KR101500522B1 - Image scanner for detecting absorbed dose of radial rays - Google Patents

Abstract

The present invention relates to an image scanner for measuring a radiation absorbed dose, which comprises: a light source unit which radiates light; a gel detector which receives the light radiated from the light source unit, and is formed inside a fluid in a water tank in order to absorb a fixed amount of radiation; a control unit which generates a control signal for controlling the rotation direction or rotation angle of the gel detector; a rotating unit which rotates the gel detector based on the control signal; a collimator which regulates the amount of the light penetrating the gel detector; and a photographing unit which continuously photographs the light penetrating the collimator in order to generate images to show the radiation absorbed dose of the gel detector. Therefore, the image scanner for measuring a radiation absorbed dose can continuously rotate the gel detector through uniform circular motions and can continuously photograph the light penetrating the gel detector in order to significantly reduce image scanning time.

Description

Technical Field [0001] The present invention relates to an image scanner for detecting an absorbed dose of radiation,

The present invention relates to an image scanner and a scanning method for measuring an absorbed dose of radiation, and more particularly, to an image scanner and a scanning method for measuring an absorbed dose of radiation capable of rapidly measuring an actual absorption amount of a radiation with respect to a radiation dose irradiated to a human body .

As a method of treating malignant or benign tumors present in the patient's body, surgery, chemotherapy, and radiotherapy are available. Among them, radiation therapy refers to a treatment method in which a radiation having a very short wavelength and a high energy is irradiated to a tumor by using various equipment outside the patient's body to remove the radiation.

Thus, prior to irradiation of the tumor tissue of the patient, a radiation treatment plan is required to determine the irradiation position and dose of the radiation considering the size and position of the tumor present in the patient's current tissue.

In particular, such radiotherapy is not a treatment to be completed by irradiating the tumor tissue with a one-time treatment, but the treatment is performed by irradiating the tumor tissue with various amounts of radiation several times over a predetermined time interval.

Since radiation is irradiated a plurality of times within a preset period, the size or position of the tumor changes over time. Therefore, if the treatment plan initially established before the initiation of radiotherapy is used until the end of therapy, the location of the tumor may shift, or as the size of the tumor may change due to the effect of the previous treatment, Radiation can be irradiated to normal tissues, resulting in serious side effects such as removal of normal tissue. In addition, although a predetermined amount of radiation was irradiated to the tumor according to the radiation treatment plan, the actual radiation dose of the tumor was not the same as the irradiation dose, resulting in a problem that the planned treatment process was not performed smoothly.

In order to solve the problems of the prior art as described above, the present invention provides a video scanner and a scanning method for measuring the absorbed dose of radiation, which can accurately and rapidly measure the radiation absorption amount of the actual tumor tissue with respect to the radiation irradiated to the tumor tissue in the body .

According to an aspect of the present invention, there is provided an image scanner for measuring an absorbed dose of radiation, comprising: a light source for irradiating light; A gel detector for receiving the light emitted from the light source unit and formed in the fluid of the water tank to absorb a predetermined amount of radiation; A control unit for generating a control signal for controlling the rotation direction or the rotation angle of the gel detector; A rotator for rotating the gel detector based on the control signal; A collimator for adjusting the amount of light transmitted through the gel detector; And a photographing unit for continuously photographing the light passing through the collimator and generating an image representing the amount of absorbed radiation of the gel detector.

More preferably, the gel detector may include a rotation unit that continuously rotates the gel detector in a constant-velocity motion state.

In particular, it may include a rotating part that rotates the gel detector at at least one of 10 degrees, 15 degrees, and 30 degrees per second.

In particular, it may include a rotating part composed of a step motor having a rotation angle of 1.8 degrees per pulse.

In particular, it may include a light source unit including a yellow LED having a wavelength band of 590 nm and a red LED having a wavelength band of 630 nm.

According to an aspect of the present invention, there is provided an image scanning method for measuring an absorbed dose of radiation according to an embodiment of the present invention includes the steps of irradiating light by a light source unit; The gel detector receiving and transmitting the irradiated light; Adjusting the amount of light transmitted by the collimator through the gel detector; The imaging unit successively capturing light passing through the collimator to generate an image representing the amount of absorbed radiation of the gel detector; Wherein the control unit controls the rotation angle or the rotation angle of the gel detector before the collimator adjusts the amount of light after performing the step of transmitting the irradiated light by the gel detector, ≪ / RTI > And rotating the gel detector based on the control signal.

More preferably, the rotating part for rotating the gel detector in a constant-velocity motion state may include rotating the gel detector.

