DE1764503A1 - Tomographic gamma ray scanner - Google Patents

Description

Shark Oscar Anger, 1771 Highland Place, Berkeley, California 94709 / USA

Tomographic gamma ray scanner

The present invention relates to display devices for mapping the distribution of radioactivity, and more particularly Devices for the simultaneous acquisition of images, each in a different plane in the one to be examined Are substance focused. The invention described herein was made in the course of or under the contract U / -7405-eng-48 with the Atameneucjiekommiaion of the association

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United States made America.

In a typical application of a radiation indicator , a radioactive substance is introduced into a subject, e.g. via an internal patient, to localize an area where such a substance is concentrated or to guide the flow of the substance through part of the subject follow. Some conventional radioactivity imaging devices provide a single image because £ is focused in a single plane in the subject. Since the depth of a radiation source in the subject is generally unknown, several readjustments of the imaging device are required before a focused image is obtained.

Even if a focused image is obtained, the spatial configuration of the radiation source in the subject cannot be determined.

In the apparatus of the present invention, a number of images are obtained simultaneously, each of the images being focused in a different plane in the subject. To obtain multiple displays, a display device for imaging radiation with a KoIi-

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mator attached next to a subject and relative movements between the collimator and the subject and / or earth. The relative movement causes radiation images of the radiation sources in the subject to move via a scintillator in the display device. The speed and extent of movement of the image on the scintillator is related to the depth of the source in the subject. The radiation image and the more precisely the scintillations in the scintillator are then converted into output signals. The output signals u / earth adjusted and combined with output signals the coordinate position of the display device for the Define radiation image so that sharply adjusted recordings of the radiation distribution are obtained and recorded in different planes, for example on a photographic film or in one Computing device.

It is an object of the present invention to provide an improved one Device for displaying the exact position of radioactive material in a selected plane of a To create the subject.

It is another object of the present invention to have multiple images of radioactive material in one Subject at the same time, with each image in

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a different plane in it is in focus.

The invention is best used in connection with the Understand drawing.

Fig. 1 is an overall view of the scanning device a, wherein the electronic circuit is shown in block form.

1 0 Fig. 2 is a sectional view taken along line Q}

in Fig. 1.

Fig. 3 is a partially sectioned view of a

Image aonde, where radiation sources are shown for the sake of explanation.

Fig. 4 is a schematic representation of the display device.

Fig. 5 shows multiple views of the oscilloscope screen

4 for different positions of the image probe of FIG. 3

Fig. 6 shows the formation of a portion of three readings for point sources on three different levels of ^f Fig * 3 and

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Figure 7 shows five complete readings of the sources of Figure 3, each focused in different planes.

Several image scanners suitable for use in the present invention are described in detail in " The Transactions of the Instrument Society of America " Vol. 5, No. 4, pp. 311-334, October 1966. The embodiment of the invention described herein employs an image display device similar to that shown on pages 313, 314 and the above publication and shown in FIG. 2b. U.S. Patent No. 3011057, issued November 1961, entitled "Radiation Image Device".

Fig. 3 shows a broken view of such an image detector 43, which has a thick scintillation crystal 61 on the inside of an outer ^ the radiation shielding housing 62 and a group of above Has crystal arranged photocells 65. On the Scintillation crystal 61 falling radiation creates a flash of light in the crystal, which is a signal in each photocell 65 is generated with an amplitude which varies in accordance with the distance between the scintillation and the photocell changed.

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Generally speaking, a colimator is one with a large number of small openings adjacent to the Scintillatexon crystal attached between the crystal and the subject containing the radiation source. The radiation from one The source passes through the collimator to generate radiation images and flashes of light in the scintillation crystal. The size of the radiation images from a source, say a point source, changes ^ - changes as a function the distance between the source and the focal plane of the colimator and therefore the distance between the colimator and the source.

During the relative movement between the collimator and the source, the radiation image moves with it a speed across the scintillation crystal, which is also a function of the distance between the colimator and the plane in which the source lies / varies. The moving radiation image causes the appearance of flashes of light in different parts of the scintillation crystals that become scintillations picked up by the photocells and converted into electrical output signals that define the position of the scintillations on the crystal. The output signals are matched with signals combined that indicate the coordinate position of the image detector and in such

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a UiEise recorded as the record of the display provides focused images of the radiation sources in a number of different planes in the subject.

