WO2024011898A1 - Double-c-arm three-dimensional imaging method and system based on dynamically adjustable multi-leaf collimator - Google Patents

Abstract

The present invention relates to the technical field of image processing. Disclosed are a double-C-arm three-dimensional imaging method and system based on a dynamically adjustable multi-leaf collimator. The method comprises the steps of acquiring a three-dimensional substrate image, which is obtained by means of each split-type collimator, of a target object in a fully-retracted state during a rack angle adjustment process of double C arms; selecting a three-dimensional region of interest; extracting therefrom a maximum projection density map at a corresponding rack angle; enabling a collimator surface to retain, in a ray direction, a light-through region in a range adaptive to the current maximum projection density region; and controlling a ray-emitting bulb tube to operate, and collecting, by means of a flat panel receiver, projection data at the current preset rack angle during an adaptive imaging process.

Description

A dynamically adjustable dual C-arm three-dimensional imaging method and system based on multi-leaf gratings Technical field

The invention relates to the field of image processing technology, and in particular to a dynamically adjustable dual C-arm three-dimensional imaging method and system based on multi-leaf gratings.

Background technique

Digital Subtraction Angiography (DSA) technology has become the first choice for imaging examinations of various vascular diseases throughout the body, and is also the "gold standard" for diagnostic imaging of cerebrovascular and cardiac large vessels. For interventional diagnosis and treatment, DSA and C-arm X-ray machine (referred to as C-arm) are the core equipment supporting interventional diagnosis and treatment, and are widely used in image navigation for interventional surgery, minimally invasive surgery and hybrid surgery. Three-dimensional C-arm/DSA is based on the traditional two-dimensional C-arm/DSA technology. It collects a series of projection data within a certain angle range around the imaging area and performs three-dimensional image reconstruction. Compared with the two-dimensional C-arm/DSA image, the three-dimensional C-arm/DS stereoscopic image has no overlap, is clearer, and provides more accurate three-dimensional spatial positioning. It can also generate transverse, sagittal, coronal, or other arbitrary section images to improve surgical procedures. Accuracy; however, on the other hand, three-dimensional imaging often requires higher imaging dose, and some clinical applications require multiple three-dimensional imaging, making the problem of high imaging dose more prominent. How to reduce the imaging dose of three-dimensional C-arm/DSA has become an urgent problem that needs to be solved.

Existing C-arm/DSA equipment often uses a beam limiting device or collimating plate. The beam limiting device or collimating plate is located between the X-ray tube and the tissue being inspected. The area within the collimating window is the imaging beam area, and the X-ray passes through the open The collimation window area is projected to the tissue under examination, and is collected and analyzed by the detector after passing through the tissue to obtain diagnostic information; X-rays outside the collimation window or outside the imaging beam area do not perform effective imaging and only increase harmful The radiation dose is blocked by the metal beam limiting device or collimating plate and is not projected to the tissue being examined, thereby reducing the radiation dose. However, although the size of the opening (beam spot) of the traditional beam limiting device or collimating plate used in C-arm/DSA equipment is adjustable, the shape of the opening will not be adjusted accordingly to the shape of the imaging area. This is This results in unnecessary radiation dose being absorbed by the tissue being examined, causing unnecessary tissue damage.

Contents of the invention

In order to further reduce the imaging dose of the dual C-arm system during the three-dimensional imaging process, the present invention proposes a dynamically adjustable dual C-arm three-dimensional imaging method based on a multi-leaf grating. The multi-leaf grating is composed of several pairs of adjustable It consists of split-type grating pairs that telescope in opposite directions. Each split-type grating pair is aligned in a row to form a grating surface perpendicular to the ray direction, including the steps:

S1: Through initial imaging, obtain the base three-dimensional imaging of the target object in the fully retracted state by each split grating during the angle adjustment process of the double C-arm gantry;