In particular, the rotating part for continuously rotating the gel detector without stopping may include rotating the gel detector.

The image scanner and the scanning method for measuring the absorbed dose of radiation according to the present invention are characterized in that a gel detector absorbing radiation is continuously rotated in a constant velocity circular motion and the light transmitted through the gel detector is continuously photographed every time the gel detector rotates, There is an effect that the scan time can be remarkably reduced.

In addition, the image scanner and the scanning method for measuring the absorbed dose of radiation according to the present invention continuously generate a 2D image by successively photographing light transmitted through a gel detector rotating continuously, convert the generated 2D image into a 3D image, It is possible to more accurately grasp the absorbed dose.

1 is a schematic view of an image scanner for measuring an absorbed dose of radiation according to an embodiment of the present invention.
2 is a view showing an actual implementation of an image scanner for measuring the absorbed dose of radiation according to the present invention.
3 is a flowchart of an image scanning method for measuring an absorbed dose of radiation according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, the present invention will be described in detail with reference to preferred embodiments and accompanying drawings, which will be easily understood by those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Hereinafter, the image scanner for measuring the absorbed dose of radiation of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG.

FIG. 1 is a schematic view of an image scanner for measuring an absorbed dose of radiation according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating an actual implementation of an image scanner for measuring an absorbed dose of radiation of the present invention.

1 and 2, the image scanner 100 for measuring the absorbed dose of radiation according to the present invention includes a light source 110, a gel detector 120, a controller 130, a rotation unit 140, a collimator 150 And a photographing unit 160. [0031]

The light source 110 generates light for transmitting the gel detector 120 and irradiates the generated light to the gel detector 120. The yellow LED has a wavelength band of 590 nm and a blue LED having a wavelength band of 630 nm And a red LED. In this case, the yellow LED and the red LED are respectively formed in a line in a chip form. The yellow LED chip and the red LED chip formed in a row are arranged to face each other, and the yellow LED chip and the red LED chip are arranged in a square shape As shown in FIG.

The gel detector 120 is located in the inner fluid of the water tank arranged in a straight line with the light source unit 110 and receives and transmits the light emitted from the light source unit 110. The gel detector 120 is a substitute for the human body to determine the actual absorbed dose of the radiation irradiated to the tumor tissue in the human body and is used to measure radiation attenuation, scattering, or distribution of the radioactive material. Accordingly, the gel detector 120 absorbs the irradiated radiation as the radiation of the same amount as the amount of radiation irradiated to the tumor tissue of the patient according to the radiation treatment plan is irradiated to the gel detector 120 in advance.

The control unit 130 generates a control signal for controlling the rotation direction or the rotation angle of the gel detector 120. The control unit 130 generates a pulse, determines a rotation direction and a rotation angle for rotating the gel detector, and then generates a control signal indicating the determined rotation direction and rotation angle, and transmits the generated control signal to the rotation unit 140 ). In particular, since the controller 130 is formed of a GPU (Graphic Processing Unit), the light source effect and the texture representation can be more precise, thereby improving 3D graphics performance. The GPU is capable of performing operations in parallel with hundreds and thousands of operation cores simultaneously. Since each core of the GPU is functionally less than the CPU's core, it can easily expand to thousands and can increase the amount of computation at the same time. Therefore, if the amount of data being processed is large, There are many benefits to doing so.

In addition, the programmatic form of GPU allows each thread to be directly accessible in the order of grid, lower block, and lower thread, as in the following formula in CUDA,

여러 개의 픽셀 또는 복셀에 대해 같은 연산을 지시할 경우, 각 픽셀 또는 복셀을 하나의 스레드에 할당하여 프로그래밍하도록 설계되어 있다.

When designating the same operation for multiple pixels or voxels, it is designed to allocate each pixel or voxel to one thread and program it.

For example, if the number of blocks is 5 and the number of threads is 256, then blockIdx.x is 0 to 4, blockDim.x is 256, and threadIdx.x is 0 to 255. Therefore, id can be assigned from 0 to 1279, and if there are a total of 1280 pixels, each id computes each pixel from 0 to 1279th.

In summary, if the same operation is performed on N voxels in the conventional CPU, if the for statement is executed from 0 to N-1, CUDA allocates 0 to N-1 threads So as to simultaneously operate them.

로 프로그래밍함으로써 값을 얻을 수 있다. In addition, the GPU provides texture memory, which allows you to quickly and easily perform interpolation at coordinates assigned to texture memory. For example, when a 2 x 2 matrix is assigned to the texture memory, if it is desired to obtain an interpolation value corresponding to a coordinate of (0.5, 0.5)

To obtain a value.

