JP6386762B2 - Radiation diagnostic apparatus, radiation detection apparatus, and radiation detection data processing method - Google Patents

Description

  Embodiments described herein relate generally to a radiation diagnostic apparatus, a radiation detection apparatus, and a radiation detection data processing method.

  The radiation diagnostic apparatus is an apparatus that creates a diagnostic image by detecting radiation such as X-rays and γ-rays. Examples of the radiation diagnostic apparatus include an X-ray diagnostic apparatus, an X-ray CT (Computed Tomography) apparatus, and a nuclear medicine diagnostic apparatus.

  X-ray diagnostic apparatuses and X-ray CT apparatuses have an X-ray generator and an X-ray detector. The X-ray generator generates X-rays and exposes the generated X-rays to the subject. The X-ray detector detects X-rays exposed to the subject. The X-ray detector has, for example, a plurality of pixels arranged two-dimensionally. In each pixel, incident X-rays are converted into electric charges. The X-ray is converted into electric charge by converting the X-ray into light by a scintillator such as cesium iodide and converting the light into electric charge by a photodiode or the like, and a photoconductive material such as amorphous selenium. The method of directly converting into electric charge is known.

  Such an X-ray detector, for example, accumulates electric charges generated by X-rays incident within a predetermined period, generates a digital value obtained by converting this into a voltage and then converting it into a voltage. Output as pixel value of data (image data).

  The X-ray diagnostic apparatus further performs image processing such as gradation processing and spatial filter processing on the “image data”, and displays an image based on the image data after the image processing on the observation monitor. The X-ray CT apparatus generates a plurality of the “image data” at predetermined intervals while rotating the X-ray generator and the X-ray detector around the subject in one imaging sequence. The X-ray CT apparatus creates three-dimensional data that is a three-dimensional distribution of the X-ray absorption characteristics of the subject by performing reconstruction processing on a plurality of image data collected in one imaging sequence. Based on the data, it is displayed on the observation monitor by various presentation methods.

[Energy integration detector]
The charges generated by the X-ray photons are approximately proportional to the product of the number of detected X-ray photons and the energy of the X-ray photons, and the charges of all the X-ray photons incident within a predetermined period are This type of X-ray detector is sometimes called an “energy integrating detector” because it accumulates and processes.

  The pixel value output from the “energy integrating detector” is subjected to offset correction, gain correction, and defective pixel correction, and is passed to the subsequent image processing process as “image data”. The offset correction is a process for correcting an offset component caused by a dark current of the semiconductor. The gain correction is a process for correcting two-dimensional variation in sensitivity of the X-ray detection substance, variation in amplifier gain, non-uniformity in X-ray distribution, and the like. The defective pixel correction is a process of estimating and determining the pixel value of a defective pixel whose output is abnormal from the pixel values of surrounding normal pixels.

  It is difficult to know the magnitude of the quantum noise directly from the pixel value output by the “energy integrating detector”. The reason is that (a) the pixel value is proportional to the sum of the generated charge amounts of a plurality of detected X-ray photons, and (b) the generated charge amount per X-ray photon is the energy of the X-ray photons. (C) the offset component cannot be ignored. However, the magnitude of the quantum noise is estimated by statistical calculation on the pixel value of the pixel in the vicinity of the desired pixel among the two-dimensionally arranged pixels and the pixel value of the same pixel of the “image data” collected repeatedly. It is possible.

  In contrast to such an “energy integrating detector”, a “photon counting detector” has been put into practical use in recent years.

[Photon counting detector]
The “photon counting detector” detects X-ray photons incident on pixels provided on the detector one by one, and the total number of X-ray photons incident within a predetermined period is the pixel value of the pixel. Output as. When an X-ray photon is incident on one pixel, a voltage pulse corresponding to the energy is generated. The “photon counting detector” determines that an X-ray photon has been detected when this pulse is within a predetermined voltage range, and performs counting. This determination is made by comparing a plurality of preset threshold voltages with the pulse height (amplitude) of the voltage pulse. Since the lower limit of the threshold voltage is set so as not to detect the dark current of the semiconductor, no offset correction is necessary for the pixel value output by the “photon counting detector”.

  In addition, in the “photon counting detector”, X energy having a certain energy is caused by variations in conversion efficiency from pixel to pixel in an X-ray-to-charge conversion process or variations in amplification factor of an amplifier that converts charge into voltage. The voltage pulse amplitude (amplitude) for one line photon varies from pixel to pixel. This variation can be made uniform by adjusting the threshold voltage set for each pixel or each group of a plurality of pixels. Alternatively, variations in the conversion efficiency of the X-ray-to-charge conversion process and the amplification factor of the amplifier that converts the charge into the voltage are reduced to the extent that it is not necessary to set a threshold voltage for each pixel or each group of pixels. By designing to be, it is possible to solve the problem of variation. As described above, the variation in gain of the “photon counting detector” is a process from when the X-ray photon is detected at each pixel to detect a voltage pulse corresponding to the generated charge amount and to count the number within the threshold range. Is solved. Therefore, “gain correction” performed after the image processing apparatus collects the pixel values from the detector as in the case of the “energy integrating detector” is not necessary for the “photon counting detector”.

  As described above, in the “photon counting detector”, it is not necessary to perform offset correction or gain correction on the result counted within a predetermined period, and the X-ray in which the counting result itself is detected by the pixel. The number of photons is n.

  It is inevitable that the image data whose pixel value is the number of detected X-ray photons n includes “quantum noise” resulting from the probability that the interaction between the photon and the substance is probabilistic. It is known that the result of this interaction follows a Poisson distribution, and when the number of detected X-ray photons is n, the noise intensity (standard deviation of fluctuation) is n 1/2 power. It has been.

When the number of X-ray photons detected by a pixel is a signal component and the quantum noise is a noise component, a signal-to-noise ratio SNR (Signal-to-Noise Ratio) is expressed by the following equation.
SNR = n / (n ^1/2 ) = n ^1/2

  This shows that the SNR increases as n, which is the number of detected X-ray photons, increases. That is, in order to obtain an image with a good SNR, it can be seen that the number of detected X-ray photons should be increased.

  Image data used in a general radiological diagnostic apparatus is assigned 8 bits to 20 bits per pixel, and expresses the density of the image, that is, the two-dimensional distribution information of the X-ray absorbing material of the subject. The number of bits is determined from the viewpoint of securing the SNR of the image necessary for using the image density information for diagnosis. Therefore, also in the “photon counting detector”, the number of bits per pixel is determined in order to obtain the SNR of an image necessary for use in diagnosis. Therefore, as described above, the “photon counting detector” needs to detect a sufficient number of X-ray photons to obtain an SNR of an image necessary for use in diagnosis, and the number of bits per pixel. Becomes larger.

  The result counted by each pixel of the “photon counting type detector” is transmitted to the output unit through the internal wiring, and is transmitted to the image processing apparatus connected to the detector. When the number of bits of data to be transmitted increases, the number of wirings inside the detector increases, which causes a problem that the detector itself increases in size.

  Further, in the transmission from the detector to the image processing apparatus, if a plurality of bits of data are transmitted in parallel, there is a problem that the number of electric wires included in the cable increases. Furthermore, when a plurality of bits of data are serially transmitted by wireless communication or the like in the transmission from the detector to the image processing apparatus, there arises a problem that the transmission time becomes long.

  In the “photon counting type detector”, the energy of the X-ray photons is divided into a plurality of groups according to a plurality of set thresholds with respect to a detection unit for detecting a voltage pulse corresponding to the detected X-ray photons, A configuration for counting photons for each energy group is also known. In this case, in each pixel, the count result is not one, but a plurality of count results corresponding to the energy groups are obtained. In the image processing apparatus provided on the rear side of the “photon counting detector”, these are handled as one piece of image data for each energy group. Therefore, for one X-ray irradiation, one image data is obtained with the “energy integrating detector”, whereas a plurality of image data is obtained with the “photon counting detector”. Therefore, when the “photon counting detector” is used, there is a problem that a storage device with a larger capacity is required.

  Therefore, it is considered to reduce the size of the detector, shorten the transmission time, and reduce the storage capacity by compressing the image data obtained by the “photon counting detector”.

JP2013-052134A JP 2012-222453 A

  However, when applying radiation detection data, which is a counting result of radiation photons such as X-ray photons, to image data, the conventional method does not consider the characteristics of quantum noise. In some cases, the signal-to-noise ratio is degraded. In addition, since the characteristics of quantum noise are not taken into consideration, radiation detection data (image data) cannot be sufficiently compressed, and it is not possible to sufficiently reduce the size of the detector, the transmission time, and the storage capacity. There was a case.

  The present invention has been made to solve the above-described problem, and provides a radiation diagnostic apparatus, a radiation detection apparatus, and a radiation detection data processing method capable of compressing radiation detection data without degrading a signal-to-noise ratio. The purpose is to provide.

The radiation diagnostic apparatus according to the embodiment includes a radiation generation unit, a radiation photon detection unit, a compression unit, a restoration unit, and an image creation unit. The radiation generating unit generates radiation photons. The radiation photon detection unit detects radiation photons generated by the radiation generation unit and transmitted through the subject, and generates radiation detection data by counting the detected radiation photons with a predetermined number of bits. The compression unit uses the bit string having the number of bits corresponding to the maximum bit position on the lower side from the maximum bit position, which is the most significant bit position as the predetermined bit data in the radiation detection data, as an effective signal bit, and is incidental corresponding to the maximum bit position. Information is attached to valid signal bits and output. The restoration unit receives the valid signal bit and the incidental information, detects the bit length of the valid signal bit, and adds additional data corresponding to the additional bit length calculated from the detected bit length and the incidental information to the lower order of the valid signal bit. By adding to the side, restoration data of radiation detection data is generated. The image creation unit creates an image based on the restoration data generated by the restoration unit.
Moreover, the radiation detection apparatus of embodiment contains a radiation photon detection part, a radiation photon counting part, and a compression part. The radiation photon detection unit detects radiation photons generated by the radiation generation unit and transmitted through the subject. The radiation photon counting unit counts the radiation photons detected by the radiation photon detection unit with a predetermined number of bits. The compression unit compresses radiation detection data obtained by counting radiation photons by the radiation photon counting unit. In addition, the compression unit uses the bit sequence of the number of bits corresponding to the maximum bit position, which is the most significant bit position, which is the most significant bit position as the predetermined bit data in the radiation detection data, as the effective signal bit, and corresponds to the maximum bit position. The accompanying information is attached to the valid signal bit and output.
The radiation detection apparatus according to the embodiment includes a plurality of pixels and a plurality of output buses. The plurality of pixels are arranged two-dimensionally. The plurality of output buses are provided in common for the pixels in each column or each row. Each pixel includes a radiation photon detection unit, a radiation photon counting unit, and a compression unit. The radiation photon detection unit detects radiation photons generated by the radiation generation unit and transmitted through the subject. The radiation photon counting unit counts the radiation photons detected by the radiation photon detection unit with a predetermined number of bits. The compression unit compresses radiation detection data obtained by counting radiation photons by the radiation photon counting unit. In addition, the compression unit uses the bit sequence of the number of bits corresponding to the maximum bit position, which is the most significant bit position, which is the most significant bit position as the predetermined bit data in the radiation detection data, as the effective signal bit, and corresponds to the maximum bit position The attached information is attached to the valid signal bit and output to each output bus.
The radiation detection apparatus according to the embodiment includes a plurality of pixels and a plurality of output buses. The plurality of pixels are arranged two-dimensionally. The plurality of output buses are provided in common for the pixels in each column or each row. Each pixel includes a radiation photon detection unit, a radiation photon counting unit, and a compression unit for each energy group. The radiation photon detection unit detects radiation photons generated by the radiation generation unit and transmitted through the subject. The radiation photon counting unit counts the radiation photons detected by the radiation photon detection unit with a predetermined number of bits. The compression unit compresses radiation detection data obtained by counting radiation photons by the radiation photon counting unit. The compression unit uses the bit string having the number of bits corresponding to the maximum bit position on the lower side from the maximum bit position, which is the most significant bit position as the predetermined bit data in the radiation detection data, as an effective signal bit, and is incidental corresponding to the maximum bit position. Information is attached to valid signal bits and output to each output bus.
The radiation detection apparatus according to the embodiment includes a plurality of pixels, a plurality of output buses, and a compression unit. The plurality of pixels are arranged two-dimensionally. The plurality of output buses are provided in common for the pixels in each column or each row. The compression unit is configured to be connectable to a plurality of output buses. Each pixel includes a radiation photon detection unit and a radiation photon counting unit. The radiation photon detection unit detects radiation photons generated by the radiation generation unit and transmitted through the subject. The radiation photon counting unit counts the radiation photons detected by the radiation photon detection unit with a predetermined number of bits. The compression unit is the number of bits corresponding to the maximum bit position on the lower side from the maximum bit position which is the most significant bit position which is predetermined bit data in the radiation detection data obtained by counting the radiation photons by the radiation photon counting unit And the accompanying information corresponding to the maximum bit position is attached to the valid signal bit and output.
The radiation detection data processing method of the embodiment includes a bit position detection step, a signal bit extraction step, and an incidental information purification step. The bit position detection step detects the maximum bit position that is the most significant bit position that is predetermined bit data in the radiation detection data obtained by counting the radiation photons. In the signal bit extraction step, a bit string having the number of bits corresponding to the maximum bit position detected in the bit position detection step is extracted as a valid signal bit from the maximum bit position of the radiation detection data. In the incidental information generation step, incidental information to be added to the effective signal bit is generated based on the maximum bit position detected in the bit position detection step.