S2: Obtain the three-dimensional region of interest in the three-dimensional basal imaging according to clinical needs;

S3: Extract the maximum projection density map at the corresponding rack angle from the three-dimensional area of interest based on the current preset rack angle of each single C-arm;

S4: Control the opposite extension of each split grating pair in the corresponding single C-arm according to the maximum projection density map, so that the grating surface retains a light pass area in the ray direction that is suitable for the current maximum projection density area;

S5: Control the operation of the ray emission tube and collect the projection data at the current preset rack angle during the adaptive imaging process through the flat-panel receiver;

S6: Determine whether the projection data collection is completed. If so, reconstruct the three-dimensional imaging of the target based on the projection data collected at each rack angle of the double C-arm. If not, adjust the rack angle to the next preset rack angle and return to step S3. .

Further, in the step S1, the acquisition conditions of the three-dimensional basal imaging include: acquisition through intraoperative initial imaging and acquisition through preoperative initial imaging.

Further, when the three-dimensional imaging of the base is obtained through preoperative initial imaging, the steps after step S1 are:

S20: Determine whether the position of the target object is the same as that of the initial preoperative imaging. If not, adjust the position of the target object.

Further, in the step S3, the line connecting the light pass area and the current maximum projection density area at the same position is parallel to the ray direction.

Further, during initial imaging, a first preset dose is used to obtain three-dimensional imaging of the substrate, and during adaptive imaging, a second preset dose is used to obtain projection data, and the first preset dose is greater than the second preset dose.

The present invention also proposes a dynamically adjustable dual C-arm three-dimensional imaging system based on multi-leaf gratings. The multi-leaf gratings are composed of several pairs of split grating pairs that can be retracted in opposite directions. Each split grating pair is arranged in a row. Fitted to a grating surface perpendicular to the ray direction, including:

The initial imaging unit is used to obtain the base three-dimensional imaging of the target object in the fully retracted state of each split grating during the angle adjustment process of the double C-arm gantry during initial imaging;

The region extraction unit is used to extract the three-dimensional region of interest in the three-dimensional basal imaging map according to clinical needs;

The density map extraction unit is used to extract the maximum projection density map at the corresponding frame angle from the three-dimensional area of interest based on the current preset frame angle of each single C-arm;

The grating adjustment unit is used to control the opposite extension of each split grating pair in the corresponding single C arm according to the maximum projection density map, and to keep the grating surface in the ray direction with a light pass area that is suitable for the current maximum projection density area;

The adaptive imaging unit is used to control the operation of the ray emitting tube and collect the projection data at the current preset frame angle during the adaptive imaging process through the flat-panel receiver;

The rack adjustment unit is used to adjust the rack angle to the next preset rack angle before the projection data collection is completed;

The three-dimensional reconstruction unit is used to reconstruct the three-dimensional imaging of the target object based on the projection data collected at each frame angle of the double C-arm after the projection data collection is completed.

Further, in the initial imaging unit, the three-dimensional imaging of the base is obtained by: obtaining through intraoperative initial imaging, and obtaining through preoperative initial imaging.

Further, when the three-dimensional imaging of the base is obtained through preoperative initial imaging, the adaptive imaging unit also includes:

The registration unit is used to provide body position registration guidance information when the position of the target object is different from the initial preoperative imaging.

Further, in the grating adjustment unit, the line connecting the light pass area and the current maximum projection density area at the same position is parallel to the ray direction.

Further, during initial imaging, a first preset dose is used to obtain three-dimensional imaging of the substrate, and during adaptive imaging, a second preset dose is used to obtain projection data, and the first preset dose is greater than the second preset dose.