As can be seen from FIG. 3, mostly the focused collimator 63 have a number of thin coaxial shields each delimiting a truncated cone, the Tips lie on a common point 64. Point 64 is the focus for the collimator and radiation from a radioactive point source 66, which is located at such a focal point, can be between all of the Spread shields in the colimator and create scintillations or flashes of light over the entire surface of the crystal 61 cause. As already discussed, cintillations in the crystal 61 are caused by photocells 65 each producing eventual output signals whose amplitude is the distance from the scintillation corresponds to the photosensitive surface of the photocells. The output signals are an image circuit 44 (shown in block form in FIG. 1) which generates deflection (coordinate) signals corresponding to the position correspond to the individual scintillations on the crystal and an intensity (brightness) signal. The image circuit 44 uses known components and their output

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Signals are fed to a cathode ray oscilloscope 46 (shown in FIG. 4). When using such Signals and ground flashes of light cause them to appear on the oscilloscope screen at positions which correspond to the positions of the individual scintulations in crystal 61 correspond.

Other sources of payment such as a point source 67 in a plane A between the focal plane and the collimator is attached and a point source 6Θ which lies on a plane E beyond the focal plane. Radiation from these sources can only pass through one or some

pass through the openings in the colimator and therefore creates images and flashes of light that spread over a smaller one Extend the surface of the scintillation crystal. The source 66 is arranged in between on a focal plane C, while planes B and D are for later use are shown.

A special lens system in a light shield 47 (shown divided in Fig. <) Projects images that appear on the screen of the oscilloscope 46 onto a forographic film in a second light shield 4Θ, which will be described in more detail below.

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1 and 2 is apparent from Figs. 1 and 2 is a device

10 is provided in order to move the collimator preferably in a straight line relative to the radiation source. General considerations of rectilinear scanning are described on pages 381-426 of Instrumentation in Nuclear Medicine by Gerald 3. Hine, published by Academic Press, New York 1967. Apparatus 10 includes a stationary platform or table

11 with supports 12, with sufficient space under the table to place a subject or specimen 13 on a To attach pad 14. Usually only a small portion 16 of the specimen is of interest. A lower be— moveable platform 17 is on the table 11 on wheels or Rollers 18 received, which are suitable to roll across the table 11 in grooves or tracks 19 therein. A Motor 21 on the table 11 pulls the movable platform 17 through as a result of the closing of a power switch 22 Winding of a rope 23 on a drum 24 which is driven by the motor 21. A normally closed one Microswitch 26 connected in series with motor 21 is finished when one is attached to the platform Tab 27 is actuated automatically the forward movement of the lower movable platform 17.

An upper movable platform 28 is on wheels 29, the

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run in grooves 31 in the upper surface of the lower movable platform 17 ^ recorded, u / obei the grooves 31 are arranged with respect to the tracks 19 in the table 11 at an angle of 90 ° to it. First and second motors 32 and 33 are alternately fed to alternately pull the upper platform in opposite directions controlled by a normally closed limit switch 34 and a normally open limit switch 36, both of which are attached to the lower platform 17. A tab 37 on the top platform actuates the limit switch at the desired limits of the ^ti ewegung. A relay coil 38 is connected in series with the limit switches 34 and 36. When a mains switch 39 is closed, the motor 33 is fed by the relay contact 41, since the relay coil 38 is not fed. When the limit switch 36 is closed by the tab 37, the ITIotor 32 is fed through the contact 41 and the motor 33 is switched off. The relay coil 38 remains in operation through the holding contact 42 until actuation of the rotor 32 causes the tab 37 to open the normally closed limit switch 34. The relay is thereby switched off and the motor 33 is switched on again.

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A couple of position indicating motors or selenium motors 49 and 51 detect the movement of the upper bzui. lower platform, u / above the motors have gears, which engage in a rack attached to these platforms. Thus, electrical output signals which indicate the coordinate position of the colimator (and the image detector) with respect to the specimen 13 and used to remotely repeat the movement of the platforms.

