WO2020082206A1

WO2020082206A1 - Ct imaging and image guidance radiation therapy device

Info

Publication number: WO2020082206A1
Application number: PCT/CN2018/111183
Authority: WO
Inventors: 高河伟; 张丽; 邢宇翔; 陈志强
Original assignee: 清华大学
Priority date: 2018-10-22
Filing date: 2018-10-22
Publication date: 2020-04-30

Abstract

CT imaging and an image guidance radiation therapy device, comprising: at least one high-energy ray source, used for generating high-energy rays for performing radiation therapy on a subject; and a first PET detector and second PET detector that are oppositely disposed. At least one kilovolt (KV) ray source for medical diagnosis is placed on the first PET detector, at an inner side of the first PET detector, or at an outer side of the first PET detector to be used to generate KV rays; the second PET detector receives the KV rays and performs CT imaging; and the first PET detector and second PET detector receive gamma photons emitted by the subject and perform PET imaging. The co-detector function of the two PET detectors is achieved by means of the KV ray source, and the present invention may assist and/or guide radiation therapy according to KVCT imaging and/or PET imaging, thus achieving the goal of commonly scanning a plane for radiation therapy, KVCT imaging and PET imaging in an image guidance radiation therapy device.

Description

CT imaging and image guided radiation therapy device

Technical field

The invention relates to the field of medical imaging and radiotherapy guidance, in particular to a computer tomography (CT) and image-guided radiotherapy device.

Background technique

Radiation therapy (Radiation Therapy) is one of the main ways to treat malignant tumors. In radiotherapy, image guidance (Image Guidance) is one of the key means to ensure high-precision treatment. Radiation therapy guidance is essentially the use of medical imaging methods to obtain accurate patient position information before or during treatment, to reduce treatment errors caused by patient body placement, heartbeat, breathing and other organ movements, thereby improving or ensuring radiation treatment Accuracy. Currently, the most common radiotherapy is the use of megavolt (MV) high-energy X-rays, and the most commonly used radiotherapy guidance is computed tomography (CT) based on kilovolt (KV) X-rays. In recent years, radiotherapy based on magnetic resonance imaging (MRI) guidance has also been successfully developed and applied in the clinic. At the same time, scientists and engineers are also actively developing new radiotherapy models based on positron emission tomography (PET) guidance.

PET is a kind of functional imaging, which can obtain biological information of human body. In PET imaging, the gamma photons produced by positron annihilation have the potential to directly reflect the real-time location information of tumors in patients. Real-time tumor location information is of great significance for high-precision tumor treatment. The movement of the patient's organs during treatment has been a major challenge for radiation therapy. Therefore, the use of PET-guided radiotherapy equipment has strong clinical application potential, and it is also one of the hotspots and difficulties currently being studied in academia and industry. In the PET-guided radiotherapy apparatus, due to the physical mechanism of PET imaging, PET cannot alone give accurate body contour information of the patient lying on the treatment bed. At the same time, PET usually needs to use CT images to achieve attenuation correction. Therefore, similar to PET / CT in medical diagnosis, a PET-guided radiotherapy apparatus usually requires a CT to "assisted" PET imaging.

In summary, CT imaging plays an important role in the radiotherapy system. At present, the common CT subsystem has two main modes: kilovolt CT (KVCT) and megavolt CT. Among them, the megavolt CT is usually directly used in the treatment of high-energy X-ray (megavolt) source-medical linear accelerator. The scan plane of the mega-volt CT is naturally in the same plane as the treatment, which brings great convenience to the image registration and at the same time helps to optimize the treatment plan. However, the quality of megavolt CT imaging is not high: the reconstructed image has low contrast and the patient receives a large radiation dose. Unlike megavolt CT, kilovolt CT generally uses a separate, medical diagnostic (kilovolt level) X-ray source. The kilovolt CT can be subdivided into two 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 and high contrast.

In the current existing PET-guided radiotherapy system design, due to the fact that PET imaging and treatment must be on the same plane, limited by spatial location, a set of independent kilovolt CT subsystems cannot share a scanning plane with treatment and PET imaging of. This imposes many restrictions on radiotherapy and guidance. It is mainly reflected in that when patients and treatment beds switch between CT imaging and PET imaging or treatment, it is easy to cause changes in the position of human organs; they cannot be simultaneously or real-time imaging during the treatment process, which limits the treatment process and implementation.