These advantages are frequently used in CT image reconstruction, and thus the speed increase is also great. In this task, voxel-driven back-projection is used. In this case, the coordinates of the detector that contacts the voxel and the focal line to be reconstructed are decimals rather than integer values. By assigning the measured values of the 2D image detector to the texture memory and then inputting the decimal point coordinates as an input value, the reverse projection can be implemented easily and quickly.

The rotation unit 140 is positioned to contact the gel detector 120 on the upper or lower part of the gel detector 120 and rotates the gel detector 120 according to a control signal received from the controller 130. At this time, the rotation unit 140 may be a step motor having a rotation angle of 1.8 degrees per pulse. This step motor represents a motor that moves at a certain angle corresponding to the number of input pulses. Since the number of input pulses and the rotation angle of the motor are directly proportional, the rotation angle can be accurately controlled.

That is, the rotation unit 140 has a rotation angle of 1.8 degrees per pulse, and 32 is a freescale (that is, to arrange the number of divider ratios in the clock generated by the MCU to recognize the bundled clock as one clock again) Assuming that the motor is rotated 360 degrees to rotate 360 times, a total of 6400 pulses are used for rotation according to the 200 × 32 operation. The rotation unit 150 may continuously rotate the gel detector 120 at an angle of 10 degrees, 15 degrees, or 30 degrees per second according to the control signal. In this case, when the rotation unit 140 rotates 10 degrees per second, it may take 36 seconds for the image scan time, 24 seconds for the rotation of 15 degrees, and 12 seconds for rotation of 30 degrees.

Particularly, since the gel detector 120, which continuously rotates by the rotation unit 140, is located in the fluid inside the water tank, the gel detector 120 is also affected by the movement of the fluid generated each time it is continuously rotated . That is, as the gel detector rotates due to the movement of the fluid in the water tank, the position may change finely as the gel detector rotates.

In this case, it is further confirmed whether the position of the gel detector 120 is changed or the vibration is generated.

The image scanner for measuring the absorbed dose of radiation according to the present invention further includes a position confirming unit (not shown), and the position confirming unit is provided with a position detecting unit Check at least one. Accordingly, the position checking unit measures the rotational direction, the position, and the angle of the gel detector 120 every time the gel detector 120 rotates, and compares the measured value with the values before the rotation.

If the measurement value at the previous rotation of the gel detector 120 is different from the measured value after the rotation, the position confirming unit transmits a stop signal for the rotation of the rotation unit 140 to the controller 130 at this time.

Accordingly, when the control unit 130 receives the stop signal for the rotation from the position confirming unit, the rotation of the rotation unit 140 is temporarily stopped and the rotation direction, position, and angle of the rotation unit 140 are readjusted After regenerating the control signal, the regenerated control signal is transmitted to the rotation unit 140.

As described above, when the rotational direction, the position, the angle, and the like change due to the movement of the fluid, the gel detector 120 that performs the constant-velocity motion by the rotation unit 140 changes the value So that the change of the gel detector due to the vibration of the fluid during rotation of the gel detector can be minimized.

The collimator 150 is disposed between the gel detector 120 and the photographing unit 160 and adjusts the amount of light transmitted through the gel detector 120 to the photographing unit 160. In particular, it is possible to control so that light is irradiated only in the direction in which the photographing section 160 is located, and not irradiated in the other direction.

The photographing unit 160 continuously photographs the light passing through the collimator 150 and generates an image representing the amount of absorbed radiation of the gel detector 120. Such a photographing unit 160 may be a CCD camera for image photographing. The CCD camera converts an image into an electrical signal using a charge coupled device (CCD), and stores the digital signal in a storage medium such as a flash memory And it has a merit that it has better image quality than a CMOS type camera, so that it is mainly used when a precise image should be photographed. At this time, the image captured and generated by the photographing unit 160 may have a maximum resolution of about 540 μm.

As described above, the image taken by the photographing unit 160 is a two-dimensional image, and the present invention further includes an image converting unit (not shown), and the image converting unit converts the two- Dimensional image of the object.

In addition, since the present invention takes about 12 seconds to scan an image by rotating the gel detector 120 360 degrees, it can be seen that the image scanning time is significantly faster than the time required for the conventional image scanner. When the present invention having such characteristics is used, since the image scan time is rapidly reduced, analysis of the acquired image can be performed rapidly, so that the examination time and waiting time of the patient can be reduced and the radiation absorbed dose Can be measured.

