Scanning an object with a radiation detector

Abstract

A method comprising: scanning an object (520) with an imaging system (500) having a radiation detector (100) and a radiation source (510) stationary relative to each other. In the scan, for i = 1,..., M, in order, one value of i at a time, a scan (i) is performed by translating the radiation detector (100) along a translation plane (106) and along a direction (i). An Ox axis and an Oy axis both lie in the translation plane (106) and are perpendicular to each other. An orthogonal projection of the direction (i) on the Oy axis does not point in two opposite directions. An orthogonal projection of the direction (i) on the Ox axis alternately points in 2 opposite directions. For i = 1,..., (M-1), the direction (i) and the direction (i+1) are not parallel to each other. Each point of the object (520) is scanned in at least two scans in the scan.

Description

[Background Technology]

[0001] A radiation detector is a device for measuring the characteristics of radiation. Examples of these characteristics can include the spatial distribution of the intensity, phase, and polarization of the radiation. The radiation measured by a radiation detector can be radiation that has already passed through an object. The radiation measured by a radiation detector can be electromagnetic radiation, such as infrared light, visible light, ultraviolet light, X-rays, or gamma rays. The radiation can also be other types, such as alpha rays and beta rays. An imaging system can include one or more image sensors, each of which can have one or more radiation detectors. [Summary of the Invention]

[0002] This document discloses a method comprising: scanning an object using an imaging system comprising a radiation detector and a radiation source stationary relative to each other. The scanned object comprises: performing a scan (i) by translating the radiation detector one value at a time, for i = 1, ..., M, by (A) translating along the same translation plane and (B) translating along direction (i). M is an integer greater than 1. The Ox axis and the Oy axis are both located in the translation plane and are perpendicular to each other. The orthogonal projections of the directions (i), i = 1, ..., M, onto the Oy axis do not point to two opposite directions. The orthogonal projections of the directions (i), i = 1, ..., M, onto the Ox axis alternately point to two opposite directions. For i = 1, ..., (M-1), the directions (i) and (i+1) are not parallel to each other. Each point of the object is scanned in at least two of the scans (i), i = 1, ..., M.

[0003] On the one hand, for i = 1, ..., (M-2), the direction (i) and the direction (i+2) are parallel to each other.

[0004] On one hand, each point is scanned in no more than two scans in the scan(i), i = 1, ..., M.

[0005] In one respect, the translation plane (A) intersects with all source-facing sensing elements of the radiation detector, or (B) is the best-fit plane for all source-facing sensing elements of the radiation detector.

[0006] On one hand, at time points during the scan (i), i = 1, ..., M, the translation plane is perpendicular to a straight line intersecting the source-facing sensing element of the radiation source and the radiation detector.

[0007] On one hand, the sensing element plane of the radiation detector intersects with the radiation source.

[0008] On one hand, for each odd value of i, the scan (i) includes sending a radiation beam (i) of the same first energy range to the object using the radiation source, and for each even value of i, the scan (i) includes sending a radiation beam (i) of the same second energy range to the object using the radiation source, the first energy range and the second energy range being different.

[0009] On the one hand, the first energy range and the second energy range do not overlap.

[0010] In one respect, for each value of i, the scan (i) includes incrementing a counter of the radiation detector in response to a radiation particle impacting the radiation detector in a third energy range, and decrementing a counter in response to a radiation particle impacting the radiation detector in a fourth energy range, wherein the third energy range and the fourth energy range do not overlap.

[0011] In one respect, for each value of i, the scan (i) includes: recording the number of radiating particles in a fifth energy range that impact the sensing element of the radiation detector using a first counter of the radiation detector; and recording the number of radiating particles in a sixth energy range that impact the sensing element using a second counter of the radiation detector. The fifth energy range and the sixth energy range do not overlap.

[0012] On one hand, all M translation distances measured in directions parallel to the Ox axis for the scans (i), i = 1, ..., M, are the same.

[0013] On one hand, for i = 1, ..., (M-1), the sum of (A) the translation distance of the scan (i) in the direction parallel to the Oy axis and (B) the translation distance of the scan (i+1) in the direction parallel to the Oy axis does not exceed the dimension of the radiation detector in the direction parallel to the Oy axis.

[0014] On the one hand, for i = 1, ..., (M-1), one of the directions (i) and (i+1) is parallel to the Ox axis.

[0015] This document discloses an apparatus comprising an imaging system including a radiation detector and a radiation source stationary relative to each other. The imaging system is configured to scan an object. Scanning the object by the imaging system comprises: performing a scan (i) by translating the radiation detector one value at a time, for i = 1, ..., M, by (A) translating the radiation detector along the same translation plane and (B) translating the radiation detector along direction (i). M is an integer greater than 1. The Ox axis and the Oy axis are both located in the translation plane and are perpendicular to each other. The orthogonal projections of the directions (i), i = 1, ..., M, onto the Oy axis do not point to two opposite directions. The orthogonal projections of the directions (i), i = 1, ..., M, onto the Ox axis alternately point to two opposite directions. For i = 1, ..., (M-1), the directions (i) and (i+1) are not parallel to each other. Each point of the object is scanned in at least two scans of the scan (i), i = 1, ..., M.

