X-ray blood irradiator calibration device and calibration method

Abstract

The invention discloses a calibration device and a calibration method for an X-ray blood irradiator. The calibration device comprises a detector, a detector host and a blood equivalent die body. According to the calibration method, after a blood equivalent motif is selected and placed according to a target irradiation container, a detector is connected with the blood equivalent motif; moving the detector to a reference point, reading the absorbed dose value of the reference point, calculating an indication error, reading the absorbed dose value of each measurement point, calculating the absorbed dose uniformity of the target irradiation container, and taking the reference point of each irradiation container as the measurement point. And reading numerical values based on the detector and calculating the consistency of the absorbed dose values among the irradiation containers. According to the scheme, measurement of the dynamic blood irradiation dose is achieved, the problem that an existing X-ray blood irradiator cannot accurately measure the irradiation dose and the uniformity of the irradiation dose is solved, data transmission can be achieved without punching in a measurement cavity, the measurement result can be reproduced, and the X-ray blood irradiator is more suitable for repeated measurement.

Description

Technical Field

[0001] The present application belongs to the technical field of medical equipment, and specifically relates to a calibration device and a calibration method for an X-ray blood irradiator. Background Art

[0002] Transfusion-associated graft-versus-host disease (TA-GVHD) is a serious related complication with a mortality rate of up to 90%. Blood irradiation is a commonly used clinical method for processing blood and blood components, using X-rays to inactivate immune-active T lymphocytes in the blood. The accuracy of the X-ray irradiation dose and the dose uniformity of the entire radiation field will directly affect the inactivation effect and thus the quality of blood transfusion. Therefore, it is very important to accurately measure the irradiation dose and dose uniformity of the X-ray blood irradiator. However, due to the need for rotation for irradiation of this type of equipment and the small measurement chamber, precise measurement of the dynamic irradiation field is required, and measurement data is difficult to transmit and signal loss occur. Currently, chemical dosimeters and films are mostly used for measurement, resulting in large errors in irradiation dose and dose uniformity. Different manufacturers even use different methods, making it impossible to unify the consistency between different devices.

[0003] Current technology still has the following problems: the ionization chamber measurement method cannot solve the problems of dynamic irradiation field dose measurement, signal transmission and excessive host size; the film dose method cannot be used for measurement, that is, the measurement results cannot be reproduced, resulting in unreliable measurement results; the chemical dosimeter has poor mechanical stability and large positioning error, large angle dependence, insufficient spatial resolution, high temperature and humidity sensitivity, and data readout relies on EPR spectrometer, resulting in an error of more than 10% in the irradiation dose measurement results. In addition, the EPR spectrometer is expensive and has high cost. Therefore, the existing technology cannot accurately measure the irradiation dose and dose uniformity of the X-ray blood irradiator. Summary of the Invention

[0004] In response to the above-mentioned problems existing in the prior art, the present application provides an X-ray blood irradiator calibration device and calibration method to solve the problem that the existing X-ray blood irradiator cannot accurately measure the irradiation dose and the irradiation dose uniformity.

[0005] To achieve the above objectives, the present application adopts the following technical solutions: In a first aspect, a method for calibrating an X-ray blood irradiator is provided, comprising the following steps:

[0006] After selecting a blood equivalent phantom according to the target irradiation container and placing it, the detector is connected to the blood equivalent phantom;

[0007] Move the detector to the reference point, set the nominal dose value for irradiation, read the absorbed dose value at the reference point and calculate the indication error. The reference point is the geometric center point of the blood equivalent phantom.

[0008] Furthermore, the mobile detector sequentially obtains the absorbed dose values ​​of the measuring points. After irradiation with a typical irradiation program, the absorbed dose values ​​of each measuring point are read and the absorbed dose uniformity of the target irradiation container is calculated. There are 15 measuring points in total.

[0009] If the X-ray blood irradiator is a multi-irradiation container X-ray blood irradiator, the corresponding blood equivalent phantom is placed in each irradiation container, and the reference point of each irradiation container is used as the measurement point. After the irradiation is completed, the value is read based on the detector and the consistency of the absorbed dose value between each irradiation container is calculated.

