CN102068272A

CN102068272A - Efficient computed tomography (CT) detector

Info

Publication number: CN102068272A
Application number: CN 201110046955
Authority: CN
Inventors: 朱险峰
Original assignee: Individual
Current assignee: Mudanjiang Medical University
Priority date: 2011-02-28
Filing date: 2011-02-28
Publication date: 2011-05-25
Anticipated expiration: 2031-02-28
Also published as: CN102068272B

Abstract

The invention relates to a medical equipment computed tomography (CT) machine, in particular to a detector of a CT machine. The detector comprises a main substrate (1) and a plurality of detection units (2), wherein each detection unit (2) comprises a crystal (21) and a photoelectric diode (22) respectively; the receiving surface (23) of the photoelectric diode (22) is tightly jointed with one surface of the crystal (21); and the detection units (2) are arranged in the same direction and are fixed on the main substrate (1) along the direction, which is parallel to X rays, of the receiving surface (23) of the photoelectric diode (22). The CT machine can receive smaller signal pixel and higher signal under the condition of not enhancing the intensity of X rays and changing other structures; pixel size is a half of that of the conventional detector; receiving efficiency is higher and is more than a hundred times that of the conventional detector; the receiving area of the photoelectric diode is expanded by more than 20 times; the detection size of a detector unit is reduced and a detected signal is not reduced; signal to noise ratio is higher; and the quality of a formed CT image is higher.

Description

Efficient CT detector

Technical field

The present invention relates to medical equipment CT machine, be specifically related to the detector of CT machine.

Background technology

Detector is the core component of CT machine, and the quality of detector directly determines the most critical technical specification of CT equipment, directly has influence on imaging effect.The detector that external more advanced at present CT manufacturer uses is luminescent crystal (rare-earth ceramic) detector, and the main distinction has scintillation crystal detectors, rare-earth ceramic detector, ceramic metal detector, gem detector etc. on luminescent crystal.But the arrangement architecture of range detector is basic identical, and the receiving plane that is X line and photodiode is perpendicular, and the roentgen radiation x crystal makes crystal send visible light, and visible light makes the photodiode conducting.

The basic reason of decision CT image quality is the pixel size of image and the intensity of signal.The size of pixel is by each unitary size decision of detector, and promptly single detector is more little, and pixel is also more little, and the spatial resolution of image is just good more, and image quality is just good more.But when detector size was too small, the signal intensity that each unit of detector is detected just obviously descended, and the signal that detects is too little, signal to noise ratio is very low, finally occur snow on image, the density resolution of CT image can sharply descend, and can not be used for image-forming diagnose.As seen, seek out between littler pixel and the stronger signal and have contradiction.

Can't realize improving under the situation of image quality dwindling the single detector size, abroad mainly concentrate on the luminous efficiency (crystal brightness) and crystalline overall luminous intensity (crystal thickness) that improves crystal (rare-earth ceramic) at present about the research of CT detector.Aspect the crystalline luminous efficiency of raising, detector research has for many years made the research of luminescent crystal material reach the peak, and ultrahigh speed rare-earth ceramic detector, gem detector have occurred.Although the crystalline luminous efficiency of current use crystal relatively in the past is improved largely, its luminosity is still very low.On the overall luminosity that improves crystal (rare-earth ceramic), although crystal is reached 2mm or more by thickening at present, but along with crystalline thickening, the following photodiode receiving plane of luminescent crystal distance (luminosity and distance square be inversely proportional to) relatively more and more far away, for crystal at a distance, photodiode receiving light power degree can obviously descend, and receiving efficiency can descend and become very low.Rare-earth ceramic is translucent near transparent, and its light transmission relatively poor relatively (crystal can only be accomplished about 2mm) so improve this method of crystal thickness, has not had the further possibility of research at present.Present crystal and photodiode designing and arranging array structure mode can't solve between littler pixel and the stronger signal and have contradiction.

Summary of the invention

The purpose of this invention is to provide a kind of efficient CT detector of realizing that pixel is littler, receiving efficiency is stronger, obtaining better imaging effect.