With the development of radiation therapy to a spiral model based on a rotating gantry, and the urgent need for an "adaptive" treatment plan, co-planar image guidance and treatment will definitely be the future trend of radiation therapy and the inevitable result of precision radiation therapy.

In the PET-guided radiotherapy system, in order to achieve CT and PET imaging (radiotherapy) in the same plane, an obvious compromise is to directly use a linear accelerator as a ray source, that is, a "common ray source" megavolt CT. However, as mentioned earlier, the megavolt CT radiation dose is large, the contrast is low, and the practicability is not good.

Summary of the invention

According to a first aspect of the embodiments of the present invention, a CT imaging and image-guided radiotherapy apparatus is provided, including:

At least one high-energy ray source;

Relatively placed first PET detector and second PET detector;

At least one kilovolt KV ray source for medical diagnosis is placed on the first PET detector, inside the first PET detector or outside the first PET detector for generating KV rays;

The second PET detector receives the KV rays and performs KVCT imaging;

The first PET detector and the second PET detector receive the gamma photons emitted by the object and perform PET imaging;

The high-energy ray source generates high-energy rays for radiotherapy of objects;

The KVCT imaging and / or PET imaging is used to assist and / or guide the radiation treatment of the object.

In some embodiments of the present invention, the KV ray source is placed outside the first PET detector, and the first PET detector is provided with an opening, and the opening is used to transmit the KV ray.

In some embodiments of the present invention, it further includes at least one high-energy detector, which is placed opposite to the position of the high-energy ray source and used for receiving high-energy rays;

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

The first PET detector and the second PET detector are located on both sides of the high-energy ray source and the high-energy detector, respectively.

In some embodiments of the present invention, when the KVCT is imaged, the KV ray source and the PET detector are relatively rotated around the object to obtain CT data at different rotation angles, and then a computer operation is performed to obtain a CT image.

In some embodiments of the present invention, the CT data and / or CT images are used to perform a combination of one or more of the following:

Assisted PET imaging and / or assisted PET guided radiotherapy, PET attenuation correction and PET motion artifact correction.

In some embodiments of the present invention, the KV ray source includes one of an X-ray tube, a carbon nanotube, and an isotope source.

In some embodiments of the present invention, the high energy ray source includes an accelerator or isotope source for radiotherapy, the high energy ray includes one of a megavolt MV photon ray and an MV particle ray, and the MV photon ray includes a mega One of volt X-rays and gamma rays; the MV particle beam includes one of protons, neutrons, and carbon ions.

In some embodiments of the present invention, before and / or after the treatment, the first PET detector and / or the second PET detector are set to an integration mode, and the KV rays are emitted to achieve independent cone beam, fan beam or Spiral CT scan; and / or

Before and / or after treatment, the first PET detector and / or the second PET detector are set to the counting mode, and the KV rays are emitted to realize independent cone beam, fan beam or spiral CT scanning; and / or

Before and / or after treatment, the first PET detector and / or the second PET detector are set to the counting mode, the KV rays are emitted, and the energy threshold of the light counting detector is used to distinguish between the KV ray photons and the positron annihilation Gamma photon to achieve simultaneous scanning of PET and CT.

In some embodiments of the present invention, during the treatment, the time gap of the pulsed treatment is used, and the KV ray source pulses the beam to achieve the simultaneous execution of CT imaging and treatment; and / or

In the treatment, the first PET detector and / or the second PET detector are set to the counting mode, the time gap of the pulse treatment is used, the KV ray source pulses the beam, and the energy threshold of the light counting detector is used to distinguish the KV rays Gamma photons produced by the annihilation of photons and positrons enable CT imaging, PET imaging, and treatment to proceed simultaneously.

In some embodiments of the present invention, the first PET detector and / or the second PET detector are composed of a plurality of PET detection modules and / or detection units, and there is uniformity between each PET detection module and / or detection unit gap.

