CN102944890B - PS-PMT (position sensitive-photomultiplier tube) based detector signal readout method and system - Google Patents
PS-PMT (position sensitive-photomultiplier tube) based detector signal readout method and system Download PDFInfo
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Abstract
The invention discloses a multianode PS-PMT (position sensitive-photomultiplier tube) based detector signal readout method and system. The signal readout method comprises the following steps of: converting M*N array signals output by a detector into M channels of signals and N channels of signals on orthogonal directions by a symmetry charge distribution circuit; respectively carrying out amplification forming and digital integration processing on the M channels of signals and the N channels of signals to generate the integral numerical values of the processed M channels and N channels; transferring the integral numerical values of the processed M channels and N channels to a computer side; and calculating the position of the center of gravity in each channel direction with a local center of gravity method so as to determine the action position of a gamma photon on the detector. According to the scheme of the invention, noise brought by invalid channels can be eliminated in a process of obtaining the position information of a gamma example, and the positioning precision of the detector (especially a big-array output detector) is improved.
Description
Technical field
The present invention relates to nuclear detection technology and medicine imaging technique field, and in particular to based on the detector signal reading method of multianode location-sensitive photomultiplier and system.
Background technology
At present based on scintillation crystal and photomultiplier (photomultiplier tube, PMT) nuclear detection technology has been widely used in positron emission computerized tomography (Positron EmissionComputed Tomography, and single photon emission computerized tomography (Single PhotonEmission Computed Tomography, SPECT) the nuclear medicine field that is representative PET).
As the start-up procedure in imaging process, the spatial resolving power of detector directly determines the spatial resolution index of imaging system, early stage detector adopts independent crystal to be coupled one to one with single pass PMT, this mode principle is simple, but because PMT size causes more greatly resolution not high and geometry arrangement bothers very much, the enormous amount of required PMT, with high costs simultaneously.Occurred that the multiple PMT of use forms array and is coupled with crystal array subsequently, utilize the distribution of passage of scintillation light to realize the position resolution of crystal array, spatial resolution increases.Along with the development of PMT technology, some multianode position sensitive photo-multiplier tubes (Position Sensitive Photomultipler tube, PS-PMT) being specifically designed to position sensing are developed out (H8500, H9500 etc. as Hamamatsu).This kind of PS-PMT output anode is made up of array usually, and compared with single pass PMT, the size of array element is less, and spatial resolving power is higher; Simultaneously the peripheral dead band of PS-PMT is less, adopt multiple PS-PMT form more large area array time geometry arrangement simply too much.
No matter be adopt single PS-PMT or PS-PMT array, the array of the output of a detector normally M × N, the signal of this M × N channel reads separately and carries out amplifications shapings process of etc.ing respectively by a simplest and resolution characteristic the best way exactly, but such needed for data-acquisition system be undoubtedly very huge and expensive.By effective signal reading method, M × N channel signal is reduced, while reduction data-acquisition system burden, higher spatial resolving power can be obtained.
M × N array signal is normally converted to M channel signal on orthogonal directions and N channel signal by scheme of the prior art.In each direction, respectively to corresponding M(or N) channel signal carries out enlarge leadingly process, again by adding circuit by each channel signal in proportion weight distribute, be transferred in shaping amplifier and form process, be transferred to a calculating board carrying out analog to digital conversion and barycentric coordinates again, wherein, this adding circuit realizes different weights by choosing different resistance values.
For scheme of the prior art, participate in coordinate calculate channel signal adopt weighting summation, corresponding signal noise is also M(or N) passage superposition result.Therefore, output array is larger, and the noise of introducing is more, and the resolution characteristic of detector is poorer, poor for the expansibility of the extensive detector program.In addition, the distribution of each channel signal realizes different weight allocation by choosing different resistance values, and resistance device has certain trueness error, thus it is linear relatively poor to cause in detector plane image.
Therefore, a kind of in the process of acquisition γ example positional information, effectively can removal the noise that non-valid channel brings, improve the scheme of the positioning precision of detector (especially large array output detector) is needed in the industry badly.
Summary of the invention
In view of the problems referred to above of the prior art, the invention provides a kind of detector signal reading method based on multianode location-sensitive photomultiplier and system.
