelerator, which is a high-energy X-ray (megavoltage) source used directly in treatment. The scan plane of megavolt CT is naturally in the same plane as the treatment, which brings great convenience to image registration and facilitates optimization of the treatment protocol. However, megavolt CT imaging is not of high quality: the reconstructed image has low contrast and the patient receives a large radiation dose. Unlike megavoltage CT, kilovoltage CT typically employs a separate, medical diagnostic (kilovoltage) X-ray source. Kilovolt CT can be subdivided into two broad categories, cone-beam CT based on flat panel detectors and diagnostic-grade CT based on multi-row spiral CT detectors. The kilovolt CT has the advantages of small radiation dose, high contrast and the like.

In the current existing PET guided radiation therapy system design, because PET imaging and treatment must be on the same plane, limited by spatial location, a set of independent kilovoltage CT subsystems cannot share a common scanning plane with treatment and PET imaging. This imposes limitations on radiation treatment and guidance. The main body is as follows: when a patient and a treatment bed are switched between CT imaging and PET imaging or treatment, the position of a human organ is easy to change due to the back-and-forth movement; the inability to image simultaneously or in real time during treatment limits the flow and implementation of the treatment.

With the development of radiation therapy towards a rotating gantry based helical treatment modality, and the urgent need for "adaptive" treatment protocols, image guidance and treatment co-planarity will certainly be a major trend in future radiation therapy, and an inevitable consequence of precision radiation therapy.

Image-guided radiotherapy apparatus based on a rotating gantry, the apparatus of which is relatively bulky and complex. Generally, the system consists of a high-energy radiation source for treatment, an auxiliary collimation subsystem of the high-energy radiation source, an imaging subsystem, a rotating frame, a treatment bed, a high-energy detector, a computer control and data processing subsystem and the like. The imaging subsystem has the main function of image guidance, and can be generally used for positioning the body position of a patient before treatment, acquiring information such as body movement and organ movement in treatment and feeding back the information to the treatment subsystem, so that the treatment is guided to be more efficient and more accurate.

Currently, there are CT imaging and image-guided radiotherapy devices based on PET detectors, and there are 2 limiting factors for the quality of CT imaging: 1) a single pixel unit of a PET detector is generally larger than a single pixel unit of a CT detector; 2) PET detectors are generally not collimated for backscatter. These limiting factors result in lower spatial resolution, greater scatter artifacts, and lower detection sensitivity for CT imaging.

Disclosure of Invention

Technical problem to be solved

It is an object of the present invention to provide a tomographic and image-guided radiation therapy apparatus that solves at least one of the above-mentioned problems.

(II) technical scheme

The embodiment of the invention provides a tomography and image-guided radiotherapy device, which comprises:

at least one high energy radiation source;

the system comprises a first detector and a second detector which are oppositely arranged, wherein the first detector is positioned at one side close to a KV ray source, the second detector is positioned at one side far away from the KV ray source, and the second detector comprises at least two sections of PET detectors and a CT type detector positioned between the at least two sections of PET detectors;

placing at least one kilovolt KV ray source for medical diagnosis on the first detector, the inner side of the first detector or the outer side of the first detector, wherein the kilovolt KV ray source is used for generating KV rays;

the second detector receives the KV ray and performs KVCT imaging;

the first detector and the second detector are also used for receiving gamma rays emitted by an object and carrying out PET imaging;

the high-energy ray source generates high-energy rays for carrying out radiotherapy on an object;

the KVCT imaging and/or PET imaging is used for assisting and/or guiding the radiotherapy of the object.

In some embodiments of the present invention, there is an intersection point between a straight line where the focus of the KV radiation source and the center of the object are located and the CT-type detector, and a distance between the intersection point and the center of the CT-type detector is not greater than half of the length of the CT-type detector.

In some embodiments of the present invention, the focus of the KV radiation source, the center of the object, and the offset from the center of the CT type detector by (n +1/4) × a are located on the same straight line, a is a detector pixel of the CT type detector, n is an integer, and n is greater than or equal to 0 and less than or equal to 8.

In some embodiments of the invention, the CT-type detector is an energy integrating detector, or a photon counting detector; and/or

The KV ray source comprises one of an X-ray tube, a carbon nano tube and an isotope source; the KV ray is an X ray or a gamma ray; and/or

The high-energy radiation source comprises an accelerator or an isotope source for radiotherapy, the high-energy radiation comprises one of megavolt MV photon radiation and MV particle radiation, and the MV photon radiation comprises one of megavolt X-ray and gamma ray; the MV particle rays include one of protons, neutrons, and carbon ions.