Explanatory drawing of the relationship between the effective signal bit in the radiation detection data which concerns on 1st Embodiment, and quantum noise. 1 is a functional block diagram of a schematic configuration of a radiation diagnostic apparatus according to a first embodiment. The functional block diagram of schematic structure of the compression part of FIG. The functional block diagram of schematic structure of the decompression | restoration part of FIG. The flowchart of the operation example of the compression part which concerns on 1st Embodiment. Operation | movement explanatory drawing of the compression part which concerns on 1st Embodiment. The flowchart of the operation example of the decompression | restoration part which concerns on 1st Embodiment. Explanatory drawing of operation | movement of the decompression | restoration part which concerns on 1st Embodiment. Explanatory drawing of operation | movement of the decompression | restoration part which concerns on 1st Embodiment. Explanatory drawing of operation | movement of the decompression | restoration part which concerns on 1st Embodiment. The functional block diagram of schematic structure of the decompression | restoration part which concerns on the modification of 1st Embodiment. Operation | movement explanatory drawing of the compression part which concerns on 2nd Embodiment. Explanatory drawing of operation | movement of the decompression | restoration part which concerns on 2nd Embodiment. Explanatory drawing of operation | movement of the decompression | restoration part which concerns on 2nd Embodiment. The functional block diagram of the principal part of schematic structure of the radiation diagnostic apparatus which concerns on 3rd Embodiment. The functional block diagram of schematic structure of the radiation diagnostic apparatus which concerns on 3rd Embodiment. The block diagram of the hardware structural example of the X-ray detector which concerns on 4th Embodiment. The block diagram of the hardware structural example of the quantum bit compressor of FIG. The block diagram of the hardware structural example of the image processing apparatus which concerns on 4th Embodiment. FIG. 20 is a block diagram of a hardware configuration example of the qubit restoration unit in FIG. 19. The block diagram of the hardware structural example of the X-ray detector which concerns on 5th Embodiment. The block diagram of the hardware structural example of the X-ray detector which concerns on 6th Embodiment. The perspective view of schematic structure of the X-ray diagnostic apparatus which concerns on 7th Embodiment. The functional block diagram of schematic structure of the X-ray diagnostic apparatus which concerns on 7th Embodiment. The functional block diagram of schematic structure of the X-ray CT apparatus which concerns on 8th Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

  Hereinafter, image data having the detected number of radiation photons as a pixel value is referred to as “radiation detection data”. Further, a bit string of information acquired by removing “quantum noise” from “radiation detection data” and to be transmitted is referred to as “effective signal bit”. Furthermore, since “image” and “image data” correspond one-to-one, in this embodiment, they may be identified with each other.

[First Embodiment]
<Operating principle>
Before describing the radiation diagnostic apparatus according to the embodiment, the operation principle will be described.

  It is assumed that the pixel value of the image data obtained by counting the detected radiation photons is P (P is an integer). When the pixel value P is expressed in binary, it is counted as “0” closest to the MSB side, counting from the least significant bit (LSB) as 0th, 1st, 2nd,... The bit position for which is set is called the “maximum bit position”. When the maximum bit position is Mth, the pixel value P can be expressed as follows using the real number q.

The intensity of the quantum noise included in the image data having the detected number n of radiation photons as a pixel value is n 1/2 power. Therefore, P ^1/2 which is the magnitude of the quantum noise is expressed as in Expression (2) when M is an even number. Here, M = 2m (m = 0, 1, 2,..., M is an integer).

  Equation (3) is established from the condition regarding q in Equation (1).

  Expression (4) is established from Expression (2) and Expression (3).

From equation (4), when the pixel value is P, the quantum noise is 2 ^m or more, that is, (2 ^m −1) or more. In (2 ^m -1), in the binary representation, the (m-1) -th bit position is 1 and all the lower bits are 1. Accordingly, when the maximum bit position is Mth (= 2m, even number) in the bit string of the radiation detection data having a pixel value of P, the upper side from the mth bit position is a valid signal bit, and the (m−1) th bit. The lower side of the bit position can be regarded as quantum noise.

Further, P ^1/2 that is the magnitude of the quantum noise is expressed as in Expression (5) when M is an odd number. Here, M = 2m + 1 (m = 0, 1, 2,..., M is an integer).

  From Expressions (3) and (5), Expression (6) is established when M is an odd number.

Equation (6) represents that when the pixel value is P, the quantum noise is 2 ^m or more, that is, (2 ^m −1) or more. Therefore, when the maximum bit position is Mth (= 2m + 1, odd number) in the bit string of the radiation detection data having the pixel value P, the upper side from the mth bit position is the effective signal bit, and the (m−1) th bit. The lower side of the bit position can be regarded as quantum noise. Accordingly, in both cases where M is an even number and an odd number, the radiation detection data can be compressed by deleting the lower m-bit data from the radiation detection data, thereby enabling the upper signal bits. It becomes possible.

  FIG. 1 is a diagram for explaining the relationship between effective signal bits and quantum noise in radiation detection data according to this embodiment. FIG. 1 shows a case where the bit length of radiation detection data is 16 bits.

  When the pixel value is not “0”, the maximum bit position is any one of the 0th bit position (LSB) to the 15th bit position (MSB). FIG. 1 shows 17 types of cases including 16 types of cases 1 to 16 having different maximum bit positions and case 17 in which the pixel value is “0”.

  As shown in FIG. 1, according to the equations (4) and (6), the radiation detection data includes an effective signal bit that is an upper bit string (J1 in FIG. 1) and a lower bit string (J2 in FIG. 1). ) And quantum noise.

  The data at the maximum bit position of the valid signal bit is “1” (predetermined bit data). In the radiation detection data, the data at the bit position higher than the maximum bit position is “0”. The valid signal bit is “0” or “1” data of a bit string of m bits (when M is an even number) or (m + 1) bits (when M is an odd number) on the lower side of the maximum bit position.

  Quantum noise is a bit string in a bit position that is lower than (m + 1) bits (when M is an even number) or (m + 2) bits (when M is an odd number) from the maximum bit position. 0 "or" 1 ".

  For example, in case 1, since “1” is set in the 15th bit, M which is the maximum bit position is “15”. In this case, the pixel value P is expressed as follows.

  Therefore, the quantum noise is expressed as follows:

  That is, in case 1, the sixth bit and below can be regarded as quantum noise (see FIG. 1).

  Similarly, in case 2, “1” is set to the 14th bit, and therefore M, which is the maximum bit position, is “14”. In this case, the pixel value P is expressed as follows.

  Therefore, the quantum noise is expressed as follows:

  That is, in case 2, as in case 1, the sixth and subsequent bits can be regarded as quantum noise (see FIG. 1).

  Similarly, in case 3 to case 15, a bit position or less that can be specified by M, which is the maximum bit position, and the parity of the maximum bit position can be regarded as quantum noise (see FIG. 1).

  In case 16, “1” is set to the 0th bit, so that the maximum bit position M is “0”. In this case, the pixel value P is expressed as follows.

  Therefore, the quantum noise is expressed as follows:

  That is, in case 16, since m = 0, the pixel value P is held by treating the 0th bit or more as a signal. In this case, since the signal-to-noise ratio SNR is 100%, the true value exists between “0” and “2”. Therefore, the case 17 may be considered to be included in the case 16, and the pixel value P is held in this case as well.

As described above, when the maximum bit position in the bit string of the radiation detection data is specified, the bit string of the quantum noise in the bit string of the radiation detection data can be specified, and the effective signal bit that is the bit string of the information to be transmitted can be specified. Identification becomes possible. Further, when the number of effective signal bits is specified, the quantum noise P1 ^{/ 2} is specified depending on whether the maximum bit position is an even number or an odd number, as shown in equations (2) and (5). It becomes possible. In this embodiment, the compression unit 100 detects the maximum bit position of the radiation detection data, and transmits effective signal bits that can be identified according to the detected maximum bit position and incidental information indicating the parity of the maximum bit position. The data is sent to the restoration unit 200 as data. The restoration unit 200 detects the maximum bit position in the transmitted valid signal bits, and refers to the incidental information received from the compression unit 100 to generate restoration data from the transmitted valid signal bits.

<Radiation diagnostic equipment>
FIG. 2 shows a functional block diagram of a schematic configuration of the radiation diagnostic apparatus according to the first embodiment. The radiation diagnostic apparatus shown in FIG. 2 includes an X-ray diagnostic apparatus, an X-ray CT apparatus, a nuclear medicine diagnostic apparatus, and the like.

  The radiation diagnostic apparatus 1 includes a radiation generation unit 10, a radiation detection unit 20, an image processing unit 30, a display control unit 40, and a display unit 50. The radiation generation unit 10 generates radiation (radiation photons) and exposes the generated radiation to the subject.

  The radiation detection unit 20 detects radiation photons exposed by the radiation generation unit 10, compresses radiation detection data obtained by counting the detected radiation photons, and generates transmission data. In this embodiment, paying attention to the fact that the intensity (standard deviation of fluctuation) of “quantum noise” generated according to the Poisson distribution when the number of detected radiation photons is n is n 1/2 power, Transmission data is generated by compressing radiation detection data with the photon number n as a pixel value.

  That is, the radiation detection unit 20 includes a radiation photon detection unit 21, a radiation photon counting unit 22, and a compression unit (qubit compression unit) 100. The radiation photon detection unit 21 detects radiation photons generated by the radiation generation unit 10. The radiation photon counting unit 22 counts the radiation photons detected by the radiation photon detection unit 21 within a predetermined period by the number of (2 × N) bits. The compression unit 100 compresses radiation detection data obtained by counting radiation photons by the radiation photon counting unit 22 to generate transmission data. In this embodiment, the compression unit 100 includes a maximum bit position that is a most significant bit position that is predetermined bit data (for example, “1”) in (2 × N) (N is a positive integer) bits of radiation detection data. A bit string having the number of bits corresponding to the maximum bit position on the lower side is used as a valid signal bit, and incidental information corresponding to the maximum bit position is added to the valid signal bit and output. The incidental information is generated according to the maximum bit position of the radiation detection data. In this embodiment, the effective signal bits are included in (N + 1) -bit signal data on the upper side of the radiation detection data, and image processing is performed as transmission data including (N + 1) -bit signal data and 1-bit auxiliary information. Is transmitted to the unit 30. The configuration and operation of the compression unit 100 will be described later.

  The image processing unit 30 receives the effective signal bits and the incidental information from the radiation detection unit 20, and restores (2 × N) bits of the radiation detection data restoration data from the effective signal bits and the incidental information. An image is created based on the restored data.

  That is, the image processing unit 30 includes a restoration unit (quantum bit restoration unit) 200 and an image creation unit 31. The restoration unit 200 detects the bit length of the effective signal bit from the radiation detection unit 20, and calculates the additional bit length from the detected bit length and the accompanying information. The restoration unit 200 generates restored data by adding additional data having a bit length determined by the calculated additional bit length and the accompanying information to the lower side of the valid signal bits. The image creation unit 31 creates an image based on the restoration data restored by the restoration unit 200. The configuration and operation of the restoration unit 200 will be described later.

  The display control unit 40 causes the display unit 50 to display the image generated by the image creation unit 31. The display unit 50 displays the image (radiation image) generated by the image creation unit 31 and other various information. The display unit 50 includes a display device such as a CRT (Cathode Ray Tube) or a liquid crystal display.

  The compression unit 100 and the restoration unit 200 can constitute a radiation detection data processing apparatus that performs data processing on radiation detection data.

  Hereinafter, the compression unit 100 and the restoration unit 200 will be described assuming that image data whose pixel value is expressed by (2 × N) bits is handled.

<Compression unit>
FIG. 3 shows a functional block diagram of a schematic configuration of the compression unit 100 of FIG.

  The compression unit 100 includes a bit position detection unit 110, a signal data extraction unit 120, and an incidental information generation unit 130.

  The bit position detection unit 110 detects the most significant bit position, which is predetermined bit data in the radiation detection data, as the maximum bit position. In the following, it is assumed that the predetermined bit data is “1”.

  The bit position detection unit 110 includes a shift up unit 111 and a most significant bit detection unit 112. The shift-up unit 111 shifts the radiation detection data (bit string) by 1 bit to the upper side. In the most significant bit detection unit 112, the shift-up data obtained by shifting the radiation detection data to the upper side by the shift-up unit 111 or the MSB data of the radiation detection data is the predetermined bit data (“1”). Whether or not is detected. The bit position detection unit 110 is based on the number of upshift bits by the upshift unit 111 when the most significant bit detection unit 112 detects that the most significant bit data is predetermined bit data (“1”). Detect bit position.

  The signal data extraction unit 120 extracts a bit string having the number of bits corresponding to the maximum bit position detected by the bit position detection unit 110 from the maximum bit position of the radiation detection data as effective signal bits. In this embodiment, the signal data extraction unit 120 extracts (N + 1) bits of signal data including valid signal bits, as will be described later.