Detector signal reading method based on multianode location-sensitive photomultiplier of the present invention, comprising:
Step S1: the M × N array signal exported by this detector by asymmetrical charge distributor circuit is converted to M channel signal on orthogonal directions and N channel signal;
Step S2: respectively amplification is carried out to this M channel signal and N channel signal and be shaped and digital integration process, generate the integrated value of M passage and N channel;
Step S3: according to the integrated value of this M passage and N channel, adopts local gravity model appoach, calculates the centre of gravity place in each channel direction, thus determine γ photon active position on the detector.
Signal read-out system based on multianode position sensitive photo-multiplier tube detector of the present invention, comprising:
Asymmetrical charge distributor circuit, the M × N array signal for being exported by this detector is converted to M channel signal on orthogonal directions and N channel signal;
Processing module, being shaped and digital integration process for carrying out amplification to this M channel signal and N channel signal respectively, generating the integrated value of M passage and N channel;
Computing module, for the integrated value according to this M passage and N channel, adopts local gravity model appoach, calculates the centre of gravity place in each channel direction, thus determine γ photon active position on the detector.
The signal reading method that the present invention proposes effectively can remove the noise that non-valid channel brings in the process obtaining γ example positional information, improves the positioning precision of detector (especially large array output detector).
Accompanying drawing explanation
Fig. 1 a is the process flow diagram of the detector signal reading method based on PS-PMT of the present invention,
Fig. 1 b is depicted as the concrete schematic diagram of the detector signal reading method based on PS-PMT;
Fig. 2 is the schematic diagram of the SCD circuit in technical solution of the present invention;
Fig. 3 is the schematic diagram of the digital integration in technical solution of the present invention;
Fig. 4 is the schematic diagram of the channel screen in technical solution of the present invention;
Fig. 5 is the detector scatter diagram of the embodiment of the present invention.
Embodiment
The exemplary embodiments embodying feature & benefits of the present invention will describe in detail in the following description.Be understood that the present invention can have various changes in different embodiments, it neither departs from the scope of the present invention, and explanation wherein and appended accompanying drawing are the use when explain in itself, and is not used to limit the present invention.
The invention provides a kind of detector signal reading method based on PS-PMT, the method can remove the noise that non-valid channel brings in the process obtaining γ example positional information, and improves the positioning precision of detector (especially large array output detector).
Be depicted as the process flow diagram of the detector signal reading method based on PS-PMT of the present invention see Fig. 1 a, Fig. 1 b is depicted as the concrete schematic diagram of the method.Composition graphs 1a and Fig. 1 b is described, and the method comprises:
Step S1: the M × N array signal exported by this detector by asymmetrical charge distributor circuit is converted to M channel signal on orthogonal directions and N channel signal.
In this step, if the output anode of detector is the anode signal of M × N array, (wherein, M and N is natural number, is that 40, M is relevant with the performance of detector with the value of N if M is 50, N.) by symmetrical SCD circuit (Symmetric Charged Division, charge distribution circuit) (being illustrated in figure 2 the schematic diagram of SCD circuit), be converted into the M channel signal (A on orthogonal directions
1, A
2..., A
m) and N channel signal (B
1, B
2..., B
n).
Step S2: respectively amplification is carried out to this M channel signal and N channel signal and be shaped and digital integration process, the M passage after generating process and the integrated value of N channel.
In this step, respectively to A
1, A
2..., A
mand B
1, B
2..., B
nsignal is done to amplify and is shaped and digital integration process (as shown in Figure 3), obtains the integrated value y of each passage
1, y
2..., y
mand x
1, x
2..., x
n.See Fig. 3, the waveform of simulating signal after amplifying and being shaped a) being depicted as detector output in figure, digital integration is as the b in figure) shown in, by certain clock period, this waveform is divided into the equally spaced time interval exactly, and to the process that the range value of waveform in each time interval is sued for peace.The channel signal exported for detector is for voltage signal V, then integration is carried out to this voltage signal V and be divided into the equally spaced time interval by the waveform of voltage signal V, and to the process that the range value of the waveform of the voltage signal V in each time interval is sued for peace.
Step S3: the integrated value of this M passage after above-mentioned process and N channel is transferred to computer terminal, adopts local gravity model appoach, calculates the centre of gravity place in each channel direction, thus determine γ photon active position on the detector.