In some embodiments of the present invention, the first detector is a PET detector, the PET detector of the first detector and the PET detector of the second detector are both composed of a plurality of PET detection modules and/or detection units, a gap exists between each PET detection module and/or detection unit, and the PET detector is in a shape of a circular arc, a straight line or a polygon.

In some embodiments of the present invention, the CT-type detector is configured with at least one set of backscatter processing units with a function of removing scattered photons, and the spatial structure of the backscatter processing unit is a one-dimensional fence or a two-dimensional grid, and the material of the fence and/or the grid is a high atomic number metal.

In some embodiments of the present invention, the CT-type detector corresponds to the PET detector in terms of detector pixels, crystal thickness, and type.

In some embodiments of the present invention, the CT-type detector is a flat panel detector with high spatial resolution, where the high spatial resolution means that a detector pixel of the flat panel detector is not greater than 1mm, and the CT-type detector is further configured to receive KV rays and perform single-frame or multi-frame perspective imaging.

In some embodiments of the present invention, the second detector receives the KV ray to perform KVCT imaging, specifically:

the CT type detector receives the KV ray, performs scattering correction on the KV ray received by the PET detector, performs data and/or image fusion, and determines a full-view KVCT imaging; or

And the PET detector receives the KV ray, performs data truncation correction and scattering correction optimization on the KV ray received by the CT type detector, and determines a local view KVCT imaging.

In some embodiments of the present invention, the apparatus further comprises at least one high-energy detector, disposed opposite to the high-energy radiation source, for receiving high-energy radiation;

the high-energy detector, the high-energy ray source, the first detector, the second detector and the KV ray source are positioned on the same plane;

the first detector and the second detector are respectively positioned at two sides of the high-energy ray source and the high-energy detector.

In some embodiments of the invention, further comprising: the rotating rack is used for placing the first detector, the second detector, the high-energy ray source and the KV ray source and enabling the first detector, the second detector, the high-energy ray source and the KV ray source to rotate around an object;

and the mechanical/electrical control and data transmission/processing unit is used for controlling the rotating rack, the first detector, the second detector, the high-energy ray source and the KV ray source, and transmitting and processing data detected by the first detector and the second detector.

(III) advantageous effects

Compared with the prior art, the tomography and image-guided radiotherapy device has at least the following advantages:

1. the CT type detectors are arranged among the PET detectors, so that the detection sensitivity of the tomography and image-guided radiotherapy device is improved while the performance of system PET imaging is not remarkably reduced, and the spatial resolution of CT imaging and scattering artifact reduction are improved.

2. Because the PET detector is generally not provided with the ray-removing collimator, the PET detector is directly used for receiving KV rays, the influence of scattered photons of the PET detector can be serious, and artifacts are easily brought to KVCT images, so that the CT type detector is provided with the ray-removing processing unit, the non-direct X rays can be effectively prevented from entering, the accuracy of KVCT imaging can be further improved, and the scattering artifacts are further reduced.

3. The second detector receives the KV ray and performs KVCT imaging, and the CT detector and the PET detector have two matching modes: the CT type detector receives the KV ray, performs scattering correction on the KV ray received by the PET detector, performs data and/or image fusion, and determines a full-field KVCT imaging; or the PET detector receives the KV ray, and data truncation correction and scattering correction optimization are carried out on the KV ray received by the CT type detector to determine a local view KVCT imaging; the user can make a selection according to the requirement.

Drawings

FIG. 1 is a perspective view of a tomographic and image-guided radiation treatment apparatus according to a first embodiment of the present invention;

FIG. 2 is a schematic structural diagram of the first embodiment of FIG. 1;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a side view of FIG. 2;

FIG. 5 is a schematic structural view of the second embodiment of FIG. 1;

FIG. 6 is a schematic structural view of the third embodiment of FIG. 1;

FIG. 7 is a schematic structural view of the fourth embodiment of FIG. 1;

FIG. 8 is a schematic structural diagram of the fifth embodiment of FIG. 1;

fig. 9 is a schematic structural diagram of the sixth embodiment of fig. 1.

Detailed Description

In the prior art, the tomography and image-guided radiotherapy device based on the PET detector has the defects of lower spatial resolution of CT imaging, larger scattering artifact and lower detection sensitivity, and in view of the defects,

in order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

The embodiment of the invention provides a tomography and image-guided radiotherapy device, which comprises: at least one high energy radiation source for radiation therapy; the system comprises a first detector and a second detector which are oppositely arranged, wherein the first detector is positioned at one side close to a KV ray source, the second detector is positioned at one side far away from the KV ray source, and the second detector comprises at least two sections of PET detectors and a CT type detector positioned between the at least two sections of PET detectors; placing at least one medical kilovolt KV ray source for breaking on the first detector, the inner side of the first detector or the outer side of the first detector, wherein the kilovolt KV ray source is used for generating KV rays; the second detector receives the KV ray and performs KVCT imaging; the first detector and the second detector are also used for receiving gamma rays emitted by an object and carrying out PET imaging; the high-energy ray source generates high-energy rays for carrying out radiotherapy on an object; the KVCT imaging and/or PET imaging is used for assisting and/or guiding the radiotherapy of the object.

