FI20205373A1 - X-ray imaging arrangement - Google Patents

Abstract

The invention relates, in particular, to structures of an arrangement applicable for use in the context of dental or medical X-ray imaging, wherein the arrangement comprises an X-ray detector (15), an X-ray source (14), a light field indicator (141) and a support construction (12) to which the X-ray source (14) construction and the light field indicator (141) construction are mounted. The support construction (12) is configured to enable positioning the X-ray source (14) construction and the light field indicator (141) construction at essentially the same location, so as to when at a given time locating at said essentially same location, to direct a given X-ray irradiation field pattern and visible light field pattern in essentially the same direction towards the X-ray detector (15).

Description

X-RAY IMAGING ARRANGEMENT |

FIELD OF THE INVENTION |

The invention relates to dental or medical radiography.

In particular, | structures of an arrangement according to the invention are applicable | for use in the context of dental or medical X-ray imaging. | BACKGROUND.

OF THE INVENTION | when exposing a living object to ionizing radiation, to generate an image | of an anatomy for medical purposes, the imaging must be implemented, in | view of the purpose of the imaging, by as low a radiation dose as possi- | ble to still get an image of reasonable quality. |

One parameter to be considered relating to the radiation dose is the vol- | ume of the anatomy getting exposed.

When not wishing to irradiate ines- | sential parts of an anatomy, one is faced with a problem of proper rela- | tive positioning of the desired anatomy and components of the imaging ar- | rangement. |

To facilitate such positioning, e.g. various positioning lights have been | used.

Such lights may be configured to cast e.g. laser lines or a light | field on an anatomy.

In the context of radiography, a term light field- | indicator is sometimes used when referring to an equipment incorporated | in an X-ray imaging system which is configured to "predict” the shape and |

Q dimensions of the irradiation field during the subsequent exposure.

Such | N systems may include components that are let to remain between the X-ray | x source and detector also during the imaging exposure while in some oth- | © 30 ers, such components that would remain between the X-ray source and de- | I tector are moved away from the X-ray beam path before the X-ray exposure. | a | S Computed tomography (CT) is a form of X-ray imaging in which a volume to | O be imaged is irradiated from different directions and, from the image in- |

2 | formation thus acguired, a desired two- or three-dimensional image can be | reconstructed.

Traditional CT apparatus are large and massive, and they are typically | mounted on a floor. A patient is positioned for imaging within an exami- | nation opening of the apparatus, typically on a horizontally extending j and laterally movable examination platform. | Since development of cone beam computed tomography (CBCT) technology in | which, for one, slower rotational speeds of the imaging means are used, | apparatus of less weight than that of the more traditional CT apparatus | have been developed. Among the CBCT apparatus, there also are those not | designed to be mounted e.g. on the floor but constructed to be mobile. | Some of the CT apparatus designed in recent times are multipurpose appa- | ratus supporting more than one imaging modality, like those configured to | enable both 2D and 3D radiography. When having more functionalities, how- | ever, complexity of the apparatus tends to increase, e.g. as a conse- | quence of a new kind of freedom of movement having been arranged to one | or more components of the apparatus. Also the weight of the apparatus may | then increase while some modifications may generate new challenges relat- | ing to getting an anatomy positioned for an exposure. | BRIEF DESCRIPTION OF THE INVENTION | | The object of the invention is a medical or dental X-ray imaging arrange- | S ment, in one particular embodimerit a CBCT apparätus, with novel features | N relating to mutual positioning of the X-ray source of the arrangement and | x an anatomy for an imaging exposure. | & 30 | x The characteristic features of the invention are defined in claim 1. More | & particularly, those features include the arrangement of the present dis- | 2 closure being configured to enable a light field indicator system to cast | 3 a visible light field pattern from essentially the same location as from | S i

3 | where an X-ray beam generating system emits an X-ray irradiation beam | during an imaging exposure. | BRIEF DESCRIPTION OF THE FIGURES |

|

The invention is now described in more detail in reference to some of its | preferable embodiments and the attached drawings, of which: |

Fig. 1 is a schematic general side view showing components, as an exam- | ple, of an imaging apparatus applicable to comprise features of the pre- | sent disclosure. |