In this step, by integrated value y
1, y
2..., y
mand x
1, x
2..., x
nbe transferred to computing machine, adopt TCOG algorithm to calculate barycentric coordinates, thus determine the active position of γ example in detection.With x
1, x
2..., x
nfor example, adopt the calculation process of TCOG algorithm as follows:
1) to N channel integrated value summation ∑ x
i=x
1+ ... + x
n, to get and the certain proportion that is worth is threshold value x
0, computing formula is: x
0=(∑ x
i)/b; Wherein the value of b can set according to detection demand.
2) channel screen (as Fig. 4): by each passage integrated value (x
i) and threshold value (x
0) compare, if x
i> x
0, then x is made
ifor x
i-x
0; If x
i≤ x
0, then x is made
ibe 0;
As shown in Figure 4, in Fig. 4 a) is the distribution plan of 24 channel signal integrated values in a direction, and wherein the signal amplitude of edge gateway is very little, is mainly noise, the threshold value that represented by dotted arrows calculates; B in Fig. 4) for threshold value relatively after the distribution plan of 24 channel signal integrated values, from figure can see to be compared by threshold value, edge gateway signal noise is disallowable, only has the channel signal of regional area to be retained participant position calculating.
3) barycentric coordinates calculate.
Computing formula for the barycentric coordinates X on x direction is: X=(∑ i × x
i)/∑ x
i, wherein i is channel number, and for x direction, i value is 1 to N, x
ifor to should the integrated value of passage.
The channel signal in y direction is processed identical with x direction with the method for center of gravity calculation, repeat no more herein.
Based on above-mentioned technical scheme, the embodiment of a kind of signal reading method based on PS-PMT detector of the present invention is as follows:
Detector by NaI scintillation crystal array (75 × 75) with 3 × 3 H8500(Hamamatsu) photomultiplier tube array forms.Crystal unit is 1.8mm × 1.8mm × 6mm, crystal interval 0.2mm, and the size of whole detector output anode array is 24 × 24.Under Na-22 source is irradiated, the barycentric coordinates of the example at every turn detected are calculated according to this programme, and draw the scatter diagram obtained as shown in Figure 5, as shown in Figure 5, on scatter diagram, separately situation between points reflects the spatial resolving power of detector, can find out that the present invention can have good spatial resolving power from this figure.
The beneficial effect of technical scheme of the present invention is as follows:
(1) in technical solution of the present invention, the object of channel screen is the digital integration value of each passage, and the calculating carried out also is linear numerical evaluation, decreases the noise that electronic devices and components under analog signal processing mode bring, improves the performance of detector.
(2) compared with prior art, the channel screen in technical solution of the present invention and barycentric coordinates calculate and all complete at computer terminal, and avoid the limitation of electronics process thus, expansibility is strong.
(3) threshold value in technical solution of the present invention sets at computer terminal, makes the debugging of detector more convenient and flexible.
In addition, the y that TCOG calculates is participated in technical solution of the present invention
1, y
2..., y
mand x
1, x
2..., x
nit is the digital integration value to respective channel signal waveform.Because the waveform of each channel signal is basically identical, the peak value of waveform and digital integration are worth proportional, and therefore as an alternative, the peak value also directly can choosing respective channel signal waveform carries out the calculating of local gravity model appoach.
Present invention also offers a kind of signal read-out system based on multianode position sensitive photo-multiplier tube detector, comprising:
Asymmetrical charge distributor circuit, the M × N array signal for being exported by this detector is converted to M channel signal on orthogonal directions and N channel signal;
Processing module, being shaped and digital integration process for carrying out amplification to this M channel signal and N channel signal respectively, generating the integrated value of M passage and N channel;
Computing module, for the integrated value according to this M passage and N channel, adopts local gravity model appoach, calculates the centre of gravity place in each channel direction, thus determine γ photon active position on the detector.
Wherein, this computing module can be a computing machine, to avoid the limitation of electronics process, improves expansibility.
The change that those skilled in the art do when should recognize the scope and spirit of the present invention disclosed in the claim do not departed from appended by the present invention and retouching, within the protection domain all belonging to claim of the present invention.
Claims (8)
1., based on a detector signal reading method for multianode location-sensitive photomultiplier, it is characterized in that, comprising:
Step S1: the M × N array signal exported by this detector by asymmetrical charge distributor circuit is converted to M channel signal on orthogonal directions and N channel signal;
Step S2: respectively amplification is carried out to this M channel signal and N channel signal and be shaped and digital integration process, generate the integrated value of M passage and N channel;
Step S3: according to the integrated value of this M passage and N channel, adopts local gravity model appoach, calculates the centre of gravity place in each channel direction, thus determine γ photon active position on the detector.