Fig. 1 is a schematic perspective view of a tomographic imaging and image guided radiation therapy apparatus according to a first embodiment of the present invention, fig. 2 is a schematic structural view of the first embodiment of fig. 1, fig. 3 is a top view of fig. 2, and fig. 4 is a side view of fig. 2, as shown in fig. 1 to 4, and a single KV radiation source is placed on a first detector for illustration.

The CT type detector is arranged between the PET detectors, so that the detection sensitivity of the tomography and image-guided radiotherapy device is improved while the performance of system PET imaging is not remarkably reduced, and the spatial resolution of CT imaging and scattering artifact reduction are improved.

The high-energy radiation source in the embodiment of the present invention may be an accelerator or an isotope source (or other devices) for radiotherapy, and is configured to generate one of megavolt MV photon rays or MV particle rays, where the megavolt photon rays include one of megavolt X-photons and gamma rays; the megavoltage particle beam includes one of a proton, a neutron, and a carbon ion.

The KV ray source comprises one of an X-ray tube, a carbon nano tube and an isotope source; accordingly, KV rays refer primarily to X-rays, but may also be GAMMA rays with isotope-generated energy in the medical diagnostic context.

In some embodiments of the present invention, the CT type detector may be an energy integrating detector, or a photon counting detector. The CT type detector can be a flat panel detector with high spatial resolution, and the high spatial resolution means that the detector pixels of the flat panel detector are not more than 1mm, so that the CT type detector can be used for receiving KV rays and carrying out single-frame or multi-frame perspective imaging.

The first detector is a PET detector, the PET detector of the first detector and the PET detector of the second detector are both composed of a plurality of PET detection modules and/or detection units, gaps (whether uniform or not) exist among the PET detection modules and/or units, and the PET detectors are circular arcs, straight lines or polygons. Preferably, the CT type detector is consistent with the PET detector in terms of detector pixels, crystal thickness and type, thereby enabling the PET detector to be compatible with the CT type detector and avoiding large errors. If the CT type detector is inconsistent with the PET detector in terms of detector pixels, crystal thickness and type, the PET detector and the CT type detector can be matched, only the compatible effect is sacrificed, and the error is large.

In fig. 2, the positional relationship between the CT-type detector and the PET detector of the second detector is as follows: an intersection point exists between a straight line where the KV ray source focus and the center of the object are located and the CT type detector, and the distance between the intersection point and the center of the CT type detector is not more than half of the length of the CT type detector.

Preferably, the focus of the KV radiation source, the center of the object, and an offset from the center of the CT-type detector, which is (n +1/4) × a, are located on the same straight line, a is a detector pixel of the CT-type detector, n is an integer, and n is greater than or equal to 0 and less than or equal to 8. Therefore, the CT type detector can more efficiently carry out imaging, the detection sensitivity of the tomography and image-guided radiotherapy device is improved, and the spatial resolution of the CT imaging and the reduction of scattering artifacts are facilitated.

In addition, because the PET detector has no ray collimation function, the PET detector is directly used for receiving KV rays, the influence of scattered photons may be serious, and artifacts are easily brought to the KVCT image, so the CT-type detector may be further configured with at least one set of the backscatter processing unit having a function of removing scattered photons, thereby improving the imaging performance of the KVCT. The spatial structure of the de-scattering processing unit can be a one-dimensional fence or a two-dimensional grid (preferably a structure with a large "aspect ratio", for example, an aspect ratio of about 15), and the material thereof can be an element with a high atomic number, such as tungsten, molybdenum, and the like. In addition, the backscatter processing unit may also be a software algorithm unit. The user can select one or two of the two according to actual conditions.

The second detector receives the KV ray to perform KVCT imaging, and the CT type detector and the PET detector can be matched in two modes: the CT type detector receives the KV ray, performs scattering correction on the KV ray received by the PET detector, performs data and/or image fusion, and determines a full-field KVCT imaging; or the PET detector receives the KV ray, and data truncation correction and scattering correction optimization are carried out on the KV ray received by the CT type detector, so that a local view KVCT imaging is determined.