  The signal data extraction unit 120 includes an upper bit extraction unit 121, a shift down bit number calculation unit 122, and a shift down unit 123. The upper bit extraction unit 121 extracts an upper (N + 1) -bit bit string from the shift-up data obtained by the shift-up unit 111 (data obtained by shifting the radiation detection data to the upper side by the number of shift-up bits). . That is, the upper bit extraction unit 121 truncates the lower (N−1) bits, leaving only the upper (N + 1) bits of the (2 × N) -bit shift-up data. The shift-down bit number calculation unit 122 shifts down-bits to be shifted to the lower side based on the number of shift-up bits by the shift-up unit 111 and the accompanying information when the maximum bit position is detected by the bit position detection unit 110. Is calculated. The downshift unit 123 shifts the upshift data to the lower side by the number of downshift bits calculated by the downshift bit number calculator 122. Data obtained by the shift-down unit 123 is (N + 1) -bit signal data. The signal data extraction unit 120 is an example of a “signal bit extraction unit”.

  The incidental information generation unit 130 generates incidental information (restoration auxiliary bit information) based on the maximum bit position detected by the bit position detection unit 110. Specifically, the incidental information generation unit 130 generates information indicating the parity of the maximum bit position detected by the bit position detection unit 110 as 1-bit incidental information. As will be described later, the incidental information generation unit 130 generates incidental information based on the LSB when the shift-up number by the shift-up unit 111 when the maximum bit position is detected by the bit position detection unit 110 is expressed in binary. It is possible to generate.

  As described above, the compression unit 100 generates (N + 2) -bit transmission data including N-bit signal data including effective signal bits and 1-bit incidental information from (2 × N) -bit radiation detection data, The generated transmission data is sent to the image processing unit 30 (restoring unit 200).

<Restore unit>
FIG. 4 shows a functional block diagram of a schematic configuration of the restoration unit 200 of FIG.

  The restoration unit 200 includes a bit length detection unit 210, an additional bit length calculation unit 220, and a restoration data generation unit 230.

  The bit length detection unit 210 receives (N + 1) -bit signal data including valid signal bits from the (N + 2) -bit transmission data from the compression unit 100. The bit length detection unit 210 detects the bit length of the valid signal bit by detecting the maximum bit position in the valid signal bit. Since the bit length of the signal data is determined in advance, the valid signal bit can be specified from the signal data based on the detected maximum bit position.

  The additional bit length calculation unit 220 receives 1-bit incidental information from the (N + 2) -bit transmission data from the compression unit 100. Based on the bit length detected by the bit length detection unit 210 and the accompanying information, the additional bit length calculation unit 220 calculates an additional bit length that is a bit length to be added to the lower side of the valid signal bits. As a specific example, the additional bit length calculation unit 220 calculates the additional bit length by adding the bit length detected by the bit length detection unit 210 and the accompanying information.

  The restoration data generation unit 230 adds predetermined additional data to the lower side of the shift data obtained by shifting the valid signal bits to the upper side by the additional bit length calculated by the additional bit length calculation unit 220. Thus, (2 × N) -bit restored data is generated.

  The restored data generation unit 230 includes a shift-up unit 231, a data addition unit 232, and an additional data storage unit 233. The shift-up unit 231 generates shift-up data by shifting the effective signal bits from the compression unit 100 to the upper side by the additional bit length calculated by the additional bit length calculation unit 220. The data adding unit 232 adds additional data to the lower side of the shift-up data generated by the shift-up unit 231. The additional data has a bit length corresponding to the upshift data. The additional data storage unit 233 stores additional data added by the data adding unit 232 in advance. As for the additional data, the data of each bit is all “0”, the data of each bit is all “1”, only the most significant bit data is “1”, and the other data is “0”. Data or only the most significant bit data is “0” and other data is “1”. The additional data may be a random number as will be described later.

<Operation example>
Next, operation examples of the compression unit 100 and the decompression unit 200 will be described with reference to FIGS.

FIG. 5 shows a flowchart of an operation example of the compression unit 100 according to this embodiment.
FIG. 6 shows an operation explanatory diagram of the compression unit 100 according to this embodiment. In FIG. 6, it is assumed that N is “8”.

(S1, S2)
The bit position detection unit 110 shifts the 16-bit radiation detection data expressed in binary number to the upper side until “1” is set in the MSB. Specifically, the most significant bit detection unit 112 determines whether or not “1” is set in the MSB of the radiation detection data or the shift-up data obtained by shifting the radiation detection data by the shift-up unit 111. Detect (S1). When it is detected that “1” is set in the MSB (S1: Y), the bit position detection unit 110 stores the number of bits upshifted by the upshifting unit 111, and the operation of the compression unit 100 proceeds to S3. Transition. When it is not detected that “1” is set in the MSB (S1: N), the shift-up unit 111 shifts the 16-bit radiation detection data to the upper side by 1 bit (S2), and the compression unit 100 Operation proceeds to S1. S1 and S2 are examples of the “bit position detection step”.

  FIG. 6 shows the shift-up data (J3 is a valid signal bit and J4 is quantum noise) and the number of shift-up bits when it is detected that “1” is set in the MSB. Note that, as in case 10 to case 17, since the number of upshift bits is large, the bit positions where the original data (pixel value) does not exist are filled with “0”. In addition, when the radiation detection data (pixel value) is “0” (case 17), even if shifting by 15 (= 2 × N−1) bits, “1” is not set in the MSB, but the shift is more than that. No operation is performed, and the number of upshift bits is 15 (= 2 × N−1).

(S3-S5)
The signal data extraction unit 120 extracts a bit string of the number of bits corresponding to the maximum bit position detected by the bit position detection unit 110 as signal data including effective signal bits from the maximum bit position of the radiation detection data. Here, the upper bit extraction unit 121 leaves only the upper 8 (= N) bits of the 16 (= 2 × N = 2 × 8) -bit shift-up data shifted to the upper side by the shift-up unit 111. Then, the lower 8 bits are discarded (S3). The downshift bit number calculation unit 122 calculates the downshift bit number according to the equation (13) (S4).

  Shift-down bit number = (0 or 1 depending on the even / odd number of shift-up bit + shift-up bit number) / 2 (13)

  For example, in case 15, since the number of upshift bits is “14” and an even number, the number of downshift bits = (14 + 0) / 2 = 7. For example, in case 14, since the number of upshift bits is “13” and an odd number, the number of downshift bits = (13 + 1) / 2 = 7.

  The even / odd number of shift-up bits is LSB data when the number of shift-up bits is expressed in binary. Therefore, it is possible to calculate the shift-down bit number by adding the shift-up bit number and the LSB data when the shift-up bit number is expressed in binary. Also, as shown in FIG. 6, since the number of upshift bits corresponds to the maximum bit position, it is also possible to calculate the number of downshift bits using the number of upshift bits and the parity at the maximum bit position. .

  The shift-down unit 123 shifts the upper 9 (= N + 1) -bit shift-up data obtained in S3 to the lower side by the number of shift-down bits, removes the bit string corresponding to the quantum noise and leaves only the effective signal bits ( S5, noise bit sweep out). As a result, 9-bit signal data including valid signal bits transmitted to the restoration side as transmission data is generated. FIG. 6 shows 9-bit signal data (J5 is a valid signal bit) after the noise bit sweep. S3 to S5 are examples of the “signal bit extraction step”.

(S6)
The incidental information generation unit 130 generates incidental information (restoration auxiliary bit information) based on the maximum bit position detected by the bit position detection unit 110. Specifically, the incidental information generation unit 130 extracts the LSB data when the number of upshift bits is expressed in binary, and uses this data as incidental information as auxiliary bit information for restoration. In this embodiment, the number of upshift bits corresponds to the maximum bit position as described above. Therefore, the incidental information generation unit 130 can generate incidental information as auxiliary bits for restoration based on the parity at the maximum bit position corresponding to the LSB data when the number of upshift bits is expressed in binary. is there. S6 is an example of an “accompanying information generation step”.

(S7)
The compression unit 100 converts (9 + 1) -bit transmission data composed of 8-bit signal data after the noise bit sweep obtained by the shift-down unit 123 and 1-bit auxiliary information generated by the auxiliary information generation unit 130. The image is output to the image processing unit 30. Thereafter, the compression unit 100 ends a series of operations (end).

FIG. 7 shows a flowchart of an operation example of the restoration unit 200 according to this embodiment.
8 to 10 are diagrams for explaining the operation of the restoration unit 200 according to this embodiment. 8 to 10, N is assumed to be “8”. In FIG. 10, the same parts as those in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

(S11)
The bit length detection unit 210 receives 9-bit signal data and detects the maximum bit position of the effective signal bits included in the signal data, thereby detecting the bit length of the effective signal bits as the detection bit length (FIG. 8). J11). Counting from the LSB side as 0th, 1st, 2nd,..., For example, when the 8th bit position is the above bit position, the bit length detection unit 210 detects “9” as the detection bit length. . S11 is an example of a “bit length detection step”.

(S12)
The additional bit length calculation unit 220 calculates the additional bit length according to Expression (14) based on the detected bit length detected in S11 and the 1-bit supplementary information from the compression unit 100 (J12 in FIG. 8). S12 is an example of an “additional bit length calculation step”.

  Additional bit length = detection bit length + accompanying information (auxiliary bit information for restoration) −2 (14)

(S13, S14)
The restoration data generation unit 230 generates 16-bit restoration data from the valid signal bits based on the additional bit length calculated by the additional bit length calculation unit 220. Specifically, the upshifting unit 231 shifts the valid signal bits from the compression unit 100 to the upper side by the number of bits of the additional bit length (S13). FIG. 9 shows 9-bit shift-up data (restored data) (J13) (valid signal bit is J14) shifted to the upper side by the shift-up unit 231. When the additional bit length calculated by the additional bit length calculation unit 220 is less than or equal to zero, the number of additional bits is set to zero.

  The data adding unit 232 adds additional data to the lower side of the shift-up data obtained by the shift-up unit 231 (S14). As described above, the additional data is data in which each bit data is all “0”, each bit data is all “1”, only the most significant bit data is “1”, and other data is The data can be selected from either “0” data or data in which only the most significant bit data is “0” and other data is “1”. S13 and S14 are examples of a “restored data generation step”.

  The additional data corresponds to the information truncated in S3 on the compression side. The information truncated in S3 is randomly distributed between data in which all the data of each bit is “0” and data in which all the data of each bit is “1”. Therefore, when only the most significant bit data is “1” and the other data is “0” as additional data, the statistical average level before truncation can be restored. . The additional data may be data in which only the most significant bit data is “0” and other data is “1”. If there is no need to restore the statistical average level before truncation, the data of each bit may be all “0” data or the data of each bit may be “1” as additional data. .

  FIG. 9 illustrates an example of restored data when data having only “1” as the additional data and “0” as the other data is selected. In FIG. 9, except for cases 14 to 17, data of each bit is added so as to restore the statistical average level. In case 13 and case 14, since the bit to be added is 1 bit, the statistical average level cannot be restored. However, in these cases, it is possible to restore the statistical average level between a plurality of radiation detection data by adding “0” or “1” randomly generated at the time of restoration. In cases 15, 16, and 17, the additional bit length is zero or less, and therefore no additional data exists. The radiation detection data before compression is set as it is.

  FIG. 10 shows an example of restoration data in the case where data of all bits of “0” is selected as additional data. In cases 15, 16 and 17, since the additional bit length is zero or less, there is no additional data, and radiation detection data before compression is set.

  Note that the radiation detection data processing apparatus including the compression unit 100 and the restoration unit 200 according to the first embodiment can be applied as a radiation data processing method. That is, the radiation detection data processing method includes a bit position detection step, a signal data extraction step, and an incidental information generation step. The bit position detection step detects the maximum bit position that is the most significant bit position that is predetermined bit data in the radiation detection data obtained by counting the radiation photons. In the signal bit extraction step, a bit string having the number of bits corresponding to the maximum bit position detected in the bit position detection step is extracted as a valid signal bit from the maximum bit position of the radiation detection data. In the incidental information generation step, incidental information to be added to the effective signal bit is generated based on the maximum bit position detected in the bit position detection step. This incidental information can be information indicating the parity of the bit position detected in the bit position detection step.

  The radiation detection data processing method further includes a bit length detection step, an additional bit length calculation step, and a restoration data generation step. The bit length detection step detects the bit length of the valid signal bit by detecting the maximum bit position in the valid signal bit. In the additional bit length calculation step, an additional bit length, which is a bit length to be added to the lower side of the effective signal bit, is calculated based on the bit length detected in the bit length detection step and the accompanying information. In the restoration data generation step, the valid signal bits are shifted to the upper side by the additional bit length calculated in the additional bit length calculation step, and predetermined additional data is added to the lower side of the shift data obtained by the shift. Thus, the restoration data of the radiation detection data is generated.

  As described above, in the first embodiment, the standard deviation of the Poisson distribution is detected with respect to the radiation detection data obtained by detecting the radiation photons generated by the radiation generator 10 and counting the detected radiation photons. The compression processing is performed based on the above.