Technical solution of the present invention is: it comprises main substrate and evenly is fixed on several probe units on the main substrate, each probe unit comprises crystal and photodiode respectively, the receiving plane of photodiode and a crystalline face are combined closely, and the direction of each probe unit is identical and be parallel to the X line, be fixed on the main substrate perpendicular to the direction of main substrate along the receiving plane of photodiode.

Technique effect of the present invention is: the CT machine use this detector can do not improve the X line strength and do not change the signal pixels that receives under the situation of other structure littler, signal is stronger, the Pixel Dimensions size is half of existing detector, its receiving efficiency is higher, be more than the Radix Achyranthis Bidentatae of existing detector, the receiving area of photodiode enlarges more than 20 times, and the signal that detects when making detector cells survey size decreases does not diminish, signal to noise ratio is higher, and formed CT picture quality is better.

This CT detector has the following advantages:

1, uses the existing CT of its x-ray radiation intensity of CT machine of this CT detector obviously to reduce (green), reduced radiation side effect human body.2, the more present detector of the signal intensity that detects obviously improves, and the image effect of acquisition is better.3, the pixel of CT image is littler, and spatial resolution is higher.Above three advantages of this CT detector have both, and are present CT detector incomparable (comprising the gem detector).

Description of drawings

Fig. 1 cuts open figure for the three-dimensional office of probe unit embodiment of the present invention;

Fig. 2 is a detector embodiment three-dimensional structure diagram of the present invention;

Fig. 3 cuts open figure for the three-dimensional office of existing detector probe unit;

Fig. 4 is existing detector and detector result of use comparison diagram of the present invention.

The specific embodiment

As shown in Figure 1 and Figure 2, it comprises main substrate 1 and evenly is fixed on several probe units 2 on the main substrate 1, each probe unit 2 comprises crystal 21 and photodiode 22 respectively, the receiving plane 23 of photodiode 22 is combined closely with a face of crystal 21, and the direction of each probe unit 2 is identical and be parallel to the X line, be fixed on the main substrate 1 perpendicular to the direction of main substrate 1 along the receiving plane 23 of photodiode 22.

Crystal 21 is rectangular column hexahedron, and the side of crystal 21 column length direction and the receiving plane 23 of photodiode 22 are combined closely.Be respectively equipped with the reflecting layer 24 of reflect visible light on other five faces that crystal 21 is not combined closely with the receiving plane 23 of photodiode 22.

Photodiode 22 constitutes by lengthy motion picture shape hexahedron photodiode body 25 with lengthy motion picture shape hexahedron photodiode substrate 26 that photodiode body 25 adapts, a big first type surface of photodiode body 25 is a receiving plane 23, and another big first type surface at photodiode body 25 receiving planes 23 back sides is fixed on the big first type surface of photodiode substrate 26.Be connected with the photo diode leads 27 of the lead hole 11 of passing on the main substrate 1 on photodiode body 25 and the end face that main substrate 1 links to each other.

Photodiode body 25 is clipped in and constitutes long column shape probe unit 2 between crystal 21 and the photodiode substrate 26, the shaft of long column shape probe unit 2 is perpendicular to main substrate 1, and an end face of a styletable face of rectangular column hexahedron crystal 21, lengthy motion picture shape hexahedron photodiode body 25 and an end face of lengthy motion picture shape hexahedron photodiode substrate 26 are fixed on the main substrate 1.X line projection side is provided with on the end face that is fixed on photodiode 22, can stops the X line and make its stereotype that can not shine photodiode 22 or steel plate 3 on each probe unit 2.Stereotype or steel plate 3 are fixed on the end face of photodiode body 25 and photodiode substrate 26.The thickness of stereotype or steel plate 3 is 3-5mm.Main substrate 1 is for being provided with the plate body of several photo diode leads through holes 11.The photodiode body 25 of probe unit 2 in a row and photodiode substrate 26 can be made integrative-structure respectively during practical application, so that processing and fabricating and installation.Stereotype on each probe unit 2 or steel plate 3 can be made the integral type sieve-plate structure with crystal X line three-way hole, are convenient to processing and fabricating and installation equally.