Figs. 2a-2c show some structural details, as an example, of an embodiment | comprising a motorized guiding construction arranged in functional con- | nection with an X-ray source and an X-ray detector. | Fig. 3 shows a guiding construction as shown in Figs. 2a-2c as partially | covered by a housing of a support construction for the X-ray source 14 | and the X-ray detector 15. |

Figs. 4a — 4c show, as an example, a construction to realize a principle | of projecting a visible light field pattern towards the X-ray detector | from essentially the same location as from where an X-ray beam is config- | ured to be emitted, during an exposure. |

Fig. 5 shows an embodiment in which the X-ray source and the X-ray detec- |

Q tor are located and extend outside the housing of the support construc- | N tion for the X-ray source and the X-ray detector. | s | 2 30 Fig. 6 shows a schematic general side view of an embodiment like the one | I shown in Fig. 1, arranged with elements enabling changing orientation. | a | S Fig. 7 is a schematic general presentation of an apparatus in horizontal | O position with certain components thereof driven to locations other than | S 35 their base positions. |

4 |

Fig. 8a shows, as an example, some details of a patient support suitable | for use in an apparatus of the present disclosure. |

Fig. 8b shows, as an example, a cross section of a patient support. |

|

Fig. 9 is a block diagram showing an example of features of a control | system of the apparatus. |

DETAILED DESCRIPTION OF THE INVENTION |

|

A more complete understanding of components, processes and apparatuses | disclosed herein can be obtained by reference to the accompanying draw- | ings.

These figures are merely schematic representations based on conven- | ience and the ease of demonstrating the present disclosure and are, | therefore, not intended to indicate relative size and dimensions of the | devices or components thereof and/or to define or limit the scope of the | exemplary embodiments. |

Although specific terms are used in the following description for the | sake of clarity, these terms are intended to refer only to the particular | structure of the embodiments selected for illustration in the drawings | and are not intended to define or limit the scope of the disclosure.

In | the drawings and the following description below, it is to be understood | that like numeric designations refer to components of like function. |

| The singular forms "a," "an," and "the" include plural referents unless |

Q the context clearly dictates otherwise. | x Terms about, generally and substantially when used herein are intended to | © 30 encompass structural or numerical modifications which do not significant- | Ir ly affect the purpose of the element or number modified by such term. | E For example, the term substantially may include a range of variance such | S as 25%, or 10%, or 0% from the stated relationship. | NN |

|

As used in the specification and in the claims, the term "comprising" may | include the embodiments "consisting of" and "consisting essentially of." |

The terms *comprisef(s),” “include(s),” “having,” “has,” “can,” “con- | tain(s),” and variants thereof, as used herein, are intended to be open- |

5 ended transitiona] phrases, terms, or words that reguire the presence of | the named elements/steps and permit the presence of other elements/steps. |

Fig. 1 shows an apparatus comprising a longitudinally extending frame | part 11 extending in a first direction and having a first end and a | second end.

From this longitudinally extending frame part 11, or “an | elongated frame part 117, extends in a second direction a support con- | struction 12 which supports an X-ray source 14 and an X-ray detector 15 |

(not as such visible in Fig. 1), the second direction being substan- | tially orthogonal to the first direction.

The X-ray source 14 and the |

X-ray detector 15, which together can be referred to as an X-ray imag- | ing assembly 14, 15, or be part thereof, may be mounted to the support | construction 12 för the X-ray source 14 and the X-ray detector 15 es- | sentially opposite to each other yet in embodiments of the invention, | their mutual position may also be arranged to be adjustable. |

|

It is to be noted that the apparatus of Fig. 1, comprising structures | as discussed above, is just an example of one preferable embodiment in | the context of which the invention can be implemented.

Just as an exam- | ple, frame and support constructions of also other kind may be applica- | ble, like those comprising "a C-shaped arm” for supporting the X-ray | source and the X-ray detector. |

N While medical and dental X-ray imaging apparatus often include a pa- | 3 tient support, Fig. 1 shows one specific kind patient support 18 struc- | 2 30 ture mechanically connected to the elongated frame part 11. This pa- | I tient support 18, applicable for use in various embodiments of the in- | a vention, comprises a surface which extends substantially in parallel | S with the elongated frame part 11. And while such patient support 18 is | S optional, in the particular embodiment of Fig. 1 the patient support 18 | S 35 is essentially of the same length as the elongated frame part 11. |

Examples on how the X-ray source 14 and the X-ray detector 15 may be i mounted to the support construction 12 for the X-ray imaging assembly 14, 15 are presented when discussing some of the other Figs. of this disclosure further below while Fig. 1 shows, in general, the support | construction 12 for the X-ray imaging assembly 14, 15 comprising a | housing 121. The housing 121 may cover a ring-shaped gantry 122, to which the X-ray imaging assembly 14, 15 is mounted.

In one embodiment, | the housing 121 may extend to cover the X-ray source 14 and the X-ray detector 15 entirely, in another the gantry housing 121 may cover the construction by which the X-ray source 14 and the X-ray detector 15 are | mounted to the gantry 122 while not the X-ray source 14 and the X-ray detector 15 themselves.

The X-ray source 14 and the X-ray detector 15 may be arranged to be ro- | tatable about a rotation axis 13. In one embodiment, the ring-shaped gantry 122 to which the X-ray source 14 and the X-ray detector 15 are | mounted is rotatable.

In the particular construction shown in Fig. 1, | showing the schematic general side view as discussed above, this rotation | axis 13 coincides ör can be made to coincide with the central axis of the | support construction 12 for the X-ray imaging assembly 14, 15, of the | housing 121 and of the ring-shaped gantry 122 as discussed above.

Thus, according to one aspect not directly visible in Fig. 1, for exam- | ple, the apparatus comprises a driving mechanism 16 arranged to drive | the X-ray source 14 and the X-ray detector 15 about a rotation axis 13. | The rotation axis 13 may be a physical axis, or a virtual rotation axis | N as in the case of Fig. 1. | N | x According to one aspect, for example, the rotation axis 13, or the cen- | © 30 ter of rotation of the X-ray source 14 and the X-ray detector 15 when | I being driven along a curved path and thus defining a location of the | E virtual rotation axis 13, coincides with the central axis of the gantry | 2 122. | S | N |

According to one aspect, the rotation axis 13 is an instantaneous (op- | tionally virtual) rotation axis and the location of the instantaneous | rotation axis in relation to the central axis of the support construc- tion 12 for the X-ray imaging assembly 14, 15, of the housing 121 and/or of the ring-shaped gantry 122 as discussed above can be arranged to be changed. | The rotation may be arranged to be performed by rotating the gantry 122 | by any conventional mechanism known to those skilled in art. In one em- | bodiment, a driving belt driven by at least one pulley is arranged to ex- tend around a ring-shaped gantry 122. Such construction can enable imple- | menting rotating the gantry 122 over an angle even exceeding 360 degrees. | According to another aspect, another driving mechanism 17 may be ar- ranged to the apparatus to enable moving the support construction 12 | for the X-ray imaging assembly 14, 15 back and forth in a direction | which is substantially parallel with the direction in which the elon- | gated frame part 11 extends. According to one aspect, the driving mech- | anism 17 may be arranged to move the support construction 12 along or | alongside the elongated frame part 11. | According to one aspect, the driving mechanism 17 to drive the support | construction 12 in a direction which is substantially parallel with the | direction in which the elongated frame part 11 extends can comprise a | motor arranged to the support construction 12 for the X-ray imaging as- | sembly 14, 15 itself. o | S | N Regardless of the details of the construction of the driving mechanism | S 17 to drive the support construction 12 along or alongside the elongat- | Q 30 ed frame part 11, in one embodiment the construction of the apparatus | x allows for driving the support construction 12 essentially the whole | & | - length between the first and second ends of the elongated frame part 0 | N 11. i O |

O < : N | O . N |

While details of the driving mechanism 17 for moving the support con- struction 12 for the X-ray imaging assembly 14, 15 back and forth in a | direction which is substantially parallel with the direction in which the elongated frame part 11 extends may vary, one preferable example of | such mechanism is disclosed in a co-pending patent application FI | 20190054, which is herein incorporated by reference. | Turning to Figs. 2a - 2c they show, as an example, some structural de- | tails of one possible embodiment which can be used when implementing | the invention.

In Figs. 2a - 2c, a part of the housing 121 of the sup- | port construction 12 for the X-ray imaging assembly 14, 15 is removed, which makes visible a guiding construction 50 which can be arranged in | functional connection with at least the X-ray source 14 of the imaging | assembly 14, 15. According to one embodiment, the guiding construction 50 is motorized. | While Figs. 2a-2c show two guiding constructions 50, which are config- ured to enable laterally moving the X-ray source 14 and the X-ray de- tector 15 in relation to their support construction 12, or in relation to the gantry 122, according to one embodiment only for the X-ray | source 14 is arranged a guiding construction 50. | The lateral movement of the X-ray source 14 and/or the X-ray detector | 15 in relation to the support construction 12, or the gantry 122, can | be implemented to take place on a plane which is orthogonal to the ro- | tation axis 13 about which the X-ray source 14 and the X-ray detector N 15 are arranged to rotate. | N | x According to one aspect, for example, the at least one guiding con- i © 30 struction 50 as discussed herein is mounted to a ring-shaped gantry 122 | I arranged to the support construction 12 supporting the X-ray imaging | E assembly 14, 15. | S | S |

The range of movement provided by the guiding construction 50 may com- | prise a base position and a first and a second extreme position, which locate in opposite directions from the base position. |

While Figs. 2a - 2c show an embodiment in which structurally identical guiding constructions 50 are arranged for both the X-ray source 14 and | the X-ray detector 15, and show the guiding construction 50 in differ- ent details, for clarity of the Figs. and since not all of the compo- | nents are even visible in all of them, not each and every component is | presented in each of the Figs. 2a -— 2c with a related reference number.

According to one aspect, as an example, the guiding construction 50 | comprising a carriage 51 (visible in Fig. 2c) mounted to at least the | X-ray source 14 to enable lateral moving of it.

A range of the lateral | movement of the carriage 51 may include a base position and a first and a second extreme position locating in opposite directions from the base | position. | Further, according to one aspect, the at least one guiding construction |

50 comprises at least one guiding groove or rail 52 on the side of the support construction 12, or of the gantry 122, and a mating construc- | tion 52” on the side of the carriage 51 (again, visible in Fig. 2c). | According to one aspect, the at least one guiding construction 50 can | comprise a motorized construction 53 in functional connection with the carriage 51, the motorized construction 53 providing the lateral moving | Q of at least the X-ray source 14 within said range of lateral movement. | x According to one aspect, the motorized construction 53 can comprise a © 30 driving screw 54 which is aligned parallel with the at least one guid- | r ing groove ör rail 52 and arranged in functional connection with the | E carriage 51. According to the embodiment shown in Figs. 2a - 2c, the | O driving screw 54 is arranged to be rotated via a belt 531 driven by a | 3 motor 532 yet another construction to rotate the driving screw 54 may | O 35 be used instead. | |

10 |

According to yet another aspect, the guiding construction 50 can in- | clude a position sensor arrangement 55 configured to acquire infor- | mation relating to a position of the X-ray source 14 and/or the X-ray | detector 15, within the range of the lateral movement of at least ei- | ther of the X-ray source 14 and the X-ray detector 15. | According to one aspect, the position sensor arrangement 55 can be con- | figured to detect a position of the carriage 51 within the range of the | lateral movement of the carriage 51. |

| According to one further aspect, a signal path can be arranged between | the at least one guiding construction 50 and the control system of the | apparatus. |

According to one aspect, the signal path can comprise a signal path be- | tween the position sensor arrangement 55 and the control system of the | apparatus. | According to one aspect, the position sensor arrangement 55 is an abso- | lute position sensor arrangement 55. | According to one aspect, the absolute position sensor arrangement 55 | can comprise a magnetic component 56 structurally connected to the car- | riage 51 and movably connected to a rod 57 extending in parallel with | the at least one guiding groove or rail 52 and the driving screw 54. |

N According to one aspect, the first longitudinally extending frame part | N 11 extends horizontally or is arranged to be moved so as to extend hor- | x izontally and the motorized construction 53 of the guiding construction | © 30 50 is arranged as self-holding regarding all i) positions of at least | I either of the X-ray source 14 and the X-ray detector 15 within the | E range of their lateral movement and ii) rotational positions at which | R the first driving mechanism 16 is configured to move the X-ray source | 3 14 and the X-ray detector 15 about the virtual or physical rotation ax- | S 35 is 13. |

