WO2018220053A1 - Configuration d'une gamma-caméra comprenant un collimateur rotatif servant à représenter des objets à rayonnement - Google Patents

Configuration d'une gamma-caméra comprenant un collimateur rotatif servant à représenter des objets à rayonnement Download PDF

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Publication number
WO2018220053A1
WO2018220053A1 PCT/EP2018/064257 EP2018064257W WO2018220053A1 WO 2018220053 A1 WO2018220053 A1 WO 2018220053A1 EP 2018064257 W EP2018064257 W EP 2018064257W WO 2018220053 A1 WO2018220053 A1 WO 2018220053A1
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collimator
gap
angle
point
detector
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German (de)
English (en)
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Kurt Osterloh
Philipp OSTERLOH
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
    • G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
    • G21K1/043—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers changing time structure of beams by mechanical means, e.g. choppers, spinning filter wheels
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators

Definitions

  • a radiating object is understood here to be an object which either emits high-energy photon radiation as a source on its own, beyond the visible light, ie gamma rays, or is irradiated to the radiation by an external radiation source or reflects scattered radiation back.
  • Excitation to radiation may be coupled with particle radiation, such as e.g. take place with neutrons, take place at the nuclear reactions, with prompt or delayed gamma radiation is emitted.
  • particle radiation such as e.g. take place with neutrons, take place at the nuclear reactions, with prompt or delayed gamma radiation is emitted.
  • X-rays can be in the low-energy range
  • the centerpiece is a rotating collimator (230), which in its entire width of one or more columns for the passage of rays in a given Direction is crossed.
  • the task of the collimator is fundamentally to select a bundle from all the rays emanating from a radiating object and directed in the direction of a detector, with which a most accurate image of the radiating body can be produced and all others that are not can help hide, especially those that can interfere with image creation.
  • a shielding housing that not only houses an adapted detector imaging detector but also supports the selection of the beams with which an image is to be built.
  • the description is in parametric form, so that the individual design of the device can be adapted by targeted modification of individual characteristic parameters of conditions that are given by the task, specific type of radiation, conditions of use, existing resources and any individual components available.
  • the parametric description of the overall system it is also possible to provide ways to restrict the shields to the necessary extent and thus contribute to the weight reduction of the entire device.
  • the description here includes the optimum shape and size of a body of revolution for the course of the beam, the precise course of the walls of one or more columns that pass through this body for radiation selection, the design of the adjoining housing for a detector and the shielding of the rest interfering radiation and adapted shapes of the parts of a detector which converts absorbed radiation into electrical signals. Irrespective of the mode of operation of the detector, it must have a sufficiently sensitive volume, particularly in the case of high-energy radiation, in order to absorb the radiation to be detected as well. Therefore, both the corresponding volume and the arrangement of the detector contribute to the functioning of the gamma camera crucial.
  • collimators provides more direct imaging without the need for electronic coincidence circuitry or image reconstruction, but may necessarily use only a small fraction of the radiation emanating from the object for imaging, especially at higher energies.
  • the classic principle is the pinhole camera, which requires a thin diaphragm for adequate imaging. This contradicts the need for thick-walled shielding, especially for high-energy beams.
  • the prior art in medicine, where working with very low radiation doses is a necessity, is the Anger camera, the heart of which consists of a parallel hole collimator with a correspondingly large, highly sensitive areal detector. Due to the parallel alignment, only 1: 1 images are possible, for imaging, only the rays arriving almost perpendicular to the detector surface contribute. Variations to magnifying images or to detect larger areas will exist through conical arrangements of the channels in a multi-hole collimator. In practice, no system has yet been introduced which images objects of any size onto a predetermined smaller area similar to a photographic camera.
  • collimators for such a purpose have been designed in the form of bodies of radiation absorbing material intersected by one or more slots for beam passage following in their course a control surface, last described in DE 10 2014 103 833. There, a fixed aperture with several adjustable slots is presented, which is suitable, for example, for X-ray backscattering. For applications in medicine, however, it seems foreseeable that, due to the design, the sensitivity for the usually very low radiation doses is insufficient.
  • a parametric representation is selected, which directly into an exact calculation of the forms for the individual Components as well as, for example, in the implementation in design drawings, even with the support of CAD programs implement.
  • the starting point is three basic elements, a collimator for selecting imaging beams, a shielding housing and a detector with sufficient sensitive volume for the conversion of radiation into image information.
  • the centerpiece here is the collimator, which consists of a rotatably mounted diaphragm body, which is intersected by one or more surface pairs (73). These are arranged at a defined distance a from a central surface (100), which predetermines the direction of a slit through the collimator, ie determines the beam selection for the imaging. Condition is that the cuts are selected for one or more columns so that the Kollimator stresses does not fall apart and no free-floating parts arise. To understand the beam guidance, only the course of the central area (100) is necessarily considered, which necessarily represents a ruled area, in order to be able to guide all beams emanating from the object to the corresponding pixel (see FIGS. 1 to 7).
  • Coordinates x, y and z will be described (10).
  • Each point P in this space can also be indicated as a vector starting from a point F on the x / y plane (11) with both Cartesian and polar coordinates (see Fig. 1): where u represents the distance from the origin O of the coordinate system (10) and ⁇ , for the time being, quite generally an arbitrary rotation angle within a full circle about the z-axis.
  • this vertex F later also referred to as the focal point, travels on a circular arc (20) which, depending on the design of the collimator (see below), can expand into a closed circle which lies on the x / y plane (11 , which can be described with:, in which the torsion T (3) is added later [18].
  • Total volume of the collimator (230).
  • the value for r can be constant over all heights, but it does not have to be, as will be shown below.
  • the collimator is made of a material that is suitable for both the absorption of high-energy radiation, as well as dimensionally stable and machinable, for example, from a suitable tungsten alloy.
  • tungsten alloy For gamma emitters in the low to medium energy range, copper, brass or iron can also be used when it comes to realizing complex collimator shapes, especially those with multiple gaps. Since it is always heavy metals, the collimator contributes noticeably to the total weight of the camera, so it makes sense to limit the size as much as possible to a necessary extent.
  • a way is proposed to achieve this (see Fig. 2).
  • this layer thickness increases with 2 r / cos ( ⁇ ), i. the Kollimator emotions could be tapered or narrowed at least the same shield to the lower and upper end.
  • the volume of the collimator (230) can be reduced to save weight without compromising the shielding effect.