Compared with the prior art, the CT imaging and image guided radiation therapy device of the present invention has at least the following advantages:

1. The KV ray source co-planar with the first PET detector, the second PET detector, the high-energy detector and the high-energy ray source is added to realize the common detector function of the first PET detector or the second PET detector, So as to achieve the purpose of KVCT imaging, PET imaging and radiotherapy co-scanning the plane.

2. The position and type of the KV ray source can be changed, and can be adjusted according to the needs of users, with strong universality.

3. The CT imaging and image-guided radiation therapy device of the present invention has a variety of imaging and / or radiation therapy guidance modes, which can be adjusted according to the actual needs of users and is applicable to various situations.

BRIEF DESCRIPTION

1 is a schematic structural view of a CT imaging and image-guided radiotherapy apparatus according to a first embodiment of the present invention;

2A is a top view of FIG. 1;

2B is a side view of FIG. 1;

3A is a schematic structural diagram of a CT imaging and image-guided radiotherapy apparatus according to a second embodiment of the present invention;

3B is a schematic structural diagram of a CT imaging and image-guided radiotherapy apparatus according to a third embodiment of the present invention;

3C is a schematic structural diagram of a CT imaging and image-guided radiotherapy apparatus according to a fourth embodiment of the present invention.

detailed description

In the prior art, when the image-guided radiotherapy apparatus realizes the PET (positron emission tomography) imaging and KVCT imaging functions, it is difficult to simultaneously make the first PET detector, the second PET detector, the high-energy detector, the high-energy ray source, and the KV The ray source is placed on the same plane. In view of this, the present invention provides a CT (Computed Tomography) imaging and image-guided radiotherapy device, which adds a KV coplanar with the first PET detector, the second PET detector, the high-energy detector, and the high-energy ray source The ray source can realize the common detector function of the first PET detector or the second PET detector, so as to achieve the purpose of co-scanning the plane of KVCT imaging, PET imaging and radiotherapy.

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail in conjunction with specific embodiments and with reference to the accompanying drawings.

A first embodiment of the present invention provides a CT imaging and image-guided radiotherapy apparatus. As shown in FIG. 1, the CT imaging and image-guided radiotherapy apparatus includes: at least one high-energy ray source for radiotherapy, the high-energy ray The source may be an accelerator for radiotherapy or an isotope source (or other device) for generating one of megavolt MV photon rays or MV particle rays, the megavolt photon rays including one of megavolt X-rays and gamma rays One; the megavolt particle beam includes one of protons, neutrons and carbon ions; the first PET detector and the second PET detector placed oppositely; on the first PET detector, the first PET detector At least one kilovolt KV ray source for medical diagnosis is placed on the inner side or the outer side of the first PET detector for generating KV rays (mainly X-rays, but can also be gamma GAMMA rays with energy generated by isotopes in the medical diagnostic range ); The second PET detector receives the KV rays and performs KVCT imaging; the first PET detector and the second PET detector receive gamma photons emitted by the object and perform PET imaging; It said high-energy radiation source generates high-energy rays, radiation treatment for an object; KVCT the imaging and / or PET imaging, for assisting and / or guiding the object radiation therapy. Therefore, the CT imaging and image-guided radiation therapy device has the advantages of low radiation dose and high contrast.

Among them, the first PET detector and the second PET detector that are placed oppositely may have a relatively arc-shaped structure (see FIG. 1 for details). In some other embodiments, the first PET detector and the second PET detector may also be It is a relatively flat structure or a straight structure.

It should be noted that the first PET detector and / or the second PET detector are generally composed of a plurality of small PET detection modules and / or detection units, and there may be a gap between each PET module and / or detection unit, preferably It is a uniform gap, that is, the PET module and / or the detection unit may not have a gap, or the gap is not uniform, and the present invention is not limited.

In Figure 1, the CT imaging and image-guided radiotherapy device generally uses a helical scanning (treatment) mode based on a rotating gantry, because the device does not require too much spatial resolution / density resolution for kilovolt CT imaging (Compared to medical diagnostic CT), therefore, its universality is extremely strong.

In the first embodiment, the KV ray source is placed on the outside of the first PET detector (the side away from the object). In order for the KV rays to reach the second PET detector, it is necessary to A certain gap or opening is provided on the top, so that KV rays are irradiated onto the second PET detector through the opening.