  Thus, the number of bits of data to be transmitted can be reduced and sent to the image processing unit 30 in consideration of the characteristics of quantum noise, and compression according to the signal generation principle becomes possible. For this reason, according to this embodiment, it is difficult for a false image to occur in an image generated by the image processing unit 30, and the radiation detection data can be compressed without impairing the signal-to-noise ratio. Also, the information amount of data to be transmitted can be compressed from (2 × N) bits to (N + 2) bits. As a result, it is possible to reduce the transmission time and wiring cost related to signal transmission inside the radiation detection unit 20 and between the radiation detection unit 20 and the image processing unit 30. Furthermore, when the radiation detection data is temporarily stored in the storage device (storage medium) between the compression side and the decompression side, the capacity of the storage device (storage medium) necessary for storing the radiation detection data should be reduced. Is possible.

[Modification of First Embodiment]
In the first embodiment, the data adding unit 232 of the restoration unit 200 has been described as adding pre-stored additional data to the lower side of the shift-up data shifted to the upper side by the shift-up unit 231. It is not limited to. In the modification of the first embodiment, the random number generated by the random number generation unit is added to the lower side of the shift-up data shifted to the upper side by the shift-up unit 231.

  Hereinafter, a radiation diagnostic apparatus according to a modification of the first embodiment will be described focusing on differences from the first embodiment. The configuration of the radiation diagnostic apparatus according to the modification of the first embodiment is different from the configuration of the radiation diagnostic apparatus 1 according to the first embodiment in a restoration unit included in the image processing unit.

  FIG. 11 shows a functional block diagram of a schematic configuration of a restoration unit according to a modification of the first embodiment. In FIG. 11, the same parts as those in FIG.

  The restoration unit 200a includes a bit length detection unit 210, an additional bit length calculation unit 220, and a restoration data generation unit 230a.

  The restored data generation unit 230 a includes a shift-up unit 231, a data addition unit 232, and a random number generation unit 234. The random number generator 234 generates a random number having the number of bits specified by the additional bit length calculated by the additional bit length calculator 220 and the accompanying information. The data addition unit 232 adds the random number generated by the random number generation unit 234 as additional data to the lower side of the upshift data generated by the upshift unit 231.

  The operation of the restoration unit 200a according to the present modification is the same as that of the first embodiment except that the additional data added to the shift-up data is a random number. Therefore, the operation of the restoration unit 200a according to the present modification is as follows. The explanation is omitted.

  As described above, since the additional data corresponds to the information truncated in S3 on the compression side, according to the present modification, quantum noise can be generated in a pseudo manner by the random number generation unit 234. It will be possible to restore the statistical average level before truncation.

[Second Embodiment]
In the first embodiment, in radiation detection data with a pixel value of P, P ^1/2 is regarded as the magnitude of quantum noise. However, since P ^1/2 is the standard deviation of noise, It can be said that it is only one standard estimation standard. Therefore, by changing the number of bits to be discarded by compression with respect to radiation detection data having a pixel value of P, it is possible to estimate more or less noise.

  In the second embodiment, it is assumed that the magnitude of noise to be discarded by compression is estimated to be small for radiation detection data having a pixel value P. In this case, since the range in which the valid signal bits are included becomes large, the capacity necessary for the storage device or the like increases, and the number of bits of transmission data increases. However, the restoration unit can restore the restored data closer to the radiation detection data before compression compared to the first embodiment.

  Therefore, in the second embodiment, when the maximum bit position is M in the radiation detection data whose pixel value is P, when 1 ≦ α <(N−1) (α is an integer) and M is an even number, For the upper (m + 1 + α) bits, when M is an odd number, the upper (m + 2 + α) bits are regarded as valid signal bits, and the lower (m−α) bits are regarded as quantum noise. The first embodiment corresponds to the case where α = 0.

  Hereinafter, the radiation diagnostic apparatus according to the second embodiment will be described focusing on differences from the first embodiment.

  The configuration of the radiation diagnostic apparatus according to the second embodiment has the same configuration as that of the radiation diagnostic apparatus 1 according to the first embodiment. In the first embodiment, (N + 1) -bit signal data is generated. On the other hand, the second embodiment is different in that (N + 1 + α) -bit signal data is generated. Therefore, in the second embodiment, the process for generating signal data on the compression side is different from that in the first embodiment, and the process for generating restoration data from signal data on the restoration side is different from that in the first embodiment.

  FIG. 12 is an operation explanatory diagram of the compression unit according to the second embodiment. 12, parts similar to those in FIG. 6 are given the same reference numerals, and description thereof will be omitted as appropriate. In FIG. 12, it is assumed that α = 1 for convenience of explanation.

  FIG. 12 shows the shift-up data (J21 is a part of the quantum noise of the first embodiment) and the number of shift-up bits when it is detected that “1” is set in the MSB. . Note that, as in case 8 to case 17, since the number of upshift bits is large, the bit positions where the original data (pixel value) does not exist are filled with “0”. As shown in FIG. 12, the signal data extraction unit according to the second embodiment has a maximum of 10 (= N + 1 + 1 = 9 + 1) bits from the maximum bit position of the radiation detection data of 16 (= 2 × N = 2 × 8) bits. The signal data including the valid signal bits are extracted. Here, the higher-order bit extraction unit according to the second embodiment includes the upper 10 (= N + 1 + α) of the 16 (= 2 × N = 2 × 8) -bit shift-up data shifted to the upper side by the shift-up unit 111. = 9 + 1) bits are left, and the lower 6 (= N-1-α = 7-1) bits are discarded. The downshift bit number calculation unit according to the second embodiment calculates the downshift bit number according to Equation (13). However, when the number of upshift bits is (2N−2 = 14) or more, 1 is added to the result calculated according to the equation (13). This is because in cases 15 to 17 where the number of upshift bits is (2N−2 = 14) or more, there is no bit to be added to the lower bits. FIG. 12 shows 10 effective signal bits (J22 and J5 are effective signal bits of the first embodiment) after noise bit sweeping.

  The compression unit according to the second embodiment includes 10-bit signal data after the noise bit sweep obtained by the shift-down unit, and 1-bit incidental information generated by the incidental information generation unit according to the second embodiment. (10 + 1) bits (α = 1) of transmission data is output to the image processing unit 30.

  FIG. 13 and FIG. 14 are diagrams illustrating the operation of the restoration unit according to the second embodiment. In FIG. 13, the same parts as those in FIG. In FIG. 14, the same parts as those in FIG. 13 and 14, it is assumed that α = 1 for convenience of explanation.

  The bit length detector according to the second embodiment detects the bit length of the valid signal bit as the detected bit length by receiving the valid signal bit and detecting the maximum bit position of the valid signal bit (J23 in FIG. 13). . For example, when the 9th bit position is the above bit position, the bit length detection unit according to the second embodiment sets the detection bit length as “0”, 1st, 2nd,. 10 ″ is detected.

  The additional bit length calculation unit according to the second embodiment calculates the additional bit length according to Expression (15) based on the detected bit length detected and the 1-bit supplementary information from the compression unit (J24 in FIG. 13). ). That is, the additional bit length calculation unit according to the second embodiment calculates the additional bit length by adding the detected bit length and the incidental information and subtracting (2 × (1 + α)) from the addition result. . When the calculation result obtained by Expression (15) is negative, the calculation result of Expression (15) is set to “0” (α = 1).

Additional bit length = detection bit length + accompanying information (recovery auxiliary bit information) −2 × (1 + α)
= Detection bit length + accompanying information (restoration bit information for restoration) -4 (15)

  The restored data generation unit according to the second embodiment generates 16-bit restored data from the valid signal bits based on the additional bit length calculated by the additional bit length calculation unit according to the second embodiment. Specifically, the shift-up unit according to the second embodiment shifts the valid signal bits from the compression unit to the upper side by the number of bits of the additional bit length. FIG. 14 illustrates 10-bit shift-up data (restored data) (J25) (the valid signal bit of the first embodiment is J26) shifted to the upper side by the shift-up unit according to the second embodiment. .

  The data addition unit according to the second embodiment adds additional data to the lower side of the shift-up data obtained by the shift-up unit according to the second embodiment. The additional data is the same as that of the first embodiment or its modification. However, as shown in FIG. 14, in case 13 to case 17, the additional bit length is “0”, so nothing is added.

  As described above, in the second embodiment, in (2 × N) -bit radiation detection data, the upper (m + 1 + α) bits are regarded as effective signal bits, and the lower (m−α) bits are quantum noise. I reckon.

  Thus, by selecting α according to the purpose of use of the radiation diagnostic apparatus, an appropriate degree of compression can be selected. Compared to controlling the degree of compression regardless of the standard deviation of the Poisson distribution, which is a characteristic of quantum noise, the degree of compression is controlled based on the standard deviation of the Poisson distribution for all pixels, so signal generation The compression is based on the principle, and the false image is less likely to occur.

  When the radiation detection data is further compressed, when the pixel value is P and the maximum bit position is M, the lower (m−1 + β) (1 ≦ β ≦ N, β is an integer) bits are defined as quantum noise. May be considered. In this case, in the second embodiment, for example, by replacing “α” with “−β”, a compression unit and a decompression unit capable of reducing the number of bits of signal data to be transmitted can be realized. .

[Third Embodiment]
In the above-described embodiment and its modified examples, the transmission data generated by the compression unit is directly sent to the restoration unit, and the restoration unit generates restoration data from the transmission data. However, the present invention is limited to this. It is not a thing. In the third embodiment, a reversible compression unit and a reversible decompression unit corresponding to the reversible compression unit are provided between the compression unit and the decompression unit according to the above-described embodiment and the modifications thereof. In the meantime, data obtained by reversibly compressing the transmission data is transmitted.

  FIG. 15 shows a functional block diagram of the main part of the schematic configuration of the radiation diagnostic apparatus according to the third embodiment. In FIG. 15, the same parts as those in FIG.

  The radiation detection unit 20c according to the third embodiment includes a data compression unit 23c. The data compression unit 23c includes a compression unit 100 and a reversible compression unit 24c.

  The image processing unit 30c according to the third embodiment includes a data restoration unit 32c. The data restoration unit 32c includes a reversible restoration unit 33c and a restoration unit 200.

  FIG. 16 shows a functional block diagram of a schematic configuration of the radiation diagnostic apparatus according to the third embodiment. In FIG. 16, the same parts as those in FIG. 2 or FIG.

  In the radiation diagnostic apparatus 1c according to the third embodiment, the compression unit 100 detects (2 × N) bits of radiation detected by counting the radiation photons by the radiation photon counting unit 22, as in the first embodiment. The data is compressed to generate (N + 2) -bit transmission data. The lossless compression unit 24c generates compressed data by performing a known lossless compression process on the (N + 2) -bit transmission data generated by the compression unit 100. Here, the lossless compression process may be a process of reducing (N + 2) bits, which is the bit size of transmission data, or a process of reducing the total data size transmitted within a predetermined period. Also good. The compressed data generated by the lossless compression unit 24c is output to the image processing unit 30c.

  The lossless decompression unit 33c receives the compressed data from the data compression unit 23c and restores the compressed data to (N + 2) -bit transmission data before the lossless compression process by performing a lossless restoration process. Here, the lossless restoration process is a process corresponding to the lossless compression process performed by the lossless compression unit 24c. The transmission data restored by the reversible restoration unit 33c is output to the restoration unit 200. As described above, the restoration unit 200 restores (2 × N) -bit restored data from the transmission data. The image processing unit 30c creates an image based on the restored data in the image creating unit.

  Since the lossless compression process and the lossless restoration process corresponding thereto may be a known lossless compression process and a lossless restoration process corresponding thereto, description of the contents of each process is omitted.

  Note that the compression unit 100 in the data compression unit 23c illustrated in FIG. 15 or 16 may be the compression unit according to the second embodiment. Similarly, the restoration unit 200 in the data restoration unit 32c illustrated in FIG. 15 or 16 may be a restoration unit according to a modification of the first embodiment on the condition that it corresponds to the compression unit, The restoration unit according to the second embodiment may be used.

  As described above, in the third embodiment, the reversible compression unit 24c and the reversible restoration unit 33c are provided between the compression unit and the restoration unit according to the above-described embodiment or a modification thereof. Thereby, according to 3rd Embodiment, compared with said embodiment or its modification, the data size transmitted from the compression side to the decompression | restoration side can be made smaller, without impairing a signal-to-noise ratio. It becomes possible. Therefore, it is possible to further reduce the transmission time and wiring cost related to signal transmission inside the radiation detection unit 20c and between the radiation detection unit 20c and the image processing unit 30c. Furthermore, when the radiation detection data is temporarily stored in the storage device (storage medium) between the compression side and the decompression side, the capacity of the storage device (storage medium) necessary for storing the radiation detection data is further reduced. It becomes possible to do.

[Fourth Embodiment]
The above-described embodiment or its modification is not limited to the configuration of the radiation detection unit or the configuration of the image processing unit. When the radiation diagnostic apparatus according to the above-described embodiment or its modification is an X-ray diagnostic apparatus or an X-ray CT apparatus, an X-ray detector having the following configuration can be applied as the radiation detection unit. Similarly, an image processing apparatus having the following configuration can be applied as the image processing unit. In the following description, the “pixel” may be a “detection block”.