The image detector 43 is mounted on the upper platform 2d, extends downward therefrom and faces the specimen 13. The image detector 43 is in a straight line Scanning pattern moved over the part 16 of the test piece 13. To provide such sampling, the Motor 21 causes the lower platform to reciprocate the upper platform 28 a lot move slowly.

In Fig. 4, a display device 45 is shown with the light shields 47 and 48 removed. A Arrow 72 is shown on the screen 71 of a cathode ray tube in the oscilloscope 46 to indicate the various optical properties of the display device easier to make understandable. However, such an arrow should 72

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not be an example of an ad like that in operation the present invention is obtained because only individual » Points of light appear temporarily on the screen 71.

A photographic film 73 is fixed on an upper movable table 74, which is received at opposite end faces of the table by guides 76, the guides in grooves 77 fit into the end faces of the table 74th A Seleyn motor 78 receives the output signals from the Selsyn motor 49 of FIG. 1 and drives a gear 79 which engages a rack on the table 74 and causes the table to move in synchronism with the upper platform 28 of FIG will. The motor 78 and guides 76 are attached to a lower table 82, which in turn is moved laterally in the same manner as the upper table 74. Guides B3 fit into grooves 84 in the lower table which is driven by a Selsyn ITIotor 86 over Gear 87 and a rack 88 is driven. The motor 86 follows the motor 51 of FIG. 1, thereby moving the film 73 in synchronism with the image detector 43. The speed of movement of the film can of course be different from that of the image detector and be greater or lesser as is best practicable.

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The film 73 is divided into a number of fields 73 a to e, which is the number of different by the Device corresponds to the levels displayed. In a currently preferred embodiment, five levels are displayed, so that five fields 73 a to 73 e are arranged on the film. Each field corresponds to the full one through the image detector 43 scanned area.

The images of the screen 71 are projected onto the film 73 through lenses of different focal lengths, to obtain in focus records of the radiation distribution of the five planes in the specimen. The five records show the position of the radiation sources in the form of readings before dissolution. The levels are chosen so that they cover the entire depth of the specimen. Create the radiation records an image of the distribution of the radiation sources in the specimen.

A lens 89 is between the screen 71 and the film 73 attached and provides a relatively large image of the screen 71 on the field 73 a. A lens 91 is also is placed between the screen 71 and the film 73 and brings a smaller image of the screen 71 onto the field 73 b of the film. A plate 92 is near the film

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attached and usually an opening 93 through which light from the screen 71 can fall on the field 73c. A combination of an erecting prism 94 and a lens 96 and a combination of an erecting prism 97 and a lens 9ti each bring increasingly larger images of the screen 71 onto the fields 73d and 73e, the images being reversed with respect to the images from the lenses B9 and 91 are. The lenses 89 and 91, the plate 92, the lenses 96 and 98 are also each designated by the letters A to E in order to indicate which lens provides an image which is focused on the correspondingly designated planes A to E in FIG is. It will be appreciated that a light shield is provided to prevent extraneous light from entering the film 73.

The reading method is considered in detail in connection with FIGS. 5-7. To simplify the explanation, the scanning movement is shown as advancing across the scanning area, rather than a slightly oblique one Sampling achieved with the device shown in Figs. If desired, a transverse scan can be achieved with a slight change in the device of FIGS. 1 and 2.

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Fig. 5, the light flashes shows on the screen 71 of the oscilloscope as Schiit images 67a to 67e, 68a to 68e, and 101 for five samples de3 image detector 43 through the sources 67, 66 and 68 on the levels A ₁ C and E of Figure 3 lie. An image of the source 67, for example two centimeters from the collimator on the plane A of Fig. 3, appears on the scintillation crystal 61 and therefore also on the screen in the form of screen images 67a during the first scan line. The screen image 67a appears on the lower part of the screen and moves across the screen in the opposite direction to the scanning direction. After the screen 67a disappears, the screen 68a of the source 6d appears on the screen 71 in the same way. Since the source 68 is beyond the focal plane C}, the screen image 6d a appears on the top of the screen and moves across the screen in the same direction as the scanning direction. During the next scan, the screen image 68b appears first and then the screen image 67b. It should be noted that during the successive scans the screen images move across the radiation sources towards the center of the screen and then to the other side of the screen. The closer a radiation source is to the focal plane, the larger the radiation image on the scintillation crystal 61 and the screen image on the