In this embodiment, for the KV ray source, conventional methods for reducing the CT dose can be directly used, such as bowtie filtering and front collimation. The KV ray source may be a traditional ray source such as an X-ray tube, or a new ray source such as carbon nanotubes, or an isotope source, etc., and the present invention is not limited.

Since the first PET detector and / or the second PET detector can also receive the 511KeV gamma photons emitted by the object (which contains the tracking agent), PET imaging can be performed together with CT imaging. The common detector function has the characteristics of high contrast and strong practicability when the radiation dose is small.

Similar to the prior art radiotherapy apparatus, the radiotherapy apparatus involved in the present invention generally further includes at least one high-energy detector. Please refer to FIG. 1, a high-energy detector is located in the middle of the first PET detector and the second PET detector, and is placed opposite to the position of the high-energy ray source, and is used to receive high-energy rays.

2A and 2B, it can be seen that the present application can make the first PET detector, the second PET detector, the KV ray source, the high-energy ray source, the high-energy detector and the high-energy ray source lie on the same plane. A PET detector and a second PET detector are located on both sides of the high-energy ray source and the high-energy detector, respectively. This brings great convenience to image registration, and at the same time helps to optimize the treatment plan.

It should also be noted that the CT imaging and image-guided radiotherapy apparatus of the present invention can be imaged before or after treatment, and imaging can use multiple modes:

Before and / or after treatment, the first PET detector and / or the second PET detector are set to the integration mode, and the KV rays are emitted to achieve independent cone beam, fan beam or spiral CT scanning; and / or

Before and / or after treatment, the first PET detector and / or the second PET detector are set to the counting mode, the KV rays are emitted, and the energy threshold of the light counting detector is used to distinguish between the KV ray photons and the positron annihilation. Gamma photon to achieve simultaneous scanning of PET and CT.

During CT scanning, the KV ray source and PET detector will make relative rotation movement around the object, so as to obtain CT data at different rotation angles.

The CT imaging and image-guided radiation therapy device of the present invention can have the following two modes in treatment:

Using the time gap of pulsed therapy, the KV ray source pulsed the beam to achieve simultaneous CT imaging and treatment; and / or

The first PET detector and / or the second PET detector are set to the counting mode, the time gap of the pulse treatment is used, the KV ray source pulses the beam, and the energy threshold of the light counting detector is used to distinguish the KV ray photon from the positron annihilation The generated gamma photons can be synchronized with CT imaging, PET imaging and treatment.

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

The imaging mode during treatment can be combined with any imaging mode before and after treatment to realize various imaging functions of the CT imaging and image-guided radiation therapy device.

For the CT data obtained by scanning, the CT image is obtained by analyzing the image reconstruction algorithm or iterative image reconstruction algorithm and using computer calculations. The obtained CT data or CT images can be used to implement assisted PET imaging and / or assisted PET guided radiotherapy, attenuation correction during PET image reconstruction, motion artifact correction, etc .; and can also be used directly to guide radiotherapy.

In some other embodiments, the KV ray source of the CT imaging and image-guided radiotherapy apparatus may be multiple ray sources, and the KV ray source may also be placed on or inside the first PET detector (towards On the side of the object), in both cases, it is not necessary to provide an opening in the first PET detector.

As shown in FIGS. 3A to 3C, a KV ray source of the second embodiment is placed inside the first PET detector in turn, and a plurality of KV ray sources of the third embodiment are placed on the first PET detector. The multiple KV ray sources of the fourth embodiment are placed inside the first PET detector.

In summary, the CT imaging and image-guided radiotherapy apparatus of the present invention adds a KV ray source coplanar with the first PET detector, the second PET detector, the high-energy detector, and the high-energy ray source, and realizes the first PET detector Or the co-detector function of the second PET detector, CT data and / or CT images, and / or PET data and / or PET images can be used to assist and / or guide radiation therapy, improve the performance of radiation therapy, and at the same time To achieve the purpose of co-scanning the plane of radiotherapy, KVCT imaging and PET imaging.

Unless well-known as contrary, the numerical parameters in this specification and the appended claims are approximate and can be changed according to the desired characteristics obtained by the content of the present invention. Specifically, all numbers used in the specification and claims to indicate the content of the composition, reaction conditions, etc., should be understood as modified by the word "about" in all cases. In general, the meaning of the expression refers to including a specific amount of ± 10% change in some embodiments, ± 5% change in some embodiments, ± 1% change in some embodiments, in some implementations In the case of ± 0.5% change.