3 is a flowchart of an image scanning method for measuring an absorbed dose of radiation according to another embodiment of the present invention.

As shown in FIG. 3, in the image scanning method for measuring the absorbed dose of radiation according to the present invention, the light source unit 110 irradiates light (S210).

The gel detector 120 receives and transmits the irradiated light (S220).

The control unit 130 generates a control signal for controlling the rotation direction or the rotation angle of the gel detector 120 (S230).

The rotation unit 140 rotates the gel detector 120 based on the control signal (S240). At this time, it is preferable that the rotation unit 140 rotates the gel detector 120 so that the gel detector 120 performs the constant-velocity motion, and in particular, the gel detector 120 is continuously rotated without stopping.

Particularly, since the gel detector 120, which continuously rotates by the rotation unit 140, is positioned in the fluid inside the water tank, it is affected by the movement of the fluid generated each time the gel detector 120 continuously rotates. That is, as the gel detector rotates due to the movement of the fluid in the water tank, the position may change finely as the gel detector rotates.

In this case, it is further confirmed whether the position of the gel detector 120 is changed or the vibration is generated.

For this, after confirming at least one of the actual rotation direction, position and angle of the gel detector 120 positioned in the internal fluid of the water tank of the present invention, the position of the gel detector 120) is measured, and the measured value is compared with the values before the rotation.

If the measurement value at the previous rotation of the gel detector 120 is different from the measured value after the rotation, the position confirming unit transmits a stop signal for the rotation of the rotation unit 140 to the controller 130 at this time.

Accordingly, when the control unit 130 receives the stop signal for the rotation from the position confirming unit, the rotation of the rotation unit 140 is temporarily stopped and the rotation direction, position, and angle of the rotation unit 140 are readjusted After regenerating the control signal, the regenerated control signal is transmitted to the rotation unit 140. When the gel detector 120 that performs the constant-velocity motion by the rotation unit 140 changes the rotation direction, position, angle, or the like due to fluid movement, the changed value is reflected upon subsequent rotation of the gel detector So that the change of the gel detector due to the vibration of the fluid during rotation of the gel detector can be minimized.

The collimator 150 adjusts the amount of light transmitted through the gel detector 120 with respect to the gel detector 120 that rotates in the constant-velocity motion state (S250).

Accordingly, the photographing unit 160 continuously photographs the light passing through the collimator 150 and generates an image representing the amount of absorbed radiation of the gel detector 120 (S260). At this time, the image taken by the photographing unit 160 is a two-dimensional image, and the image converting unit can convert the two-dimensional image into a three-dimensional image for the gel detector.

Hereinafter, a process of converting a two-dimensional image into a three-dimensional image will be described in detail.

The FDK algorithm is a reconstruction algorithm for cone beam CT.

를 θ 만큼 회전시켜 평행 투사하면 하기의 수학식 1과 같다.Objects on a 2D plane

Is rotated by &thetas; and parallel projection is performed.

관계가 성립함에 따라 데카르트 좌표(cartesian coordinate)를 극좌표로 변환하고,

라 하면,

로 나타낼 수 있다. 이때, 는 푸리에 슬라이스 정리에 의해,

의 푸리에 변환과 같게 된다. On the other hand, from the two-dimensional Fourier transform,

As the relationship is established, Cartesian coordinates are converted into polar coordinates,

In other words,

. At this time, By Fourier slice theorem,

. ≪ / RTI >

Therefore, the above equation implies that the projections obtained between 0 and 180 degrees in the Fourier domain | w | And then projected back into space to summarize.

The difference between a fan beam CT and a parallel beam CT is the radiation pattern of the beam. Therefore, by converting the parameters related to the fan beam geometry to the parameters of the parallel beam geometry, the fan beam reconstruction equation can be easily derived.

를 β각에서 얻은 s 좌표에서의 팬 빔 투사값이라 하면,

의 관계가 성립된다.When the fan angle is represented by gamma and the focal shift angle is represented by beta, it is derived as? =? +? In the parallel beam. Meanwhile,

Is the pan-beam projection value at the s-coordinate obtained at the angle [beta]

.

와 같다. 이를 팬 빔 파라미터로 나타내면, 하기의 수학식 2와 같다. By plotting the filtered back projection after filtration in a parallel beam in polar coordinates,

. This can be expressed by the following equation (2).

,

라 하면, 상기 수학식 2는 하기의 수학식 3과 같이 간단하게 여과 후 역투사 형태로 표현된다.At this time,

,

, Equation (2) is simply expressed as a post-projection form after filtering as shown in Equation (3) below.