2. method according to claim 1, is characterized in that, the integrated value of this M passage and N channel is transferred to computer terminal, is calculated the coordinate of the center of gravity in each channel direction by computer terminal.
3. method according to claim 1, it is characterized in that, the computing method of this local gravity model appoach are: for the M channel signal on same direction or N channel signal, get a predetermined ratio of the cumulative sum value of each passage integrated value as threshold value, each passage integrated value and this threshold value are compared, if a passage integrated value is less than this threshold value, then direct this passage integrated value is set to zero; If a passage integrated value is greater than this threshold value, then get the integrated value of difference as this passage of this passage integrated value and this threshold value; According to the integrated value of each passage, calculate the coordinate of the center of gravity in each channel direction.
4. method according to claim 3, is characterized in that, the method calculating the barycentric coordinates X in a channel direction is wherein: X=(∑ i × x
i)/∑ x
i, wherein i is channel number, x
ifor to should the integrated value of passage.
5., based on a signal read-out system for multianode position sensitive photo-multiplier tube detector, it is characterized in that, comprising:
Asymmetrical charge distributor circuit, the M × N array signal for being exported by this detector is converted to M channel signal on orthogonal directions and N channel signal;
Processing module, being shaped and digital integration process for carrying out amplification to this M channel signal and N channel signal respectively, generating the integrated value of M passage and N channel;
Computing module, for the integrated value according to this M passage and N channel, adopts local gravity model appoach, calculates the centre of gravity place in each channel direction, thus determine γ photon active position on the detector.
6. system according to claim 5, is characterized in that, described computing module is a computing machine, and the integrated value of this M passage and N channel is transferred to this computing machine, by the coordinate of the center of gravity in each channel direction of this computer calculate by this processing module.
7. system according to claim 5, it is characterized in that, the computing method of this local gravity model appoach are: for the M channel signal on same direction or N channel signal, get a predetermined ratio of the cumulative sum value of each passage integrated value as threshold value, each passage integrated value and this threshold value are compared, if a passage integrated value is less than this threshold value, then direct this passage integrated value is set to zero; If a passage integrated value is greater than this threshold value, then get the integrated value of difference as this passage of this passage integrated value and this threshold value; According to the integrated value of each passage, calculate the coordinate of the center of gravity in each channel direction.
8. system according to claim 7, is characterized in that, the method calculating the barycentric coordinates X in a channel direction is wherein: X=(∑ i × x
i)/∑ x
i, wherein i is channel number, x
ifor to should the integrated value of passage.
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| CN103645491B (en) * | 2013-11-25 | 2016-12-07 | 中国科学院高能物理研究所 | Radioactive source localization method, Apparatus and system |
| CN104539243B (en) * | 2014-12-12 | 2017-11-21 | 北京永新医疗设备有限公司 | The position read out device of gamma rays and the position read-out system of gamma rays |
| CN106580359B (en) * | 2016-12-02 | 2020-04-14 | 中国科学院深圳先进技术研究院 | Detector signal processing method and device |
| WO2019000389A1 (en) | 2017-06-30 | 2019-01-03 | Shanghai United Imaging Healthcare Co., Ltd. | System and method for positron emission tomography |
| CN107874773B (en) * | 2017-10-16 | 2020-12-08 | 中派科技（深圳）有限责任公司 | Photon detection method, device, equipment and system and storage medium |
| CN110426730B (en) * | 2019-07-19 | 2022-11-01 | 东软医疗系统股份有限公司 | Signal reading circuit, signal reading method and device |
| CN113850093B (en) * | 2021-09-08 | 2024-05-14 | 中国原子能科学研究院 | Positioning method, detection device and storage medium |
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| Title |
|---|
| 《多阳极光电倍增管读出ASIC设计》;肖腾飞;《核电子学与探测技术》;CNKI;20120930;第32卷(第9期);1004页 * |
| 多阳极位置灵敏光电倍增管位置读出电路的设计实现;赵翠兰等;《原子核物理评论》;20100331;第27卷(第01期);64-66页 * |
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