<X-ray detector>
FIG. 17 shows a block diagram of a hardware configuration example of the X-ray detector according to the fourth embodiment. FIG. 17 shows only a part of the configuration of the X-ray detector for convenience of explanation.
FIG. 18 shows a block diagram of a hardware configuration example of the qubit compressor of FIG. In FIG. 18, the same parts as those in FIG.

The X-ray detector 300 according to the fourth embodiment includes J × K (J and K are integers of 2 or more) pixels 310 _{11 to} 310 _JK arranged two-dimensionally and J provided in each column. an output bus _BS 1 to BS _J for each column of the present, and the J output buffers ₃₂₀ 1 to 320 _J provided in each column, and is configured to include an output bus BO. Each of the pixels 310 _{11 to} 310 _JK has the same configuration. In FIG. 17, the pixel 310 _i1 among the pixels 310 _i1 to 310 _iK of the i-th (1 ≦ i ≦ J, i is an integer) column, the output bus BS _i for the i-th column, and the output for the i-th column Only the output buffer 320 _i connected to the bus BSi and the output bus BO of the X-ray detector 300 connected to the output buffer 320 _i are shown. The pixels 310 _{i1 to} 310 _iK in the i-th column are connected to the output bus BS _i . The output buses BS _i and BO each have a bus width of (N + 2) bits. That is, a common output bus (BS _i ) is connected to pixels in each column among a plurality of pixels arranged in a two-dimensional manner, and one output data among the pixels in each column is connected to this output bus. Is output. The output bus (BS _i ) of each column is connected to an output buffer provided in each column, and the output buffer provided in each column is connected to the output bus BO of the X-ray detector 300.

The pixel 310 _i1 includes an X-ray-to-charge converter 311 _i1 , a charge-voltage converter 312 _i1 , a comparator 313 _i1 , a photon number counter 314 _i1 , a qubit compressor 315 _i1, and an output buffer 316 _i1 . It is configured to include.

The X-ray-charge conversion unit 311 _i1 generates a charge when X-rays generated by the X-ray generation unit as the radiation generation unit 10 and transmitted through the subject are incident and absorbed. The charge-voltage converter 312 _i1 converts the voltage pulse corresponding to the charge generated by the X-ray-charge converter 311 _i1 . The comparator 313 _i1 receives the voltage pulse converted by the charge voltage converter 312 _i1 and preset upper and lower thresholds.

The comparator 313 _i1 outputs a detection pulse when the peak value (amplitude value) of the voltage pulse converted by the charge-voltage converter 312 _i1 is equal to or lower than the upper limit threshold and equal to or higher than the lower limit threshold. The upper limit threshold is set in consideration of, for example, the tube voltage of the X-ray tube constituting the X-ray generation unit, the pile-up peak, and the like. For example, the lower threshold is set so as not to detect the dark current of the semiconductor constituting the X-ray-charge converter 311 _i1 . The upper threshold value is configured to be changeable afterwards. The lower threshold is also configured to be changeable afterwards. The upper threshold and the lower threshold may be set in common for (J × K) pixels 310 _{11 to} 310 _JK , may be set for each pixel in a predetermined region, or may be set for each pixel. It may be set individually.

The photon number counter 314 _i1 receives the X-ray irradiation start timing signal from the control unit (not shown) and the detection pulse output from the comparator 313 _i1 . The control unit is provided in a console device such as an X-ray diagnostic apparatus or an X-ray CT apparatus on which the X-ray detector 300 is mounted, for example. The X-ray irradiation start timing signal is a signal for notifying the start timing of X-ray irradiation in the X-ray diagnostic apparatus and the X-ray CT apparatus. When the photon number counter 314 _i1 is notified of the X-ray irradiation start timing signal by the X-ray irradiation start timing signal, the photon number counter 314 _i1 initializes the count value and then sets the number of detection pulses from the comparator 313 _{i1 as} the number of X-ray photons. Start counting. The photon number counter 314 _i1 outputs the count value to the qubit compressor 315 _i1 as (2 × N) -bit radiation detection data.

The qubit compressor 315 _i1 receives the X-ray irradiation end signal from the control unit and the radiation detection data output by the photon number counter 314 _i1 . The X-ray irradiation end signal is a signal for notifying the end of X-ray irradiation in the X-ray diagnostic apparatus or the X-ray CT apparatus. As shown in FIG. 18, the qubit compressor 315 _i1 includes a most significant bit detector 317 _i1 and a noise bit sweeper 318 _i1 , and includes a compression unit according to any one of the above-described embodiments or modifications thereof. Realize the function. The most significant bit detector 317 _i1 realizes the function of the bit position detection unit according to any one of the above-described embodiments or modifications thereof. The noise bit sweeper 318 _i1 realizes the functions of the signal data extraction unit and the incidental information generation unit according to any of the above embodiments or modifications thereof.

When such an end of X-ray irradiation is notified by the X-ray irradiation end signal, the qubit compressor 315 _i1 takes in the radiation detection data at the time of the notification. When the qubit compressor 315 _i1 realizes the function of the compression unit 100 according to the first embodiment, the qubit compressor 315 _i1 converts the captured (2 × N) -bit radiation detection data into (N + 2) -bit radiation detection data. Compress to transmission data.

The output buffer 316 _i1 receives the first row selection signal from the control unit and the transmission data generated by the qubit compressor 315 _i1 . First row selection signal is a signal for selecting the pixel ₃₁₀ 11 to 310 _J1 arranged in a first row of the arranged two-dimensionally (J × K) pixels ₃₁₀ 11 to 310 _JK is there. When selected by the first row selection signal, the output buffer 316 _i1 outputs the transmission data generated by the qubit compressor 315 _i1 to the output bus BS _i for the i-th column.

The X-ray-charge converter 311 _i1 , the charge-voltage converter 312 _i1 , and the comparator 313 _i1 realize the function of the radiation photon detector 21. The photon number counter 314 _i1 realizes the function of the radiation photon counting unit 22. The qubit compressor 315 _i1 realizes the function of the compression unit according to any one of the above-described embodiments or modifications thereof. This compression unit may realize the function of the output buffer 316 _i1 .

As described above, in the X-ray detector 300, the transmission data generated in the pixel selected by the row selection signal among the pixels in each column is output to the output bus for each column. Accordingly, by selecting one of the pixels in each column one by one using the row selection signal, transmission data generated in the two-dimensionally arranged pixels 310 _{11 to} 310 _JK can be sequentially output.

Hereinafter, a case where the compression unit 100 according to the first embodiment is applied to the qubit compressor 315 _i1 will be described.

In the i-th column, the X-ray detector 300 receives the X-ray irradiation start timing signal from the control unit, initializes the count value of the photon number counter 314 _i , and then starts counting. The X-ray-to-charge converter 311 _i1 generates a charge when an X-ray photon is incident and absorbed. The charge-voltage converter 312 _i1 converts the voltage pulse with a peak value (amplitude value) corresponding to the charge generated by the X-ray-charge converter 311 _i1 . The comparator 313 _i1 compares the peak value (amplitude value) of the voltage pulse with the upper threshold voltage and the lower threshold voltage, and when the peak value (amplitude value) of the voltage pulse is between both threshold values, Output. The photon number counter 314 _i1 receives this detection pulse and increments the count value.

When the X-ray irradiation period ends, the X-ray detector 300 receives an X-ray irradiation end signal from a control unit (not shown). Then, the qubit compressor 315 _i1 performs the above-described compression processing on the radiation detection data that is a count value of (2 × N) bits counted by the photon number counter 314 _i1 .

In the qubit compressor 315 _i1 , the most significant bit detector 317 _i1 detects the maximum bit position while shifting the (2 × N) -bit radiation detection data to the upper side by 1 bit, and determines the number of upshift bits. To do. For example, N bits of data and the number of shift-up bits, which are shifted to the upper side and counted from the upper side, are sent to the noise bit bit sweeper 318 _i1 , and noise sweeping is performed from the N bit data. By this noise sweeping, only the valid signal bits remain, and the remaining valid signal bit string is placed on the upper side from the LSB. Also, 1-bit supplementary information as auxiliary bit information for restoration is determined based on the number of upshift bits. The noise bit sweeper 318 _i1 outputs transmission data including signal data including effective signal bits from which noise has been swept out and 1-bit auxiliary information to the output buffer 316 _i1 .

When the pixel 310 _i1 is selected by the row selection signal from the control unit, the output buffer 316 _i1 outputs the transmission data to the output bus BS _i for the i-th column. This control unit selects one row at a time from the first row to the Kth row in response to a row selection signal. When a certain row is selected, the pixels in each column in the X-ray detector 300 simultaneously output transmission data to the output bus for each column and are held in an output buffer provided in each column. The transmission data held in the output buffer of each column is sequentially output from the first column to the Jth column to the output bus BO when selected by a column selection signal from the control unit. The output bus BO of the X-ray detector 300 is connected to the image processing unit on the restoration side.

  The X-ray detector 300 as described above can be applied to the radiation detection units 20 and 20c in the radiation diagnostic apparatuses 1 and 1c. In FIG. 17, the row direction and the column direction can be interchanged.

<Image processing device>
FIG. 19 shows a block diagram of a hardware configuration example of an image processing apparatus according to the fourth embodiment.
FIG. 20 shows a block diagram of a hardware configuration example of the qubit restoration unit in FIG. 20, parts that are the same as those in FIG. 19 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

  The image processing apparatus 400 according to the fourth embodiment includes a qubit restoration unit 410, an image creation unit 420, and an image storage unit 430. The qubit restoration unit 410 realizes the function of the restoration unit according to any one of the above embodiments or modifications thereof. The image creation unit 420 realizes the function of the image creation unit according to any one of the above-described embodiments or modifications thereof.

  As illustrated in FIG. 20, the qubit restoration unit 410 includes a most significant bit detector 411, an adder 412, a shift register 413, and an additional data generator 414. The most significant bit detector 411 realizes the function of the bit length detection unit according to any one of the above embodiments or modifications thereof. The adder 412 realizes the function of the additional bit length calculation unit according to any one of the above-described embodiments or modifications thereof. The additional data generator 414 outputs additional data. The additional data generator 414 has a memory for storing predetermined additional data in advance, and outputs the additional data stored in this memory. Further, the additional data generator 414 includes a random number generator, and the random number generated by the random number generator can be output as additional data. The shift register 413 uses the additional data output from the additional data generator 414 to realize the function of the restored data generation unit according to any one of the above-described embodiments or modifications thereof.

  In the image processing device 400, the qubit restoration unit 410 restores (2 × N) -bit restoration data from the transmission data, and passes it to the image creation unit 420.

  In the qubit restoration unit 410, the most significant bit detector 411 detects, for example, the maximum bit position of the effective signal bits included in the N-bit signal data out of the (N + 2) -bit transmission data, and the detected maximum bit Outputs detection bit length based on position. The adder 412 calculates the additional bit length from the detected bit length and the 1-bit incidental information of the (N + 2) -bit transmission data. The shift register 413 adds predetermined additional data to the lower side of the valid signal bit and outputs it as (2 × N) -bit restored data.

  The image creation unit 420 creates an image based on the (2 × N) -bit restoration data output from the qubit restoration unit 410. The image created by the image creation unit 420 is stored in the image storage unit 430. A display control unit (not shown) displays an image stored in the image storage unit 430 on a display unit (not shown).

  The image processing apparatus 400 as described above can be applied to the image processing units 30 and 30c in the radiation diagnostic apparatuses 1 and 1c.

As described above, in the fourth embodiment, the X-ray detector 300 as the radiation detection apparatus is commonly used for the pixels 310 _{11 to} 301 _JK arranged two-dimensionally and for each pixel in each column or each row. And a plurality of output buses BS _{1 to} BS _J provided. Each pixel includes an X-ray-charge converter, a charge-voltage converter, a comparator (radiation photon detector), a photon number counter (radiation photon counter), a qubit compressor and an output buffer (compressor) including. The X-ray-to-charge converter, the charge-voltage converter, and the comparator detect X-ray photons generated by the radiation generator. The photon number counter counts the number of X-ray photons detected by the X-ray-to-charge converter, the charge-voltage converter, and the comparator with a predetermined number of bits. The qubit compressor and the output buffer compress radiation detection data obtained by counting X-ray photons by a photon number counter. The qubit compressor and the output buffer use the bit string of the number of bits corresponding to the maximum bit position that is the most significant bit position, which is the most significant bit position, which is the predetermined bit data in the radiation detection data, as the effective signal bit, and the maximum bit The additional information corresponding to the position is added to the valid signal bit and output to each output bus.

  The qubit compressor and the output buffer include a most significant bit detector (bit position detection unit) and a noise bit sweeper (signal data extraction unit, incidental information generation unit). The most significant bit detector detects the maximum bit position. The noise bit sweeper extracts a bit string having the number of bits corresponding to the maximum bit position detected by the most significant bit detector from the maximum bit position of the radiation detection data as effective signal bits. The noise bit sweeper generates incidental information based on the bit position detected by the most significant bit detector.

  According to such an embodiment, the number of bits of data corresponding to the count value of the photon number counter in each pixel can be reduced with a very simple configuration. As a result, it is possible to reduce the number of wires arranged in the X-ray detector and the number of wires arranged between the X-ray detector and the image processing apparatus. It can also contribute to the miniaturization of the X-ray detector.