[0010] Wherein, when the X-ray blood irradiator is a multi-irradiation container X-ray blood irradiator, the calibration method further includes the following steps:

[0011] A corresponding blood equivalent phantom is placed in each irradiation container, and the reference point of each irradiation container is used as the measurement point. After irradiation is completed, the value is read based on the detector and the consistency of the absorbed dose value between each irradiation container is calculated;

[0012] Determine whether the consistency standard is met, and if so, complete the calibration;

[0013] If not, adjust the irradiation parameters corresponding to each irradiation container and repeat the above steps until the consistency reaches the standard. The calibration of the X-ray blood irradiator is completed.

[0014] The consistency of absorbed dose values ​​between irradiation containers is calculated based on the following formula:

[0015]

[0016] Where C is the absorbed dose consistency between irradiation containers, D max is the maximum absorbed dose value of the irradiated container, D min is the minimum absorbed dose value of the irradiated container.

[0017] Among them, reading the absorbed dose value of the reference point and calculating the indication error include:

[0018] Set the nominal dose value to D0, and after the irradiation is completed, read the absorbed dose D;

[0019] The indication error of the absorbed dose at the reference point is calculated according to the following formula:

[0020]

[0021] Where ΔD is the absorbed dose error at the reference point; D0 is the nominal absorbed dose value at the reference point; and D is the absorbed dose value at the reference point.

[0022] The calculation formula for the uniformity of the absorbed dose of the target irradiation container is:

[0023]

[0024] Where Ci is the absorbed dose uniformity of each measurement point, i = 1, 2, ..., n; Di is the absorbed dose value of each measurement point; D is the absorbed dose value of the reference point;

[0025] The maximum absolute value is taken as the uniformity of the irradiation container.

[0026] A second aspect provides an X-ray blood irradiator calibration device, applicable to the X-ray blood irradiator calibration method as shown in the first aspect, comprising:

[0027] The detector is provided with a crystal probe, connected to the detector host via a connecting wire, the connecting wire has a micro photomultiplier tube integrated therein, and the inner ring of the detector is provided with a rotatable bearing for connecting to the blood equivalent phantom;

[0028] The detector host integrates wireless transmission module and wired transmission module and is connected to the terminal software;

[0029] The blood equivalent phantom includes a first type of blood equivalent phantom for calibration of vertically placed irradiation containers and a second type of blood equivalent phantom for calibration of horizontally placed irradiation containers.

[0030] Among them, the first type of blood equivalent phantom is cylindrical, with five cylinders vertically opened at equal distances in the center and around the periphery and running through the phantom. The upper, middle and lower points inside the cylinder are measurement points, for a total of 15 measurement points.

[0031] Among them, the second type of blood equivalent phantom is a transverse cylindrical shape, with three through holes in the middle of its side, and the upper, middle and lower points of the middle through hole are used as measurement points. The two sides each have three through holes in the upper, middle and lower positions, and the middle points of the side through holes are used as measurement points, for a total of 15 measurement points.

[0032] Beneficial effects of this application:

[0033] The present application provides an X-ray blood irradiator calibration device and calibration method, which can realize dynamic blood irradiation dose measurement, solving the problem that the X-ray blood irradiator cannot measure irradiation dose;

[0034] A scintillator detector with high energy response and compact size was developed based on Lyso crystals. A radiation-resistant, small-volume signal receiver and offline data processing software were also developed, forming a measurement system suitable for measuring the irradiation dose of X-ray blood irradiators. A calibration method for X-ray blood irradiators was proposed to address the inability of existing X-ray blood irradiators to accurately measure irradiation dose and irradiation dose uniformity.

[0035] Compared with existing rough measurement methods, data transmission can be achieved without drilling holes in the measurement chamber, and the signal transmission loss rate is no more than 3%. The measurement results can be reproduced, making it more suitable for repeated measurements.