  • FIG. 2 Graphically, this is shown in Fig. 2 above, which has been taken into account that the collimator rotates in its function and thus sufficient shielding must be present both from one side and from the corresponding opposite side. Therefore, the focal point F is introduced with G in a position of the diaphragm body (230) which is rotated by 180 °.
  • the cylindrical basic shape (230) with its surface (200), characterized by the radius r, is penetrated by a straight line (52) passing through the focal point, likewise in a rotated position starting from G.
  • the height h re d is sufficient Shielding a reduced radius r red , bringing a new circular
  • variable quantities herein are r, ⁇ and ⁇ , the design-determined size is the focal length.
  • the angle ⁇ goes through a full circle, r and ß are set by the body size limits.
  • the value r must be within the maximum
  • the collimator with its outer surface (200) and its volume (230) on the one hand and the columns passing through it for the beam guidance with their orientation (74) along a twisted ruled surface (100) and its side walls (73) at a distance a of the central surface (100) on the other hand are two completely independent of each other geometric figures. It is shown below how the profile of the gap (100) arises from the surface (90), which in turn is defined by the focal point F and the axis of rotation (210). Common to both figures is the axis of rotation (210), which applies to both rotation and torsion and lies on the z-coordinate axis.
  • the gap with its central surface (100) cuts through the collimator (230) of one side to the other through the central axis (210). This is expressed formulaically in that the variable u runs through all values from -r to r. Thus, it can be considered as a separate geometric figure from the main body of the collimator (230). Common to both basic characters is the
  • the collimator (230) must not mechanically fall apart.
  • variable angle ⁇ passes through the collimator (230) within the limits of ⁇ and 72, in general terms . As the value of ⁇ approaches 0, the collimator with a gap becomes a simple hole collimator, a trivial case. If the value ⁇ reaches the size
  • the decisive factor for the directional selection of the beams incident on the detector is the running surface (100) of the gap (also referred to as the central or guide surface), which results from the torsion of the output surface (90). Without torsion it is only possible to distinguish between the directions which can be described with the horizontal angle ⁇ , but not those with different elevation angles ⁇ . A torsion about the central axis (210), which is on the z-ordinates of the
  • a torsion The purpose of a torsion is to remove the ambiguity in the height of the beam passage between the bounding lines (80) on the surface (90).
  • a collimator With a torsion of this surface with the angle a, which is in communication with the point P, around the common axis of rotation (210) is formed a collimator (230) as a body of revolution, which creates uniqueness.
  • This torsion can be described with the tensor by introducing a fixed relationship between the torsion and the height h of each point on the plane (90). It can already be read from FIGS. 1 and 3 that the following relationship holds for the angle ⁇ : h
  • the design of the gap guide (100) is therefore independent of the rotation angle ⁇ .
  • the vector contains the description of a rule surface, as described in another form already in the publications DE 10 2015 008 272 and DE 10 2016 004 624 or US Pat.
  • PCT / EP2017 / 058883 was treated here, but specifically not used.
  • angles ⁇ and ⁇ are two variables in different dimensional directions and relate independently to different rotations, once to a torsion (a) and the other to a rotation ( ⁇ ) , A separation of the two movements, described by ⁇ and ⁇ , on the one hand on the instantaneous rotational position of the collimator, whereby the current position of the focal point F is fixed, on the other hand on his torsion phase exactly in this position from the starting position. From this, the angle ⁇ can be determined, which then the Torsionskonstante c T the
  • Elevation angle ß determined.
  • the torsion of a surface causes the receipt of height information.
  • About the horizontal direction to the object point P out gives the current rotational position information.
  • the collimator (230) together with the rotation body described in (1), ie the collimator (230), one obtains both information.
  • the torsion is limited to the vector ⁇ and is defined by the torsion constant c T.
  • the limits for u are given by the circular boundary (200) of the collimator, ie by -r and r.
  • FIG. 4 the effect of different degrees of torsion is shown from above, here by means of a point P at the height h at the edge of the surface (100).
  • the two parts of Fig. 4 differ in angle a. Due to the torsion, the point P leaves its starting position (22), which he previously held. The torsion affects not only this point, but also on all superimposed points in the position (22), which differ in height above the x / y-plane (11), ie lie one above the other. After the torsion, these are all on the line (101), which also represents the gap opening in the collimator when it comes to rest on the surface (200). The migration of the point P is through the
  • Relation (2) can also directly derive upper limits for the torsional constant as follows:
  • torsion constant c T depends strongly on the size of / and the ratio of Ai, 2 /. In any case, ⁇ c T ⁇ »O must be in order to allow a beam path from one side of the collimator to the other. The sign of he indicates the direction of the twist.
  • the Variable u is used to describe the path of a beam through the collimator.
  • each imaging beam (50) is determined by the associated focal point F and by the z-axis which coincides with the central axis of rotation (210).
  • ⁇ a picture line is generated.
  • the diaphragm body (230) with the gap in its orientation (100) has to rotate about the axis (210), which is also expressed in the clear separation of ⁇ and ⁇ in the system of equations (4).
  • the rotation ie as the change of ⁇ progresses, an image is created line by line.
  • This is also the basis for the ability of the rotating collimator (300) to create, with columns along one or more twisted areas (100), an image that can be registered with a suitable detector.
  • the parameters / and c r are crucial for imaging, as this determines the line geometry.
  • Another shape-defining parameter for the collimator (230) is the radius r to the outer surface (200), which does not necessarily have to be kept constant, but can be adjusted with the height for weight optimization (see above). 5 illustrates that with the radius r, the extent of the outer boundaries (200) of the collimator is freely selectable within wide limits. A lower limit is through the
  • low-energy gamma lasers such as 99m Tc
  • 5 cm of any heavy metal such as copper, iron or alloys such as brass can be sufficient, with high energy from 131 1 a denser material such as tungsten is attached. It can also be realized larger layer thicknesses.
  • Rotational body shapes preferably output values for the application of practically used gamma emitters in the manner mentioned.
  • the focal points F lie on the surface (200) of the collimator. If r exceeds this value, the circular arc (20) with the focal points comes to lie within the collimator body (230) (see Fig. 5 below), which is quite possible in design terms.
  • the gap exit (102) from the collimator on the surface (200) in the direction of the detector is still visible
  • the value for the distance / the focal points does not run to 0, ie not coincide with the axis of rotation (210), otherwise the body (230) falls apart.
  • the body heights h ⁇ and h 2 are set from the x / y plane (11), which may well be different. With these two values, the limits ⁇ and 72 are given (see above), which dictate the vertical viewing angle of the gamma camera.