The core of this detector is the physical arrangement of detector and the change of arrangement mode.Up to the present the research and the report that also do not have this respect both at home and abroad.Adopting the inclined to one side hole of the quadrature of creating to collimate acquisition technique can be on the basis of existing detector cells size constancy, one times of the spatial resolution of raising image.

Abroad mainly concentrate on the overall luminous intensity (crystal thickness) of the luminous efficiency (crystal brightness) that improves crystal (rare-earth ceramic) and crystal (rare-earth ceramic) about the research of CT detector, consider to increase the research (because at present external research direction and thinking restriction think that it is absolutely not increasing receiving area raising receiving efficiency) of receiving area raising receiving efficiency.The research of this detector is carried out at the blind area of foreign study exactly.

The arrangement mode of crystal of this new detector (rare-earth ceramic) and light emitting diode is former probe unit (crystal and photodiode) to be revolved turn 90 degrees on substrate, make the photodiode receiving plane by originally with the X line vertical become parallel.Crystal (rare-earth ceramic) can extend to 5-10mm along X line direction like this.The X line penetrates and makes when shining crystal (rare-earth ceramic) the long crystal (rare-earth ceramic) of 5-10mm all luminous, the photodiode of radiation of visible light lateral distance 0.25mm.Because all luminous points have only 0.25mm apart from the receiving plane of photodiode apart from maximum, so receiving efficiency is very high, be present detector can not compare.Its receiving efficiency is more than the Radix Achyranthis Bidentatae of present structure detector.Because the photodiode of the existing detector of the receiving area of its photodiode enlarges more than 20 times, the also corresponding raising of receiving efficiency.Owing to above two reasons obviously strengthen signal intensity, make the spatial resolution of CT and density resolution all have one obviously to improve.

The crystal of this detector (rare-earth ceramic) makes crystallo-luminescence when the roentgen radiation x crystal, near the photodiode receiving plane of (0.25mm) light of most light and process reflective layer reflects directly arrives.Existing detector crystal (rare-earth ceramic) makes crystallo-luminescence when the roentgen radiation x crystal, but arrive the faint luminous ray of having only of photodiode receiving plane at last, light is propagated in not exclusively transparent pottery just can arrive photodiode receiving plane (relative luminous intensity is very low) behind multiple reflection, light losing is excessive, and receiving efficiency is very low.Fig. 3 is the structure of existing each probe unit of detector, the photodiode 22 that it is combined closely by cubic column crystal 21, with the lower surface of column crystal 21 constitutes, the X line is respectively equipped with reflecting layer 24 perpendicular to the receiving plane 23 of photodiode 22 on other five faces that cubic column crystal 21 combines with photodiode 22.The back side of photoelectricity two pipe receiving planes 23 is fixed on the main substrate 1, and the face that photodiode 22 links to each other with main substrate 1 is provided with the photo diode leads 27 of the lead hole 11 of passing on the main substrate 1.

The area that each detector cells of this detector always receives the X line is 0.5 mm * 0.5 mm, wherein 0.25 mm * 0.5 mm is effective crystal (rare-earth ceramic) receiving area, account for 50%, detector has 50% blind area in X-axis or Y direction, can address this problem by present widely used orthogonal deflection technology.Cooperate the stereotype of front to shelter from 1/2 passage, improve forming the inclined to one side hole of quadrature collimation acquisition technique, the detector cells size after this technology is finished is equivalent to 0.25 mm * 0.5 mm, that is to say that the unit size in X-axis or Y direction is equivalent to 0.25 mm.Pixel Dimensions reduces one times, does not have overlapping between the neighbor.The orthogonal deflection technology is quite ripe at present, this technology is improved a little promptly may be used on this detector, and this technology after improving is more perfect.