[0016] On the one hand, for i = 1, ..., (M-2), the direction (i) and the direction (i+2) are parallel to each other.

[0017] On one hand, each point is scanned in no more than two scans in the scan(i), i = 1, ..., M.

[0018] In one respect, the translation plane (A) intersects with all source-facing sensing elements of the radiation detector, or (B) is the best-fit plane for all source-facing sensing elements of the radiation detector.

[0019] On one hand, at time points during the scan (i), i = 1, ..., M, the translation plane is perpendicular to a straight line intersecting the source-facing sensing element of the radiation source and the radiation detector.

[0020] On one hand, the sensing element plane of the radiation detector intersects with the radiation source.

[0021] On one hand, for each odd value of i, the scan (i) includes sending a radiation beam (i) of the same first energy range to the object using the radiation source, and for each even value of i, the scan (i) includes sending a radiation beam (i) of the same second energy range to the object using the radiation source, the first energy range and the second energy range being different.

[0022] On the one hand, the first energy range and the second energy range do not overlap.

[0023] In one respect, for each value of i, the scan (i) includes incrementing a counter of the radiation detector in response to a radiation particle impacting the radiation detector in a third energy range, and decrementing a counter in response to a radiation particle impacting the radiation detector in a fourth energy range, wherein the third energy range and the fourth energy range do not overlap.

[0024] In one respect, for each value of i, the scan (i) includes: recording the number of radiating particles in a fifth energy range that impact the sensing element of the radiation detector using a first counter of the radiation detector; and recording the number of radiating particles in a sixth energy range that impact the sensing element using a second counter of the radiation detector. The fifth energy range and the sixth energy range do not overlap.

[0025] On one hand, all M translation distances measured in directions parallel to the Ox axis for the scans (i), i = 1, ..., M, are the same.

[0026] On one hand, for i = 1, ..., (M-1), the sum of (A) the translation distance of the scan (i) in the direction parallel to the Oy axis and (B) the translation distance of the scan (i+1) in the direction parallel to the Oy axis does not exceed the dimension of the radiation detector in the direction parallel to the Oy axis.

[0027] On the one hand, for i = 1, ..., (M-1), one of the directions (i) and (i+1) is parallel to the Ox axis. [Attached Image Description]

[0028] Figure 1 A radiation detector according to an embodiment is illustrated schematically.

[0029] Figure 2 A simplified cross-sectional view of a radiation detector according to an embodiment is shown schematically.

[0030] Figure 3 A detailed cross-sectional view of a radiation detector according to an embodiment is schematically shown.

[0031] Figure 4 A detailed cross-sectional view of a radiation detector according to an alternative embodiment is schematically shown.

[0032] Figure 5 A perspective view of an imaging system according to an embodiment is shown schematically.

[0033] Figures 6A to 6F The operation of the imaging system according to an embodiment is shown.

[0034] Figure 7 A flowchart illustrating the operation of a generalized imaging system according to an embodiment is shown.

Detailed Implementation Methods

[0035] Radiation detector

[0036] Figure 1 A radiation detector 100 is schematically shown as an example. The radiation detector 100 may include an array of pixels 150 (also referred to as sensing elements 150). This array may be a rectangular array (such as...). Figure 1 (as shown), cellular array, hexagonal array, or any other suitable array. Figure 1 The example array of 150 pixels has 4 rows and 7 columns; however, in general, an array of 150 pixels can have any number of rows and any number of columns.

[0037] Each pixel 150 can be configured to detect radiation incident on it from a radiation source (not shown) and can be configured to measure characteristics of the radiation (e.g., particle energy, wavelength, and frequency). The radiation can include radiant particles such as photons (X-rays, gamma rays, etc.) and subatomic particles (alpha particles, beta particles, etc.). Each pixel 150 can be configured to count the number of radiant particles incident on it and whose energy falls into multiple energy bins over a period of time. All pixels 150 can be configured to count the number of radiant particles incident on it and falling into multiple energy bins simultaneously over the same period of time. When the incident radiant particles have similar energies, pixel 150 can be configured simply to count the number of radiant particles incident on it over a period of time without measuring the energy of individual radiant particles.

[0038] Each pixel 150 may have its own analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of an incident radiating particle into a digital signal, or to digitize an analog signal representing the total energy of multiple incident radiating particles into a digital signal. Pixels 150 may be configured to operate in parallel. For example, while one pixel 150 is measuring an incident radiating particle, another pixel 150 may be waiting for the radiating particle to arrive. Pixels 150 do not necessarily need to be individually addressable.