[Fifth Embodiment]
The configuration of the X-ray detector is not limited to the configuration described in the fourth embodiment. The X-ray detector according to the fifth embodiment can perform the above-described compression processing on radiation detection data obtained by detecting X-ray photons for each energy group. Hereinafter, the X-ray detection apparatus according to the fifth embodiment will be described focusing on differences from the fourth embodiment.

FIG. 21 shows a block diagram of a hardware configuration example of the X-ray detector according to the fifth embodiment. FIG. 21 shows only the configuration of the pixel 310 _i1 for convenience of explanation. In FIG. 21, the same components as those in FIG. In FIG. 21, it is assumed that the qubit compressor has the function of the compression unit according to the first embodiment.

The X-ray detector 300a according to the fifth embodiment includes J × K pixels 310a _{11 to} 310a _JK arranged two-dimensionally and an output bus BS ₁ for each of J columns provided in each column. to BS _J and, J-number of the output buffers ₃₂₀ 1 to 320 _J provided in each column, and it is configured to include an output bus BO. Each of the pixels 310a _{11 to} 310a _JK has the same configuration. In FIG. 21, the pixel 310a _i1 among the pixels 310a _i1 to 310a _iK in the i-th column, the output bus BS _i for the i-th column, and the output buffer 320 _i connected to the output bus BSi for the i-th column Only the output bus BO of the X-ray detector 300a connected to the output buffer 320 _i is shown. The pixels 310a _{i1 to} 310a _iK in the i-th column are connected to the output bus BS _i . The output buses BS _i and BO each have a bus width of (2 × (N + 2)) bits.

The pixel 310a _i1 includes an X-ray-to-charge converter 311 _i1 , a charge-voltage converter 312 _i1 , comparators 313a _i1 and 313b _i1 , a photon number counter 314a _i1 and 314b _i1, and a qubit compressor 315a _i1 and 315b. _i1 and output buffers 316a _i1 and 316b _i1 .

The comparator 313a _i1 receives the voltage pulse converted by the charge-voltage converter 312 _i1, and the preset upper threshold and first threshold. The comparator 313b _i1 receives the voltage pulse converted by the charge voltage converter 312 _i1 and the first threshold value and the lower threshold value set in advance. The first threshold is a value set between the upper limit threshold and the lower limit threshold. The first threshold value is configured to be able to be changed later, similarly to the upper limit threshold value and the lower limit threshold value.

The comparator 313a _i1 outputs the first detection pulse when the peak value (amplitude value) of the voltage pulse converted by the charge voltage converter 312 _i1 is equal to or lower than the upper limit threshold and equal to or higher than the first threshold. The comparator 313b _i1 outputs the second detection pulse when the peak value (amplitude value) of the voltage pulse converted by the charge voltage converter 312 _i1 is smaller than the first threshold value and equal to or larger than the lower limit threshold value. The upper threshold, the first threshold, and the lower threshold may be set in common for (J × K) pixels 310a _{11 to} 310a _JK , or may be set for each pixel in a predetermined region, Each may be set individually.

The photon number counter 314a _i1 receives the X-ray irradiation start timing signal from the control unit and the first detection pulse output from the comparator 313a _i1 . The photon number counter 314b _i1 receives the X-ray irradiation start timing signal from the control unit and the second detection pulse output from the comparator 313b _i1 . When the photon number counter 314a _i1 is notified of the X-ray irradiation start timing by the X-ray irradiation start timing signal, the photon number counter 314a _i1 initializes the count value, and then calculates the number of first detection pulses from the comparator 313a _i1. Start counting as a number. The photon number counter 314a _i1 outputs the count value to the qubit compressor 315a _i1 as (2 × N) -bit radiation detection data. When the photon number counter 314b _i1 is notified of the X-ray irradiation start timing by the X-ray irradiation start timing signal, the photon counter 314b _i1 initializes the count value and then determines the number of second detection pulses from the comparator 313b _i1. Start counting as a number. The photon number counter 314b _i1 outputs the count value to the qubit compressor 315b _i1 as (2 × N) -bit radiation detection data.

The qubit compressor 315a _i1 receives the X-ray irradiation end signal from the control unit and the radiation detection data output by the photon number counter 314a _i1 . The qubit compressor 315b _i1 receives the X-ray irradiation end signal from the control unit and the radiation detection data output by the photon number counter 314b _i1 . The qubit compressors 315a _i1 and 315b _i1 have the configuration shown in FIG.

When the end of the X-ray irradiation is notified by the X-ray irradiation end signal, the qubit compressor 315a _i1 takes in the radiation detection data at the time of the notification. The qubit compressor 315a _i1 compresses the captured (2 × N) -bit radiation detection data into (N + 2) -bit transmission data. When the end of the X-ray irradiation is notified by the X-ray irradiation end signal, the qubit compressor 315b _i1 takes in the radiation detection data at the time of the notification. The qubit compressor 315b _i1 compresses the captured (2 × N) -bit radiation detection data into (N + 2) -bit transmission data.

The output buffer 316a _i1 receives the first row selection signal from the control unit and the transmission data generated by the qubit compressor 315a _i1 . The output buffer 316b _i1 receives the first row selection signal from the control unit and the transmission data generated by the qubit compressor 315b _i1 . When selected by the first row selection signal, the output buffer 316a _i1 outputs the transmission data generated by the qubit compressor 315a _i1 to the output bus BS _i for the i-th column. When selected by the first row selection signal, the output buffer 316b _i1 outputs the transmission data generated by the qubit compressor 315b _i1 to the output bus BS _i for the i-th column.

X-ray - electric charge conversion unit _{311 i1,} charge-voltage converter _{312 i1,} and the comparator 313a _i1 realizes a function of the radiation photon detector 21. The X-ray-to-charge converter 311 _i1 , the charge-voltage converter 312 _i1 , and the comparator 313 b _i1 also realize the function of the radiation photon detector 21. The photon number counters 314a _i1 and 314b _i1 realize the function of the radiation photon counting unit 22, respectively. Each of the qubit compressors 315a _i1 and 315b _i1 realizes the function of the compression unit according to any one of the above-described embodiments or modifications thereof. This compression unit may realize the functions of the output buffers 316a _i1 and 316b _i1 .

In the X-ray detector 300a, similarly to the X-ray detector 300, transmission data generated in the pixel selected by the row selection signal among the pixels in each column is output to the output bus for each column. Accordingly, by selecting one of the pixels in each column one by one using the row selection signal, transmission data generated in the two-dimensionally arranged pixels 310a _{11 to} 310a _JK can be sequentially output.

In the i-th column, upon receiving an X-ray irradiation start timing signal from a control unit (not shown), the photon number counter 314a _i1 counts the X-ray photons of the energy group between the upper threshold and the first threshold, and the number of photons The counter 314b _i1 counts the X-ray photons of the energy group between the first threshold value and the lower threshold value. When the X-ray irradiation period ends, the qubit compressor 315a _i1 performs the above-described compression processing on the radiation detection data that is the count value of (2 × N) bits counted by the photon number counter 314a _i1 , The bit compressor 315b _i1 performs the above-described compression processing on the radiation detection data that is the count value of (2 × N) bits counted by the photon number counter 314b _i1 .

When the pixel 310a _i1 is selected by a row selection signal from a control unit (not shown), the output buffer 316a _i1 outputs the transmission data to the output bus BS _i for the i-th column, and the output buffer 316b _i1 outputs the transmission data. Output to the output bus BS _i for the i-th column.

  As described above, in the fifth embodiment, the voltage pulse as the detection result of the X-ray photon is input to the two comparators provided for each energy group, and the two photon number counters provided for each energy group. Counted.

  In addition, although the example which counts the X-ray photon of two energy groups was demonstrated in FIG. 21, 5th Embodiment is not limited to this. When counting X-ray photons of three or more energy groups, a plurality of threshold values are provided between the upper threshold value and the lower threshold value, and a comparator, a photon number counter, a qubit compressor, and an output buffer are provided for each energy group. By providing, it can be operated in the same manner as described above.

  FIG. 21 shows an example in which the qubit compressor and the output buffer are arranged for each energy group, and the bit width of the output bus for each column is arranged in proportion to the number of energy groups. However, the fifth embodiment is not limited to this. For example, the bit width of the output bus for each column is arranged for one energy group, and data of a plurality of energy groups is output in a time-sharing manner at different timings based on a timing control signal from the control unit. May be. In this case, the bus width of the output bus for each column and the output bus BO can be reduced.

  The X-ray detector 300a as described above can be applied to the radiation detection units 20 and 20c in the radiation diagnostic apparatuses 1 and 1c. In FIG. 21, the row direction and the column direction can be interchanged.

As described above, in the fifth embodiment, the X-ray detector 300a as the radiation detection apparatus is shared by the pixels 310a _{11 to} 301a _JK arranged two-dimensionally and for each column or each row of pixels. And a plurality of output buses BS _{1 to} BS _J provided. Each pixel includes, for each energy group, an X-ray-charge converter, a charge-voltage converter, a comparator (radiation photon detector), a photon number counter (radiation photon counter), a qubit compressor, and an output buffer. (Compressor). The X-ray-to-charge converter, the charge-voltage converter, and the comparator detect X-ray photons generated by the radiation generator. The photon number counter counts the number of X-ray photons detected by the X-ray-to-charge converter, the charge-voltage converter, and the comparator for a predetermined period. The qubit compressor and the output buffer compress radiation detection data obtained by counting X-ray photons by a photon number counter. The qubit compressor and the output buffer use the bit string of the number of bits corresponding to the maximum bit position that is the most significant bit position, which is the most significant bit position, which is the predetermined bit data in the radiation detection data, as the effective signal bit, and the maximum bit The additional information corresponding to the position is added to the valid signal bit and output to each output bus.

  According to such an embodiment, the X-ray detector that detects X-ray photons of two or more energy groups has a very simple configuration, and the number of bits of data corresponding to the count value of the photon number counter in each pixel. Can be reduced. As a result, it is possible to reduce the number of wires arranged in the X-ray detector and the number of wires arranged between the X-ray detector and the image processing apparatus. It can also contribute to the miniaturization of the X-ray detector.

[Sixth Embodiment]
The configuration of the X-ray detector is not limited to the configuration described in the fourth embodiment or the fifth embodiment. In the X-ray detector according to the sixth embodiment, one qubit compressor is provided for (J × K) pixels. Hereinafter, the X-ray detection apparatus according to the sixth embodiment will be described focusing on differences from the fourth embodiment.

  FIG. 22 shows a block diagram of a hardware configuration example of the X-ray detector according to the sixth embodiment. In FIG. 22, the same parts as those in FIG.

The X-ray detector 300b according to the sixth embodiment includes J × K pixels 310b _{11 to} 310b _JK arranged two-dimensionally and an output bus BS ₁ for each of J columns provided in each column. and to BS _J, and J-number of the output buffers ₃₂₀ 1 to 320 _J provided in each column, and an output bus BO, is configured to include a qubit compressor 315b. The pixels 310b _{i1 to} 310b _iK in the i-th column and the output buffer 320 _i are connected to the output bus BS _i . The output buffers 320 _{1 to} 320 _J are connected to the output bus BO. Each of the pixels 310b _{11 to} 310b _JK has the same configuration. The output buses BS _i and BO each have a bus width of (2 × N) bits.

For example, the pixel 310b _i1 has a configuration in which the qubit compressor 315 _i1 is omitted from the pixel 310 _i1 . That is, the pixel 310b _i1 includes an X-ray-to-charge converter 311 _i1 , a charge-voltage converter 312 _i1 , a comparator 313 _i1 , a photon number counter 314 _i1, and an output buffer 316 _i1 . .

The photon number counter 314 _i1 receives the X-ray irradiation start timing signal from the control unit and the detection pulse output from the comparator 313 _i1 . When the photon number counter 314 _i1 is notified of the X-ray irradiation start timing signal by the X-ray irradiation start timing signal, the photon number counter 314 _i1 initializes the count value and then sets the number of detection pulses from the comparator 313 _{i1 as} the number of X-ray photons. Start counting. The photon number counter 314 _i1 outputs the count value to the output buffer 316 _i1 as (2 × N) -bit radiation detection data.

The output buffer 316 _i1 receives the first row selection signal from the control unit and the radiation detection data from the photon number counter 314 _i1 . When selected by the first row selection signal, the output buffer 316 _i1 outputs the radiation detection data from the photon number counter 314 _i1 to the output bus BS _i for the i-th column.

Each of the output buffers 320 _{1 to} 320 _J outputs the radiation detection data output to each column to the output bus BO when selected by the selection signal of each column. The radiation detection data output to the output bus BO is compressed by the qubit compressor 315b. The configuration of the qubit compressor 315b has the configuration shown in FIG.

The X-ray-charge converter 311 _i1 , the charge-voltage converter 312 _i1 , and the comparator 313 _i1 realize the function of the radiation photon detector 21. The photon number counter 314 _i1 realizes the function of the radiation photon counting unit 22. The qubit compressor 315b realizes the function of the compression unit according to any one of the above embodiments or modifications thereof.