Compared with the prior art, the present invention at least contains the following beneficial effects:

(1) A dynamically adjustable dual C-arm three-dimensional imaging method based on multi-leaf gratings according to the present invention and The system, based on the identification of the maximum projection density area at each rack angle, performs adaptive range adjustment of the light flux area to avoid non-interesting areas of the target being irradiated by rays;

(2) Obtain three-dimensional imaging of the base through normal dose irradiation during initial imaging, and screen the area of interest based on the three-dimensional imaging of the base, so as to perform adaptive imaging according to the area of interest (that is, perform support interventional diagnosis and treatment). During the process), the multi-leaf grating light-passage area is dynamically adjusted, the projection data is collected and the three-dimensional imaging splicing is obtained at a low dose, which greatly reduces the overall irradiation dose during the interventional diagnosis and treatment process.

Description of drawings

Figure 1 is a step diagram of a dual C-arm three-dimensional imaging method based on dynamically adjustable multi-leaf gratings;

Figure 2 is a structural diagram of a dual C-arm three-dimensional imaging system based on dynamically adjustable multi-leaf gratings.

Detailed ways

The following are specific embodiments of the present invention combined with the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

Embodiment 1

As the name suggests, the dual C-arm system has two sets of C-arm systems (two sets of ray emission tubes-flat receivers, C-arm frame motion devices, etc.). Generally speaking, the two sets of C-arm systems are one suspended and one floor-mounted. formula, coordinate movement and imaging. Compared with the single C-arm system, the dual C-arm system has more flexible imaging, higher temporal resolution, and fewer motion artifacts. But like the single C-arm system, the imaging dose of the dual C-arm system is also an issue that needs to be solved urgently. In order to further reduce the imaging dose in the three-dimensional imaging process of supporting interventional data based on the existing technology, as shown in Figure 1, the present invention proposes a dynamically adjustable dual C-arm three-dimensional imaging method based on multi-leaf grating. The multi-leaf grating It consists of several pairs of split-type grating pairs that can be retracted in opposite directions. Each split-type grating pair is aligned in a row to form a grating surface perpendicular to the ray direction, including the steps:

S1: Through initial imaging, obtain the base three-dimensional imaging of the target object in the fully retracted state by each split grating during the angle adjustment process of the double C-arm gantry;

S2: Obtain the three-dimensional region of interest in the three-dimensional basal imaging according to clinical needs;

S3: Extract the maximum projection density map at the corresponding rack angle from the three-dimensional area of interest based on the current preset rack angle of each single C-arm;

S4: Control the opposite extension of each split grating pair in the corresponding single C-arm according to the maximum projection density map, and Make the grating surface retain a light-passage area in the ray direction that is suitable for the current maximum projection density area;

S5: Control the operation of the ray emission tube and collect the projection data at the current preset rack angle during the adaptive imaging process through the flat-panel receiver;

S6: Determine whether the projection data collection is completed. If so, reconstruct the three-dimensional imaging of the target based on the projection data collected at each rack angle of the double C-arm. If not, adjust the rack angle to the next preset rack angle and return to step S3. .

As we all know, supporting interventional diagnosis and treatment requires constantly adjusting the gantry angle of the C-arm to obtain projection data at different imaging angles during the operation, and splicing these projection data to obtain three-dimensional imaging of the target object. Therefore, if the imaging dose during the actual surgical procedure can be reduced without affecting the imaging quality, this problem can be significantly solved. On this basis, the present invention puts forward an idea, that is, is it possible to maintain the acquisition of only the projection data of the area of interest during the C-arm imaging angle adjustment process? If this can be achieved, unnecessary imaging dose exposure to non-interest areas can be avoided. At the same time, since there is no scattering interference from rays outside the area, the imaging dose in the area of interest can be appropriately reduced while ensuring imaging quality.

Based on the above, the present invention proposes an improved three-dimensional imaging method for dual C-arms. First, through initial imaging, the base three-dimensional imaging of the target object in the fully retracted state of each split grating during the angle adjustment process of the dual C-arm gantry is obtained. And extract three-dimensional regions of interest based on clinical needs. During the initial imaging process, since the opening size of the multi-leaf grating is not controlled, in order to ensure the quality of the three-dimensional imaging, the imaging dose under conventional C-arm scanning (that is, the first preset dose ).