[0039] The radiation detector 100 described herein can be used in applications such as X-ray telescopes, X-ray mammography, industrial X-ray defect detection, X-ray microscopy or microradiography, X-ray casting inspection, X-ray non-destructive testing, X-ray welding inspection, and X-ray digital subtraction angiography. Using this radiation detector 100 in place of photographic plates, photographic films, light-excited phosphor plates (PSP plates), X-ray image intensifiers, scintillators, or other semiconductor X-ray detectors may be suitable.

[0040] Figure 2 The illustration schematically shows an embodiment. Figure 1 A simplified cross-sectional view of the radiation detector 100 along line 2-2. Specifically, the radiation detector 100 may include a radiation absorbing layer 110 and an electronic circuitry layer 120 (which may include one or more ASICs or application-specific integrated circuits) for processing and analyzing the electrical signals generated in the radiation absorbing layer 110 by incident radiation. The radiation detector 100 may or may not include a scintillator (not shown). The radiation absorbing layer 110 may include a semiconductor material such as silicon, germanium, GaAs, CdTe, CdZnTe, or combinations thereof. The semiconductor material may have a high-quality attenuation coefficient for the radiation of interest.

[0041] As an example, Figure 3 schematically shown Figure 1 A detailed cross-sectional view of the radiation detector 100 along line 2-2. Specifically, the radiation absorption layer 110 may include one or more diodes (e.g., pin or pn) formed by one or more discrete regions 114 of a first doped region 111 and a second doped region 113. The second doped region 113 may be separated from the first doped region 111 by an optional intrinsic region 112. The discrete regions 114 may be separated from each other by either the first doped region 111 or the intrinsic region 112. The first doped region 111 and the second doped region 113 may have opposite types of doping (e.g., the first doped region 111 is p-type and the second doped region 113 is n-type, or the first doped region 111 is n-type and the second doped region 113 is p-type). Figure 3 In the example, each discrete region 114 of the second doped region 113 forms a diode with the first doped region 111 and an optional intrinsic region 112. That is, in Figure 3 In the example, the radiation-absorbing layer 110 has multiple diodes (more specifically, 7 diodes corresponding to...). Figure 1 The array has 7 pixels (150) per row; for simplicity... Figure 3 Only two pixels 150 are marked in the image. Multiple diodes may have electrical contacts 119A as a common electrode. The first doped region 111 may also have multiple discrete portions.

[0042] Electronic circuitry layer 120 may include electronic system 121 adapted to process or interpret signals generated by radiation incident on radiation-absorbing layer 110. Electronic system 121 may include analog circuitry such as filter networks, amplifiers, integrators, and comparators, or digital circuitry such as microprocessors and memories. Electronic system 121 may include one or more analog-to-digital converters. Electronic system 121 may include components shared by multiple pixels 150 or components dedicated to a single pixel 150. For example, electronic system 121 may include an amplifier dedicated to each pixel 150 and a microprocessor shared among all pixels 150. Electronic system 121 may be electrically connected to pixels 150 via vias 131. The space between vias may be filled with filler material 130, which may increase the mechanical stability of the connection between electronic circuitry layer 120 and radiation-absorbing layer 110. Other bonding techniques may connect electronic system 121 to pixels 150 without using vias 131.

[0043] When radiation from a radiation source (not shown) impacts the radiation-absorbing layer 110 of a diode, the radiation particles can be absorbed and generate one or more charge carriers (e.g., electrons, holes) through various mechanisms. The charge carriers can drift to the electrode of one of the diodes under an electric field. This electric field can be an external electric field. Electrical contacts 119B can include multiple discrete portions, each electrically contacting a discrete region 114. The term "electrical contact" is used interchangeably with the term "electrode." In one embodiment, charge carriers can drift in multiple directions such that the charge carriers generated by a single radiation particle are substantially not shared by two different discrete regions 114 (here, "substantially not shared" means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a discrete region of the plurality of discrete regions 114 that is different from the discrete region to which the remaining charge carriers flow). The charge carriers generated by radiating particles incident on the footprint of one of these discrete regions 114 are substantially not shared by the other discrete regions 114. A pixel 150 associated with a particular discrete region 114 can be a region surrounding that discrete region 114 in which substantially all (more than 98%, more than 99.5%, more than 99.9%, or more than 99.99%) of the charge carriers generated by radiating particles incident therein flow towards that discrete region 114. That is, less than 2%, less than 1%, less than 0.1%, or less than 0.01% of these charge carriers flow out of that pixel 150.

[0044] Figure 4 An illustration of an alternative embodiment is shown. Figure 1A detailed cross-sectional view of the radiation detector 100 along line 2-2. More specifically, the radiation absorbing layer 110 may include resistors made of semiconductor materials such as silicon, germanium, GaAs, CdTe, CdZnTe, or combinations thereof, but not diodes. The semiconductor material may have a high-quality attenuation coefficient for the radiation of interest. In one embodiment, Figure 4 The electronic circuit layer 120 is similar in structure and function to Figure 3 The electronic circuit layer 120.