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Screen 71 and the faster I move the images across the crystal and screen. Thus, the screen image 101 displayed by the source 66, for example, β cm geometric T _r is ennebene of the collimator at the level C, only briefly on the screen, as the response zone is closest to the focal plane.

FIG. 5 therefore illustrates the screen images during five scans over the sources shown in FIG. Each of the S _c hirmbilder 67a to 67 and β 68 a to 68 e moves naturally from its first appearance on the screen until its l / erschwinden constantly and evenly over the screen. When the image detector 43 scans the source 67 (scan line 1 of FIG. 5), radiation from the source propagates through only passages in one side of the collimator 63, thus directing radiation to only one side of the crystal 61 and causing it to appear of the screens 67 a. As the detector 43 continues to move over the source 67 during subsequent scans, radiation propagates through the passages in the center of the colimator to give the screens 67c and then through the passages on the opposite side of the collimator to effect the screen images 67e. When the source 66 is at the focal point 64 of the collimator 63, the radiation therefrom can travel through all of the co-

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Spread limator passages. The screen 101 that obtained when the image detector 43 is on the source 66 is directed, spreads over the entire screen 71 and therefore covers it completely.

Recall that film 73 moves in synchronism with detector 43 so that the X-Y position of the detector relative to specimen 13 is the same as the X-Y position of the film with respect to screen 71. The latter, however, preferably has a reduced scale so that radiation records are relatively easy large subject, such as, for example, the head of an I-man read from a relatively small film u / earth. From the set of oscilloscope displays shown, several levels can be made with the help of the lenses and the plate of Fig. 4 in sharp detail.

First consider the level C reading. The pinhole plate 92 is almost in contact with the Field 73c of the photographic film attached and remains stationary or stationary with regard to the oscilloscope. If a radiation source is at the focal point of the Kolimator8 appears, a fully illuminated one exposed Screen 71 (screen 101) the film through the opening,

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which results in a high resolution exposure due to the high light intensity and the short duration of the flash. Screen images t / on radiation sources in other planes result in blurred, low-resolution exposures of the film in the field 73c through the opening in the plate 92, sometimes screen images such as one of the screen images 67a to 67e over relatively long periods of time on the screen remain. Thus, only film exposures from sources in the focal plane of the colimator will clearly and sharply ground.

Figure 6 is a graphical representation of a scintillator scan reading from the source shown in Figure 3 as created by lens 69, lens 98 and plate. The top part of Fig. 6 illustrates the size and the relative position of the flashes of light on the scintillation crystal or the screen images 67 c, 68 c and 1Q1 on the oscilloscope screen 71, while of the third scan line illustrated in FIG. 5, where the image detector 43 is directly above the sources 66, 67 and 68 moves.

The reading of radiation sources in plane A which are, for example, two centimeters away from the collimator

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is, consider first. When the image detector 43 the source 67 scans, the screen image 67c moves over the slide 71 from right to left. The screen 67 c u / ird through the lens 39 on the field 73 a des photographic film 73 is projected. The film 73 moves in the same direction and at the same speed, u »ie the screen image 67c projected onto the film through the lens 89, so that all screen images 67c are on the same Area of the film can be recorded. Thus uiird the source 67 on the film read with sharp resolution.

Only one scan line is shown in Figure 6, however causes the source 67 also screens 67a, 67b, 67d and 67e while other scans past the Source, but not directly above where the radiation from that source reaches the scintillation crystal. Although the screens 67 a, b, d, and e are not centered on the screen 71, as is the screen 67 c they nonetheless superimposed on the same area of the image 73 a of the film because the transverse displacement of the images on the screen as shown in Fig. 5 is copied through the table 74 and the film. On reading A of FIG. 6, the source 67 is thus sharply resolved because of the movement of the screen images 67a to 67e

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is equal to the motion of the film 73.