  • filigree structures can form in the volume (230) of the collimator, which can be poured out and solidified with a binding material that is transparent to gamma rays, ie. consists of light elements such as long-chain hydrocarbons.
  • a binding material that is transparent to gamma rays, ie. consists of light elements such as long-chain hydrocarbons.
  • An odd number is preferably chosen for the number of columns in order to avoid or minimize as far as possible the mutual interference of opposing columns.
  • the circular arc (20) can be extended in both ways beyond a full circle if it is ensured on the detector side that several image lines can be registered simultaneously (see also DE 10 2016 004 624).
  • Image detector falls, ie the sum of the angles ⁇ and ⁇ as a direction sensor for the point P in the angular range ⁇ 1 ⁇ 2 falls, which is covered by the detector.
  • rays that run through the focal points F inv which lies on the opposite side of the central axis (210), ie the object side facing, but also on the circle (20) of all focal points (middle part of Fig. 7) is located. Since these rays interfere with the image structure, they must be shielded or appropriately avoided.
  • the principle of shielding is shown in Fig. 7 below, with a shielding wall (310) which leaves at the height of the circle (20) with the focal points, a gap (330) for the imaging rays. In principle, the need for shielding has previously been demanded (see DE 10 2016 004 624), but without proposing a specific embodiment.
  • focal point F lies on a "wrong" side of collimator 230, thus disturbing the image, and its penetration can be mechanically suppressed by designing suitable shielding walls, which will be further elaborated here
  • a phase-locked gating is possible, ie, switching on and off of detector areas as a function of the instantaneous rotational position of the collimator body 230, ie, of the instantaneous angular position ⁇ Focal point F is directly opposite the circle 20.
  • the detector areas which are reached by inverse rays (51) via the remote foci F inv , are then inactive, so that only beams (50) are selected for image construction If such a circuit is not t is set up, can also subsequently a picture interference by the inverse beams (51) arithmetically by a Deconvolution of the distorted image done with a function that describes the inverse beam path.
  • FIGS. 8 to 10 Other ways of suppressing the influence of in-directed beams (51) on the imaging are provided by several types of collimator (230) design and the adjacent housing, which also provides shielding inside the housing. Examples of this are shown in FIGS. 8 to 10.
  • a principal shield (310) which can be seen in FIG. 7, is structurally implemented such that inversely incident beams (51) are absorbed as effectively as possible.
  • rays from different directions arrive at the same location, which then becomes one
  • Optimal shielding should provide a sufficiently long distance s in the absorbing medium towards the beam (51) to be absorbed.
  • the length of this distance can be calculated by the projection onto the x / y plane (11), which results from the angle of inclination ⁇ iHV of the relevant inverse beam (51) passing through the detector-distant focal point F inv .
  • the projected distance s P can be divided into two sections s t] and s t2 , which are located in front of or behind the position of the focal point F from the view of the detector. These can each be arranged in their height h s] and h s2 above or below the x / y plane (11), as shown in FIG. 8.
  • the avoidance of the falsification of an image by inversely incident rays (51) is effected by a weighing of the parameters / and ⁇ depending on the radiation energy, the absorptivity of the shielding material and the size of the collimator and the tolerance limits for ⁇ iHV which one is prepared to accept.
  • the shielding of inversely incident beams (51) can be achieved by changing the design of the collimator (230) with its splitting curves (100).
  • this can also be achieved in that both
  • Limit angle ⁇ and ⁇ 2 are provided with the same sign, that point, starting from the direction of origin 0 ° in the same direction. With such measures, only beam paths from one side up to the other side down or vice versa for the imaging beam (50) are possible, while the inverse (51) diametrically
  • FIG. 9 Such an arrangement is shown in Fig. 9, wherein the detector is arranged bottom left and thus the object to be imaged must be located in the upper right of the image.
  • the focal points F including F inv, are here on the surface (200) of the collimator.
  • the arc (20) coincides with the focal points F with the line of the exit points (102), so that
  • Detector housing with the walls (315) only a small gap is needed. Inversely incident beams (51) can only run in the horizontal plane, ie via the x / y plane (11) to the detector space.
  • the upper cover wall (315) of the housing was slightly raised against the Horizontal plane, given by the x / y plane (11) in the height of the origin O in the coordinate system (10), inclined, as can be seen from the illustration in FIG. 9 with the solid lines.
  • the same principle can also be made more efficient by shifting the foci into the collimator body (230) (see Fig. 5). As a result, the beam guidance in the x / y plane (11) through the
  • housing wall (315) are totally blocked, as shown in Fig. 10).
  • the outputs for the imaging beams (50) are all below this plane of the coordinate origin O.
  • the collimator (230) deviating from the cylindrical shape can be designed as a rotational body (201), as demonstrated in FIG.
  • the coincidence principle can also be used to differentiate between imaging (50) and inverse (51) beams. These are two separate sensitive
  • the second sensitive volume (300) is located beyond the circular arc (20). From the point P, an imaging beam (50) passes through the first sensitive volume (320) into the second (300) outside. Thus, the signals from the passages in the first and second volumes (300) coincide.
  • Detector material must be considered directional deviations due to the Compton scattering. However, this can conversely also be used to determine the beam direction, as is in principle practiced in Compton cameras (for example US Pat. No. 4,529,882). Thus, electronic discrimination of the beam directions may complement or even replace selection by shielding.
  • the gap oriented at the ruled surface (100) must have a width which may or may not be constant over the path through the collimator.
  • a vertical elevation angle ß is assigned, is expected from a torsion ⁇ e 2 - ejvon about 120 ° a circular beam profile transverse to the beam direction. At a constant width, this results in a cylindrical beam profile when the width in the direction of the
  • Focus F should converge, as described in DE 10 2016 004 624 or
  • a conical profile is formed.
  • focus on focus F must always be guaranteed.
  • this claim is not guaranteed in the cited patent.
  • a distance function a (u) is generally introduced which describes the distance of the wall surfaces from the central beam (52) at each point u along the beam passage through the collimator volume (230). This can either consist of a constant ⁇ a for a cylindrical beam path or have the half angle ⁇ for a funnel-shaped gap opening as a parameter.
  • the image sharpness always depends on how well the rays within the profile (65) are focused in the focal point F. Ideally, this is to be achieved with a conical beam path.
  • the perpendicular profile surfaces 57 shown in FIG. 12 are formed on the collimator surface 200, which are simplified here as tangential rectangles crossed in the middle.
  • Point P is displayed. In the middle, i. along the axis of rotation (210) the walls are still perpendicular to each other, i. the distance a has a horizontal orientation.