Therefore, when the KVCT is imaged, the KV ray source and the second detector rotate around the object relatively to obtain KVCT projection data under different rotation angles, a user can select a matching mode according to requirements, and KVCT images in different forms are obtained through external computer operation.

In fig. 1, the tomographic and image guided radiation therapy apparatus generally adopts a helical scanning (therapy) mode based on a rotating gantry, and is highly universal because the spatial resolution/density resolution of the apparatus for kv CT imaging and the like are not too high (compared to medical diagnosis CT).

In the first embodiment, the KV radiation source is disposed at the outer side (the side far from the object) of the first detector, so that the KV radiation can reach the second detector, a certain gap or opening needs to be disposed on the first detector, so that the KV radiation can irradiate the second detector through the opening or gap.

In this embodiment, conventional methods for reducing the CT dose are directly available for the KV radiation source, such as bowtie (bowtie) filtering, pre-collimation, etc. The KV radiation source may be a conventional radiation source such as an X-ray tube, a novel radiation source such as a carbon nanotube, or an isotope source, etc., which are not limited in the present invention.

Because the first detector and/or the second detector can also receive 511KeV gamma rays emitted by the object (including a tracking agent), PET imaging can be carried out, meanwhile, the function of a common detector can be realized by combining CT imaging, and the common detector has the characteristics of high contrast and strong practicability under the condition of small radiation dose.

Similar to prior art radiotherapy devices, the radiotherapy device referred to in the present invention typically further comprises at least one high-energy detector. Referring to fig. 1, the high-energy detector is located between the first detector and the second detector, and is disposed opposite to the high-energy source for receiving high-energy rays.

Further, as shown in fig. 1, the tomographic imaging and image guided radiation therapy apparatus of the present invention is based on a helical scanning (treatment) mode of a rotating gantry, and further includes:

the rotating rack is used for placing the first detector, the second detector, the high-energy ray source and the KV ray source and enabling the first detector, the second detector, the high-energy ray source and the KV ray source to rotate around an object;

and the mechanical/electrical control and data transmission/processing unit is used for controlling the rotating rack, the first detector, the second detector, the high-energy ray source and the KV ray source (such as the rotating rack, the first detector, the second detector, the rotation of the high-energy ray source and the KV ray source and the emergent light beams of the high-energy ray source and the KV ray source), and transmitting and processing the data detected by the first detector and the second detector.

Referring to fig. 3 and 4 again, the first detector, the second detector, the KV radiation source, the high-energy detector and the high-energy radiation source can be located on the same plane, and the first detector and the second detector are respectively located at two sides of the high-energy radiation source and the high-energy detector, which brings great convenience to image registration and is beneficial to optimizing a treatment scheme.

It should also be noted that the tomographic and image-guided radiation therapy device of the present invention can be used for imaging before or after treatment, and that the imaging can be performed in a variety of modes:

before and/or after treatment, the first detector and/or the second detector are set to be in an integral mode, KV rays are output, and independent cone beam, fan beam or spiral CT scanning is realized; and/or

Before and/or after treatment, the first detector and/or the second detector are set to be in a counting mode, KV rays are output, and independent cone beam, fan beam or spiral CT scanning is realized; and/or

Before and/or after treatment, the first detector and/or the second detector are set to be in a counting mode, KV rays are emitted, KV ray photons and gamma rays generated by positron annihilation are distinguished through an energy threshold value of the light counting detector, and PET and CT simultaneous scanning is achieved.

During CT scanning, the KV ray source and the PET detector perform relative rotation motion around an object, so that CT data under different rotation angles are acquired.

The tomographic and image guided radiation therapy apparatus of the present invention can have the following two modes in the treatment:

the KV radiation source outputs beams in a pulse mode by utilizing the time gap of pulse type treatment, and CT imaging and treatment are synchronously carried out; and/or

The first detector and/or the second detector are set to be in a counting mode, the KV ray source emits beams in a pulse mode by utilizing the time gap of pulse type treatment, KV ray photons and gamma rays generated by positron annihilation are distinguished through the energy threshold value of the optical counting detector, and CT imaging, PET imaging and treatment are carried out synchronously.

It should be noted that the three modes before and/or after treatment and the two modes in treatment can be combined arbitrarily.

The imaging mode in the treatment can be combined with any one of the imaging modes before and after the treatment, and the multiple imaging functions of the tomography and image-guided radiotherapy device are realized.

And (3) obtaining the CT image by analyzing the CT data obtained by scanning through an image reconstruction algorithm or an iterative image reconstruction algorithm and utilizing computer operation. The obtained CT data or CT images can be used for realizing auxiliary PET imaging and/or auxiliary PET guide radiotherapy, attenuation correction during PET image reconstruction, motion artifact correction and the like; can also be directly used for guiding the radiation therapy.