[0045] When radiation impacts the radiation-absorbing layer 110, which includes resistors but not diodes, it can be absorbed and generate one or more charge carriers through various mechanisms. The radiating particles can generate 10 to 100,000 charge carriers. These charge carriers can drift to electrical contacts 119A and 119B under an electric field. This electric field can be an external electric field. Electrical contact 119B can include multiple discrete sections. In one embodiment, charge carriers can drift in multiple directions such that charge carriers generated by a single radiating particle are substantially not shared by two different discrete sections of electrical contact 119B (here, "substantially not shared" means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a discrete section different from the discrete section to which the remaining charge carriers flow). Charge carriers generated by radiating particles incident on the space occupied by one of these discrete sections of electrical contact 119B are substantially not shared by the other discrete section of electrical contact 119B. A pixel 150 associated with a discrete portion of the electrical contact 119B can be a region surrounding that discrete portion, in which substantially all (more than 98%, more than 99.5%, more than 99.9%, or more than 99.99%) of the charge carriers generated by incident radiant particles flow to that discrete portion of the electrical contact 119B. That is, less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow out of the pixel associated with that discrete portion of the electrical contact 119B.

[0046] Imaging system

[0047] Figure 5 A perspective view of an imaging system 500 according to an embodiment is shown schematically. In one embodiment, the imaging system 500 may include a radiation detector 100 and a radiation source 510.

[0048] In one embodiment, object 520 may be located between radiation detector 100 and radiation source 510. For example, object 520 may be a part of a human body (e.g., a thigh). In one embodiment, imaging system 500 may be used to scan object 520.

[0049] In one embodiment, the radiation detector 100 and the radiation source 510 can be as follows: Figure 5 The arrangement shown (referred to as a side-incident arrangement) is such that the sensing element plane 104 of the radiation detector 100 intersects with the radiation source 510. Regarding the sensing element plane 104, if all sensing elements 150 of the radiation detector 100 are coplanar, then the sensing element plane 104 can be a plane that actually intersects with all sensing elements 150 of the radiation detector 100. However, if all sensing elements 150 of the radiation detector 100 are not coplanar, then the sensing element plane 104 can be a best-fit plane (e.g., least squares) for all sensing elements 150 of the radiation detector 100.

[0050] If (A) a plane intersects with the radiation detector 100, and (B) every point of the radiation detector 100 that is located on the plane at any point in time during the translation of the radiation detector remains on the plane throughout the entire translation of the radiation detector 100, then the radiation detector 100 is said to be translated along the plane.

[0051] The source-facing sensing element 150 is the sensing element 150 facing the radiation source 510. In other words, radiation particles from the radiation source 510 can collide with the source-facing sensing element 150 without being disturbed by any other sensing element 150. Figure 5 There are 7 source-oriented sensing elements 150 (top row).

[0052] Operation of the imaging system

[0053] In one embodiment, reference Figure 5 Typically, the imaging system 500 can operate as follows: A radiation source 510 can send a radiation beam 512 toward an object 520. The radiation beam 512 can include X-rays. In one example, the radiation beam 512 is a fan-shaped beam.

[0054] In one embodiment, the radiation detector 100 and the radiation source 510 may be stationary relative to each other during operation of the imaging system 500.

[0055] In one embodiment, when the imaging system 500 scans the object 520, the radiation detector 100 and the radiation source 510 can be translated along direction 102. In other words, as the radiation detector 100 and the radiation source 510 translate along direction 102, the radiation detector 100 captures multiple images of the object 520.

[0056] The term "image" in this patent application (including the claims) is not limited to the spatial distribution of the characteristics (e.g., intensity) of radiation. For example, the term "image" may also include the spatial distribution of the density of a substance or element.

[0057] In one embodiment, direction 102 can be selected such that the radiation detector 100 translates along the translation plane 106, as shown below. Figure 5 As shown. In one embodiment, the translation plane 106 along which the radiation detector 100 translates may (A) intersect with all source-facing sensing elements 150 of the radiation detector 100, or (B) be the best-fit plane of all source-facing sensing elements 150 of the radiation detector 100.

[0058] Furthermore, in one embodiment, the translation plane 106 along which the radiation detector 100 translates may be perpendicular to the line 108, which intersects the radiation source 510 and the source-facing sensing element 150 at a certain point in time during the translation of the radiation detector 100 (at point X).

[0059] Zigzag scanning

[0060] Figures 6A to 6F The illustration shows the operation of the imaging system 500 according to an embodiment when the imaging system 500 performs six scans of the object 520. Please note that... Figures 6A to 6F A top view of the radiation detector 100 and object 520 as seen from the radiation source 510 is shown. For simplicity, object 520 is only shown in the image. Figure 6A and Figure 6F It is shown in (i.e., not in) Figures 6B to 6E (as shown in the image).

[0061] Specifically, in one embodiment, reference is made to Figure 6A During the first scan, the radiation detector 100 can be translated from position S to position A along the translation plane 106 and in the direction 102A. Note that if the imaging system 500 scans an area of ​​the translation plane 106 only once, the area appears (A) brighter, and if the imaging system 500 scans the area at least twice, the area appears (B) darker.

[0062] Next, in one embodiment, reference is made to Figure 6B During the second scan, the radiation detector 100 can be translated from position A to position B along the translation plane 106 and along the direction 102B.

[0063] Next, in one embodiment, reference is made to Figure 6C During the third scan, the radiation detector 100 can be translated from position B to position C along the translation plane 106 and along the direction 102C.

[0064] Next, in one embodiment, reference is made to Figure 6D During the fourth scan, the radiation detector 100 can be translated from position C to position D along the translation plane 106 and along the direction 102D.

[0065] Next, in one embodiment, reference is made to Figure 6E During the fifth scan, the radiation detector 100 can be translated from position D to position E along the translation plane 106 and along the direction 102E.

[0066] Next, in one embodiment, reference is made to Figure 6F During the sixth scan, the radiation detector 100 can be translated from position E to position F along the translation plane 106 and along the direction 102F.

[0067] In one embodiment, the Ox axis and the Oy axis can be defined such that the Ox axis and the Oy axis lie in the translation plane 106 and are perpendicular to each other, as shown below. Figures 6A to 6F As shown.

[0068] In one embodiment, reference Figures 6A to 6F The six orthogonal projections of the six directions 102A, 102B, 102C, 102D, 102E, and 102F onto the Oy axis do not necessarily point in two opposite directions. For example, in Figures 6A to 6F In the middle, all six orthogonal projections of the six directions 102A, 102B, 102C, 102D, 102E, and 102F onto the Oy axis point downwards.

[0069] In one embodiment, reference Figures 6A to 6F The six orthogonal projections of the six directions 102A, 102B, 102C, 102D, 102E, and 102F onto the Ox axis can alternately point in two opposite directions. For example, in Figure 6A In the middle, the orthogonal projection of direction 102A onto the Ox axis points to the right. Figure 6B In the center, the orthogonal projection of direction 102B onto the Ox axis points to the left. Figure 6C In the middle, the orthogonal projection of direction 102C onto the Ox axis points to the right. Figure 6D In the center, the orthogonal projection of direction 102D onto the Ox axis points to the left. Figure 6E In the middle, the orthogonal projection of direction 102E onto the Ox axis points to the right. Figure 6F In the diagram, the orthogonal projection of direction 102F onto the Ox axis points to the left. In other words, the six orthogonal projections of directions 102A, 102B, 102C, 102D, 102E, and 102F onto the Ox axis alternately point to the left and right (i.e., two opposite directions).

[0070] In one embodiment, for any two consecutive scans out of six scans, the two corresponding directions 102 may not be parallel to each other. For example, for the first and second scans described above, the two corresponding directions 102A and 102B are not parallel to each other. As another example, for the second and third scans described above, the two corresponding directions 102B and 102C are not parallel to each other.

[0071] In one embodiment, reference Figures 6A to 6F Each point of object 520 can be scanned in at least two of the following scans: a first scan, a second scan, a third scan, a fourth scan, a fifth scan, and a sixth scan (i.e., the imaging system 500 scans at least twice). Assuming object 520 is a human thigh, then, for each point of the human thigh, data from the at least two scans can be used to determine the bone mineral density at each point of the human thigh (referred to as bone mineral density measurement).

[0072] A flowchart summarizing the operation of the imaging system

[0073] Figure 7 A flowchart 700 illustrating the operation of a generalized imaging system 500 according to an embodiment is shown. In step 710, the operation may include scanning an object using the imaging system, which includes a radiation detector and a radiation source stationary relative to each other. For example, in the above embodiment, reference... Figure 5 The imaging system 500 scans the object 520, and the imaging system 500 includes a radiation detector 100 and a radiation source 510 that are stationary relative to each other.

[0074] Additionally, in step 710, the scanned object includes a scan (i) performed sequentially, one value of i at a time, for i = 1, ..., M, by translating the radiation detector (A) along the same translation plane and (B) along direction (i), where M is an integer greater than 1. For example, in the above embodiment, referring to... Figures 5 to 6F For i = 1, ..., 6, the scan (i) is performed sequentially, one i value at a time, by translating the radiation detector 100 along the same translation plane 106 and (B) along direction (i), where M = 6. Specifically, for example, refer to... Figure 6A For i=1, the scan (1) (i.e., the first scan) includes (A) translating the radiation detector 100 along the translation plane 106 and (B) translating the radiation detector 100 along the direction 102A.

[0075] Furthermore, in step 710, both the Ox and Oy axes lie in the translation plane and are perpendicular to each other. The orthogonal projections of directions (i), i = 1, ..., M, onto the Oy axis do not point in two opposite directions. For example, in the above embodiment, the reference... Figures 5 to 6F The Ox and Oy axes are both located in the translation plane 106 and are perpendicular to each other. In addition, all orthogonal projections of directions 102A, 102B, 102C, 102D, 102E, and 102F onto the Oy axis point downwards.

[0076] Furthermore, in step 710, the orthogonal projections of directions (i), i = 1, ..., M, onto the Ox axis alternately point in two opposite directions. For example, in the above embodiment, referring to... Figures 5 to 6F The orthogonal projections of directions 102A, 102B, 102C, 102D, 102E, and 102F onto the Ox axis alternately point to the left and right (i.e., two opposite directions).

[0077] Furthermore, in step 710, for i = 1, ..., (M-1), direction (i) and direction (i+1) are not parallel to each other. For example, in the above embodiment, referring to... Figures 5 to 6F For any two consecutive scans out of the six scans, the two corresponding directions 102 are not parallel to each other. Specifically, for example, direction 102A ( Figure 6A ) and direction 102B ( Figure 6B They are not parallel to each other. Similarly, direction 102B ( Figure 6B ) and direction 102C ( Figure 6C They are not parallel to each other, and so on.

[0078] Additionally, in step 710, each point of the object is scanned in at least two scans of scan (i), i = 1, ..., M. For example, in the above embodiment, refer to... Figure 6F Each point of object 520 is scanned in at least two of the first, second, third, fourth, fifth, and sixth scans.

[0079] Other embodiments

[0080] Exactly two scans

[0081] In the above embodiments, reference is made to Figures 5 to 6F Each point of object 520 is scanned at least twice by imaging system 500. In one embodiment, each point of object 520 is scanned no more than twice by imaging system 500. In other words, each point of object 520 is scanned exactly twice by imaging system 500, such as... Figures 6A to 6F As shown.

[0082] Alternating energy range of zigzag scanning

[0083] In one embodiment, reference Figure 6ADuring the first scan, radiation source 510 can send a first radiation beam (as part of radiation beam 512) with a first energy range to object 520. In other words, each radiation particle in the first radiation beam has energy within a first energy range. The first radiation beam can be used by radiation detector 100 to perform the first scan.

[0084] Similarly, in one embodiment, reference is made to... Figure 6C During the third scan, radiation source 510 can send a third radiation beam of the first energy range (as part of radiation beam 512) to object 520. The third radiation beam can be used by radiation detector 100 to perform the third scan.

[0085] Similarly, in one embodiment, reference is made to... Figure 6E During the fifth scan, radiation source 510 can send a fifth radiation beam of the first energy range (as part of radiation beam 512) to object 520. The fifth radiation beam can be used by radiation detector 100 to perform the fifth scan.

[0086] In one embodiment, reference Figure 6B During the second scan, radiation source 510 can send a second radiation beam (as part of radiation beam 512) with a second energy range to object 520. In other words, each radiation particle in the second radiation beam has energy within the second energy range. The second radiation beam can be used by radiation detector 100 to perform the second scan.

[0087] Similarly, in one embodiment, reference is made to... Figure 6D During the fourth scan, radiation source 510 can send a fourth radiation beam of the second energy range (as part of radiation beam 512) to object 520. The fourth radiation beam can be used by radiation detector 100 to perform the fourth scan.

[0088] Similarly, in one embodiment, reference is made to... Figure 6F During the sixth scan, radiation source 510 can send a sixth radiation beam of the second energy range (as part of radiation beam 512) to object 520. The sixth radiation beam can be used by radiation detector 100 to perform the sixth scan.

[0089] In one embodiment, the first energy range and the second energy range may be different. In another embodiment, the first energy range and the second energy range may not overlap.

[0090] Bidirectional counter for each sensing element of the radiation detector

[0091] In one embodiment, reference Figures 1 to 5The electronic circuit layer 120 of the radiation detector 100 may include a counter (not shown) for each sensing element 150 of the radiation detector 100.

[0092] In one embodiment, if a radiating particle of a third energy range strikes each of the sensing elements 150, the counter of each sensing element can be incremented by 1 (i.e., its count increases by 1); if a radiating particle of a fourth energy range strikes each of the sensing elements 150, the counter of each sensing element can be decremented by 1 (i.e., its count decreases by 1), and the third and fourth energy ranges do not overlap. Note that the counter of each of the sensing elements 150 of the radiation detector 100 is a bidirectional counter.

[0093] Two counters for each sensing element

[0094] In one embodiment, reference Figures 1 to 5 The electronic circuit layer 120 of the radiation detector 100 may include a first counter (not shown) and a second counter (not shown) for each sensing element 150 of the radiation detector 100. In one embodiment, the first counter of each sensing element 150 may record the number of radiation particles impacting each sensing element 150 in a fifth energy range; the second counter of each sensing element 150 may record the number of radiation particles impacting each sensing element 150 in a sixth energy range, and the fifth energy range and the sixth energy range do not overlap.

[0095] The translation distance on the Ox axis is the same.