In the X-ray detector 300b, radiation detection data generated in the pixel selected by the row selection signal among the pixels in each column is output to the output bus for each column. Therefore, by selecting one of the pixels in each column one by one with the row selection signal, the radiation detection data generated in the two-dimensionally arranged pixels 310b _{11 to} 310b _JK can be sequentially output. . Then, compression processing is sequentially performed by the qubit compressor 315b provided at the final stage of the X-ray detector 300b, and is output as (N + 2) transmission data.

  The X-ray detector 300b as described above can be applied to the radiation detection units 20 and 20c in the radiation diagnostic apparatuses 1 and 1c. In FIG. 22, the row direction and the column direction can be interchanged.

As described above, in the sixth embodiment, the X-ray detector 300a serving as the radiation detection apparatus is shared by the pixels 310b _{11 to} 301b _JK arranged in a two-dimensional manner and for each pixel in each column or each row. A plurality of output buses BS _{1 to} BS _{J provided,} and a qubit compressor 315b (compression unit) configured to be connectable to the plurality of output buses BS _{1 to} BS _J are included. Each pixel includes an X-ray-to-charge converter, a charge-voltage converter, a comparator (radiation photon detector), and a photon number counter (radiation photon counter). The X-ray-to-charge converter, the charge-voltage converter, and the comparator detect X-ray photons generated by the radiation generator. The photon number counter counts the number of X-ray photons detected by the X-ray-to-charge converter, the charge-voltage converter, and the comparator for a predetermined period. The qubit compressor 315b receives radiation detection data obtained by counting X photons by a photon number counter via a plurality of output buses BS _{1 to} BS _J. The qubit compressor 315b uses a bit string having the number of bits corresponding to the maximum bit position on the lower side from the maximum bit position, which is the most significant bit position, which is predetermined bit data in the radiation detection data, as an effective signal bit, and sets the maximum bit position. Corresponding incidental information is appended to the valid signal bit and output.

  According to such an embodiment, the 2 × N-bit radiation detection data generated in each pixel is transmitted as it is inside the X-ray detector, and is compressed into (N + 2) -bit transmission data at its output unit, Output to an external image processing unit. Thereby, in the connection between the X-ray detector 300b and the image processing unit, in the case of parallel transmission in which one conductor is assigned to each bit in the cable, the number of conductors can be reduced, so the cost, thickness, There is an effect of improving flexibility. In addition, when the connection between the X-ray detector 300b and the image processing unit is wireless or wired serial transmission, the amount of data to be transmitted can be reduced, so that the transmission time can be shortened.

[Seventh Embodiment]
The above-described embodiment or its modification can be applied to an X-ray diagnostic apparatus as a radiation diagnostic apparatus having the following configuration. In the seventh embodiment, the radiation diagnostic apparatus according to the above-described embodiment or its modification is an X-ray diagnostic apparatus.

FIG. 23 is a perspective view of a schematic configuration of an X-ray diagnostic apparatus as a radiation diagnostic apparatus according to the seventh embodiment.
FIG. 24 shows a functional block diagram of a schematic configuration of the X-ray diagnostic apparatus according to the seventh embodiment. In FIG. 24, the same parts as those in FIG.

  The X-ray diagnostic apparatus 500 is a biplane X-ray diagnostic apparatus, and includes a front system X-ray imaging system (frontal imaging system) and a side system X-ray imaging system (lateral system imaging system). The front system X-ray imaging system has a first arm 530, and the side system X-ray imaging system has a second arm 532. With the two X-ray imaging systems, the X-ray diagnostic apparatus 500 can image the subject E placed on the top of the bed 540 from two directions.

  That is, the X-ray diagnostic apparatus 500 two-dimensionally detects the first X-ray generation unit 510 that irradiates the subject E with X-rays and the X-rays that have passed through the subject E, and the X-ray detection data. A first X-ray detection unit 520 that generates X-ray projection data based on the first X-ray projection data, and a first arm 530 that holds the first X-ray generation unit 510 and the first X-ray detection unit 520 facing each other. . In addition, the X-ray diagnostic apparatus 500 two-dimensionally detects the second X-ray generator 512 that irradiates the subject E with X-rays and the X-rays that have passed through the subject E, and the X-ray detection data. A second X-ray detection unit 522 that generates X-ray projection data based on the second X-ray projection data, and a second arm 532 that holds the second X-ray generation unit 510 and the first X-ray detection unit 520 facing each other. . Furthermore, the X-ray diagnostic apparatus 500 includes a top 542 on which the subject E is placed, a high voltage generator 550 that generates a high voltage necessary for X-ray irradiation in the first X-ray generator 510, and a second X-ray generator. A high voltage generation unit 552 that generates a high voltage necessary for X-ray irradiation in the unit 512.

  In addition, the X-ray diagnostic apparatus 500 includes a mechanism unit 560 that rotates and moves the first arm 530, the second arm 532, or the top plate 542, and the first X-ray detection unit 520 and the second X-ray detection unit 522. An image processing unit 570 that creates and stores an image based on the detection result, and a display unit 580 that displays the image created by the image processing unit 570 are included. In addition, the X-ray diagnostic apparatus 500 performs an input of setting conditions necessary for image generation, such as subject information and imaging conditions, and an operation unit 590 for inputting various commands, and for performing heartbeat synchronization imaging. An ECG electrode 592 and an ECG measurement unit 594 that collect an electrocardiogram (ECG) with respect to the subject E, and a system control unit 596 that collectively controls the above-described units of the X-ray diagnostic apparatus 500 are included.

  The first X-ray generation unit 510 includes an X-ray tube that irradiates the subject E with X-rays, an X-ray diaphragm that forms an X-ray weight (cone beam) with respect to the X-rays irradiated from the X-ray tube, It has. An X-ray tube is a vacuum tube that generates X-rays, and accelerates electrons emitted from a cathode (filament) by a high voltage to collide with a tungsten anode to generate X-rays. On the other hand, the X-ray diaphragm is located between the X-ray tube and the subject E and has a function of narrowing the X-ray beam irradiated from the X-ray tube to a predetermined irradiation field size. The second X-ray generator 512 has the same configuration as the first X-ray generator 510.

  The first X-ray detection unit 520 detects X-rays generated by the first X-ray generation unit 510 and transmitted through the subject E. The first X-ray detection unit 520 is configured by any of the X-ray detectors 300, 300a, and 300b. The first X-ray detection unit 520 generates radiation detection data by detecting the X-rays generated by the first X-ray generation unit 510 and transmitted through the subject E, and transmits the generated radiation detection data as described above. Compress to data. The compressed transmission data is output to the image processing unit 570. The second X-ray detection unit 522 detects X-rays generated by the second line generation unit 512 and transmitted through the subject E. Such a second X-ray detector 522 is configured by any of the X-ray detectors 300, 300a, and 300b. The second X-ray detection unit 522 generates radiation detection data by detecting the X-rays generated by the second X-ray generation unit 512 and transmitted through the subject E, and transmitted to the generated radiation detection data as described above. Compress to data. The compressed transmission data is output to the image processing unit 570.

  The mechanism unit 560 is configured to move the first X-ray generation unit 510, the first X-ray detection unit 520, the second X-ray generation unit 512, and the second X-ray detection unit 522 relative to each other in the body axis direction of the subject E. The top plate moving mechanism 561 that linearly moves the plate 542 in the body axis direction of the subject E, and the first arm 530 and the second arm 532 are rotated around the subject E, or in the body axis direction and the body axis direction. First / second arm rotation / movement mechanism 562 that moves in a right angle direction, and first / second arm / top board for controlling the top plate movement mechanism 561 and the first / second arm rotation / movement mechanism 562. Mechanism controller 563.

  The first / second arm / top plate mechanism control unit 563 determines a desired image magnification for the diagnosis target region of the subject E according to the control signal supplied from the system control unit 596. Set the distance (SID). The first / second arm / top plate mechanism control unit 563 controls the first / second arm rotation / movement mechanism 562 to rotate and move the first arm 530, the second arm 532, and the top plate 542. Control the direction, size and speed of movement.

  The image processing unit 570 includes a qubit restoration device corresponding to a qubit compressor included in an X-ray detector applied as the first X-ray detection unit 520 and an X-ray detector applied as the second X-ray detection unit 522. A qubit decompressor corresponding to the qubit compressor. The image processing unit 570 generates restoration data by performing the restoration processing on the transmission data from the first X-ray detection unit 520, and creates an image based on the generated restoration data. Further, the image processing unit 570 generates restoration data by performing the restoration processing on the transmission data from the second X-ray detection unit 522, and creates an image based on the generated restoration data.

  Display unit 580 includes a monitor such as a liquid crystal display or a CRT (Cathode Ray Tube) that displays an image created by image processing unit 570.

  The operation unit 590 is an interactive interface including an input device such as a keyboard, a trackball, a joystick, a mouse, a display panel, various switches, and the like. The operation unit 590 inputs subject information (subject ID) and imaging part (imaging target organ), X-ray irradiation conditions, imaging direction, imaging magnification (SID), and setting of imaging conditions such as an imaging position. Inputs a command signal to start shooting.

  The system control unit 596 includes a CPU (Central Processing Unit) and a storage circuit (not shown). The system control unit 596 temporarily stores information such as operator commands and shooting conditions supplied from the operation unit 590, and then performs overall system control such as image creation and control related to the moving mechanism based on the information. .

  The system control unit 596 determines the rotation speed of the first arm 530 and the second arm 532 and the relative angle between both arms according to the heart rate measured by the ECG measurement unit 594 via the ECG electrode 592. The system control unit 596 controls the first / second arm rotation / movement mechanism 562 based on the determined rotation speed and relative angle.

  The image processing unit 570 creates an image based on the transmission data from the first X-ray detection unit 520 and the transmission data from the second X-ray detection unit 520. The display unit 580 displays two images generated by the image processing unit 570.

  According to this embodiment, the radiation detection data is compressed in consideration of the characteristics of quantum noise and output to the image processing unit, and is restored in the image processing unit. Therefore, compression and restoration in accordance with the signal generation principle are performed. This makes it possible to provide an X-ray diagnostic apparatus that is unlikely to generate false images. Further, since the amount of data to be transmitted can be reduced, there are effects of reducing the cost of the transmission system and shortening the transmission time. Further, when the image data is temporarily stored in the storage device between the compression side and the decompression side, the necessary storage device capacity can be reduced.

[Eighth Embodiment]
The above-described embodiment or its modification can be applied to an X-ray CT apparatus as a radiation diagnostic apparatus having the following configuration. In the eighth embodiment, the radiation diagnostic apparatus according to the above-described embodiment or its modification is an X-ray CT apparatus.

  FIG. 25 shows a functional block diagram of a schematic configuration of an X-ray CT apparatus as a radiation diagnostic apparatus according to the eighth embodiment.

  X-ray diagnostic apparatus 600 includes a gantry device 610, a couch device 620, and a console device 630.

  The gantry device 610 is a device that collects radiation detection data by irradiating the subject E with X-rays, and includes a high voltage generation unit 611, an X-ray tube 612, an X-ray detector 613, and a data collection unit 614. The rotating frame 615 and the gantry driving unit 616 are provided. Furthermore, the gantry device 610 includes a data processing unit 617 that performs data processing on the radiation detection data.

  The high voltage generator 611 is a device that generates a high voltage and supplies the generated high voltage to the X-ray tube 612. The X-ray tube 612 is a vacuum tube that generates X-rays with a high voltage supplied from the high voltage generator 611, and the X-ray generated by the X-ray tube 612 is irradiated to the subject E.

  The X-ray detector 613 is a detector that detects radiation detection data indicating the intensity distribution of X-rays that have been irradiated from the X-ray tube 612 and transmitted through the subject E. That is, the X-ray detector 613 detects radiation detection data indicating the degree of X-ray absorption that occurs inside the subject E.

  The rotating frame 615 supports the X-ray tube 612 and the X-ray detector 613 so as to face each other with the subject E interposed therebetween. The gantry driving unit 616 is a driving device that rotates the rotary frame 615 to rotate the X-ray tube 612 and the X-ray detector 613 on a circular orbit around the subject E.

  The data collection unit 614 is a DAS (Data Acquisition System) and collects radiation detection data detected by the X-ray detector 613. Specifically, the data collection unit 614 collects radiation detection data corresponding to each X-ray irradiation direction from the X-ray tube 612. Then, the data collection unit 614 outputs the collected radiation detection data to the data processing unit 617.

  The data processing unit 617 has the function of a compression unit according to any one of the above embodiments or modifications thereof. The data processing unit 617 generates transmission data by performing the above compression processing on the radiation detection data, and transmits the generated transmission data to the console device 630.

  The couch device 620 is a device on which the subject E is placed, and includes a couchtop 622 and a couch driving device 621 as shown in FIG. The top plate 622 is a bed on which the subject E is placed, and the bed driving device 621 rotates the subject E by moving the top plate 622 in the body axis direction (Z-axis direction) of the subject E. Move into frame 615.

  The console device 630 is a device that accepts an operation of the X-ray CT apparatus by an operator and reconstructs a tomographic image from the projection data group collected by the gantry device 610. The console device 630 includes an input device 631, a display device 632, a scan control unit 633, a data second processing unit 634, an image storage unit 635, and a system control unit 636.

  The input device 631 includes a mouse, a keyboard, buttons, a trackball, a joystick, and the like for an operator such as a doctor or engineer who operates the X-ray CT apparatus to input various instructions, and receives various commands received from the operator. Then, the data is transferred to the system control unit 636.