In other embodiments, the KV radiation source of the tomography and image-guided radiation therapy device can be a plurality of radiation sources, and the KV radiation source can also be arranged on the first PET detector or on the inner side (the side facing the object) of the first PET detector, and in both cases, an opening is not required to be arranged on the first PET detector.

As shown in fig. 5 to 7, in sequence, one KV ray source of the second embodiment is disposed inside the first detector, and a plurality of KV ray sources of the third embodiment are disposed on the first detector; the plurality of KV radiation sources of the fourth embodiment are placed inside the first detector. These embodiments are similar to the first embodiment and will not be described herein.

Fig. 8 is a schematic structural diagram of the fifth embodiment of fig. 1, fig. 9 is a schematic structural diagram of the sixth embodiment of fig. 1, and referring back to fig. 2, 8 and 9, the PET detector and the CT-type detector in fig. 2 as a whole are symmetric about the KV central ray beam, and the PET detector and the CT-type detector in fig. 8 and 9 as a whole are asymmetric about the KV central ray beam. In the example of fig. 9, the KV source side PET detector is also asymmetric with respect to the KV source. Generally, the first embodiment of fig. 2 is preferred, that is, the detector ensemble (PET detector and CT type detector as a whole) is symmetric about the KV central beam, enabling a more uniform beam to be received by the detector ensemble.

In summary, the tomography and image-guided radiotherapy device of the invention arranges the CT type detector between the PET detectors, which is helpful for improving the detection sensitivity of the tomography and image-guided radiotherapy device and the spatial resolution of the CT imaging and reducing the scattering artifacts while not remarkably reducing the performance of the system PET imaging.

Unless otherwise indicated, the numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present invention. In particular, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Generally, the expression is meant to encompass variations of ± 10% in some embodiments, 5% in some embodiments, 1% in some embodiments, 0.5% in some embodiments by the specified amount.

Furthermore, "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element does not by itself connote any ordinal number of the element or any ordering of one element from another or the order of manufacture, and the use of the ordinal numbers is only used to distinguish one element having a certain name from another element having a same name.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A tomographic and image-guided radiation therapy apparatus comprising:

at least one high energy radiation source;

the second detector receives the KV ray and performs KVCT imaging;

the KVCT imaging and/or PET imaging is used for assisting and/or guiding the radiotherapy of the object;

the second detector receives the KV ray and performs KVCT imaging, and the method specifically comprises the following steps:

2. The tomographic and image-guided radiation treatment apparatus according to claim 1, wherein a straight line where the focal point of said KV radiation source and the center of said object are located has an intersection with said CT-type detector, and a distance between said intersection and the center of said CT-type detector is not more than half of a length of said CT-type detector.

3. The tomographic and image-guided radiation treatment apparatus according to claim 2, wherein said KV source focal point, a center of said object, and an offset from a center of said CT-type detector by (n +1/4) × a are located on a same straight line, a is a detector pixel of said CT-type detector, n is an integer, and 0 ≦ n ≦ 8.

4. The tomographic and image guided radiation therapy apparatus of claim 1, wherein said CT-type detector is an energy integrating detector, or a photon counting detector; and/or

5. The tomographic and image-guided radiation therapy apparatus of claim 1, wherein said first detector is a PET detector, said first detector PET detector and said second detector PET detector are each comprised of a plurality of PET detection modules and/or units, with a gap between each PET detection module and/or unit, said PET detectors are in the shape of a circular arc, a straight line, or a polygon.

6. The tomographic imaging and image guided radiation therapy apparatus as claimed in claim 1, wherein said CT-type detector is configured with at least one set of de-scattering processing unit having a function of removing scattered photons, and the spatial structure of said de-scattering processing unit is a one-dimensional fence or a two-dimensional grid, and the material of the fence and/or grid is a high atomic number metal.

7. The tomographic and image guided radiation therapy apparatus of claim 1 wherein said CT-type detector is consistent with detector pixels, crystal thickness and type of said PET detector.

8. The tomography and image guided radiation therapy apparatus according to claim 1, wherein said CT-type detector is a flat panel detector with high spatial resolution, said high spatial resolution means that the detector pixels of said flat panel detector are not larger than 1mm, said CT-type detector is further used for receiving KV rays and performing single-frame or multi-frame perspective imaging.

9. The tomographic and image guided radiation treatment apparatus of claim 1, further comprising at least one high energy detector positioned opposite said high energy source for receiving high energy radiation;

10. The tomographic and image guided radiation therapy apparatus of claim 1, further comprising: