CN104622486A - Medical X ray measuring device and boundary detecting method - Google Patents

Abstract

The invention provides a medical X ray measuring device and a boundary detecting method. A bone mineral density measuring device of the medical X ray measuring device is provided with the boundary detecting function. To be specific, the detection value column is constituted by a plurality of L detection values (low energy X ray detecting value) (56) and a plurality of H detection values (high energy X ray detecting value) (58). The boundary between the adjacent two detecting values (the detecting value pair) can be detected. Under the above mentioned condition, the tissue category of each of the detection values can be detected (symbols 74,76), when the two independent results are different, the boundary (symbol 78) can be detected comprehensively. The bone area (symbol 80) can be detected according to the above mentioned boundary, and the image processing (symbol82) can be carried out correspondingly. Or the pixel column (symbol 84) can be set based on the detected boundary, the bone mineral density can be calculated according to the pixel units used to form the pixel column.

Description

Medical X-ray measuring device and border determination methods

Technical field

The present invention relates to a kind of medical X-ray measuring device, especially relate to a kind of judgement of organizational boundary.

Background technology

As medical X-ray measuring device, known X-ray organizational diagnosis device, X-ray imaging device, X ray CT (Computed Tomography: computed tomography) device etc.Hereinafter, list a kind of bone density (bone density) measuring device as X-ray organizational diagnosis device, and be described.

Generally, bone density measurement device is, based on Dual energy X ray absorptiometry (dual-energy x-ray absorptiometry (DEXA) method), the bone density of the skeleton in measured body is measured and the device (with reference to Japanese Patent No. 4980862 publication and Japanese Unexamined Patent Publication 2012-192118 publication) of computing.In bone density measurement device, such as, the X-ray of pencilbeam (pencil-beam) shape mechanically carries out two-dimensional scan, meanwhile detects the X-ray through measured body.More specifically, low-energy X-ray and high-energy X-rays is alternately irradiated while the scanning of enforcement beam, and it is (following to obtain the low-energy X-ray detected value be alternately arranged on mechanical scanning direction thus, be called " L detected value ") and high-energy X-rays detected value (hereinafter referred to as " H detected value ").

In existing bone density measurement device, relative to the two-dimensional detection value array be made up of multiple L detected value and multiple H detected value, and be set with two-dimensional array regularly.That is, all the time, the illumination sequence no matter position of object skeleton and shape and fixing.Each pixel forming pel array is made up of the L detected value be first obtained and the H detected value be obtained afterwards, or, be made up of the H detected value be first obtained and the L detected value be obtained afterwards.By in units of pixel, and based on forming the L detected value of this pixel unit and H detected value, computing is carried out to bone density (the bone mineral amount in per unit area).All the time, in bone density measurement device, there is irradiation and there is the fan beam (fan-beam) that two dimension is dispersed or the device with the conical beam (con-beam) that three-dimensional is dispersed.

Summary of the invention

Invent problem to be solved

In existing bone density measurement device, as described above, each pixel is made up of the L detected value be first obtained (or H detected value) and the H detected value (or L detected value) that is obtained afterwards.In each pixel, two detected values to obtain coordinate strict mutually internally inconsistent.Although also depend on mechanical scanning speed or power conversion cycle, between these coordinates, there is fixing difference.This is because, when comprising the border between Bone and soft tissue in pixel inside, incorrect value may be become about this pixel by the bone density calculated or the tissue class be judged out based on bone density.In order to avoid this problem, and when the pixel near the border (profile) in bony areas being rejected from operand without exception, bone density operating range will reduce.That is, the valid pixel number that can be used in measurement will reduce.Because the skeleton of the toy of mouse or mouse etc. is very little, therefore when setting operating range relative to them, although there is the request wishing to expand its operating range as much as possible, above-mentioned same rejecting will cause the result contrary with this requirement.

Generally, existing bone density measurement device has following function, that is, based on bone density pixel or bone density distribution and automatically to the function that the border of the profile of bony areas, i.e. Bone and soft tissue judges.But this judgement is the judgement being set to minimum unit with pixel.Therefore, the resolution improving border judgement is required.Even if in the medical X-ray measuring device beyond bone density measurement device, also require the resolution improving border judgement.

In addition, in Japanese Unexamined Patent Publication 2012-192118 publication, disclose a kind of can to the bone density measurement device shown by the information being equivalent to L detected value and H detected value obtained in units of pixel (Fig. 2 and Fig. 3 with reference to the document).But, in the publication and unexposed border in units of detected value or in units of half-pixel judge.In addition, do not record yet about according to border afterwards to the situation that pixel column or pel array suitably set.

The object of the invention is to, in medical X-ray measuring device, can judge border more accurately.Or, improve the resolution that border judges.Or, can judge the classification of pixel more accurately.

For solving the method for problem

The feature of medical X-ray measuring device involved in the present invention is, comprise: X-ray generating unit, it is arranged on the side of measured body, and while carrying out movement, alternately repeatedly irradiates low-energy X-ray and high-energy X-rays relative to described measured body; X-ray detecting unit, it is arranged on the opposite side of described measured body, and detects through the low-energy X-ray of described measured body and high-energy X-rays, thus output detections value row; Judging unit, it arranges based on described detected value, border between the first tissue in described measured body and minor microstructure is judged, described detected value row comprise, multiple low-energy X-ray detected value that the moving direction of described X-ray generating unit alternately arranges and multiple high-energy X-rays detected value, described judging unit by judging tissue class for each detected value in described detected value row, thus judges described border.

Pass through said structure, by repeatedly carrying out while making X-ray beam carry out movement relative to the low-energy X-ray of measured body and alternately irradiating of high-energy X-rays, thus obtain the multiple low-energy X-ray detected values (multiple L detected value) and multiple high-energy X-rays detected value (multiple H detected value) that alternately arrange in the direction of movement.These detected values form detected value row.Judging unit judges the border of the first tissue and minor microstructure based on this detected value row.Specifically, judging unit is not in units of pixel but judges border in units of detected value.Therefore, if according to said structure, and implementing compared with situation that border judges, judgement resolution can be made to be set to twice in units of pixel.Be preferably adjacent detected value between judge border, in this case, preferably determine whether border.

Be preferably, arrange relative to described detected value, with the multiple adjacent detected value pair of the contextual definition being mutually repeated half, described judging unit for each described adjacent detected value pair, and judges described border.According to this structure, although implement the judgement on border as unit using two detected values (adjacent detected value to), but be repeated half owing to arranging relative to detected value each other with adjacent and multiple be set with adjacent detected value pair, namely, owing to constituting the judgement unit of the number of the twice of the pixel count being equivalent to be defined in existing apparatus, therefore, as described above, can will judge that resolution is set to twice.

Be preferably, described judging unit comprises: the first judging unit, its low-energy X-ray detected value based on described adjacent detected value centering and judging tissue class; Second judging unit, its high-energy X-rays detected value based on described adjacent detected value centering and tissue class is judged; Comprehensive descision unit, it judges described border based on for the right judged result of described first judging unit of described adjacent detected value and the judged result of described second judging unit.According to said structure, the first judging unit judges individually tissue class in units of detected value, and passes through with reference to these independent judged results between adjacent detected value, thus carries out comprehensive judgement to border.When carrying out the judgement of tissue class, such as, judge skeleton or soft tissue, or, judge skeleton, soft tissue or both borders.