The screen 101 from the source 66, on the other hand, becomes

at reading 73 a not sharply resolved and because the screen image 101 covers the entire screen 71 it is enlarged by the lens 89. Though an exposure of the film takes place, it is out of focus. The screen images 68 a to 68 β from the source 68 also cause exposure of the film in the field 73 a, but it is likewise not sharply resolved at the reading A because their movement across the screen 71 is not equal to the movement of the film. Thus only the screens result 67 a to 67 e from the source 67 in the plane A a sharply resolved image or a reading in the field 73 a, which indicates that a radiation source is in this level is located. The coordinate position of the reading in the field 73a of the film is of course determined by determines the position of the table 74, which in turn corresponds to the position of the detector 43 with respect to the specimen 13, so that the reading exactly matches the position the radiation sources shows.

When reading 73c, the screen image 101 is sharply resolved by the source 66 because the opening in the plate 92 is small and the scintillations appear on the screen 71 only for a short time, namely when the focused collimator 63 is aimed precisely at the source 66. Screens of sources, such as the sources

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67 and 60 in planes other than the focal plane C. not sharply resolved in reading C, but while appear on the screen for a long time after scanning. Thus, the film exposures in the Field 73 c uon sources that are not in the focal plane do not have a high resolution.

When reading 73 e, the screen images 68 a to

68 e are projected onto the field 73 e of the film sharply resolved, uieil the erecting prism 97 the direction of movement of the screen image on the screen 71 is reversed. The projected screen images 66 a to 68 e move with it the film as did screens 67a through 67e referred to above. Same area of film in that Field 73 e is exposed as long as the screen images 68 a to 68 e appear on the screen.

If there is a source on level B, maybe 5 cm away from the colimator, the corresponding screens move across the screen faster than the Screen images from the source 67 in the plane A. Uiie mentioned earlier, this is due to the fact that the speed with which the scintillations from a radiation source move over the crystal 61 and therefore the speed at which the umbrella

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move images across screen 71, a function of the distance between the colimator. 63 and the source is. Oa, the speed of the table 74 and the film is constant, i $ t it necessary _f the focal length of the lens 91 to be chosen so that the screen image projected on the panel 73 b of the film at the same speed moved as the table 74 and the film .

Thus it can generally be said that the lenses of the display device 45 must be selected as follows: Each lens must have a focal length that corresponds to the projected screen images produced by a radiation source originate in a plane to be read through each lens, causes them to move at the same speed and in the same direction as the film on which it Image is projected. Screen images of all radiation sources in other than the specified plane move although they are projected onto the film at different speeds than the film and do not give a clear image. Radiation sources can be placed on this U / Eise can be recorded in the specific plane with high resolution on the film. A reading of several of these Levels provides a radiation record from different levels of the specimen and thus ensures

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that essentially every part of the specimen is sharply resolved in one of the readings.

To read planes D and E the 11 and 14 cm from that Coimator 63 are remotely located, and / or ground them Image sizes used as for layers B bziu. A, however, prisms 94 and 97 invert each image. For sources on the planes D and E, which are beyond the geometric separation plane of the colimator, move the irradiated Area in the opposite direction to the corresponding movement of the sources. Therefore become a reading of planes D and E erecting prisms 94 and 97 are used to track the reproduced flashes with respect to the moving film to make stationary.

Figure 7 shows a graphical representation of the readings from 5 scintillator samples from 3 sources 66, 67 and 68 on fields 73 a to 73 e. These readings are made up of many scan lines that are necessary to completely map the sources during an actual straight-line scan instead of the only one Line shown as an example in FIG. 6. Only 3 well-resolved photographic readings 66 R, 67 R and 68 R are obtained from the sources. You are in fields 73 c, 73 a, or 73 d of the film

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Stable in the fields corresponds to the position of the Sources in the specimen and their appearance on one or the other of the fields of photographic film determines at what level or how deep in the specimen they lie.