After obtaining the angle adjustment basis through the initial scan (that is, the three-dimensional area of interest information including the frame angle information), the adaptive scan can be entered. In order to reduce the imaging dose, the present invention proposes that in adaptive scanning, according to the current preset gantry angle of each single C-arm, the maximum projection density map at the corresponding gantry angle is first extracted from the three-dimensional area of interest. Then, according to the maximum projection density map, each split grating pair can be controlled to extend in opposite directions, so that the grating surface retains a luminous flux area in the ray direction that is suitable for the current maximum projection density area. Among them, the line connecting the luminous flux area and the current maximum projection density area at the same position is parallel to the ray direction. The advantage of this setting is that when the ray passes through the light pass area, since the line connecting the light pass area and the current maximum projection density area at the same position is parallel to the direction of the ray, the ray will only illuminate the direction of the current frame angle. Corresponding area of interest plane Therefore, no excess imaging dose will be irradiated to planes other than the plane of the area of interest, reducing the damage of rays to tissues. At the same time, since the influence of ray scattering in other non-target irradiation areas is avoided, the imaging dose can be appropriately reduced while ensuring the imaging quality (that is, the second preset dose, the specific dose can be obtained according to experiments).

After controlling the operation of the launch tube and collecting the projection data at the current preset rack angle through the flat-panel receiver, and the projection data is before the collection is completed (that is, the support interventional diagnosis and treatment has not ended), the rack can be adjusted. angle to the next preset rack angle. In the process of rack angle adjustment, in order to improve the collection speed of projection data, the split grating pair is adaptively adjusted during the rack angle adjustment process, so that its luminous area range is adaptive to the next preset machine. The maximum projection density area corresponding to the frame angle.

It should be noted that in order to meet different diagnosis and treatment requirements, the acquisition of three-dimensional basal imaging can be divided into two situations, one is obtained through initial intraoperative imaging, and the other is obtained through initial preoperative imaging. For the initial preoperative imaging acquisition, due to some special requirements, the target may require other operations midway and the initial imaging cannot be completed during the operation. The three-dimensional region of interest obtained from the initial imaging must be used in adaptive imaging. It is necessary to ensure that the position of the front and rear three-dimensional areas of interest remains unchanged, that is, the body position of the target object needs to remain consistent. The present invention is aimed at this situation. When the three-dimensional imaging of the base is obtained through preoperative initial imaging, the steps after step S1 are also included:

S20: Determine whether the position of the target object is the same as that of the initial preoperative imaging. If not, adjust the position of the target object.

Of course, in actual application scenarios, in addition to the need to adjust the position of the target, the relative positions of the imaging components in the dual C-arm imaging system also need to be adjusted to be consistent. The specific registration technology is conventional and will not be described in detail here. .

Embodiment 2

In order to better understand the technical content of the present invention, this embodiment illustrates the present invention in the form of system structure. As shown in Figure 2, a dual C-arm three-dimensional imaging system based on multi-leaf grating dynamically adjustable, multi-leaf grating dynamically adjustable Leaf gratings are composed of several split-type grating pairs that can be retracted in opposite directions. Each split-type grating pair is aligned in a row to form a grating surface perpendicular to the ray direction, including:

The initial imaging unit is used to obtain the base three-dimensional imaging of the target object in the fully retracted state of each split grating during the angle adjustment process of the double C-arm gantry during initial imaging;

The region extraction unit is used to extract the three-dimensional region of interest in the three-dimensional basal imaging map according to clinical needs;

The density map extraction unit is used to extract the maximum projection density map at the corresponding frame angle from the three-dimensional area of interest based on the current preset frame angle of each single C-arm;

The grating adjustment unit is used to control the opposite extension of each split grating pair in the corresponding single C arm according to the maximum projection density map, and to keep the grating surface in the ray direction with a light pass area that is suitable for the current maximum projection density area;

The adaptive imaging unit is used to control the operation of the ray emitting tube and collect the projection data at the current preset frame angle during the adaptive imaging process through the flat-panel receiver;

The rack adjustment unit is used to adjust the rack angle to the next preset rack angle before the projection data collection is completed;

The three-dimensional reconstruction unit is used to reconstruct the three-dimensional imaging of the target object based on the projection data collected at each frame angle of the double C-arm after the projection data collection is completed.