[0036] The selection of measurement points in the measurement method, combined with the rotational characteristics of blood irradiation, can cover the maximum dose point and the minimum dose point, which can well evaluate the uniformity of blood irradiation dose; the consistency parameters between blood cups of the multi-blood cup irradiation device are introduced, and an evaluation method is proposed, which can more comprehensively evaluate the performance of different devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic flow chart of the calibration method of an X-ray blood irradiator according to the present application;

[0038] Figure 2 This is a schematic diagram of the structure of the calibration device of the X-ray blood irradiator of this application;

[0039] Figure 3 This is a schematic structural diagram of the first type of blood equivalent phantom of the X-ray blood irradiator calibration device of this application;

[0040] Figure 4 This is a schematic diagram of the top view of the first type of blood equivalent phantom of the X-ray blood irradiator calibration device of this application;

[0041] Figure 5 This is a schematic diagram of the layout of the first type of blood equivalent phantom of the X-ray blood irradiator calibration device of this application;

[0042] Figure 6 This is a schematic diagram of the three-dimensional structure of the second type of blood equivalent phantom of the X-ray blood irradiator calibration device of this application;

[0043] Figure 7 This is a schematic diagram of the layout of the second type of blood equivalent phantom of the X-ray blood irradiator calibration device of this application;

[0044] Figure 8 This is another schematic diagram of the layout of the second type of blood equivalent phantom of the X-ray blood irradiator calibration device of this application;

[0045] In the figure, 1 is a detector, 10 is a crystal probe, 2 is a detector host, 3 is a blood equivalent phantom, 31 is a first type of blood equivalent phantom, 32 is a second type of blood equivalent phantom, and 4 is a connecting line. DETAILED DESCRIPTION

[0046] The following describes embodiments of the present application in more detail with reference to the accompanying drawings. Although the accompanying drawings illustrate embodiments of the present application, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0047] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0048] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0049] Unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0050] Example 1

[0051] like Figure 2 The X-ray blood irradiator calibration device shown includes: a detector 1, a detector host 2, a connecting line 4 for connecting the detector 1 and the detector host 2, and a blood equivalent phantom 3.

[0052] Detector 1 uses a Lyso crystal. Compared to the ionization chamber probe, this detector 1 has a sensitive volume of less than 0.1 cm3 and is connected to the detector host 2 via optical fiber (with a micro photomultiplier tube integrated inside). The detector host 2 can store 50,000 measurement points, enabling the collection of measurement points and the integration of electrical signals at measurement points. It also integrates a wireless transmission module and a limited transmission module, enabling communication with terminal software, ultimately achieving the collection of dose points and data analysis. Furthermore, the outer surface of the host is wrapped in lead to reduce radiation damage to electronic components in high-dose-rate radiation fields. The connecting wire 4 is designed to be wrapped in soft rubber and fixed to the set measurement position of the blood equivalent phantom 3 via an inner ring rotatable bearing, thereby achieving synchronous rotation of the detector 1 and the blood equivalent phantom 3, thus solving the problems of a small measurement chamber, a high irradiation chamber dose rate, dynamic irradiation dose measurement, and signal transmission loss.

[0053] To fix the probe in the blood equivalent phantom 3, it is necessary to first determine the measurement point. This technical solution mainly includes two types of blood equivalent phantoms 3. Figure 3 、 Figure 4 As shown, the equivalent phantom of the first type of blood is cylindrical, with a cylindrical hole running through the phantom on the top, suitable for detector size 1, with a hole in the middle and 4 holes distributed evenly around the phantom, with the hole center 10mm away from the edge of the phantom; the center of the axial position of the middle hole is used as the reference point for irradiation dose measurement, and in the cylinder with 5 holes, 3 points (upper, middle and lower) are selected respectively, for a total of 15 points as measurement positions for dose distribution uniformity, of which the upper and lower measurement points are both 2cm away from the surface. The specific point arrangement scheme is shown in Figure 5 ,There are 15 measurement points in the figure, among which the number “2” is the reference point position.

[0054] like Figure 6 As shown, the second type of blood equivalent phantom 32 is a horizontal cylindrical shape. This type of phantom is punched from the side of the cylinder, wherein three through holes are punched in the middle of the side, the center of the upper and lower through holes are 10mm away from the edge of the phantom. The three through holes are respectively selected at the upper, middle and lower measurement points, wherein the upper and lower measurement points are both 2cm away from the surface, and the three middle through holes have a total of 9 measurement points. The upper, middle and lower through holes are punched in the two sides (the center of the through hole is 10mm away from the edge of the phantom), and the middle position of the through hole is selected as the side measurement point, for a total of 6 measurement points. In summary, there are a total of 15 measurement points. The specific point arrangement scheme is shown in Figure 7 、 Figure 8 ,There are 15 measurement points in the figure, among which number “5” is the reference point position.