If a subject with radiation sources located therein is thus scanned, the intensity and the spatial position of the sources can be determined. Of course, if desired, a greater or lesser number of readings can be provided in order to obtain high resolution images from sources located between the in Fig. 3 levels shown are located. This requires no more than a corresponding change in the number of lenses and fields on the film. The rest of the device remains unchanged.

In order to read the activity on a given plane with maximum resolution, there must be a certain relationship between the scanning speed S of the image detector 43, the scanning speed S ^{1 of} the film 73, the recording angle (entire field of view) alpha of the focused collimator 63, the diameter D of the the film 73 projected oscilloscope image, the distance f from the focal point to the collimator and the distance b from the given

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nerve level to the colimator. The relationship is: D = 2 SJ ( _f _ _b ) tan a

The equation gives the required diameter D of image projected onto the film 73 for maximum resolution of the activity taking place on a plane at a distance b from the colimator. Without any change in scanning speeds or other parameters, activity can be read at other levels with maximum resolution by taking pictures of different Sizes are projected onto the film. The image size is determined by the position and the focal length of the used Lens controlled. For b f, D is a negative number and an image inversion is required.

When the above parameters are set to get a maximum level A resolution, source becomes 67 represented in Fig. 7 by a small intensive area, the diameter of which is equal to the irradiated area of the scintillator is how it is projected onto film 73. The source 66 is responsive to this reading by a Represents area whose diameter is equal to the screen image diameter D as projected onto the film will. The source 6b is represented by an area

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which is about twice as large as the image diameter D. Similar relationships exist in the other readings of the scintillator scan.

Many variations are possible within the spirit and scope of the invention, e.g. Point off the central axis or on a point in front of or behind the colimator or it can be focused be replaced by a pointed cone (not shown) with a needle hole-like opening. To achieve the relative movement between the collimator and the subject evidently various aids can be used and the subject could be moved while the image detector and the collimator are stationary. E.g. can the device can be constructed instead of a rectilinear scan of the subject in a circular or spiral motion to feel. In addition, the display device and / or the lenses can be moved while the film is stationary. The particular illustrated image detector can of course be replaced by other types of known image detectors will.

Instead of the photographic reading system just described, other reading systems can be provided, such as for example, a system in which the same images are stored in a digital computing device 111 as in FIG

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Fig. 1 is shown. The images can then be subsequently viewed on a display device 112 for visual examination and the numerical data are extracted by conventional techniques. Such a display device can be either an oscilloscope or an X-Y recorder of the type that uses a color pen establishes at each point of a display on paper for which corodinates information is obtained.

Assuming five complete memory core systems are provided in the computing device 111, one core system for each of the levels A to E, the images are stored as follows. First, XY signals obtained from the apparatus that causes the relative movement between the collimator and the subject, such as motors 49 and 51, are indicative of the coordinates of the image detector 43 relative to the specimen 13. Such X and Y signs can also be obtained, for example, by replacing the Hflotoren 49 and 51 with potentiometers which are mechanically coupled to the detector 43 by the described gearwheel and rack and pinion arrangement. In a straight line scanner, the origin of this coordinate system is assumed to be at a corner of the scan. When radiation is displayed, a second SeL of signals X- and Y- is displayed by the image circuit 44 for each.

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showed radiation generated as in that previously described Display device. The origin of this co-ordinate system at times is in the middle of the scintillator 61 accepted in the image detector 43.

When the image detector 43 scans the subject, each scintillation is stored in each of the 5 memory core systems in the computing device 111 as a simple operation. The memory parts are different in each memory system with the exception of the special case, mo a scintillation occurs exactly in the center of the scintillator 61, since xy- are then only. Before saving, the coordinates of the position of each scintillation are X = x + knx ¹ Y Jf y + kny ¹ _f

Ifrobei X is the x-coordinate of the stored operations in a given storage system.

Y the Y-coordinate of the stored processes in one given storage system.

k and η are constants, the amounts of which correspond to the distance from the geometric focal plane C of the collimator 63 to the determine different reading levels A, B, D and E.