  • the beam path (52) starting from the central axis (210), it is twisted in both directions in a manner as can be seen in the following FIG. 14 as a series of paths (70).
  • the torsional movement moves a point (22) at the height h to the position of the point P (see Fig. 13).
  • both points should be above the circle (20) on which the foci F move.
  • the associated central beam (52) passes through the focal point F and the point P.
  • the inclination of the distance sections (70) between the two gap walls (73), which are described below, is determined by the path (160). determines the point P in the torsion by the angle ⁇ from the position (22) travels. Thus, the slope of the inner walls (73), which are to be parallel in point P, brought from 0 ° to the value ⁇ , the one
  • the path (160) is created by rolling the path traveled by the point P on its way from the point (22), as previously shown in FIG. Taking into account that the height h with the twist out of the
  • FIG. 14 shows the directions of the distance sections (70) with their pitch angles ⁇ in relation to the gap alignment (100).
  • the width from wall to wall (54), whose amount is twice the distance a shown oversized. It can be seen their flat course in the center of the collimator, which increases with increasing distance from the central axis (210), i. becomes steeper with increasing amount of u.
  • the angle ⁇ further serves to design the gap profile.
  • FIG. 15 The interaction between a beam and the gap walls is shown separately in FIG. 15 for the cylindrical (top) and conical (bottom) beam paths.
  • the vector On the beam path (52) with the rise angle ⁇ , the vector is paus obtained from the focal point to the point P in the collimator.
  • the beam around this passage (52) has a circular cross-section (152).
  • the radius a of this cross section remains unchanged over the scalar distance of the vector p, but in the case of the conical, it continuously decreases to the value 0 at the focal point F.
  • a broadening of the beam is possible by the length of the vector is increased, which would introduce a further parameter.
  • the essential difference between the two profile profiles lies in the position of the center of the ellipse. In the first case (152) the center remains on the beam path (52), in the second case (154) its position changes with the distance (156) from the focal point F,
  • the vertex of the opening angle z is at the focal point F, but this is not absolutely necessary. It can lie at any point on the beam (50) which, starting from the focal point F, coincides with the beam (52) in the direction of the object. If we denote the distance of the shifted vertex from the focal point F on the planes of the zero point O with v, then the above formula expands in full consideration of the displacement as follows: tan (ß + + tan (ß - ⁇ )
  • the possibility of shifting the vertex of the opening angle along the beam direction opens up further design possibilities of the gap shape, e.g. in a funnel shape towards the detector or, to a certain extent, as a sliding pinhole with a funnel-shaped opening on both sides.
  • A is merely the distance between the center of the beam, characterized by the course of the beam (52), and one of the gap walls (73) before the torsion or in the collimating center also afterwards.
  • the values for g are dependent on at least the torsion and the instantaneous angle ⁇ .
  • the conical can be easily combined with the cylindrical course. Farther away from the focal point F, the funnel-shaped conical shape may prevail, while in the narrowing areas, it may be transposed in the vicinity of the tubular cylindrical profile.
  • Section profile along the beam direction (52) is in this case, however, always determined by the height h M , ie the formula (6).
  • FIG. 16 the result of the construction of a cylindrical gap is shown, for clarity, with exaggerated gap width (54).
  • the central beam (50) viewed here from the object point, runs exactly on the control surface (100) and enters the collimator (230) at the line (101), passes through a cylindrical lumen (55) and leaves it again the line (102).
  • Two points of view are shown, once with a direct view from the front in the cleavage direction to the detector (top) and laterally rotated by 90 ° (bottom).
  • the gap width is defined here by the parameter a.
  • Gap inner walls (73) no longer follow the definition of a control surface.
  • a conical beam path which is defined by the angle parameter ⁇ for the funnel-shaped Mige opening of the beam channel (55) is defined instead of the parameter a, is shown in FIG. 17.
  • the upper and middle parts of the image contain spacings (70) and the line of the contact points (75) for the conical beam path.
  • a borderline case is shown in which the area of the beam cross section at the focal point F is reduced to the value 0. This situation can be prevented by specifying a minimum value for the parameter a with different algorithms.
  • the problem of the tapered optical path converging to a point can be circumvented, for example, by enlarging the elliptical profile (154), as shown in FIG. 15, by dividing the distance
  • FIG. 19 summarizes the three basic configurations of a split lumen in a collimator body (230).
  • a cylindrically shaped lumen (top) due to the parallelism of the gap walls, obliquely incident rays (67) may intersect and thus create blurring in the image.
  • Beam guidance is possible to a much wider extent in the case of the collimator model presented here than in a parallel-hole or Soller collimator.
  • This intersection (25) is identical to the focal point F for the relevant beam direction (52).
  • a sensitive volume may consist of either a suitable scintillator material, such as BGO, or even a crystal in which gamma photons are converted directly into electrical signals, e.g. CdTe. The choice is left to an overall concept for the detector.
  • sensitive volumes can be arranged both between the collimator surface (200) and the circular arc (20) with the focal points F as well as outside this circular arc, as shown in FIG.
  • Optimum utilization of the available interior and the provision of the longest possible absorption path for high efficiency is achieved by a curved arrangement, as can be seen in the lower part of FIG. 20. It is bounded by vertical circles (322) whose center is on the
  • Circular arc (20) of all focal points F with the radius / moves this means that the space for the sensitive detector elements is limited on the one hand by the envelope described and on the other hand by the angles ⁇ and 72, which resembles a part of a donut, that is, is correspondingly curved.
  • the volume limits from the circular arc (20) two radii d ⁇ and d 2 can be used. With the sign of these radii, the position inside or outside the circle (20) can be marked. Upwards and downwards, the areas for the volumes (300) and (320) are limited by the angles 71 , 2.
  • the volume limitation can be described as follows, whereby a curved
  • Both the detector shape and the design of the shield case are significantly influenced by whether the circular arc (20) with the focal points F outside the Kollimatorvolumens (230), on the surface (200) or within the collimator.
  • positioning of the sensitive volume is possible both between the collimator surface (200) and the arc (20) as well as outside of it, as previously shown in FIG.
  • the inner shield (315) must directly adjoin the areas in which the sensitive volumes (300) and (320) are housed, as discussed in section [28] with FIG.
  • the proposed coincidence circuit for determining the direction of incident rays [30] it is not necessary to divide the detector into the two separate regions (300) and (320) mentioned above. Both parts can also be located in the outer area (300).