[0096] In one embodiment, reference Figures 6A to 6F (A) The first scan measured in a direction parallel to the Ox axis. Figure 6A The translation distance (i.e., distance 102Ax) and the second scan measured in the direction parallel to the Ox axis (B) Figure 6B (C) The translation distance (not shown), and the third scan measured in the direction parallel to the Ox axis. Figure 6C The translation distance (not shown), and (D) the fourth scan measured in the direction parallel to the Ox axis. Figure 6D The translation distance (not shown), and (E) the fifth scan measured in the direction parallel to the Ox axis. Figure 6E The translation distance (not shown) and (F) measured in the direction parallel to the Ox axis during the sixth scan ( Figure 6F The translation distances (not shown) of the six scans can be the same. In other words, the six horizontal translation distances for the six scans are all the same. Note that for simplicity (i.e., the other five horizontal translation distances are not shown), only... Figure 6AThe first horizontal translation distance is shown in the figure (i.e., distance 102Ax).

[0097] The sum of two consecutive vertical translation distances

[0098] In one embodiment, reference Figure 6B The sum of (A) the translation distance in the direction parallel to the Oy axis during the first scan (i.e., distance 102Ay) and (B) the translation distance in the direction parallel to the Oy axis during the second scan (i.e., distance 102By) may not exceed the dimension of the radiation detector 100 in the direction parallel to the Oy axis (i.e., dimension 100y).

[0099] In general, the above embodiments can be described as follows: (A) the translation distance of scan (i) in the direction parallel to the Oy axis and (B) the translation distance of scan (i+1) in the direction parallel to the Oy axis can not exceed the size of the radiation detector 100 in the direction parallel to the Oy axis (i = 1, 2, 3, 4, 5).

[0100] Special case—Horizontal translation

[0101] In one embodiment, reference Figures 6A to 6F For any two consecutive scans, one of the two corresponding translation directions 102 can be parallel to the Ox axis. For example, refer to... Figure 6A and Figure 6B One of the two directions, 102A and 102B, can be parallel to the Ox axis. Specifically, for example, direction 102A can point southeast, and direction 102B can point due west (i.e., parallel to the Ox axis). In this particular example, refer to... Figure 6B The distance 102Ay is equal to the size 100y, and the distance 100By is zero.

[0102] More information about the translation direction

[0103] In one embodiment, reference Figures 6A to 6F and Figure 7 In step 710, for i = 1, ..., (M-2), direction (i) and direction (i+2) can be parallel to each other. For example, direction 102A and direction 102C are parallel to each other. Another example is that direction 102B and direction 102D are parallel to each other.

[0104] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for illustrative purposes and are not intended to be limiting; the true scope and spirit are indicated by the appended claims.

Claims

1. An imaging method, comprising: An object is scanned using an imaging system comprising a radiation detector and a radiation source stationary relative to each other, wherein the object being scanned comprises: For i=1, ..., M, the values ​​of i are sequentially assigned one at a time, by translating along the same translation plane and in the direction D. i The radiation detector is shifted to perform a scan S i Where M is an integer greater than 1. The Ox and Oy axes are both located in the translation plane and are perpendicular to each other. Wherein, for i=1, ..., M, the direction D i The orthogonal projections on the Oy axis do not point in two opposite directions. Wherein, for i=1, ..., M, the direction D i The orthogonal projections on the Ox axis alternately point in two opposite directions. For i=1, ..., M-1, the direction D i and the direction D i+1 They are not parallel to each other, and Wherein, each point of the object is in M ​​scans S i The object is scanned in at least two scans of i=1, ..., M, where for i=2, ..., M-1, the object is scanned in scan S. i The points being scanned in the S-axis include a first set of points and a second set of points. The points in the first set are scanned in the S-axis. i-1 The points in the second set of points are scanned in the middle, and the points in the second set of points are scanned in the middle. i+1 Scanned in Wherein, for each odd value of i, the scan S i This includes sending a radiation beam I of the same first energy range to the object using the radiation source. i , Wherein, for each even value of i, the scan S i This includes sending a radiation beam I of the same second energy range to the object using the radiation source. i , The first energy range and the second energy range are different.

2. The method according to claim 1, wherein, For i = 1, ..., M-2, the direction D i and the direction D i+2 parallel to each other.

3. The method according to claim 1, wherein, Each point is in M ​​scans S i It is scanned in two scans of i=1, ..., M.

4. The method according to claim 1, wherein, The translation plane intersects with all source-facing sensing elements of the radiation detector, or The translation plane is the best-fit plane for all source-facing sensing elements of the radiation detector.

5. The method according to claim 4, wherein, For i=1, ..., M, in the scan S i At a given time point during the scanning period, the translation plane is perpendicular to a straight line intersecting the source-facing sensing element of the radiation source and the radiation detector.

6. The method according to claim 1, wherein, The sensing element plane of the radiation detector intersects with the radiation source.

7. The method according to claim 1, wherein, The first energy range and the second energy range do not overlap.

8. The method according to claim 1, in, For each value of i, the scan S i This includes incrementing a counter on the radiation detector in response to a radiation particle impacting the radiation detector in a third energy range, and decrementing a counter in response to a radiation particle impacting the radiation detector in response to a radiation particle impacting the radiation detector in a fourth energy range. The third energy range and the fourth energy range do not overlap.

9. The method according to claim 1, wherein, For each value of i, the scan S i include: The first counter of the radiation detector records the number of radiation particles in the fifth energy range that impact the sensing element of the radiation detector; and The number of radiant particles in the sixth energy range that impact the sensing element is recorded using the second counter of the radiation detector, and The fifth energy range and the sixth energy range do not overlap.

10. The method according to claim 1, wherein, The Mth scan S i All M translation distances measured in directions parallel to the Ox axis for i = 1, ..., M are the same.

11. The method according to claim 10, wherein, For i = 1, ..., M-1, the scan S i The translation distance in the direction parallel to the Oy axis and the scan S i+1 The sum of the translation distances in the direction parallel to the Oy axis does not exceed the dimension of the radiation detector in the direction parallel to the Oy axis.

12. The method according to claim 11, wherein, For i = 1, ..., M-1, the direction D i and the direction D i+1 One of the directions is parallel to the Ox axis.

13. An imaging apparatus comprising an imaging system, the imaging system including a radiation detector and a radiation source stationary relative to each other. in, The imaging system is configured to scan objects. The imaging system scans the object by: For i=1, ..., M, the value of i is sequentially assigned one at a time, by translating along the same translation plane of the radiation detector and along direction D. i The radiation detector is shifted to perform a scan S i Where M is an integer greater than 1. The Ox and Oy axes are both located in the translation plane and are perpendicular to each other. Wherein, for i=1, ..., M, the direction D i The orthogonal projections on the Oy axis do not point in two opposite directions. Wherein, for i=1, ..., M, the direction D i The orthogonal projections on the Ox axis alternately point in two opposite directions. For i=1, ..., M-1, the direction D i and the direction D i+1 They are not parallel to each other, and Wherein, each point of the object is in M ​​scans S i The object is scanned in at least two scans of i=1, ..., M, where for i=2, ..., M-1, the object is scanned in scan S. i The points being scanned in the S-axis include a first set of points and a second set of points. The points in the first set are scanned in the S-axis. i-1 The points in the second set of points are scanned in the middle, and the points in the second set of points are scanned in the middle. i+1 Scanned in Wherein, for each odd value of i, the scan S i This includes sending a radiation beam I of the same first energy range to the object using the radiation source. i , Wherein, for each even value of i, the scan S i This includes sending a radiation beam I of the same second energy range to the object using the radiation source. i , The first energy range and the second energy range are different.

14. The apparatus according to claim 13, wherein, For i = 1, ..., M-2, the direction D i and the direction D i+2 parallel to each other.

15. The apparatus according to claim 13, wherein, Each point is in M ​​scans S i It is scanned in two scans of i=1, ..., M.

16. The apparatus according to claim 13, wherein, The translation plane intersects with all source-facing sensing elements of the radiation detector, or The translation plane is the best-fit plane for all source-facing sensing elements of the radiation detector.

17. The apparatus according to claim 16, wherein, For i=1, ..., M, in the scan S i At a given time point during the scanning period, the translation plane is perpendicular to a straight line intersecting the source-facing sensing element of the radiation source and the radiation detector.

18. The apparatus according to claim 13, wherein, The sensing element plane of the radiation detector intersects with the radiation source.

19. The apparatus according to claim 13, wherein, The first energy range and the second energy range do not overlap.

20. The apparatus according to claim 13, in, For each value of i, the scan S i This includes incrementing a counter on the radiation detector in response to a radiation particle impacting the radiation detector in a third energy range, and decrementing a counter in response to a radiation particle impacting the radiation detector in response to a radiation particle impacting the radiation detector in a fourth energy range. The third energy range and the fourth energy range do not overlap.

21. The apparatus according to claim 13, wherein, For each value of i, the scan S i include: The first counter of the radiation detector records the number of radiation particles in the fifth energy range that impact the sensing element of the radiation detector; and The number of radiant particles in the sixth energy range that impact the sensing element is recorded using the second counter of the radiation detector, and The fifth energy range and the sixth energy range do not overlap.

22. The apparatus according to claim 13, wherein, The Mth scan S i All M translation distances measured in directions parallel to the Ox axis for i = 1, ..., M are the same.

23. The apparatus according to claim 22, wherein, For i = 1, ..., M-1, the scan S i The translation distance in the direction parallel to the Oy axis and the scan S i+1 The sum of the translation distances in the direction parallel to the Oy axis does not exceed the dimension of the radiation detector in the direction parallel to the Oy axis.

24. The apparatus according to claim 23, wherein, For i = 1, ..., M-1, the direction D i and the direction D i+1 One of the directions is parallel to the Ox axis.

Images