Further, in the initial imaging unit, the acquisition of the three-dimensional basal imaging includes: acquisition through intraoperative initial imaging and acquisition through preoperative initial imaging.

Further, when the three-dimensional imaging of the base is obtained through preoperative initial imaging, the adaptive imaging unit also includes:

The registration unit is used to provide body position registration guidance information when the position of the target object is different from the initial preoperative imaging.

Further, in the grating adjustment unit, the line connecting the light pass area and the current maximum projection density area at the same position is parallel to the ray direction.

Further, during initial imaging, a first preset dose is used to obtain three-dimensional imaging of the substrate, and during adaptive imaging, a second preset dose is used to obtain projection data, and the first preset dose is greater than the second preset dose.

In summary, the present invention is a dynamically adjustable dual C-arm three-dimensional imaging method and system based on multi-leaf gratings, which performs adaptive range adjustment of light flux based on the identification of the maximum projection density area at each frame angle. Area adjustment to avoid non-interesting areas of the target being irradiated by rays;.

Three-dimensional imaging of the substrate is obtained through normal dose irradiation during initial imaging, and during the three-dimensional imaging of the substrate Based on the screening of the area of interest, the multi-leaf grating light-passage area is dynamically adjusted during the adaptive imaging process (that is, during the support interventional diagnosis and treatment process) according to the area of interest, and the projection data is collected and Three-dimensional imaging splicing acquisition greatly reduces the overall radiation dose during interventional diagnosis and treatment.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiment of the present invention are only used to explain the relationship between components in a specific posture (as shown in the drawings). Relative positional relationship, movement conditions, etc., if the specific posture changes, the directional indication will also change accordingly.

In addition, descriptions such as "first", "second", "a", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the indicated technical features. quantity. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

In the present invention, unless otherwise clearly stated and limited, the terms "connection", "fixing", etc. should be understood in a broad sense. For example, "fixing" can be a fixed connection, a detachable connection, or an integral body; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interactive relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on what a person of ordinary skill in the art can implement. When the combination of technical solutions appears to be contradictory or cannot be realized, it should be considered that such a combination of technical solutions It does not exist and is not within the protection scope required by the present invention.

Claims (10)