  • the shields (315) collide from above and below at focal point F and leave no room for unhindered beam passage, adequate clearance must be cut free as slit lumens (340) (see Fig. 21).
  • the height and height of the upper and lower parts of the shield (315) may be changed in order to create or vary such a lumen. Both ways must be weighed against each other with regard to the image sharpness to be achieved. The height of this space depends, on the one hand, on the efficiency to be achieved in the form of beam yield, and, on the other hand, on the extent to which impairments to the image quality due to this broadening are acceptable. Central to this is the efficiency of the shielding, as discussed in [28], i. it also brings the energy of the prevailing radiation to bear.
  • the detector Since there are also imaging (50) as well as reversed beams (51) in the arrangement described last, as has already been described in principle in FIG. 7, the detector must be mounted in front of the inverted or This can be done, for example, with a housing which is pyramid-shaped on a detector and on which the collimator is placed obliquely in a suitable manner, as with the recess (345) for the collimator in FIG. The slope for the recess for the collimator and its support is then aligned such that the interfering inversely extending beams 51 are directed onto the covering shielding wall 315.
  • this pyramid-shaped device can be mounted on any planar matrix detector. 360), whereby commercially available detectors for a gamma camera can be used ines flat
  • Matrix detector is that in the imaging referred to as a cushion effect distortion, as shown in DE 10 2016 004 624, does not occur here.
  • the disadvantage is that increasingly in the peripheral areas the sharpness of the image, especially with thick sensitive volume layers in the detector, can be impaired by an oblique incidence of the imaging radiation.
  • FIG. 47 Further possible openings for the penetration of unwanted radiation into the detector space are shown in FIG. These free spaces or gap gaps (78) for irregular beams are created by the gap openings (54) on the surface (200). of the collimator, which are oversized here for clarity.
  • the laterally-passing beams (79) extend along the gap-opening lines (101) and (102) that lie on the surface (200) and at those locations utilize the gap created by the gap for lateral passage past the collimator. This possibility for interfering radiation (79) must be taken into account when designing a lateral shielding and also when defining the horizontal field of view between the angles ⁇ and n.2.
  • the pitch angle ⁇ for the passing beam (79) can be calculated as follows. Between the two associated angles ⁇ and 02, the secant arises between the two points 1 and P2, which can be projected onto the path (89) lying on the x / y plane (11).
  • This path (89) forms an equilateral triangle (87) with the associated radii, ie.
  • This limit is reached when the gap gaps (78) no longer overlap at the points P ⁇ and P2 in the direction of the detector. In other words, this means that the gap gaps (78) overlap each other with their width (54) and must therefore lie on the same straight line or beam direction so that a laterally passing beam (79) can pass outside into the detector space past the collimator. Expressed in formulas, this means nothing other than: r ⁇ ⁇ Asin (a) ⁇ ⁇ tan (a) ⁇ ⁇ 2 ⁇ equals ⁇ tan (a) ⁇ ⁇ - 2 "
  • must be taken into account when defining the horizontal range limits ⁇ and n.2 to avoid an open area between collimator and shield.
  • the shape-defining parameters for the collimator are finally the heights Ai, 2 starting from the x / y plane (11) with the coordinate origin O, the outer boundaries (200) of the body of revolution which forms the collimator, the circular arc (20) for the foci with the radius /, the torsion constant c T , the distance a of the gap walls from the surface (1 00), which defines the cleavage direction, the half angle ⁇ of the slit opening for a conically shaped beam guide and the number of columns at the respective angular distance ⁇ , As parameters describing the interior of the collimator, a and ⁇ influence the image quality in the form of intensity and spatial resolution.
  • the outer dimensions of the collimator are determined by the heights and the radius r.
  • the vertical limit angle ⁇ and 72 apply, but not mandatory, as long as the entire beam path is not affected. Heights and radii have no direct influence on the characteristics of the actual imaging as long as the minimum shielding requirements are met. They can be chosen for design reasons and according to the requirement of the required layer thickness for shielding.
  • Decisive for the imaging is the torsion constant c T , which firmly defines all angle ratios ⁇ / ⁇ , ⁇ ⁇ and 72 82. Conversely, one of these quotients defines the torsion constant c T and thus the value of all other angular relationships.
  • the height of the imaging range is defined either by ⁇ and 72 or by ⁇ and 82.
  • Standard values for the heights Ai , 2 and the critical angles ⁇ , 2 can replace each other like angle and edge length in a right-angled triangle.
  • the spaces for the accommodation of the sensitive volumes (300) and (320) of detectors are controlled by the distances d ⁇ and cfe, the horizontal image area by the angles ⁇ and r ⁇ 2 .
  • the variable u describes the path of a ray (50) from -r to r right through the collimator volume (230) and thus does not itself constitute a shape-defining variable.
  • the execution of the camera body has on the inside the task to suppress the disturbing rays during imaging.
  • This task for example, the design of the gap lumen (340) in FIG. 21 with its environment, as shown for example in FIG. 8, or the wall position in relation to the axis of rotation (210) as in FIG see is.
  • a simplified solution is shown in FIG. 10, wherein the beam guidance is restricted by a suitable choice of / and ⁇ or 82, namely from the upper collimator half in the direction of the lower or vice versa.
  • the rotating collimator is to be enclosed laterally to the beam direction by the housing so that no interfering rays penetrate past its sides, as discussed in [51] and [52].
  • the space can be adapted closely to the needs of the detector with its sensitive volume (300) or (320) or alternatively depending on existing detector systems. To the outside is only to ensure that the detector is protected on all sides from extraneous radiation, which usually ten times the half-value layer thickness should be sufficient for the radiation in question.
  • the camera proposed here promises a smaller size, lower weight, higher resolution compared to the Anger camera with the usual parallel hole collimators, as well as larger fields of view and advanced imaging capabilities with high-energy radiation isotopes over a pinhole camera.
  • the latter aspect is particularly relevant in the environmental field when it comes to nuclear residues or unexpectedly occurring strays
  • a collimator for generating a convergent beam path of incident radiation comprises a rotatably mounted rotationally symmetrical diaphragm body (230) of an intransparent material incident to incident radiation intersected by one or more gaps, the side walls of the gap are spaced as pairs of surfaces (73) from an imaginary central surface (100) formed as a twisted ruled surface, the central surface (100) defining the direction of the respective gap for guiding the rays emanating from an object point to a pixel, wherein during rotation of the diaphragm body (230), the beams are focused in focus F along a focal circle, the diaphragm body (230) along its height h on the axis of rotation z in cross-section a circular outer boundary with a height-dependent outer radius r (z) around the Has rotation axis z, wherein the outer radius r (z) of the diaphragm body (230) tapers towards the ends.