[0055] Example 2

[0056] like Figure 1The X-ray blood irradiator calibration method shown is applied to the X-ray blood irradiator calibration device shown in the first embodiment, and includes the following steps:

[0057] S1. After selecting a blood equivalent phantom according to the irradiation container and placing it, establish a connection between the detector and the blood equivalent phantom.

[0058] The first type of cylindrical blood equivalent phantom is suitable for measuring dose distribution in both the longitudinal and depth directions, effectively simulating the irradiation of blood in a relatively vertical position within a cylindrical container. The design of the central and peripheral holes comprehensively reflects the dose distribution at various locations along the longitudinal and peripheral sides of the phantom. In particular, the reference point, positioned at the axial center of the central hole, facilitates baseline dose measurements and is highly suitable for calibrating conventional vertically positioned irradiation containers.

[0059] The second type of transverse cylindrical blood equivalent phantom is suitable for simulating the scenario of blood being irradiated in a horizontally placed container, and can focus on measuring the dose situation at different positions in the transverse direction. Through multiple through-holes and measurement points on the side, the dose distribution in different directions such as up and down, left and right can be accurately obtained during transverse irradiation, which makes up for the shortcomings of the first type of phantom in transverse measurement and is more suitable for calibrating transversely placed irradiation containers. The phantom is selected based on the placement of the blood container corresponding to the X-ray blood irradiator being calibrated. If the blood container is placed vertically during irradiation, the first type of phantom is preferred; if it is placed horizontally, the second type of phantom is used.

[0060] S2. Move the detector to the reference point, set the nominal dose value for irradiation, read the absorbed dose value at the reference point and calculate the indication error. The reference point is the geometric center point of the blood equivalent phantom.

[0061] Measurement of reference point absorbed dose indication error: Place a matching blood equivalent phantom in a sample container of a certain specification and type, and select the geometric center point of the blood equivalent phantom as the reference point. Place the detector at the reference point in the blood equivalent phantom, set a typical irradiation program, set the nominal dose value to D0, and after the irradiation is completed, read the absorbed dose D. Calculate the reference point absorbed dose indication error according to the following formula:

[0062]

[0063] in, is the absorbed dose error of the reference point; D0 is the nominal value of the absorbed dose at the reference point, and D is the measured value of the absorbed dose at the reference point.

[0064] S3. The mobile detector obtains the absorbed dose values ​​of the measuring points in sequence. After irradiation with a typical irradiation program, the absorbed dose values ​​of each measuring point are read and the absorbed dose uniformity of the target irradiation container is calculated. There are 15 measuring points in total.

[0065] Measurement of absorbed dose uniformity: Select a sample container of a certain specification and place the corresponding blood equivalent phantom. Place the detectors on a line parallel to the central axis and 1 cm from the phantom surface. The distance between the top measurement point and the top surface of the phantom and the distance between the bottom measurement point and the bottom surface of the phantom are both 2 cm. A total of 15 measurement points are selected. A typical irradiation program is selected and irradiation is performed. After irradiation is completed, the absorbed dose value of each point is read. The absorbed dose uniformity of each point is calculated according to the following formula. The one with the largest absolute value is taken as the uniformity of the device:

[0066]

[0067] Wherein, Ci is the uniformity of absorbed dose at each measuring point, i = 1, 2, ..., n; Di is the absorbed dose measurement value at each measuring point; and D is the absorbed dose measurement value at the reference point.

[0068] S4. If the X-ray blood irradiator is a multi-irradiation container X-ray blood irradiator, then the corresponding blood equivalent phantom is placed in each irradiation container, and the reference point of each irradiation container is used as the measurement point. After the irradiation is completed, the value is read based on the detector and the consistency of the absorbed dose value between each irradiation container is calculated.