Present orthogonal deflection technology is to finish double data acquisition, and it is to finish the data acquisition that Pixel Dimensions reduces a times that this detector utilizes the inclined to one side hole of quadrature collimation acquisition technique.Principle is as shown in the figure:

The left side is the reception condition of present conventional CT detector and 0 ° and 180 ° among Fig. 4,0 ° of signal with 180 ° of receptions is identical, the right side is the reception condition of 0 ° of the inclined to one side hole of our quadrature that designs collimation acquisition technique detector and 180 ° among Fig. 3, because stereotype on this detector probe unit or steel plate have blocked irradiation to the X of half area of probe unit line, add up for its 0 ° and 180 ° and just can constitute complete signal, and the signal of 0 ° of existing detector and 180 ° is multiple, and as seen the two 0 ° of signal with 180 ° of receptions is different.It below among the figure image of each self-forming.Conventional CT detector is with the small lesion magnification distortion, and focus density attenuating desalination, and this detector adopts the inclined to one side hole of quadrature collimation acquisition technique can detect littler focus.

The new detector detector performance index of main flow at present obviously improves, and finishes the once leap of CT the quality of device images.And can significantly reduce the using dosage of X line, more environmental protection, more green, more healthy, can also prolong service life of X spool.

At present the problem that exists of the detector of CT is not the littler problem that unit size can be done, but do littler after the signal that detects too little, signal to noise ratio is too low, can not be used for image-forming diagnose.The signal that this detector detects in detector X line unit receiving area size decreases does not diminish, and the signal that detects is strong all the better, and signal to noise ratio is higher, and the picture quality of CT is better.Solved the problem that the signal intensity that detects when the single detector size reduces or not, made littler that single detector can do, signal can be stronger, finally makes the spatial resolution of CT and density resolution that significant a raising is all arranged.

Claims

1. efficient CT detector, it comprises main substrate (1) and evenly is fixed on several probe units (2) on the main substrate (1), each probe unit (2) comprises crystal (21) and photodiode (22) respectively, the receiving plane (23) of photodiode (22) and a face of crystal (21) are combined closely, and it is characterized in that: the direction of each probe unit (2) is identical and be parallel to the X line, be fixed on the main substrate (1) perpendicular to the direction of main substrate (1) along the receiving plane (23) of photodiode (22).

2. efficient CT detector as claimed in claim 1 is characterized in that described crystal (21) is rectangular column hexahedron, and the side of crystal (21) column length direction and the receiving plane (23) of photodiode (22) are combined closely.

3. efficient CT detector as claimed in claim 2 is characterized in that being respectively equipped with on other five faces that described crystal (21) do not combine closely with the receiving plane (23) of photodiode (22) reflecting layer (24) of reflect visible light.

4. efficient CT detector as claimed in claim 1, it is characterized in that the lengthy motion picture shape hexahedron photodiode substrate (26) that described photodiode (22) adapts by lengthy motion picture shape hexahedron photodiode body (25) with photodiode body (25) constitutes, a big first type surface of photodiode body (25) is receiving plane (23), and another big first type surface at photodiode body (25) receiving plane (23) back side is fixed on the big first type surface of photodiode substrate (26).

5. efficient CT detector as claimed in claim 4 is characterized in that being connected with on described photodiode body (25) and the end face that main substrate (1) links to each other the photo diode leads (27) of the lead hole (11) of passing on the main substrate (1).

6. efficient CT detector as claimed in claim 4, it is characterized in that described photodiode body (25) is clipped in formation long column shape probe unit (2) between crystal (21) and the photodiode substrate (26), the shaft of long column shape probe unit (2) is perpendicular to main substrate (1), and an end face of an end face of crystal (21), lengthy motion picture shape hexahedron photodiode body (25) and an end face of lengthy motion picture shape hexahedron photodiode substrate (26) are fixed on the main substrate (1).

7. efficient CT detector as claimed in claim 1 is characterized in that each probe unit (2) goes up X line projection side and be provided with on the end face that is fixed on photodiode (22), can stop the X line and make its stereotype that can not shine photodiode (22) or steel plate (3).

8. efficient CT detector as claimed in claim 1 is characterized in that described main substrate (1) is for being provided with the plate body as if a photo diode leads through hole (11).