In the stage of comprehensive descision, be preferably, the judged result of the judged result of the first judging unit and the second judging unit is contrasted.As carried out example, judge soft tissue at the first judging unit, and when the second judging unit also judges soft tissue, finally judge soft tissue.Judge skeleton at the first judging unit, and when the second judging unit also judges skeleton, finally judge skeleton.Judge soft tissue at the first judging unit, and when the second judging unit judges skeleton, judge the border between soft tissue and skeleton.Judge skeleton at the first judging unit, and when the second judging unit judges soft tissue, judge the border between Bone and soft tissue.In this way by contrasting independent evaluation result thus can judging the position on border more accurately.As changed viewpoint, owing to implementing to judge with half-pixel unit, therefore, it is possible to make judgement resolution be the twice of existing apparatus.Naturally, as Change Example, the comprehensive descision by 1 pel spacing (pitch) can be listed.Generally, pixel is that bone density, fat attenuation etc. are carried out the unit of computing, and is made up of adjacent two kinds of detected values.

Be preferably, described judging unit also comprises: bone density arithmetic element, and it is for each described adjacent detected value pair, carries out computing according to forming the right low-energy X-ray detected value of described adjacent detected value and high-energy X-rays detected value to bone density; 3rd judging unit, it judges tissue class based on described bone density, described comprehensive descision unit based on the judged result of described first judging unit, the judged result of described second judging unit and described 3rd judging unit judged result and described border is judged.Also consider the border judged result based on the bone density of carrying out computing in units of detected value, border more accurately can be implemented and judge.Also can carry out bone density on the basis of computing in units of pixel, it is being carried out reference in comprehensive descision.

Be preferably, comprise scope determining unit, described scope determining unit is determined bone density operating range based on described border.Be preferably, comprise pixel column selection unit, described pixel column selection unit based on described border to the first pixel column pattern and the second pixel column pattern of the half-pixel that staggered is selected relative to this first pixel column pattern, each pixel forming described first pixel column pattern comprises, the low-energy X-ray detected value pre-existed in a predetermined direction and be present in its tight after high-energy X-rays detected value, each pixel forming described second pixel column pattern comprises, the high-energy X-rays detected value that described predetermined direction pre-exists and be present in its tight after low-energy X-ray detected value.Predetermined direction be the benchmark become on basis that the first pixel column pattern and the second pixel column pattern are compared mutually such as, towards, the forward on beam scanning direction.

Be preferably, described first is organized as skeleton, and described minor microstructure is soft tissue, and described organizational boundary is the border between described skeleton and described soft tissue.Be preferably, described first is organized as fat, and described minor microstructure is the soft tissue beyond described fat, and described border is the border between the soft tissue beyond described fat and described fat.

Method involved in the present invention is, according to by alternately repeatedly irradiating low-energy X-ray and high-energy X-rays relative to measured body while carrying out movement and the detected value row detecting low-energy X-ray and the high-energy X-rays through described measured body and obtain, judge the method on the border between Bone and soft tissue, the feature of described method is, described detected value row comprise, multiple low-energy X-ray detected value that the moving direction of described X-ray generating unit alternately arranges and multiple high-energy X-rays detected value, the method comprises judgement operation, described judgement operation is by judging tissue class for each detected value in described detected value row, thus described border is judged.This border determination methods can realize as the function of program.Involved program is installed in information processor by storage medium or network, and is performed in described information processor.

Accompanying drawing explanation

Fig. 1 is the figure of the first example representing bone density measurement device.

Fig. 2 is the figure representing the two-dimensional array be set relative to two-dimensional detection value array.

Fig. 3 is the figure for being described the mechanical scanning of fan beam.

Fig. 4 is the figure for being described the mechanical scanning of pencilbeam.

Fig. 5 is the figure of the first example representing border determination methods.

Fig. 6 is for representing the figure of the Rule of judgment in the border determination methods shown in Fig. 5.

Fig. 7 is the figure of the second example representing border determination methods.

Fig. 8 is for representing the figure of the Rule of judgment in the border determination methods shown in Fig. 7.

Fig. 9 is the figure of the first example representing pixel column setting.

Figure 10 is the figure of the second example representing pixel column setting.

Figure 11 is the figure of the 3rd example representing pixel column setting.

Figure 12 is the figure of the 4th example representing pixel column setting.

Figure 13 represents the figure as the two-dimensional array of comparative example.

Figure 14 is the figure representing the two-dimensional array be suitably set according to border.

Figure 15 is the figure for being described interpolation value process and the resampling process relative to two-dimensional array.

Figure 16 is the figure be described for the setting of the pel array to the border based on rear side.

Figure 17 is the figure for being described the setting of the pel array based on the border of front side and the border of rear side.

Figure 18 is the figure of the second example representing bone density measurement device.

Figure 19 is the figure for being described prescan (pre-scan).

Figure 20 is the figure of the first setting example of the two-dimensional array represented based on prescan result.

Figure 21 is the figure of the second setting example of the two-dimensional array represented based on prescan result.

Figure 22 is the figure of the 3rd setting example of the two-dimensional array represented based on prescan result.

Figure 23 is the figure of the 4th setting example of the two-dimensional array represented based on prescan result.

Figure 24 is the figure of the concrete example representing light filter.

Figure 25 is the figure for being described main scanning.

Figure 26 is the figure of an example of the illumination sequence of indication cycle's changeable type.

Figure 27 is the figure of the 3rd example representing bone density measurement device.

Figure 28 is the figure of the structure example representing pre-treatment portion.

Figure 29 is the figure for being described Pretreatment.

Figure 30 represents the figure as the two-dimensional array of comparative example.

Figure 31 represents the figure being implemented the two-dimensional array of replacement Treatment.

Figure 32 is the figure of the first example representing replacement Treatment.

Figure 33 is the figure of the second example representing replacement Treatment.

Figure 34 is the figure of the 3rd example representing replacement Treatment.

Figure 35 represents the figure with the bone density image of the resolution of twice.

Detailed description of the invention

Below, be preferred embodiment described of the present invention with reference to the accompanying drawings.

(1) first example (judging and the explanation afterwards set of pel array about apparatus structure, border) of bone density measurement device

In FIG, the first example of bone density measurement device is illustrated by concept map.Bone density measurement device is medical X-ray measuring device, and is the device by forming bone density image to measured body X-ray irradiation.Generally, bone density is the bone mineral amount in per unit area.In the present embodiment, according to DEXA (dual-energy x-ray absorptiometry: dual-energy X-ray absorption) method, bone density is measured and computing.

In FIG, bone density measurement device is made up of measuring unit 10 and Operations Analysis 12 substantially.Measuring unit 10 is such as arranged in X-ray management area.Operations Analysis 12 is such as made up of information processor.

First, measuring unit 10 is described.As shown in Figure 1, the platform 14A of camera stand 14 is placed with measured body 16.Measured body 16 has the skeleton 16A as measuring object.This skeleton 16A is such as lumbar vertebra, Thigh bone etc.Measuring unit 10 has bottom 18 and top 20.As being described bottom 18, in the below of platform 14A, the mode can carrying out horizontal movement is provided with generator 24.Generator 24 has the X-ray generator tube 26 producing X-ray.In the example depicted in fig. 1, the upside of generator 24 is provided with filter elements 28.Also chopper unit can be together set with filter elements 28.From high voltage source (HV) 30 pairs of X-ray generator tube 26 service voltages.Specifically, to X-ray generator tube 26, when based on control signal 31 when, alternately apply low-voltage and high voltage.Thus, in X-ray generator tube 26, alternately produce low-energy X-ray and high-energy X-rays.By the effect of not shown collimator and filter elements 28, and in the structure example shown in Fig. 1, be formed with the fan beam 32 as two dimensional beam profile.Fan beam 32 is the beam expanded upward from below, i.e. the beam of planar (or fan-shaped).Filter elements 28 possesses the light filter plate be driven in rotation, and this light filter plate possesses low-energy X-ray filter part and high-energy X-rays filter part.According to the kind of X-ray, the light filter be applicable to corresponding thereto is inserted into X-ray by path.Filter elements 28 is controlled by control part 44 described later.