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176A503

For a clear reading of activity at EbBne C (the geometric Focal plane of the focused collimator 63) kn is zero. For this reading depends on the position in which the detected radiation is stored, only depends on the position of the detector gate 43. To the sharp Reading of levels A and B kn is positive and for levels D and E kn is negative. The positions of the scintillations in the detector 43 then acquire meaning and run the polarity and size of kn are correct, the movement of the irradiated areas across the scintillator 61 is the same the deflection of the detector 43 precisely. Then other planes than the geometric focal plane are brought into focus read.

If k is a constant and η is assigned the values +2, +1, 0-1 and -2 for the corresponding levels A to E, a topographical series of levels arranged at the same distance from one another is stored in the b storage systems. A negative liiert for kn is equivalent / hange with the image from screen 71 with a prism in the above-described photographic reading system and the V inversion of tU _e RTEs is η equivalent to the projected with the change in the size of the screen 71 onto the film Image. If the coordinates are fed from a selected memory core system in the computing device 111 to the display device 112, an image is obtained,

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u / ΐθ with the previously described photographic device.

As a variation, it is possible to use the data from the Image circuit 44 and the motors 49 and 51 to store directly and the calculations described below perform to one focused on a desired level Get reading. It goes without saying that there is no limit to the number of levels which can be read off and dap the various numbers and dimensions used in the description above are only intended as an example. Therefore, it is not intended to limit the invention, except of the definitions in the following claims.

Claims

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Claims (1)