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

The ordinal numbers used in the specification and claims, such as "first", "second", "third", etc., are used to modify the corresponding element, which does not mean that the element has any ordinal number, nor Represents the order of a certain element and another element, or the order of manufacturing methods. The use of these ordinal numbers is only used to make a certain element with a certain name can be clearly distinguished from another element with the same name.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

A CT imaging and image guided radiation therapy device, including:

At least one high-energy ray source;

Relatively placed first PET detector and second PET detector;

At least one kilovolt KV ray source for medical diagnosis is placed on the first PET detector, inside the first PET detector or outside the first PET detector for generating KV rays;

The second PET detector receives the KV rays and performs KVCT imaging;

The first PET detector and the second PET detector receive the gamma photons emitted by the object and perform PET imaging;

The high-energy ray source generates high-energy rays for radiotherapy of objects;

The KVCT imaging and / or PET imaging is used to assist and / or guide the radiation treatment of the object.
The CT imaging and image-guided radiotherapy apparatus according to claim 1, wherein the KV ray source is placed outside the first PET detector, the first PET detector is provided with an opening, and the opening is Yu passes through the KV rays.
The CT imaging and image-guided radiotherapy apparatus according to claim 1, further comprising at least one high-energy detector, which is placed opposite to the position of the high-energy ray source for receiving high-energy rays;

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

The first PET detector and the second PET detector are located on both sides of the high-energy ray source and the high-energy detector, respectively.
The CT imaging and image-guided radiotherapy apparatus according to claim 1, wherein, during the KVCT imaging, the KV ray source and the PET detector rotate relative to the object, acquire CT data at different rotation angles, and then calculate by computer, Obtain CT images.
The CT imaging and image-guided radiotherapy apparatus according to claim 4, wherein the CT data and / or CT images are used to perform a combination of one or more of the following:

Assisted PET imaging and / or assisted PET guided radiotherapy, PET attenuation correction and PET motion artifact correction.
The CT imaging and image guided radiotherapy apparatus according to claim 1, wherein the KV ray source includes one of an X-ray tube, a carbon nanotube, and an isotope source.
The CT imaging and image guided radiotherapy apparatus according to claim 1, wherein the high-energy ray source includes an accelerator or isotope source for radiotherapy, and the high-energy ray includes one of a megavolt MV photon ray and an MV particle ray First, the MV photon rays include one of megavolt X-rays and gamma rays; the MV particle rays include one of protons, neutrons, and carbon ions.
The CT imaging and image-guided radiotherapy apparatus according to claim 1, wherein, before and / or after the treatment, the first PET detector and / or the second PET detector are set to an integration mode, and the KV rays are emitted, Achieve independent cone-beam, fan-beam or spiral CT scanning; and / or

Before and / or after treatment, the first PET detector and / or the second PET detector are set to the counting mode, and the KV rays are emitted to realize independent cone beam, fan beam or spiral CT scanning; and / or

Before and / or after treatment, the first PET detector and / or the second PET detector are set to the counting mode, the KV rays are emitted, and the energy threshold of the light counting detector is used to distinguish between the KV ray photons and the positron annihilation. Gamma photon to achieve simultaneous scanning of PET and CT.
The CT imaging and image-guided radiotherapy apparatus according to claim 1, wherein in the treatment, the time interval of the pulsed treatment is used, and the KV ray source pulses the beam to realize the simultaneous execution of the CT imaging and the treatment; and / or

In the treatment, the first PET detector and / or the second PET detector are set to the counting mode, the time gap of the pulse treatment is used, the KV ray source pulses the beam, and the energy threshold of the light counting detector is used to distinguish the KV rays Gamma photons produced by the annihilation of photons and positrons enable CT imaging, PET imaging, and treatment to proceed simultaneously.
The CT imaging and image guided radiotherapy apparatus according to claim 1, wherein the first PET detector and / or the second PET detector are composed of a plurality of PET detection modules and / or detection units, each PET detection module and There is a uniform gap between the detection units.