  • Cylindrical diaphragm bodies are used in the prior art. However, since the layer thickness increases with 2 r / cos (.beta.) With increasing .beta., The collimator can be tapered or narrowed with at least the same shielding towards the lower and upper end. Consequently, the volume of the collimator (230) can be reduced to save weight without compromising the shielding effect.
  • the beam channel (55) has conical or cylindrical sections between the side walls of the gap formed as surface pairs (73) along the direction of the gap. While the center of the beam channel is thus formed as a twisted control surface (central surface), the side walls of the gap may deviate from this shape.
  • the pairs of surfaces (73) may in particular have sections in which the distance between the surfaces remains constant (cylindrical) or variable (conical). This allows for an additional
  • Aperture function within a gap In the prior art, the walls of the gap are formed as a control surface with the central surface.
  • the focal points F lie along the focal circle on the surface of the diaphragm body (230) or within the diaphragm body (230). This has the advantage that it is possible to dispense with a part of the shielding required in the prior art, since the burning circuit is already shielded by the diaphragm body (230).
  • all focal points F belonging to a course of the gap lie on a circular arc (20) which is closed by the gap guidance or by the arrangement of several columns at least to a full circle.
  • Torsion e.g. 180 ° left and 180 ° right.
  • the efficiency can be increased by several columns with a total torsion of ⁇ 360 °, whereby at least one full circle is closed.
  • the guidance of the beams (50) is limited to one half of the diaphragm body (230) and only beam paths from one half to the other half are possible.
  • inversely incident rays (51) can be shielded.
  • the visor body (230) is rotatably mounted on one side, whereby the overall construction of a gamma camera is facilitated. This further allows better optical access to the visor body (230) and allows easier replacement. This is made possible in particular by the reduced weight and the improved design of the prior art
  • the inner structures of the collimator lying between the columns are mechanically stabilized by means of a material transparent to the radiation in the gaps or in the outer regions of the gaps.
  • the stabilization can be achieved by pouring out with a binding or filling material, preferably with long-chain
  • the volume of the collimator (230) can create filigree structures which are sensitive to mechanical disturbances. In order to stabilize these structures, these can be replaced by one for the radiation
  • a gamma camera preferably comprises a collimator and a
  • planar, preferably curved, matrix detector Furthermore, a
  • Gamma camera comprise a housing, wherein the housing has a shield (315).
  • a gamma camera for forming an image of a radiating object whose rays have penetrating properties that can be shielded only with thicker layers of a material dense to the rays, comprising a rotating collimator with one or more columns for the beam passage, the inner walls of which deviate from the regularity of ruled surfaces, with adapted shielding housing with complementary internal shielding, leaving room for detectors of different types and functions, the functional design being able to be described parametrically throughout to adapt it to different requirements in different applications, for example Nuclear medicine, in non-destructive testing, in radiation protection, in the safety of nuclear installations and their dismantling, in the inventory of radioactive waste repositories, in the location of vagabond Radiation sources, in imaging X-ray backscattering, in general in the
  • the torsional constant c T with which the Bridge between the horizontally oriented torsion angle ⁇ and the vertical elevation angle ß is struck, where ß has its apex on the focal point F associated with each value of ⁇ , the rotation angle ⁇ for the specification of the horizontal direction, the distance angle ⁇ between adjacent columns in the execution a collimator with several columns, the half angle ⁇ with apex at the focal point e for the gap opening with conical course of the beam leading to the detector and the half width a of the gap measured from the center of the beam (50) or (52) to the gap inner walls in a conical Gap profile, where b) the limits for the torsion angle ⁇ with ⁇ and 82 can be set differently on both sides, whereby the associated minimum heights h ⁇ and the collimator on the torsional constant c T are set [This is an approach to
  • Origin O of the coordinate system is i) the depth of the sensitive volume (300) or (320) in the detector has a value between the distances d ⁇ and d 2 , measured from the circular arc (20) with the focal points F, j) the k) the collimator comprising a gamma-ray absorbing material has a rotationally symmetric shape which, in a simple case, is cylindrical but may deviate therefrom to save weight while maintaining a layer thickness necessary for adequate shielding;
  • the space for the sensitive volume (300) or (320) of the detector system comprises the range of the horizontal angles ⁇ and r ⁇ 2 , starting from the coordinate origin O, and the vertical elevation angles ⁇ and ⁇ 2 and the depth d ⁇ and d 2 , both starting from, or with apex in the circular arc (20) with the
  • Focal points F which may not collide in depth with the outside (200) of the collimator and may have a curvature, for example, in which
  • the space for the sensitive volume (300) or (320) can be divided into successive detectors, for example in (320) between the circular arc (20) with the focal points and in (300) outside the circular arc (20), for the purpose that the separate detectors are interconnected in a coincidence circuit for the detection of beams exclusively from the collimator (230), o) the inner shield in the housing (315) takes over the task, inversely and laterally incident beams which form the image to be recorded disturbing, absorbing in various ways [The position of the (outer) wall (315) takes over the task of the shield (310) (slit aperture between rotating aperture and detector), which then can be omitted otherwise. It is therefore the task to hide inversely incident rays, quasi taken over by the burning circuit on the surface or inside, under the condition of the same sign of ⁇ and S2.].
  • the circular arc (20) can be smaller than the maximum outer radius r of the collimator, whereby the focal points also lie on the surface (200) or within the collimator body (230) [This allows the detector to be reduced to a curved line, the image coordinate (height) being determined by the rotation phase, eg can be detected by a light barrier.].
  • the gap or columns in the described collimator and the associated walls have a shape that can be described as follows:
  • the gap inner walls (73) of the collimator described are formed by the torsion and skew for passage of a beam (55) having the following properties such that a) this ray bundle passes through a focal point F on the circle (20) and through the central axis of rotation (210) for rotation and also for torsion, b) the beam passage has, for example, an approximately circular cross-section with the radius a along the Path through the collimator (230), which is described with the variable u with the values of -r after r, c) the cross section of the beam passage remains constant along its path through the collimator (230), for example with a fixed radius a and thus a d) this cross-section along the path with a function a (u) can be made variable, for example, to the focal point F with the angle ⁇ , for example, its vertex at focal point F or behind it on the extension of the beam ( 50) beyond the focal point, can decrease and thus gives the beam a conical profile, e) a
  • the parameter ⁇ maintains its value for the calculation of the center M of the beam (55).