A dynamically adjustable dual C-arm three-dimensional imaging method based on multi-leaf gratings, characterized in that the multi-leaf gratings are composed of several pairs of split grating pairs that can be telescoped in opposite directions, and each split grating pair is arranged in a row. Combined into a grating surface perpendicular to the ray direction, the steps include: S1: Through initial imaging, obtain the base three-dimensional imaging of the target object in the fully retracted state by each split grating during the angle adjustment process of the double C-arm gantry; S2: Obtain the three-dimensional region of interest in the three-dimensional basal imaging according to clinical needs; S3: Extract the maximum projection density map at the corresponding rack angle from the three-dimensional area of interest based on the current preset rack angle of each single C-arm; S4: Control the opposite extension of each split grating pair in the corresponding single C-arm according to the maximum projection density map, so that the grating surface retains a light pass area in the ray direction that is suitable for the current maximum projection density area; S5: Control the operation of the ray emission tube and collect the projection data at the current preset rack angle during the adaptive imaging process through the flat-panel receiver; S6: Determine whether the projection data collection is completed. If so, reconstruct the three-dimensional imaging of the target based on the projection data collected at each rack angle of the double C-arm. If not, adjust the rack angle to the next preset rack angle and return to step S3. . A dynamically adjustable dual C-arm three-dimensional imaging method based on multi-leaf gratings as claimed in claim 1, characterized in that, in step S1, the acquisition of three-dimensional substrate imaging includes: acquisition through intraoperative initial imaging, acquisition through Preoperative initial imaging acquisition. A dynamically adjustable dual C-arm three-dimensional imaging method based on multi-leaf gratings according to claim 2, characterized in that when the three-dimensional substrate imaging is obtained through preoperative initial imaging, the step S1 further includes the following steps: S20: Determine whether the position of the target object is the same as that of the initial preoperative imaging. If not, adjust the position of the target object. A dynamically adjustable dual C-arm three-dimensional imaging method based on multi-leaf gratings as claimed in claim 1, characterized in that, in step S3, the connection between the light-passage area and the current maximum projection density area is at the same position. Parallel to the ray direction. A dynamically adjustable dual C-arm three-dimensional imaging method based on multi-leaf gratings as claimed in claim 1, characterized in that during initial imaging, a first preset dose is used to obtain three-dimensional imaging of the substrate, and during adaptive imaging, a third Two preset doses are used to obtain projection data, and the first preset dose is greater than the second preset dose. A dynamically adjustable dual C-arm three-dimensional imaging system based on multi-leaf gratings, characterized in that the multi-leaf gratings are composed of several split-type grating pairs that can be telescopic in opposite directions, and each split-type grating pair is arranged in a row. Combined into a grating surface perpendicular to the ray direction, including: The initial imaging unit is used to obtain the base three-dimensional imaging of the target object in the fully retracted state of each split grating during the angle adjustment process of the double C-arm gantry during initial imaging; The region extraction unit is used to extract the three-dimensional region of interest in the three-dimensional basal imaging map according to clinical needs; The density map extraction unit is used to extract the maximum projection density map at the corresponding frame angle from the three-dimensional area of interest based on the current preset frame angle of each single C-arm; The grating adjustment unit is used to control the opposite extension of each split grating pair in the corresponding single C arm according to the maximum projection density map, and to keep the grating surface in the ray direction with a light pass area that is suitable for the current maximum projection density area; The adaptive imaging unit is used to control the operation of the ray emitting tube and collect the projection data at the current preset frame angle during the adaptive imaging process through the flat-panel receiver; The rack adjustment unit is used to adjust the rack angle to the next preset rack angle before the projection data collection is completed; The three-dimensional reconstruction unit is used to reconstruct the three-dimensional imaging of the target object based on the projection data collected at each frame angle of the double C-arm after the projection data collection is completed. A dynamically adjustable dual C-arm three-dimensional imaging system based on multi-leaf gratings according to claim 6, characterized in that, in the initial imaging unit, the acquisition of three-dimensional substrate imaging includes: acquisition through intraoperative initial imaging, Acquired via initial preoperative imaging. A dynamically adjustable dual C-arm three-dimensional imaging system based on multi-leaf gratings according to claim 7, characterized in that when the base three-dimensional imaging is obtained through preoperative initial imaging When , the adaptive imaging unit also includes: The registration unit is used to provide body position registration guidance information when the position of the target object is different from the initial preoperative imaging. A dynamically adjustable dual C-arm three-dimensional imaging system based on multi-leaf gratings according to claim 6, characterized in that, in the grating adjustment unit, the light-passage area and the current maximum projection density area are connected at the same position. The line is parallel to the ray direction. A dynamically adjustable dual C-arm three-dimensional imaging system based on multi-leaf gratings as claimed in claim 6, characterized in that, during initial imaging, a first preset dose is used to obtain three-dimensional imaging of the substrate, and during adaptive imaging, a third Two preset doses are used to acquire projection data, and the first preset dose is greater than the second preset dose.