Bottom 18 has sweep mechanism 22.The action of described sweep mechanism 22 is controlled by control part 44.In the present embodiment, the lower movable body comprising generator 24 and the upper movable body comprising detector 34 described later in the X direction, namely paper vertical direction in FIG are mechanically scanned simultaneously.The scanning of this machinery is effective by sweep mechanism 22.By making fan beam 32 scan in the X direction, thus form pyramidal 3-dimensional irradiation region.That is, Y-direction be fan beam disperse direction, the direction of illumination that Z-direction is X-ray, more specifically for fan beam centrage towards direction.Also in the following way, that is, X-ray can be implemented by top and produce, and implement X-ray detection by bottom.

As being described top 20, top 20 has detector 34.Detector 34 has the multiple detecting elements (multiple sensor) be set up along the dispersing direction, i.e. Y-direction of fan beam 32.Each detecting element is the parts of the detection implementing separately X-ray.Such as about 500 detecting elements are arranged in the mode of one dimension.Therefore, by these detecting elements, obtain by the Y direction namely the detected value that multiple detected values that direction arranges form of dispersing of fan beam arrange.By implementing the irradiation of X-ray successively in each position of X-direction, thus obtain the detected value row of each position of X-direction.But, owing to alternately irradiating low-energy X-ray and high-energy X-rays as described above, therefore alternately obtain low-energy X-ray detected value row (L detected value row) and high-energy X-rays detected value row (H detected value row).

Along with the mechanical scanning of the X-direction of fan beam 32, detector 34 is mechanically scanned in the X direction.Can fan beam be replaced, utilize pencilbeam.In this case, pencilbeam scans in the mode of two-dimentional zigzag (in a zig-zag manner).In addition, the narrower fan beam of width also can be made to scan in the zigzag mode of two dimension.In addition, conical beam (con-beam) can also be utilized.

In addition, in the structure example shown in Fig. 1, camera stand 14 and bottom 18 are formed in the mode of mutual split.But, also can arrange camera stand 14 and bottom 18 in the mode of integration.

Next, Operations Analysis 12 is described.As described above, Operations Analysis 12 is made up of information processor, such as personal computer.Operations Analysis 12 is implement the control of measuring unit 10 and the parts processed the data obtained by measuring unit 10.Each process performed by Operations Analysis 12 is implemented as the function of software in the structure example shown in Fig. 1.In FIG, each process is expressed as block diagram.

Multiple detected value row are stored in data storage 36.Arranged by these detected values and form two-dimensional detection value array.Two-dimensional detection value array is arranged by the multiple L detected values be arranged along the X direction and alternately and multiple H detected value row are formed.As view carried out the transformation of 90 degree, then obtain following idea, that is, in two-dimensional detection value array, be arranged with multiple detected value row along the Y direction.Multiple detected values that each detected value in this case arranges by arranging in the X direction are formed, and specifically, are made up of the multiple L detected value be alternately configured in the X direction and multiple H detected value.Multiple pixel is defined relative to this detected value row.Be described in detail hereinafter about detected value row and pixel column.

The module of border judging part 38 for judging border based on two-dimensional detection value array.Pel array configuration part 42 is following module, that is, based on the judged result of border judging part 38, namely based on the border be judged out, define for two-dimensional detection value array or set two-dimensional array.Hereinafter be described in detail about border judging part 38 and acting on of pel array configuration part 42.

Bone density operational part 40 is following module, namely, for form in each pixel of two-dimensional array of being set by pel array configuration part 42 each, specifically for each in each valid pixel belonged in bony areas, and computing is carried out to bone density.In this case, with reference to a pair detected value (L detected value and H detected value) forming each pixel.In the present embodiment, according to DEXA method, computing is carried out to bone density as described above.In order to realize which, when bone density computing, to utilize under the state not inserting measured body on X-ray course of the beam the measurement result measured by other means.That is, before the measurement relative to measured body, under the state weakened not being subject to being caused by measured body, X-ray intensity is measured.The X-ray intensity this measured is considered as the incident X-rays intensity under the state inserting measured body.

In the structure example shown in Fig. 1, border judges that mode is as described above performed based on two-dimensional detection value array.In this case, each detected value is the output valve of each detecting element.But border judges also to be performed based on attenuation (pad value), and can be performed based on other the data being equivalent to described attenuation.

Bone density as with R _l-α R _hproportional value and being calculated.Herein, R _l=ln (I _oL/ I _l), R _h=ln (I _oH/ I _h), α=R _l/ R _h.But each value is as follows.α is by the coefficient measured in soft tissue area's (beyond bony areas).

I _oL: the incident intensity of low-energy X-ray

I _oH: the incident intensity of high-energy X-rays

I _l: the injection intensity (detected value in the region that Bone and soft tissue exists) of low-energy X-ray

I _h: the injection intensity (detected value in the region that Bone and soft tissue exists) of high-energy X-rays

Above-mentioned L detected value and H detected value are such as respectively I _land I _h.But, also can use the value suitable with it, such as R _land R _h.

In FIG, control part 44 is the module of the control performing bone density measurement.In addition, control part 44 has the function etc. of the computing implementing mean bone density in operating range (Region Of Interest).Further, operating range is set by bone density operational part 40 or control part 44.Input part 46 is the parts operated by tester.Display part 48 is the display shown bone density image etc.

In fig. 2, figure is shown with the two-dimensional array 62 be set relative to two-dimensional detection value array 50.First two-dimensional detection value array 50 is described.Two-dimensional detection value array 50 is made up of the multiple detected value row 52,54 arranged in the X direction.Each detected value row 52 are made up of the multiple L detected values 56 arranged in the Y direction.Each detected value row 54 are made up of the multiple H detected values 58 arranged in the Y direction.That is, by while the irradiation of the irradiation and high-energy X-rays of repeatedly implementing low-energy X-ray, fan beam is scanned in the X direction, thus alternately obtain L detected value row 52 and H detected value row 54, its result is, forms two-dimensional detection value array 50.

As adopted other view, then two-dimensional detection value array is consisted of the multiple detected value row 60 arranged in the Y direction.In this case, each detected value row 60 are made up of the multiple L detected value alternately arranged in the X direction and multiple H detected value.Relative to this two-dimensional detection value array 50, if the bone density measurement device according to Fig. 1, then can for each detected value row 60, suitably set pixel column 64 according to the position on the border be contained in wherein.That is, as mentioned below, can for each detect in row 60 each, from the first pixel column pattern and the second pixel column pattern, select the pixel column pattern of the position being suitable for border.

Each pixel column 64 is made up of the multiple pixels 63 arranged in the X direction.Each pixel 63 is made up of L detected value and H detected value.That is, by detected value to forming.But, as paired kind, there are two kinds.That is, by the L detected value pre-existed in the positive direction of X-direction and be present in its tight after H detected value " LH to " that form and by the same H detected value pre-existed forward in X-direction and be present in its tight after L detected value " HL to " that form.First pixel column pattern by multiple LH of tight union to and form.Second pixel column pattern by multiple HL of tight union to and form.Structure example according to Fig. 1, can for each detect in row 60 each, select the first pixel column pattern or the second pixel column pattern according to the position on border.If compatibly select pixel column pattern for each pixel column 60, then can form best two-dimensional detection value array 50 according to the form of object skeleton, the content concrete for it is described in detail hereinafter.

By the way, when carrying out border and judging, although make use of the output valve of detecting element in the present embodiment, the judgement on border also can be implemented as described above based on attenuation etc.Although in the illustrated example shown in fig. 2, have selected pixel column pattern for each independent pixel column 60, also can select pixel column pattern in units of multiple pixel column.No matter adopt which kind of mode, method that all can be this by the selection of applying pixel column pattern, thus compared with prior art can increase the valid pixel number of the object as bone density computing, or, compared with prior art can improve precision and the repeatability of measurement.

In figure 3, the mechanical scanning of fan beam is conceptually illustrated.Symbol 34 represents detector, and it is made up of the multiple detecting element 34a arranged in the Y direction.When this detector 34 mechanically scans in the X direction in the mode of transversal object skeleton 66, form the scanning area 65 of rectangle.

In the diagram, the mechanical scanning of pencilbeam is illustrated.Illustrate pencilbeam to symbol 68 medelling.This pencilbeam 68 scans in a two-dimensional manner for object skeleton 70.Symbol 72 represents the saw-tooth sweep path in this situation.Saw-tooth sweep path 72 has: the path sections 72-1 being equivalent to the scanning of X-direction forward, be equivalent to Y-direction forward scanning path sections 72-2, be equivalent to the scanning of X-direction negative sense path sections 72-3 and, be equivalent to the path sections 72-4 of the scanning of Y-direction negative sense.Naturally, in the structure of Fig. 4, such as, X-direction corresponds to main scanning direction, and Y-direction corresponds to sub scanning direction.Naturally, saw-tooth sweep path 72 90-degree rotation can also be made.

Next, use Fig. 5 to Fig. 8, border determination methods is described.

In Figure 5, the first example that border judges is illustrated.In Figure 5, direction from left to right corresponds to the forward of X-direction.(A) represent the first pixel column pattern of alternatively candidate, (B) represents the second pixel column pattern of alternatively candidate.(C) represent by along the X direction and the detected value that forms of multiple detected values of arrangement arranges, specifically, be made up of the multiple L detected value 56 alternately arranged and multiple H detected value 58.(D) represent by adjacent detected value in units of the judgement on border.As shown in (D), relative to detected value row, with the relation being mutually repeated half respectively multiple be set with multiple detected value pair.Use Fig. 6 to be hereinafter described about border Rule of judgment.

In the example depicted in fig. 5, judged result based on the tissue class of L detected value 56 and the judged result based on the tissue class of H detected value 58 are contrasted mutually, judge " non-boundary " when they are consistent, and judge when they are inconsistent " having border ".

Specifically, with in the decision block shown in symbol 74, be judged as non-boundary, and with in the decision block shown in symbol 76, be judged as border 78.Although judged border in the prior art in units of pixel, in the method shown in Fig. 5, border can be judged in units of detected value as a result.That is, compared with prior art can be judged the presence or absence on border by the resolution of two times.Also can when being judged as border (symbol 78), the determining program after omitting it.Certainly, the determining program after also can performing it, thus next border is judged.

When being judged as border (symbol 78), various process can be realized based on described judgement.Such as, also can assert (symbol 80) on the basis of bony areas based on the border be judged out, perform image procossing or measurement (symbol 82) relative to the bony areas be identified.Or, also based on the border be judged out, the setting (symbol 84) of the pixel column being used for bone density computing can be implemented.Also according to this pixel column for the equal computing bone density of each pixel, and based on described operation result, bone density image (symbol 86) can be formed.As described above, if the structure example according to Fig. 5, based on the position on the border be judged out, best pixel column pattern can be selected in two pixel column patterns.Two pixel column patterns have the relation of the half-pixel amount that mutually staggered in the X direction.By the selection of pixel column pattern, thus realize the increase of the valid pixel number belonged in bony areas.

In figure 6, the Rule of judgment in the border determination methods shown in Fig. 5 is illustrated.Symbol 88 represents the judged result based on L detected value, and symbol 90 represents the judged result based on H detected value.Symbol 92 represents comprehensive judged result.As shown in symbol 94 and symbol 96, when two independent judgment results are consistent with each other, in comprehensive descision, two independent judgment results are directly used.On the other hand, when two independent judgment results are inconsistent, as shown in symbol 98, border is judged.Namely border is judged out.

Fig. 7 and Fig. 8 is used to be described the second example that border judges.In the figure 7, (A) illustrates the first pixel column pattern of alternatively candidate, and (B) illustrates the second pixel column pattern of alternatively candidate.(C) detected value row are illustrated.(D) medelling border determination methods is illustrated.

Before border judges, calculate bone density (symbol 88) based on adjacent detected value to 56,58.In this case, the value as bone density so is then calculated about soft tissue.With in the frame shown in symbol 90, judge tissue class based on forming each right detected value 56,58 of adjacent detected value.In addition, tissue class is judged based on bone density.Further, by making three independent judged results mutually contrast, thus finally tissue class is judged.Use Fig. 8 to be hereinafter described about Rule of judgment.In the example depicted in fig. 7, which the classification among soft tissue, skeleton and border is judged based on three independent judged results.When judging border, based on the position judging this border, and assert bony areas (symbol 98), and performing (symbols 100) such as image procossing relative to bony areas.

In fig. 8, the Rule of judgment in the border determination methods shown in Fig. 7 is illustrated.Symbol 102 represents the judged result based on L detected value, and symbol 104 represents the judged result based on H detected value, and symbol 106 represents the judged result based on bone density.In addition, symbol 108 represents comprehensive judged result.As shown in symbol 110, when three independent judged results 102,104,106 are skeleton, with in the comprehensive judgement shown in symbol 108, be judged as skeleton.On the other hand, beyond this situation, be judged as the situation beyond skeleton and soft tissue (reference marks 112).Naturally, when three independent judged results all represent soft tissue, comprehensive descision goes out soft tissue, and considers outside this situation and fail to understand to the true and false the various change carrying out judging etc.Be preferably, determine Rule of judgment according to the object of bone density computing or required precision etc.

As described above, by based on by multiple detected values of multiple settings to and border is judged, thus compared with the judgement on the border based on the multiple pixels be set with non-duplicate relation, the resolution of twice can be realized.

(2) explanation of the setting example of pel array

Next, use Fig. 9 to Figure 17, the establishing method of two-dimensional array is described.In Fig. 9 to Figure 12, illustrate the setting example of the pixel column of the position according to border.First, Fig. 9 is used to be described the first example.

In fig .9, (A) represents wayside signaling.In fig .9, laterally X-direction is corresponded to.In wayside signaling, symbol " L " represents between the low-energy X-ray light period, and symbol " H " represented between the high-energy X-rays light period.(B) represent tissue class, namely represent in X direction and the content of tissue that exists.At this, between soft tissue and skeleton, have actual boundary 110.This actual boundary 110 is consistent with from the interval place (drop point) of carrying out changing to L interval of H.

In (C), illustrate the arrangement of L detected value.These L detected values with for distinguishing that the threshold value 112 of soft tissue and skeleton compares.If L detected value is greater than threshold value 112, be judged as soft tissue, if be less than threshold value 112, be judged as skeleton.(D) arrangement of H detected value is represented.These H detected values and threshold value 114 contrast.Be judged out soft tissue about the H detected value being greater than threshold value 114, be judged out skeleton about the H detected value being less than threshold value 114.

In X direction and definition has multiple detected value to using as evaluation object.When be conceived to detected value wherein to 116 time, about at X-direction first (upstream side place) H detected value 118 of existing and be judged out soft tissue forward, on the other hand, skeleton is judged out about the L detected value 120 being present in its tight rear (downstream place).Its result is, two independent judged results are inconsistent, thus judges to there is border between two detected values.(E) for illustrating above-mentioned situation.That is, at this, illustrate respective judged result, at first on the basis having judged soft tissue 122, as the place of carrying out changing from this soft tissue 122 to skeleton 124, and judge border (between interval border) 126.And, as shown in (F), according to the position on border 126, and select which pixel column pattern, thus it is set.

Specifically, among the first pixel column pattern and the second pixel column pattern, the mode increased as far as possible to make to belong to the valid pixel in bony areas selects specific pixel column pattern.In the example depicted in fig. 9, as shown in (F), have selected by multiple LH the first pixel column pattern formed.In the example depicted in fig. 9, suppose, when have selected by multiple HL the second pixel column pattern formed, the situation making actual boundary 110 be present in the position of the middle of specific pixel will be become.In contrast, in the example depicted in fig. 9, owing to setting the first pixel column pattern using the position of actual boundary 110 as benchmark, therefore, it is possible to increase valid pixel number.

When the first pixel column pattern is set, as shown in (G), for forming each pixel of this pixel column and computing bone density.Although obtain the operation values being equivalent to bone density value in soft tissue, ignored in its computing at mean bone density etc.In addition, symbol 128 represents the threshold value distinguished tissue class, and is judged out skeleton about the value only having exceeded this threshold value.Naturally, due in the example depicted in fig. 9, based on each detected value, implement comprehensive descision, therefore may not implement the judgement of the tissue class based on bone density.By the way, the arrangement of the L detected value shown in Fig. 9 etc. and the example being arranged as explanation of H detected value.

In Fig. 10, the second example is illustrated.In addition, to the structure identical with the structure shown in Fig. 9 by symbol identical for labelling, and the description thereof will be omitted.In the example depicted in fig. 10, as shown in (B), in during the actual boundary 130 between soft tissue and skeleton slightly enters into L compared with above-mentioned drop point.In this case, when being conceived at the detected value row shown in (C) and (D), particularly when be conceived to detected value to 132 time, judge soft tissue about H detected value 134, judge skeleton about L detected value 136.Its result is, border (between interval border) 142 is judged in the position as be equivalent to drop point as shown in (E).That is, judge soft tissue 138 by upstream side place compared with described border 142, downstream place judges skeleton 140 compared with described border 142.Its result is, as shown in (F), identical with the first example shown in Fig. 9, selects the first pixel column pattern and sets it.Naturally, by shown bone density row in (G), when being conceived to pixel n, slightly decline compared with the bone density of the pixel n shown in its bone density with Fig. 9.The size that also can decline according to it, carrys out the process outside application examples.

In fig. 11, the 3rd example is illustrated.In fig. 11, to the structure identical with the structure shown in Fig. 9 by symbol identical for labelling, and the description thereof will be omitted.In the 3rd example, as shown in (B), actual boundary 132 be present in L interval latter half (for from drop point away from place and close to the place of next rising point).Shown in (C) and (D) detected value row in, particularly when be conceived to detected value to 134 time, about by the L detected value shown in symbol 136, judge soft tissue, about by the H detected value shown in symbol 138, judge skeleton.That is, two independent judged results are mutually internally inconsistent, thus, as comprehensive descision result and judge border.In this case, as shown in (E), at the place place consistent with the rising point in wayside signaling (with reference to Figure 11 (A)), judge border 144.Part before this border 144 is judged as soft tissue 140, and the part after this border 144 is judged as skeleton 142.In contrast between the first example shown in Fig. 9 and Figure 10 and the second example, the result staggered to the forward of X-direction further in the position of actual boundary 132 is, has only staggered namely corresponding with the half-pixel amount of the amount corresponding with 1 detected value in the position on the border 144 be finally judged out.

In fig. 12, the 4th example is illustrated.In fig. 12, to the structure identical with the structure shown in Fig. 9 etc. by symbol identical for labelling, and the description thereof will be omitted.In the 4th example, as shown in (B), have border 146 in the position of rising point.Shown in (C) and (D) detected value row in, particularly when be conceived to detected value to 148 time, be judged out soft tissue about L detected value 150, be judged out skeleton about H detected value 152.That is, at this, two independent judged results produce inconsistent, as its result, judge border 160.The border 160 be judged out is consistent with the rising point in (A).

As described above, according to said method, detection boundaries can be carried out in units of half-pixel, and suitably can set voxel model based on this.Such as, as paying close attention in the particular anatomy of tissue, more measurement pixel (valid pixel) can be set.Particularly when measuring object and being less, measurement precision can be improved.

In fig. 13, the two-dimensional array 164 as comparative example is illustrated.This two-dimensional array 164 is set relative to two-dimensional detection value array 50.As described above, two-dimensional detection value array 50 is arranged by the multiple detected values arranged in the X direction and forms.Described multiple detected value arranges and is made up of multiple L detected value row 52 and multiple H detected value row 54.As adopted other view for two-dimensional detection value array 50, two-dimensional detection value array 50 is the aggregation of the multiple detected value row 60 arranged in the Y direction, and each detected value row 60 in this situation are made up of the multiple L detected value alternately arranged in the X direction and multiple H detected value.In addition, symbol 34 represents detector.

Relative to two-dimensional detection value array 50 mentioned above, be set with two-dimensional array 164 uniformly in the prior art.The position on border 162 and shape when no matter and set each pixel without exception time, the number of valid pixel 168 cannot be increased.By the way, symbol 166 represents that namely inactive pixels is not identified as the pixel of the pixel in bony areas.

In situation mentioned above, by applying the selection method be applicable to of above-mentioned voxel model, and can set the two-dimensional array 166 shown in Figure 14.In addition, in fig. 14, to the structure identical with the structure shown in Figure 13 by symbol identical for labelling.Two-dimensional array 166 is made up of the multiple detected value row 170,172 arranged in the Y direction.Wherein, pixel column 170 is for having the pixel column of the first pixel column pattern, and 172 for having the pixel column of the second voxel model.First voxel model is the aggregation that multiple LH is right, and the second voxel model is the aggregation that multiple HL is right.The pixel column of each position in the Y direction all selects applicable pixel column pattern according to the position on the border 162 in X-direction among two pixel column patterns.Thereby, it is possible to the number of valid pixel 168 in increase bony areas.And make the precision of measurement improve thus.

In fig .15, interpolation value process and resampling process is illustrated.(A) two-dimensional array 166 after pattern setting is illustrated.When based on this direct measurement or directly image procossing comparatively difficulty, be preferably, relative to two-dimensional array 166, application is by the interpolation value process shown in symbol 174 and resampling process.This result is the two-dimensional array 176 shown in (B).It is for having the array of standard in the two directions.

In figure 16, the setting of the two-dimensional array 180 on the border 178 based on rear side is illustrated.By shown in symbol 182, illustrate with each frame of hatching the valid pixel belonging to bony areas.Each position in the Y direction, according in X-direction, the position on the border 178 of rear side selects applicable pixel column pattern.That is, voxel model is selected to make the valid pixel belonged in bony areas become more mode.In addition, as shown in figure 17, also more mode can be become to determine two-dimensional array 186 to make valid pixel in former and later two borders 182,184.

(3) second example explanation of the suitable setting of illumination sequence and the prior setting of pel array (judge about prescan, border) of bone density measurement device

In figure 18, the second example of bone density measurement device is illustrated.In addition, to the structure identical with structure illustrated in the first example shown in Fig. 1 by symbol identical for labelling, and the description thereof will be omitted.

In the second example shown in Figure 18, bone density measurement device is roughly made up of measuring means 188 and Operations Analysis 190.Measuring means 188 has bottom 192 and top 194.Bottom 192 has generator 196.Generator 196 has X-ray generator tube 198.In addition, the upside of generator 196 is provided with filter elements 200.Be preferably, chopper unit is together set with filter elements 200.Generate in this second example and have pencilbeam 203.Pencilbeam 203 mechanically scans in X-direction and Y-direction.Mechanism for described scanning is sweep mechanism 22.

Top 194 has by the detector 202 of two-dimensional scan.It is for receiving the parts of pencilbeam 203.Sweep mechanism 22 pairs of lower movable bodies together carry out the scanning of machinery with the upper movable body possessing detector 202.

The hereinafter illustrated two-dimensional detection value array obtained by the execution of main scanning is stored in two-dimensional data memory 36.In this second example, before main scanning, first perform prescan.Prescanned data as its scanning result is sent to border judging part 204.This prescanned data also forms two-dimensional detection value array.Border judging part 204 judges the border between soft tissue and skeleton based on prescanned data.Its judged result is output to control part 206.

Control part 206 has the function controlled prescan and the function controlled main scanning, and in figure 18, these functions are illustrated as prescan control part 208 and main scanning control part 210.

In the structure example shown in Figure 18, when performing prescan, using low-energy X-ray, by pencilbeam, two-dimensional scan being carried out to object entirety.Thus, two-dimensional detection value array is obtained as prescanned data.By analyzing this prescanned data, thus judging profile and the border of skeleton in advance, determining the executive condition of main scanning based on its position be judged.That is, to make valid pixel as far as possible more belong to mode in bony areas to determine main-scan condition.This is described in detail hereinafter.

When being performed main scanning according to above mode by the main-scan condition determined, in two-dimensional data memory 36, store the two-dimensional detection value array be made up of multiple L detected value and multiple H detected value.Therefore, bone density operational part 40 for forming each pixel of two-dimensional array be set, specifically for each pixel in bony areas, according to the detected value forming this pixel to and computing is carried out to bone density.

In the second example shown in Figure 18, be different from the first example, by prescan, border judged, and suitably main-scan condition and illumination sequence or two-dimensional array are set based on this.This is specifically described hereinafter.

In Figure 19, illustrate an example of prescan.Symbol 212 represents scanning area, and this region is the maximum region that pencilbeam can carry out scanning.When carrying out prescan, the shape of the profile 214A had according to object skeleton 214 and suitably determine scanning pattern 216.As being specifically described, at first, as shown in symbol 216-1, pencilbeam scans to the positive side of X-direction, in this scanning process, utilizes edge detection method to come the position of specific border (profile) 214A.When detecting border 214A, as shown in symbol 216-2, pencilbeam moves to the minus side of X-direction.In this case, the only distance that is preset of movement.Afterwards, as shown in symbol 216-3, pencilbeam only moves preset distance to the positive side of Y-direction.Light from this ground as shown in symbol 216-4, pencilbeam moves to the positive side of X-direction again.In this scanning process, rim detection is performed in a juxtaposed fashion, thus the position of the border 214A of object skeleton 214 is specific.As described above, when repeatedly carrying out the scanning of a series of part, as a result, the scanning pattern 216 shown in Figure 19 is constituted.

As shown in Figure 4, when setting saw-tooth sweep path when the entirety throughout scanning area without exception, although need the long period when carrying out border 214A specific, but due to the method according to Figure 19, and sweep limits can be reduced according to the position of border 214A, therefore obtain the advantage that can make prescan time shorten.Naturally, under specific situation is carried out to the profile of the both sides in object skeleton 214 or under specific situation is carried out to the profile of the skeleton having complicated shape, also can carry out specific to the border of object skeleton as a whole by the saw-tooth sweep shown in Fig. 4.

When carrying out specific border in the manner, each position in the Y direction, pixel column is determined in the position according to the border in X-direction.In this case, the mode be optimized with pixel column in bony areas regulates pixel column entirety.About the establishing method of pixel column, below utilize concrete example and be described.

Illustrate the first setting example in fig. 20.Symbol 218 represents soft tissue, and symbol 220 represents skeleton.Border 222 is had between described soft tissue and skeleton.Symbol 228 represents above-mentioned two-dimensional detection value array, and symbol 230 represents two-dimensional array.

As shown in figure 20, each position in the Y direction, with when pixel column in X direction defines, sets the mode of more valid pixel as far as possible, sets pixel column in the inner side and bony areas on border 222.Symbol 224 represents the scanning to the positive side of X-direction in main scanning, and symbol 226 represents the scanning to X-direction minus side in main scanning.When any one, all define pixel column using border 222 as standard.In fig. 20, four pixel columns on the upside of paper are all consisted of the first pixel column pattern, and three pixel columns on the downside of paper are all consisted of the second pixel column pattern.In the first example shown in Figure 20, between the multiple pixel columns arranged in the Y direction, the arrangement that L is interval and H is interval is consistent.According to this first setting example, the advantage that can simplify the illumination sequence of each position of Y-direction in this scanning well can be obtained.

In figure 21, the second setting example is illustrated.In addition, to the structure identical with the structure shown in Figure 20 by symbol identical for labelling, and the description thereof will be omitted.This situation is also identical in Figure 22 and Figure 23 be described afterwards.

In figure 21, two-dimensional array 234 is set with relative to two-dimensional detection value array 232.Two-dimensional array 234 is made up of the multiple pixel columns arranged in the Y direction.In this second setting example, four pixel columns of upside are all consisted of the first pixel column pattern, and three pixel columns of downside are also all consisted of the first pixel column pattern.That is, each position in the Y direction, based on border 222, and when in bony areas, interval to L and that H is interval arrangement sets, the mode setting L interval with the right side (the positive side of X-direction) on border 222 at first determines illumination sequence.But each position in the Y direction, at least makes interzone spacing consistent in bony areas.When adopting this second setting example, the not system of selection of necessarily pixel column pattern.Can simplify in this to irradiate and control.

Illustrate the 3rd setting example in fig. 22.Two-dimensional array 238 is set with relative to two-dimensional detection value array 236.In the 3rd setting example, each position in the Y direction, have adjusted illumination sequence (Irradiation sequence) meticulously according to the position on border 222, namely when observing along the Y direction, multiple pixel column does not line up in the X direction.In other words, each position is in the Y direction bordering on the mode on border 222 with the pixel-by-pixel basis foremost making valid pixel arrange and is set with each illumination sequence i.e. each pixel column in advance.Detect border 222 in advance by the execution result based on prescan, thus this careful control can be realized.

In fig 23, the 4th setting example is illustrated.Two-dimensional pixel row 244 are set with relative to two-dimensional detection value array 242.In the 4th setting example, be set with two-dimensional array 244 based on two borders 222,240.Specifically, about the scanning with the positive side of the X-direction shown in 224, set pixel column using border 222 as standard, about the scanning 226 to X-direction minus side with its opposition side, be set with pixel column using border 240 as standard.

In above setting example, particularly in the setting example shown in Figure 22 and Figure 23, when scanning in the X direction, according to the position on border, dynamic variable setting is carried out to illumination sequence.Particularly as required, to scanning speed and between the light period, (siding-to-siding block length) carries out variable setting.Be described according to Figure 26 hereinafter about this.

In fig. 24, the light filter plate 246 be arranged in filter elements is illustrated.In order to regulate illumination sequence according to border, light filter plate is preferably made to rotate with low speed.In the example shown in Figure 24, light filter plate 246 is made up of nine low-energy X-ray filter parts 248 and nine high-energy X-rays filter parts 250.These filter parts of two kinds 248,250 circumferentially and are alternately configured.If arrange multiple light filter plate in this way, then may reduce the rotating speed of light filter plate, make the adjustment of rotating speed become easy.In fig. 24, although illustrate circular light filter plate, the light filter plate of drum type also can be set.

In fig. 25, an example of the scanning pattern in main scanning is illustrated.Object skeleton 255 is had in scanning area 254.Also by specific situation, can be set the path of main scanning based on this by prescan at the profile of the both sides of object skeleton 255.One of them example is represented by symbol 258.Symbol 256 represents pencilbeam.

Scanning pattern 258 has the path sections 258-1 of the scanning be equivalent to the positive side of X-direction.This path sections 258-1 is set to starting point with the position having retreated preset distance to X-direction minus side the border from X-direction minus side, and is set to terminal with the position to the positive side of X-direction away from preset distance the border from the positive side of X-direction.Pencilbeam is scanned in the mode to the positive side of Y-direction throughout preset distance the terminal from path sections 258-1.It is expressed by path sections 258-2.Afterwards, pencilbeam is moved to X-direction minus side.Even if in this case, according to the border of the both sides of the X-direction on object skeleton 255, determine starting point and the terminal of scanning.Symbol 258-4 represent then path sections 258-3, to the path sections in the scanning of the positive side of Y-direction.As above a series of program is repeatedly executed at predetermined intervals to cover the mode of the entirety of object skeleton 255.According to the setting of this main scan path, the main scanning time can be shortened.Naturally, in order to suitably set pixel column in object skeleton, and during the nearly body side of object skeleton needs fixing run-up, as long as in order to blank in the setting of the both sides of object skeleton during this run-up.

In fig. 26, the illumination sequence in main scanning is illustrated.It is fixed that it is scanned into professional etiquette to the X-direction that specific location is in the Y direction performed.Symbol 260 represents the cross section of object skeleton.Its width is represented by W1.W2 represents main scanning scope in the X direction.This scope W2 can each position in the Y direction different.By the way, W3 represents the Breadth Maximum of scanning area.

(A) action of chopper unit is represented.Chopper unit is the unit be set up as required.When chopper is in closed condition, X-ray is blocked in the nearly body side of measured body, thus reduces the exposure of measured body.When chopper is in open mode, X-ray transparent measured body.(B) scanning 262 to the positive side of X-direction is represented.Illumination sequence is in this case represented by symbol 264.(C) scanning 272 to X-direction minus side is represented.Illumination sequence is in this case represented by symbol 274.

As shown in (B), in this example, the border 282 of the side (being left side in the drawings) in object skeleton 260 becomes standard, the mode be set appropriately with R1 between the interval foremost in the valid pixel row relative to this border 282 and standard regions, namely between standard regions, R1 to be set in bony areas and the mode of position close to border 282, determines illumination sequence 264.Specifically, illumination sequence is by run-up part 266, actual effect part 268 and exceed part 270 and form.Run-up part is equivalent between the runway of nearly body side, and actual effect part 268 is equivalent to surveying range, and what exceed that part 270 is equivalent to depth side exceeds interval.In run-up parts 266, by controlling sweep mechanism or filter elements etc., specifically, by implementing the control of the umber of pulse etc. as the motor of drive source, thus can realize stable and applicable illumination sequence in bony areas.

Even if in the scanning 272 round about shown in (C), to form the mode of stable illumination sequence in actual effect part 278, in run-up part 276, regulate scanning speed or light filter rotating speed etc.In this example, be also provided with after actual effect part 278 and exceed part 280.In scanning 272, to make border 282 as standard, and suitably determine the mode of (finally interval) R2 between the standard regions closest to described border 282, determine the illumination sequence in actual effect part 278.By the way, in the example shown in Figure 26, between progress path scanning 262 and return path 272, L is interval and H interval is consistent on a timeline.Setting example shown in this with Figure 20 is corresponding.Certainly, under the situation shown in Figure 26, the illumination sequence corresponding with the setting example shown in Figure 21 to Figure 23 also can be applied.

As described above, if according to the second structure example shown in Figure 18 to Figure 26, then can obtain following advantage, namely, on the basis on the border of object skeleton specific for prescan, can determine main-scan condition (i.e. bone density computing pixel column) in advance according to the border of described object skeleton.Although only increase the amount corresponding with prescan for the exposure of measured body, as long as main scanning region can be cut down, then can implement the minimizing of the light exposure under main scanning.In addition, can obtain and carry out, on specific basis, can setting main-scan condition meticulously to border in advance.

(4) the 3rd example (about the explanation that border judges and detected value is replaced) of bone density measurement device

Next, use Figure 27 to Figure 34, the 3rd example of bone density measurement device is described.In addition, in the structure shown in Figure 27, to the structure identical with the structure shown in Fig. 1 by symbol identical for labelling, and the description thereof will be omitted.

In figure 27, in data storage 36, two-dimensional detection value array is stored.The module of border judging part 286 for judging the border of symmetrical skeleton based on two-dimensional detection value array.Although its determination methods is the method be substantially illustrated in Fig. 5 to Figure 12 etc., this border judging part 286 particularly judges with or without containing border for each detected value.Such as, in the Rule of judgment shown in Fig. 6, by the situation (situation that namely two independent judgment value are inconsistent) shown in symbol 98, be judged out containing border.In addition, in the Rule of judgment shown in Fig. 8, when learning multiple independent judgement structure, also can contain border and judging.

Bone density operational part 288 is, is setting uniformly on the basis of two-dimensional array relative to two-dimensional detection value array, the module of computing bone density for each pixel.Naturally, before the computing of bone density, first application has pre-treatment, and this function is expressed as pre-treatment portion 290 in figure 27.As mentioned below, this pre-treatment is the process of the detected value detected value be regarded as containing border being replaced into other.Thus, the increase of the valid pixel number in bony areas can be realized on apparent.Such as, when carrying out measuring about the femoral mean bone density of experiment toy, Thigh bone itself is less, cannot guarantee that the situation of pixel count is effectively more fully relative to this.In this case, if except belonging to the pixel in bony areas completely, also using the pixel that not exclusively belongs in bony areas also as operand, then can improve precision or the reliability of mean bone density.Therefore, in order to apply fixing correction or correction for this incomplete pixel, and become quasi-full pixel, thus perform replacement Treatment described later.

Below, pre-treatment portion is described in detail.

In Figure 28, illustrate the concrete structure example in pre-treatment portion 290.Object particular portion 296 based on two-dimensional detection value array 298, and is carried out specific according to Rule of judgment 300 to the detected value that should be set to displacement object.Operational part 302 has one or more detected values of fixing relation based on displacement object, and to replacing the substitution value of displacement object to carry out computing.But also can copy detected value simply when not implementing the computing of substitution value.Displacement enforcement division 304 performs following process, that is, make the detected value be prepared for described displacement object replace displacement object.

In Figure 29, particularly exemplified with Rule of judgment.When meet by replacing object when two conditions shown in symbol 316 and 318 specific.Specifically, by the condition shown in symbol 316 be, the condition that " detected value internal a detected value belong in bony areas " paid close attention at present is this.By the condition shown in symbol 318 be, the condition that " detected value internal another detected value contain border " paid close attention at present is this.When meeting this two kinds of conditions, shown in symbol 320, another detected value be judged as containing border is displacement object, and carries out correction to this another detected value.That is, replacement Treatment is implemented relative to this another detected value.In addition, also when judging whether to perform replacement Treatment, the size of another detected value can be considered.Concrete example about replacement Treatment considers several method, uses Figure 32 to Figure 34 to be described this hereinafter.

Illustrate comparative example in fig. 30.Symbol 322 represents bony areas, and symbol 324 represents two-dimensional detection value array.Two-dimensional array 326 is similarly set with in the prior art relative to this.In this case, the detected value be illustrated by the broken lines is to being valid pixel.By the detected value shown in symbol 328,330 to by the detected value shown in symbol 332,334 to not being regarded as valid pixel.This is because their detected value contains border 322.

In Figure 31, illustrate the typical example of the replacement Treatment be performed in the bone density measurement device shown in Figure 27.Using the situation shown in Figure 30 as prerequisite, as shown in figure 31, be judged as detected value 328,332 for displacement object, and relative to detected value 328,332, and replicate same kind and the most contiguous effective detected value 338 (reference marks 340,342).That is, replacement Treatment is implemented relative to detected value 328,332.Thus, as shown in figure 31, two valid pixels can be increased.In this example, three L13 are created.By being suitable for this process to the displacement object of necessity thus constituting the two-dimensional array after pre-treatment 336.The detected value considering due to displacement to belong in bony areas and is the most contiguous value, even if be therefore regarded as the value of displacement object, also can not produce great error.Be effective detected value with displacement group of objects detected value in a pair, thus replacement Treatment can be called the method that this effective detected value is applied flexibly.Owing to increasing valid pixel number according to this replacement Treatment, therefore improve the reliability of measurement on that point.