  The display device 632 has a monitor for displaying a GUI (Graphical User Interface) for receiving an instruction from the operator via the input device 631 and displaying a reconstructed image stored in the image storage unit 635. .

  The scan control unit 633 controls operations of the high voltage generation unit 611, the gantry driving unit 616, the data collection unit 614, the data processing unit 617, and the bed driving device 621. Accordingly, the scan control unit 633 controls the X-ray scan processing of the subject E in the gantry device 610, the collection processing of the radiation detection data group, and the data processing for the radiation detection data group.

  Specifically, the scan control unit 633 performs X-ray scanning by irradiating the X-ray tube 612 continuously or intermittently while rotating the rotating frame 615. For example, the scan control unit 633 executes a helical scan that performs imaging by continuously rotating the rotating frame 615 while moving the top plate 622. Alternatively, the scan control unit 633 executes a conventional scan in which imaging is performed by rotating the rotating frame 615 once or continuously while the position of the subject E is fixed.

  The data second processing unit 634 has a function of a restoration unit corresponding to the compression unit according to any one of the above-described embodiments or modifications thereof. The data second processing unit 634 generates restoration data by performing the restoration processing on the transmission data from the data processing unit 617, and reconstructs a tomographic image (X-ray CT image) based on the generated restoration data. A processing unit that performs configuration processing. That is, the data second processing unit 634 performs X-ray CT image reconstruction processing using the transmission data received from the data processing unit 617. The image storage unit 635 stores the X-ray CT image generated by the data second processing unit 634.

  The system control unit 636 performs overall control of the X-ray CT apparatus by controlling operations of the gantry device 610, the couch device 620, and the console device 630. Specifically, the system control unit 636 controls the collection processing of the radiation detection data group by the gantry device 610 and the couch device 620 by controlling the scan control unit 633. Further, the system control unit 636 controls the compression processing on the radiation detection data group by controlling the data processing unit 617 via the scan control unit 633. Further, the system control unit 636 controls the image reconstruction processing by the console device 630 by controlling the data second processing unit 634. In addition, the system control unit 636 controls to read the reconstructed image from the image storage unit 635 and display the reconstructed image on a monitor included in the display device 632.

  Note that the X-ray detector 613 may be provided with the function of the compression unit according to the above-described embodiment for performing the compression process on the radiation detection data or the modification thereof, instead of the data processing unit 617. Such an X-ray detector 613 is configured by any of the X-ray detectors 300, 300a, and 300b described above.

  According to this embodiment, as in the seventh embodiment, the radiation detection data is compressed and restored in consideration of the characteristics of the quantum noise, so that compression and restoration in accordance with the signal generation principle becomes possible. Thus, it is possible to provide an X-ray diagnostic apparatus that is unlikely to generate a false image. Further, since the amount of data to be transmitted can be reduced, there are effects of reducing the cost of the transmission system and shortening the transmission time. Further, when the image data is temporarily stored in the storage device between the compression side and the decompression side, the necessary storage device capacity can be reduced.

  In addition, the compression part which concerns on said embodiment or its modification is not limited to said structure. In addition, the restoration unit according to the embodiment or the modification thereof is not limited to the above configuration.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

DESCRIPTION OF SYMBOLS 1,1c Radiation diagnostic apparatus 10 Radiation generation part 20, 20c Radiation detection part 21 Radiation photon detection part 22 Radiation photon counting part 23c Data compression part 24c Reversible compression part 30, 30c Image processing part 31, 420 Image creation part 32c Data restoration part 33c reversible restoration unit 40 display control unit 50 display unit 100 compression unit 110 bit position detection unit 111 shift up unit 112 most significant bit detection unit 120 signal data extraction unit 121 upper bit extraction unit 122 shift down bit number calculation unit 123 shift down unit 130 Additional information generation unit 200, 200a Restoration unit 210 Bit length detection unit 220 Additional bit length calculation unit 230, 230a Restored data generation unit 231 Shift up unit 232 Data addition unit 233 Additional data storage unit 234 Random number generation unit 300, 300a, 300b X-ray detector 31 0 _{11 to} 310 _JK , 310a _{11 to} 310a _JK , 310b _{11 to} 310b _JK pixel 311 _i1 X-ray to charge converter 312 _i1 charge voltage converter 313 _i1 , 313a _i1 comparator 314 _i1 , 314a _i1 photon number counter 315 _i1 , 315a _i1 , 315b _i1 , 315b quantum bit compressor 316 _i1 , 316a _i1 , 316b _i1 , 320 _{1 to} 320 _J output buffer 317 _i1 , 411 most significant bit detector 318 _i1 noise bit sweeper 400 image processor 410 quantum bit reconstruction Unit 412 adder 413 shift register 414 additional data generator 430 image storage unit BO, BS _{1 to} BS _J output bus

Claims (20)

A radiation generator that generates radiation photons;
A radiation photon detector that generates radiation detection data by detecting the radiation photons generated by the radiation generator and transmitted through the subject, and counting the detected radiation photons by a predetermined number of bits;
In the radiation detection data, a bit string of the number of bits corresponding to the maximum bit position on the lower side from the maximum bit position which is the most significant bit position which is predetermined bit data is set as a valid signal bit, and incidental information corresponding to the maximum bit position Is attached to the effective signal bit and output,
The effective signal bit and the incidental information are received, the bit length of the effective signal bit is detected, and additional data corresponding to the additional bit length calculated from the detected bit length and the incidental information is obtained as the effective signal bit. A restoration unit for generating restoration data of the radiation detection data by adding to the lower side of
An image creating unit that creates an image based on the restored data generated by the restoring unit;
A radiation diagnostic apparatus comprising: The compression unit is
A bit position detector for detecting the maximum bit position;
A signal bit extraction unit that extracts a bit string of the number of bits corresponding to the maximum bit position detected by the bit position detection unit as the effective signal bit from the maximum bit position of the radiation detection data;
Based on the maximum bit position detected by the bit position detection unit, an auxiliary information generation unit that generates the auxiliary information;
The radiation diagnostic apparatus according to claim 1, comprising: The incidental information generation unit
The radiation diagnostic apparatus according to claim 2, wherein information indicating parity of the maximum bit position is generated as the incidental information. The bit position detector is
A shift-up unit that shifts the radiation detection data to the upper side;
Most significant bit detection for detecting whether the shift-up data obtained by shifting the radiation detection data to the upper side by the shift-up unit or the data of the most significant bit of the radiation detection data is the predetermined bit data And
Including
The maximum bit position is detected based on the number of upshift bits by the upshift unit when it is detected by the most significant bit detection unit that the data of the most significant bit is the predetermined bit data. The radiation diagnostic apparatus according to claim 2 or 3. The signal bit extraction unit includes:
A shift-down bit number calculation unit for calculating a shift-down bit number to be shifted to the lower side based on the shift-up bit number;
A shift-down unit that shifts the shift-up data downward by the number of shift-down bits calculated by the shift-down bit number calculation unit;
The radiological diagnostic apparatus according to claim 4, comprising: The radiation according to claim 4 or 5, wherein the incidental information generation unit generates the incidental information by extracting a least significant bit when the number of upshift bits is expressed in binary. Diagnostic device. The restoration unit
A bit length detector that detects the bit length of the valid signal bit by detecting the maximum bit position in the valid signal bit;
Based on the bit length detected by the bit length detection unit and the incidental information, an additional bit length calculation unit that calculates an additional bit length that is a bit length to be added to the lower side of the valid signal bits;
The restored data is added by adding predetermined additional data to the lower side of the shift data obtained by shifting the effective signal bit to the upper side by the additional bit length calculated by the additional bit length calculation unit. A restoration data generation unit to generate,
The radiation diagnostic apparatus according to any one of claims 1 to 6, wherein the radiation diagnostic apparatus includes: The predetermined additional data is data in which each bit data is all 0 data, each bit data is all 1 data, only the most significant bit data is 1 and other data is 0, the most significant data The radiological diagnostic apparatus according to claim 7, wherein only the bit data is 0 and the other data is 1 or random numbers. The radiation detection data is (2 × N) (N is a positive integer) bit data,
The radiation diagnostic apparatus according to any one of claims 2 to 8, wherein the compression unit uses a bit string of upper (N + 1) bits of the radiation detection data as the effective signal bits. The radiological diagnostic apparatus according to claim 7 , wherein the additional bit length is calculated by adding the bit length and the incidental information. The radiation detection data is (2 × N) (N is a positive integer) bit data,
The said compression part makes the effective signal bit the bit string of the high-order (N + 1 + (alpha)) (1 <= alpha <(N-1), (alpha) is an integer) bit of the said radiation detection data. The radiation diagnostic apparatus according to any one of 8. The radiological diagnostic apparatus according to claim 10 , wherein the additional bit length is calculated by adding the bit length and the incidental information and subtracting (2 × α) from the addition result. A radiation photon detector that detects radiation photons generated by the radiation generator and transmitted through the subject;
A radiation photon counting unit that counts radiation photons detected by the radiation photon detection unit with a predetermined number of bits;
A compression unit that compresses radiation detection data obtained by counting the radiation photons by the radiation photon counting unit;
Including
The compression unit uses a bit string of the number of bits corresponding to the maximum bit position on the lower side from the maximum bit position which is the most significant bit position which is predetermined bit data in the radiation detection data as a valid signal bit, and the maximum bit position The radiation detection apparatus according to claim 1, wherein incidental information corresponding to is attached to the effective signal bit and output. A plurality of pixels arranged two-dimensionally;
A plurality of output buses provided in common for each column or each row of pixels;
Including
Each pixel is
A radiation photon detector that detects radiation photons generated by the radiation generator and transmitted through the subject;
A radiation photon counting unit that counts radiation photons detected by the radiation photon detection unit with a predetermined number of bits;
A compression unit that compresses radiation detection data obtained by counting the radiation photons by the radiation photon counting unit;
Including
The compression unit uses a bit string of the number of bits corresponding to the maximum bit position on the lower side from the maximum bit position which is the most significant bit position which is predetermined bit data in the radiation detection data as a valid signal bit, and the maximum bit position Ancillary information corresponding to the above is added to the effective signal bit and output to each output bus. A plurality of pixels arranged two-dimensionally;
A plurality of output buses provided in common for each column or each row of pixels;
Including
Each pixel is for each energy group
A radiation photon detector that detects radiation photons generated by the radiation generator and transmitted through the subject;
A radiation photon counting unit that counts radiation photons detected by the radiation photon detection unit with a predetermined number of bits;
A compression unit that compresses radiation detection data obtained by counting the radiation photons by the radiation photon counting unit;
Including
The compression unit uses a bit string of the number of bits corresponding to the maximum bit position on the lower side from the maximum bit position which is the most significant bit position which is predetermined bit data in the radiation detection data as a valid signal bit, and the maximum bit position Ancillary information corresponding to the above is added to the effective signal bit and output to each output bus. A plurality of pixels arranged two-dimensionally;
A plurality of output buses provided in common for each column or each row of pixels;
A compression unit configured to be connectable to the plurality of output buses;
Including
Each pixel is
A radiation photon detector that detects radiation photons generated by the radiation generator and transmitted through the subject;
A radiation photon counting unit that counts radiation photons detected by the radiation photon detection unit with a predetermined number of bits;
Including
In the radiation detection data obtained by counting the radiation photons by the radiation photon counting unit, the compression unit shifts the maximum bit position which is the most significant bit position which is predetermined bit data from the maximum bit position on the lower side. A radiation detection apparatus, wherein a bit string having a corresponding number of bits is used as an effective signal bit, and additional information corresponding to the maximum bit position is output along with the effective signal bit. The compression unit is
A bit position detector for detecting the maximum bit position;
A signal bit extraction unit that extracts a bit string of the number of bits corresponding to the maximum bit position detected by the bit position detection unit as the effective signal bit from the maximum bit position of the radiation detection data;
Based on the maximum bit position detected by the bit position detection unit, an auxiliary information generation unit that generates the auxiliary information;
The radiation detection apparatus according to claim 13, comprising: A bit position detection step of detecting a maximum bit position which is a most significant bit position which is predetermined bit data in radiation detection data obtained by counting radiation photons;
A signal bit extraction step of extracting a bit string of the number of bits corresponding to the maximum bit position detected in the bit position detection step as an effective signal bit from the maximum bit position of the radiation detection data;
Ancillary information generating step for generating incidental information to be added to the effective signal bit based on the maximum bit position detected in the bit position detecting step;
The radiation detection data processing method characterized by including. The radiation detection data processing method according to claim 18, wherein in the incidental information generation step, information indicating parity of the maximum bit position is generated as the incidental information. A bit length detection step of detecting a bit length of the valid signal bit by detecting the maximum bit position in the valid signal bit;
An additional bit length calculating step of calculating an additional bit length, which is a bit length to be added to the lower side of the valid signal bit, based on the bit length detected in the bit length detecting step and the incidental information;
The effective signal bits are shifted to the upper side by the additional bit length calculated in the additional bit length calculating step, and predetermined additional data is added to the lower side of the shift data obtained by the shifting. A restoration data generation step for generating restoration data of radiation detection data;
The radiation detection data processing method according to claim 18 or 19, characterized by comprising:

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