[0069] When measuring multiple blood cups using an X-ray blood irradiator, the absorbed dose consistency between the cups must also be considered. Place the blood equivalent phantom in the blood cup, and fill the remaining blood cups with the corresponding blood equivalent phantoms. Select the reference point of each blood cup as the measurement point, select a typical irradiation program, and perform the irradiation. After the irradiation is completed, calculate the absorbed dose consistency between the blood cups using the following formula:

[0070]

[0071] Where C is the absorbed dose consistency between blood cups.

[0072] Finally, it should be noted that, in this document, relationships such as first and second, etc., are used solely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms include, comprise, or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0073] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0074] The embodiments of the present application have been described above. The above description is illustrative and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for calibrating an X-ray blood irradiator, characterized in that: The following steps are involved: After a blood equivalent phantom is selected and placed according to the target irradiation container, a detector is connected to the blood equivalent phantom; Moving the detector to a reference point, setting a nominal dose value for irradiation, reading the absorbed dose value at the reference point and calculating the indication error, wherein the reference point is the geometric center point of the blood equivalent phantom; and, moving the detector to sequentially obtain absorbed dose values ​​at measurement points, selecting a typical irradiation program for irradiation and reading the absorbed dose value at each measurement point, and calculating the absorbed dose uniformity of the target irradiation container, wherein the number of measurement points is 15; If the X-ray blood irradiator is a multi-irradiation container X-ray blood irradiator, the corresponding blood equivalent phantom is placed in each irradiation container, and the reference point of each irradiation container is used as the measurement point. After irradiation is completed, the value is read based on the detector and the consistency of the absorbed dose value between each irradiation container is calculated.

2. The X-ray blood irradiator calibration method according to claim 1, wherein: The consistency of the absorbed dose values ​​between the irradiation containers is calculated based on the following formula: Where C is the absorbed dose consistency between irradiation containers, D max is the maximum absorbed dose value of the irradiated container, D min is the minimum absorbed dose value of the irradiated container.

3. The X-ray blood irradiator calibration method according to claim 1, wherein: Reading the absorbed dose value at the reference point and calculating the indication error includes: Set the nominal dose value to D0, and after the irradiation is completed, read the absorbed dose D; The indication error of the absorbed dose at the reference point is calculated according to the following formula: in, is the absorbed dose error of the reference point; D0 is the nominal value of the absorbed dose at the reference point, and D is the absorbed dose value at the reference point.

4. The X-ray blood irradiator calibration method according to claim 1, wherein: The calculation formula for obtaining the absorbed dose uniformity of the target irradiation container is: Where Ci is the absorbed dose uniformity of each measurement point, i = 1, 2, ..., n; Di is the absorbed dose value of each measurement point; D is the absorbed dose value of the reference point; The maximum absolute value is taken as the uniformity of the irradiation container.

5. An X-ray blood irradiator calibration device, suitable for the X-ray blood irradiator calibration method according to any one of claims 1 to 4, characterized in that: include: The detector is provided with a crystal probe and is connected to the detector host via a connecting wire. The connecting wire has a micro photomultiplier tube integrated therein. The inner ring of the detector is provided with a rotatable bearing for connecting to a blood equivalent phantom. The detector host integrates wireless transmission module and wired transmission module and is connected to the terminal software; The blood equivalent phantom includes a first type of blood equivalent phantom for calibration of vertically placed irradiation containers and a second type of blood equivalent phantom for calibration of horizontally placed irradiation containers.

6. The X-ray blood irradiator calibration device according to claim 5, characterized in that: The first type of blood equivalent phantom is cylindrical, with five cylinders vertically opened at equal distances in the center and around the periphery and penetrating the phantom. The upper, middle and lower points in the cylinder are measurement points, for a total of 15 measurement points.

7. The X-ray blood irradiator calibration device according to claim 5, characterized in that: The second type of blood equivalent phantom is a transverse cylindrical shape, with three through holes in the middle of its side, and the upper, middle and lower points of the middle through hole are used as measurement points. The two sides each have three through holes in the middle and lower, and the middle points of the side through holes are used as measurement points, for a total of 15 measurement points.

8. The X-ray blood irradiator calibration device according to claim 5, characterized in that: The outer side of the detector host is provided with a wrapping lead layer.

Images