By the way, in the example shown in Figure 31, also detected value L11 can be set to displacement object, and above-mentioned replacement Treatment is applied to it.In addition, also detected value L15 can be set to displacement object, and above-mentioned replacement Treatment is applied to it.Naturally, also can adopt following mode, that is, not all detected values be judged out containing border are all set to displacement object, and only when detected value meets predetermined condition, implement replacement Treatment.

Next, the concrete example of Figure 32 to Figure 34 to replacement Treatment is used to be described.

The first example is illustrated in Figure 32.(A) two-dimensional detection value array 344 is illustrated in.Symbol 350 represents border.(B) specified conditions and the replacement Treatment content of displacement object is illustrated in.In this example, using the permutizer condition shown in Figure 29 as prerequisite, shown in symbol 400, when the detected value containing border is below predetermined value, namely, when being regarded as the probability in bony areas and being higher, this detected value is judged as displacement object.Further, shown in symbol 402, relative to this displacement object, in bony areas and with kind and the most contiguous detected value be replicated (reference marks 354).Specifically, when detected value constitutes a pixel to 346,348, and when detected value 346 by specifically for displacement object, can refer to nearest and congener valid pixel value 354 relative to this detected value 346 and it is copied to displacement object.

Illustrate the second example in fig. 33.Illustrate two-dimensional detection value array 344 in (A) of Figure 33, in described two-dimensional detection value array 344, have border 350.Specified conditions and the replacement Treatment content of displacement object is illustrated in (B) of Figure 33.Shown in symbol 404, using the condition shown in Figure 29 as prerequisite, the detected value 346 containing border and below predetermined value is specific as displacement object.And, shown in symbol 406, by bony areas, using replace object as standard specific go out proximity detection value group, and carry out computing based on described proximity detection value group to interpolation value (extrapolated value), thus displacement object 346 is replaced by this interpolation value.This process is represented by symbol 358.

The 3rd example is illustrated in Figure 34.In (A) of Figure 34, symbol 344 represents two-dimensional detection value array, and symbol 350 represents border.Symbol 346 is for as displacement object and by specific detected value.That is, by shown in the symbol 408 in (B) of Figure 34, using the condition shown in Figure 29 as prerequisite, specificly go out to replace object, using as the detected value containing border and below predetermined value.And, shown in symbol 410, the specific proximity detection value group going out to replace object in bony areas, and by the weighted addition process based on described proximity detection value group to calculating substitution value.Further, replace object to be replaced by this substitution value.It is represented by symbol 362.

As described above, by implementing replacement Treatment for specific detected value, namely by application pre-treatment, thus the valid pixel number be present in bony areas can be increased on apparent, its result is, obtaining such as when carrying out computing to mean bone density, the advantage that this operational precision is this can be improved.

(5) there is the bone density image of the resolution of twice

In Figure 35, illustrate the generation method of the bone density image of the resolution with twice.Two-dimensional pixel value array 364 is set with relative to two-dimensional detection value array 366.Two-dimensional pixel value array 364 is for being made up of the multiple pixels be set in units of half-pixel amount in the X direction.Such as, when being conceived to n-th pixel 368 and (n+1)th pixel 370, be repeated half-pixel amount between which, as its result, picture element density doubles in the X direction.

Although exemplified with bone density measurement device in each above-mentioned structure example, also above be described principle can be applied in fats measurement etc.The animal beyond human body and human body can be considered as measured body.Particularly, because the situation that cannot increase valid pixel when the measurement of toy is more, therefore, preferably said method is applied.

Claims (10)

1. a medical X-ray measuring device, is characterized in that, comprising:

X-ray generating unit, it is arranged on the side of measured body, and while carrying out movement, alternately repeatedly irradiates low-energy X-ray and high-energy X-rays relative to described measured body;

X-ray detecting unit, it is arranged on the opposite side of described measured body, and detects through the low-energy X-ray of described measured body and high-energy X-rays, thus output detections value row;

Judging unit, it arranges based on described detected value, judges the border between the first tissue in described measured body and minor microstructure,

Described detected value row comprise, multiple low-energy X-ray detected value that the moving direction of described X-ray generating unit alternately arranges and multiple high-energy X-rays detected value,

Described judging unit by judging tissue class for each detected value in described detected value row, thus judges described border.

2. medical X-ray measuring device as claimed in claim 1, is characterized in that,

Arrange relative to described detected value, with the multiple adjacent detected value pair of the contextual definition being mutually repeated half,

Described judging unit for each described adjacent detected value pair, and judges described border.

3. medical X-ray measuring device as claimed in claim 2, is characterized in that,

Described judging unit comprises:

First judging unit, its low-energy X-ray detected value based on described adjacent detected value centering and tissue class is judged;

Second judging unit, its high-energy X-rays detected value based on described adjacent detected value centering and tissue class is judged;

Comprehensive descision unit, it is based on for the right judged result of described first judging unit of described adjacent detected value and the judged result of described second judging unit, and judges described border.

4. medical X-ray measuring device as claimed in claim 3, is characterized in that,

Described comprehensive descision unit based on the judged result of described first judging unit and the judged result of described second judging unit difference and judge described border.

5. medical X-ray measuring device as claimed in claim 3, is characterized in that,

Described judging unit also comprises:

Bone density arithmetic element, it is for each described adjacent detected value pair, carries out computing according to forming the right low-energy X-ray detected value of described adjacent detected value and high-energy X-rays detected value to bone density;

3rd judging unit, it judges tissue class based on described bone density,

Described comprehensive descision unit based on the judged result of described first judging unit, the judged result of described second judging unit and described 3rd judging unit judged result and described border is judged.

6. medical X-ray measuring device as claimed in claim 1, is characterized in that,

Comprise scope determining unit, described scope determining unit is determined bone density operating range based on described border.

7. medical X-ray measuring device as claimed in claim 1, is characterized in that,

Comprise pixel column selection unit, described pixel column selection unit is selected to the first pixel column pattern and relative to staggered the second pixel column pattern of half-pixel of this first pixel column pattern based on described border,

Each pixel forming described first pixel column pattern comprises, the low-energy X-ray detected value pre-existed in a predetermined direction and be present in its tight after high-energy X-rays detected value,

Each pixel forming described second pixel column pattern comprises, the high-energy X-rays detected value that described predetermined direction pre-exists and be present in its tight after low-energy X-ray detected value.

8. medical X-ray measuring device as claimed in claim 1, is characterized in that,

Described first is organized as skeleton, and described minor microstructure is soft tissue,

Described border is the border between described skeleton and described soft tissue.

9. medical X-ray measuring device as claimed in claim 1, is characterized in that,

Described first is organized as fat, and described minor microstructure is the soft tissue beyond described fat,

Described border is the border between the soft tissue beyond described fat and described fat.

10. a border determination methods, it is for according to by alternately repeatedly irradiating low-energy X-ray and high-energy X-rays while carrying out movement relative to measured body and the detected value row detecting low-energy X-ray and the high-energy X-rays through described measured body and obtain, judge the method on the border between Bone and soft tissue

The feature of described border determination methods is,

Described detected value row comprise, multiple low-energy X-ray detected value that the moving direction of described X-ray generating unit alternately arranges and multiple high-energy X-rays detected value,

The method comprises judgement operation, and described judgement operation by judging tissue class for each detected value in described detected value row, thus judges described border.