&Quot; (3) "

Conebeam CT differs from the preceding parallel beam or fan beam in that the detector has two dimensions in the rotational direction dimension plus a vertical dimension perpendicular thereto. Therefore, the reconstructed image is not a two-dimensional image but a three-dimensional image. It is possible to use the two-dimensional measurement information obtained by projecting the three-dimensional object without separately measuring each slice of the image, so that the time required for scanning and the amount of X-ray irradiation can be greatly reduced.

The most basic algorithm of the Cone Beam CT is the FDK algorithm that extends the backward projection algorithm in the vertical direction after fan beam filtering.

축에 해당하는 슬라이스에 대해서는 팬 빔 알고리즘과 정확히 일치한다. FDK 알고리즘을 근사치 알고리즘이라고 하는 이유는

일 경우

,

로 가정하기 때문이다. 따라서,

일 때, ν가 커질수록, 위의 등호가 큰 에러로 성립하지 않기 때문에, ν₀ 에서 멀어질수록 복원된 영상이 틀어질 수 있다. 하지만, 본 발명에서는 큰 에러없이 모든 슬라이스에 대해 영상이 정확히 복원된다는 것을 확인하였다.

The slice corresponding to the axis exactly matches the fan beam algorithm. The FDK algorithm is called the approximate algorithm because

If

,

. therefore,

When, as the ν is large, because of the equal sign in the above does not hold true in a large error, it can be a more far away quality reconstructed image at ν ₀ turn. However, in the present invention, it is confirmed that the image is correctly reconstructed for all slices without a large error.

The FDK reconstruction equation derived from the above approximation is shown in Equation (4) below.

&Quot; (4) "

To summarize the FDK algorithm, first, the beam projection is normalized to the distance, filtered, and weighted according to the back projection distance, and then projected backward.

The image scanner for measuring the absorbed dose of radiation according to the present invention continuously rotates the gel detector absorbing the radiation by constant-velocity motion, continuously capturing the light transmitted through the gel detector every rotation of the gel detector, There is an effect that can be remarkably reduced.

In addition, the image scanner for measuring the absorbed dose of radiation of the present invention continuously captures light transmitted through a gel detector rotating continuously to generate a 2D image, converts the generated 2D image into a 3D image, There is an effect that can be grasped more accurately.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Do.

110: light source part 120: gel detector
130: controller 140:
150: collimator 160: photographing unit

Claims (8)

A light source unit for irradiating light;
A gel detector for receiving the light emitted from the light source unit and formed in the fluid of the water tank to absorb a predetermined amount of radiation;
A control unit for generating a control signal for controlling the rotation direction or the rotation angle of the gel detector;
A rotator for rotating the gel detector based on the control signal;
A position determiner for determining at least one of an actual rotation direction, a rotation position, and a rotation angle of the gel detector, thereby reducing a change in the gel detector due to the movement of fluid in the water tank;
A collimator for adjusting the amount of light transmitted through the gel detector; And
A photographing unit which continuously photographs the light passing through the collimator and generates an image showing a radiation absorption amount of the gel detector;
And measuring the absorbed dose of radiation.
The method according to claim 1,
The rotating part
And the gel detector is continuously rotated in a constant-velocity motion state.
The method according to claim 1,
The rotating part
Wherein the gel detector rotates at least one angle of 10 degrees, 15 degrees, and 30 degrees per second.
The method according to claim 1,
The rotating part
And a step motor having a rotation angle of 1.8 degrees per pulse.
The method according to claim 1,
The light source unit
A yellow LED having a wavelength band of 590 nm and a red LED having a wavelength band of 630 nm.
Irradiating the light source with light;
The gel detector receiving and transmitting the irradiated light;
Adjusting the amount of light transmitted by the collimator through the gel detector; And
The imaging unit successively capturing light passing through the collimator to generate an image representing the amount of absorbed radiation of the gel detector;
, ≪ / RTI &
After the step of transmitting the irradiated light by the gel detector, before the step of adjusting the amount of light by the collimator,
Generating a control signal for controlling a rotation direction or a rotation angle of the gel detector;
Rotating the gel detector based on the control signal;
Reducing the change of the gel detector due to the movement of the fluid in the water tank by confirming at least one of the actual rotation direction, the rotation position and the rotation angle of the gel detector;
The method of claim 1, further comprising the steps of:
The method according to claim 6,
The step of rotating the rotating part of the gel detector
And the gel detector is rotated in a constant velocity motion state.
The method according to claim 6,
The step of rotating the rotating part of the gel detector
Wherein the gel detector is continuously rotated without stopping.

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