  • the gamma camera described above is preferably scalable in its entire embodiment, with which thicknesses of shielding layers adapted to the expected radiation conditions while size and weight can be reduced to a necessary level, without changing the image reproduction with their characteristics at least substantially ,
  • inverse rays (51) preferably from horizontally near directions to the inner
  • the lateral penetration of rays between collimator and outer shield at locations of the stomata can be prevented preferably by lateral covering or reducing the horizontal angle of view at least over a required range, for example, calculated according to ⁇ ⁇ ⁇ » 2 a'180 7r leaves
  • the described gamma camera has the ability to be combined with existing areal matrix detectors by increasing the space for the sensitive volume (300) of a detector system far away from the collimator until the existing detector can be integrated therein.
  • FIG. 2 Volume reduction of the collimator body (230) for weight reduction.
  • the radius r of the outer boundaries (200) can be reduced to a value r red without restricting the shield at a reduced height h re d.
  • Fig. 3 collimator with a cutting surface (90) for the beam passage through the rotary body (230) with the outer boundaries (200) and the rotation axis (210) and the intersection (21) of the limiting straight line (80), here still without torsion ,
  • the heights hl and hl do not have to be the same.
  • the flat surface (90) becomes the control surface (100). If the point (21) with its vector p and its focus F should remain at the same position, the position of the point (21) shifts accordingly. With torsion the rotation angle is also adjusted here.
  • the torsion in the directions (30) causes a wandering of the focal point F on the arc (20) as a function of the angle ß, whereby the position of the point P in existing torsion is determined only by the two variables ß and u.
  • Fig. 4 Effect of torsions of different magnitude from the view from above.
  • the point (22) on the circle (120) moves in the height h in the direction (31) to the position P.
  • On the line (101) are all points that were perpendicular to each other before the torsion.
  • From the surface (100), the part (110) is additionally separated, which, viewed from the rotation axis (210), lies beyond all possible foci F and is indicated by dashed lines.
  • M term direction according to the x-axis, starting, which need not be the same size.
  • the principle of a shield (310) is shown to keep inverse incident rays (51) passing through a focal point F inv lying on the far detector side of the collimator away from the sensitive volume of the detector (300).
  • a horizontal gap (330) passes the regular rays (50).
  • FIG. 8 Device for optimal suppression of inversely incident beams (51), which would otherwise collide with regular (50) in the sensitive volume of the detector (300). Particularly shallow incident inverse beams with a small tilt angle ⁇ iHV are a problem to be counteracted by effective shielding from the housing side (310). All sub-parameters for calculating an optimum absorption distance s for an inversely incident beam (51) are included.
  • Fig. 9 Variant for shielding inversely incident beams (51) by a restricted beam guidance through the collimator with the position of all focal points F on the surface (200) and corresponding alignment of the upper and lower housing wall (315).
  • the height is set at 0 in the installation of the gap alignment, whereby beams (50) only from the upper right side of the object in the lower left
  • Detector side can run. All inversely incident rays hit either a portion of the upper shield (315) or do not even get into the housing interior. To avoid horizontally inversely extending beams, the upper cover wall (315) of the housing is slightly inclined downwards.
  • Fig. 10 Embodiment for preventing the penetration of inversing beams (51) of squat design, which can be achieved by in the collimator volume (230) lying focal points F. All regularly incident rays pass through the collimator (230) into the housing space with the sensitive volume (300) of the detector.
  • inversing beams (51) of squat design which can be achieved by in the collimator volume (230) lying focal points F. All regularly incident rays pass through the collimator (230) into the housing space with the sensitive volume (300) of the detector.
  • Fig. 11 Electronic variant for filtering inverse incident rays over regular (50), without resort to mechanical shielding, with the ability to use Compton effects similar to those in a Compton camera.
  • the basis here is the arrangement of two sensitive volumes (300) and (320) of detectors, the latter between the arc (20) and the collimator, the other (300) beyond this Bow (20).
  • the collimator between the inner detector volume (300) and the object point P has been omitted in the drawing for clarity, only the axis of rotation (210) is shown. This design can do with significantly less shielding material.
  • Fig. 12 Fundamentals and parameters for a slit lumen for the passage of rays (52). Based on the representation of a vertical profile (57) transverse to the beam direction basic parameters for the gap shape and width are presented here, the distance a from the center of the beam to one side wall and the
  • Opening half-angle ⁇ of a conical beam guide with vertex at the focal point e which opens to the object side.
  • the beam passing through the collimator is bounded by the straight line (65), which does not continuously contact one of the gap inner walls, but results from the total passage of the beam through the collimator.
  • Fig. 13 Rolling of the arcuate path (160) from the starting point (22) before a torsion to its target point P to torsion to determine the inclination of the inner walls, expressed by the angle ⁇ , or the slope v of the distance distance between them. Due to the torsion, the originally vertical inner walls experience a distortion over the distance (160) at the height h, from which the
  • Fig. 14 slope of the distance lines (70) between the split walls along a beam (50) in plan view and side view with the twisted surface (100) and the arc (20) for the focal points F.
  • the width of the gap lumen (54) is Explanation exaggerated.
  • Fig. 15 Description of a cylindrical and a conical beam path with perpendicular beam profiles transverse to the beam path (52). In particular, the differences between the profiles in the cylindrical (153) and conical (154) beam path.
  • the points, distances and angles which are important for the parametric description of the gap through the collimator for the beam guidance are indicated
  • Fig. 16 beam channel (55) through the collimator (230) with deviating from the horizontal plane course (50) with a view into the beam path and in side view, rotated by 90 ° (190), shown enlarged for clarity.
  • the spirally extending walls (73) envelop the passage (55) in a width (54), corresponding to the double Distance a from the center of the beam on the twisted surface (100) a circular. You can see the distances (70) from wall to wall and the lines of
  • Fig. 17 beam channel (55) as shown in Fig. 16, but with a conical course, which closes inevitably at the circular arc (20) for the position of the focal points.
  • Fig. 18 Solution to the problem of converging to a point beam path, as shown in Fig. 17.
  • the solution consists in a combination of conical and cylindrical course. The latter is necessary in the vicinity of the focal point F in order to allow a passage of radiation at all.
  • Both the schematic representation and the view into the beam channel (55) show the funnel-shaped shape of the beam guide for adapting or optimizing the image quality.
  • Fig. 19 Summary of the possible arrangements of a cylindrical, conical and combined beam path.