Claims 1. Apparatus for obtaining an indication of the distribution of radiation from radiation sources in a subject, marked by: (a) a radiation image producing and displaying means (43) varies for generating images of the radiation sources (66, 67, Gd) ₁ ujorin the position of the image from each source with the distance between the device (43) and the source, and the device (43) provides a first output defining the position of the images; (b) a device (17, 2ü, 49, 51) coupled to the detector device (43) for examining the subject (13) of more than one position which provides a second exit which is the position of the detector device (43) defined relative to the subject (13); and (c) an arrangement (44) for modifying at least one of the outputs and for combining the modified outputs, a preferred focus effect - 32 - 209810/0546 To provide radiation sources located at a selected level in the subject (13). 2. Device according to_Anspruch 1, g e k e η η draws by a device (45) for recording the combined outputs. 3. Device according to claim 1, characterized in that that the modifying device (44) comprises a number of modified sets of at least one of the outputs and wherein the modified outputs are separately combined to give a number of readings of radiation distribution, each focusing on a different plane in the subject are. 4. Apparatus according to claim 3, characterized in that that the image-producing and detector device (43) is a radiation-sensitive material (61) and a collimator (63) for generating the images on the material (61), the detector device (43) is moved with respect to the subject (13) and thereby the images at speeds across the material (61) moved, which vary with the distance between the detector device (43) and the sources (66, 67, 68). - 33 - 209810/0546 5. Apparatus according to claim 4, characterized in that then the collimator (63) and the material (61) are connected for common movement. 6. Apparatus according to claim 2, characterized in that the relative movement between the subject (13) and the detector device (43) causes the images to move over the detector device (43) at speeds which vary with the distance between the detector device (43) and the sources (66, 6Y, bd) and the modifying and combining device (44) contains a display device (45) which is connected to the detector device (43) in order to generate second images which correspond to the first images correspond, and a medium (/ 3) for recording the second images and a device (/ 4, Vo, ö2, b6) are present which. provides relative movement between the display device (45) and the recording medium (73) in synchronism with the movement between the subject (13) and the detector device (43). 7. Apparatus according to claim 6, characterized by a device (46) (71, 39, 91, 96, 98) for setting and projecting the second images on the recording medium (73) so that the projected - 34 - BAD ORIGINAL 20981 0/0546 178A503 Images originating from radiation sources in the selected plane move at the same speed and in the same direction as the recording medium (73). ti. Device according to Claim 7, characterized in that the projection device (71, b9, 91, 96, 9B) provides a number of adjusted second images, each balanced by a different factor and projected onto the recording medium (73), whereby the projections of the second images originate from radiation sources in a number of selected planes, move at the same speed and in the same direction as the recording medium (73). 9. Apparatus according to claim B, characterized * by a device (94, 97) .the Direction of movement of at least one of the projections changes. 10. Apparatus according to claim 7, characterized in that the projection device includes a number of lenses (89, 91, 96, 93) for projecting the second images onto separate parts (73a to 73e) of the recording - 35 -2 0 9 8 1 0/0 5 U 6 BAD ORIGINAL medium (/ 3) and to set the size of the contains projected images so in each of the parts (r3a to 73e) the projected images from the radiation sources (66, 67, 6ü) in different planes, move at the same speed and in the same direction as the recording medium (73). 11. Apparatus according to claim 10, characterized by a device (94, 97). Which changes the direction of at least one of the projected images. 12. Apparatus according to claim 11, characterized in that the detector device (43) is a converging imaging tool (63) and the lenses (d9, 91, 96, 9ö) are selected to a projected second image size D according to the relationship S
D = 2 S (fb) χ tan | to provide a focused reading of second images obtained by radiation sources (66, 67, 6a) in the different planes on the parts (73a to 73e) of the recording medium (73), where S ¹ = speed of relative movement between the display device and the corresponding part of the recording medium - 36 - BAD OBfQJNAL 2 0 9 8 10/05 46 S = the speed of relative movement between the subject and the imaging device D = diameter of the projected second image on the corresponding part of the recording medium f = the distance between the imaging device and the focal plane of the imaging device b = the distance from the imaging device to a preselected plane in the subject and a = the angle of view of the imaging device, 13. Apparatus according to claim 1, characterized in that the modifying and combining Device (44) contains a computing device (111). 14. Apparatus according to claim 13, characterized in that the modifying and combining Apparatus includes means for varying the size of the first output by at least two different factors in order to obtain at least two different sets of balanced outputs, the second outputs - 37 - 209810/0546 Signals are the coordinate position of the detector device with respect to the subject and the modifying and combining device define the coordinate position Signals to each of the sets of balanced outputs are added to give at least two readings with each reading focused on a different plane. 15. Method for producing a survey of the radiation distribution of radiation sources in a subject, characterized by: (a) the generation of images of the radiation sources (66, 67, 63) on a radiation image detector (43) in such a way, da $ the position of the image from each source with the distance varies between the detector and the source; (b) generating a first output from the detector (43) which defines the position of the images; (c) examining the subject (13) from more than one pose and creating a second exit ^ which defines the position from which the subject examines has been; - 3d - 20981 0/0546 (d) modifying at least one of the outputs and combining the modified outputs by one preferred focusing effect on the radiation sources which are at a selected level in the subject. 16. The method of claim 15, characterized by recording the combined outputs QP from subsection (d) 17. The method according to claim 15, characterized in that that the detector (43) moves relative to the subject (13) to the images over the Move the detector at speeds which vary with the distance between the detector and the sources. 18. The method according to claim 17, characterized in that that the modification of at least one of the outputs includes the following measures: (a) making second images from the first Exit · (b) resizing the second images. (c) projecting the modified second images onto a 2 0 9 8 i "o / 0 5 A 6 ^0RIGINAL recording medium, and (d) moving the recording medium synchronously with the detector at a speed wherein the projection of the second altered images originate from radiation sources in the selected plane, located in the same speed and direction as the recording medium. 19. The method according to claim 1 o, characterized in that that projecting is the measure of changing the direction of at least one the second contains images. 20 .. A method according to claim 17, characterized in that the bilaerzeugende device adjacent the detector is placed list and the measure of the relative position by Altered joint loading Jk movement of the detector with the biiderzeugenden device is characterized. 21. The method according to claim 15, characterized in that that the first and second outputs are characterized by coordinate signals and the Measure of combining the outputs, adding the - 40 - 2098 10/0546 Contains signals. 22. The method according to claim 21, characterized in that that the acceptance of modification Iodify at least one of the outputs contains the deprivation of rights by means of constants. The method of claim 22 for making readings of the radiation distribution of a number of selected ones Planes in the subject, characterized in that one of the coordinate signals modified by a set of constants whose UJet as a function of the distances to the detector and the selected levels varied. 2098 10/0546