  • FIG. 20 Requirements for areas in which spaces of the sensitive volumes (300) and (320) of detectors on either side of the circular arc (20) for the focal points F can be found.
  • the depths d ⁇ and d2 of such areas may be different within and outside the circular arc (20).
  • FIG. 21 Slit lumens (340) in the shielding housing on the circular arc (20) with the focal points F for the beam passage.
  • Fig. 22 An example of a construction of a housing for a gamma camera on a commercial flat detector (360) with a recess for the collimator and its holder.
  • Fig. 23 Problem from the side, the collimator surface (200) in a gap opening (101) cutting direction passing rays (79) with their pitch angle ⁇ and the two points P1 and P2 on the line (101) through which this beam passes, and their spacing (89) on the x / y plane (11).
  • the gap widths (54) are to clarify shown exaggeratedly big.
  • Gap inner wall slopes
  • Angle ⁇ indicates, line of the contact points B between gap inner wall and cross section of the beam through the collimator, gap at the Kollimatorober Structure (200), created by a gap opening along the line (101), in principle also (102), laterally passing beam through the or along the stomata on the surface (200) of the collimator, boundary straight up or down for the perpendicular surface (90) which passes through the axis of rotation (210) and the vertex (21) of the angle ß before torsion, at the same time legs for the angles ⁇ and ⁇ 2 , straight line formed by a torsion about the angle ⁇ in the directions (30) from the straight line (80), isosceles triangle from the distance of the point positions i and P2 (89) and the associated radii r, 89 distance on the x / y plane (11) between two points P ⁇ and P 2 laterally on the surface of Kollinnators (200) in the gap entrance (101), at the same basis of an isosceles triangle with
  • F inv focal point in the corresponding rotational position ⁇ on the object side of the camera corresponds in its position G, f vector with the scalar quantity / which describes the circular arc (20) on which all focal points F or Fj " v move,
  • the indices 1 and 2 stand for the height of the collimator in each case up and down the index 0 for the height of the beam passage on the z-axis, h M height to the shifted point M in the middle of a beam due to a conical beam path, h P height to the point P in the middle of a beam, h r ed reduced height in the rotating body (230) to save
  • Ah difference between h re d and h 0 equivalent to r ⁇ cos ( ⁇ ), si, S 2 altitude of parts of the distance s of a beam absorbed in a medium, k vector describing a functionally reduced volume of a collimator.
  • Coordinates x P , y P and z P , indices refer to the context, q vector transverse to the main direction of a ray (50) or (52) or to the
  • the indexes refer to projections of sections on the horizontal plane: for the entire distance s, ti and t 2 on the parts between the detector and the focal point F and between this and the collimator (230), s vector for describing a beam profile in the form of an ellipse (153) or (154), u distance of a point P from the vertical axis z from
  • Ruled surface (100) is aligned, with apex in the relevant point P on the surface (100), ⁇ , 2 critical angle for ⁇ on both sides.
  • both values have opposite signs, ⁇ , 2 opening angle horizontally to both sides of the detector on the x / y plane (11) with apex in the coordinate origin O, v complementary angle to the angle ⁇ of the wall slope, slope of

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Abstract

L'invention concerne un collimateur et une gamma-caméra équipée d'un collimateur de ce type. L'invention concerne en particulier un collimateur servant à générer un tracé de rayons convergent d'un rayonnement incident, de préférence d'un rayonnement gamma. L'invention décrit un collimateur comprenant un corps (230) de diaphragme symétrique en rotation monté de manière à pouvoir tourner, composé d'un matériau opaque au rayonnement incident, lequel matériau est fendu par un ou plusieurs fentes. Les parois latérales de la fente sont espacées en tant que paires de surfaces (73) d'une surface centrale (100) imaginaire intermédiaire et réalisée sous la forme d'une surface réglée à torsions. La surface centrale (100) prédéfinit la direction de la fente respective afin de guider sur un pixel les rayons sortant d'un point d'objet. Lors de la rotation du corps (230) de diaphragme, les rayons sont concentrés en le point focal le long d'un cercle focal. Le corps (230) de diaphragme comporte, le long de sa hauteur, sur l'axe de rotation par rapport à la section transversale, une délimitation extérieure de forme circulaire présentant un rayon extérieur r(z) dépendant de la hauteur autour de l'axe de rotation z. Le rayon extérieur r(z) du corps (230) de diaphragme se rétrécit en direction des extrémités.
PCT/EP2018/064257 2017-05-30 2018-05-30 Configuration d'une gamma-caméra comprenant un collimateur rotatif servant à représenter des objets à rayonnement Ceased WO2018220053A1 (fr)

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EP4040447A3 (fr) * 2021-02-09 2022-11-02 Bruker AXS GmbH Collimateur segmenté réglable

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WO2021094591A1 (fr) 2019-11-14 2021-05-20 Kurt Osterloh Système d'imagerie à optique géométrique

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DE102005048519A1 (de) 2005-10-06 2007-04-19 BAM Bundesanstalt für Materialforschung und -prüfung Brennpunktorientierte Blende
EP2062705A1 (fr) 2007-11-26 2009-05-27 BAM Bundesanstalt für Materialforschung und -prüfung Dispositif et procédé de fabrication de diaphragmes à fentes pour le rayonnement hautement énergétique
DE102007057261B3 (de) 2007-11-26 2009-08-06 BAM Bundesanstalt für Materialforschung und -prüfung Vorrichtung und Verfahren zur Herstellung von Schlitzblenden
DE102014103833B3 (de) 2014-03-20 2015-07-09 Bundesrepublik Deutschland, Vertreten Durch Den Bundesminister Für Wirtschaft Und Energie, Dieser Vertreten Durch Den Präsidenten Der Bundesanstalt Für Materialforschung Und -Prüfung (Bam) Schlitzblende für Anwendungen in der Radiographie
DE102015008272A1 (de) 2015-06-18 2016-12-22 Kurt Osterloh Schlitzblendensystem für bildgebende Verfahren mit harter Strahlung
GB2542000A (en) * 2015-09-04 2017-03-08 Secr Defence Collimator for providing constant collimation effect
DE102016004624A1 (de) 2016-04-13 2017-10-19 Kurt Osterloh Das Gammaauge: Ein Gerät zur Abbildung hochenergetisch strahlender Objekte

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4040447A3 (fr) * 2021-02-09 2022-11-02 Bruker AXS GmbH Collimateur segmenté réglable
US11742104B2 (en) 2021-02-09 2023-08-29 Bruker Axs Gmbh Adjusted segmented collimator comprising a Soller slit

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