11 |

According to one embodiment, the X-ray source 14 and the X-ray detector |

15 extend from one same side of the ring-shaped gantry housing 121, | while that particular side of the ring-shaped gantry housing 121 can | comprise an otherwise closed surface but on which surface there is an | opening 59 for at least either of the X-ray source 14 and the X-ray de- | tector 15. The opening 59 can be dimensioned to allow for the range of | lateral movement of the X-ray source 14 and/or the X-ray detector 15 as | guided by the at least one guiding construction 50. |

Figs. 2c and 3 show an embodiment including a mounting bracket 58 con- | figured to extend through the opening 59 in the gantry housing 121. The | mounting bracket 58 can be fixed to the carriage 51 at one side and, to | the X-ray source 14 and/or the X-ray detector 15 at the other.

Differ- | ently dimensioned mounting brackets 58 can be used.

As another detail, | concerning the guiding construction in general, the movement in enables | needs not necessarily to be lateral. | Referring to Figs. 4a -— 4c, a configuration is shown which as compared | to Figs. 2a - 2c further includes a light emitting component.

Or, in | reference to the disclosure of background to the invention above, shows | a light field indicator 141 comprising a visible light emitting con- | struction 141” configured to emit a visible light field pattern. |

In the example construction of Figs. 4a - 4c, the visible light emit- | ting construction 141’ is arranged to locate as fixed to a collimator | construction 142 of the X-ray source 14 and these three components are |

Q arranged movable together as a fixed assembly.

Moving of that assembly | N can be realized, for example, by the kind of guiding construction 50 as | x discussed above. | s 30 | x The light emitting construction 141’ may also, as an alternative, be | E directly attached to the (housing of the) X-ray source 14, or elsewhere | O to a frame structure of a collimator construction 142 attached to or | D being functionally connected to the X-ray source 14. |

12 |

In a construction such as shown in Figs. 4a — 4c, the visible light | emitting construction 141’ can be configured to be capable of project- | ing different light field patterns as for their shape and size.

Prefer- | ably, of essentially the same shapes and/or sizes to which the X-ray | beam collimator construction 142 is configured to be able to limit an | X-ray beam. |

Thus, when considering using the construction, the arrangement as shown | in Figs. 4a - 4c comprising the X-ray source 14, the collimator con- | struction 142 and the visible light emitting construction 1417” can be | moved, prior to an imaging exposure, to a position according to Fig. 4a | so that the visible light emitting construction 1417 will locate essen- | tially at the same location as where the X-ray source locates in Fig. |

4b, i.e. at a position from which an X-ray beam will be emitted during | an imaging exposure. |

In other words and more generally, the support construction 12 carrying | the X-ray source 14 may be configured to enable positioning the X-ray | source 14 and the visible light emitting construction 1417 at essen- | tially the same location, so as to when at a given time locating at | said essentially same location, they may direct a given field pattern | in essentially the same direction towards the X-ray detector 15. | Constructions like the one shown in Figs. 4a — 4c thus enable e.g. a | procedure to first drive the visible light emitting construction 141” | in the position according to Fig. 4a, position an anatomy to be imaged |

Q in the imaging area of the arrangement, and then adjust the light field | N pattern thus cast on the anatomy according to a given imaging mode to | x be applied, and according to that particular individual anatomy. | & 30 | | Ir The procedure may further include the control system of the arrangement | & comprising information concerning correlation between dimensions of the | 2 light field pattern cast towards the X-ray detector 15 and collimation | 3 of the X-ray beam, so as to have dimensions of the visible light and X- | O 35 ray irradiation beams substantially correspond to each other, at the |

13 | proximity of the X-ray detector 15. Or, in other words, to have dimen- | sions of the visible light pattern and the X-ray irradiation field pat- | tern substantially correspond to each other at a given distance from | the X-ray detector 15. |

| According to one embodiment, information of the size and shape of the | visible light pattern is provided for the X-ray beam collimator control | and a component or components of the collimator construction 142 are | moved so as to delimit an opening by which the shape and size of the X- | ray beam pattern hitting the anatomy will at least substantially corre- | spond to that of the light pattern, when the X-ray source 14 has been | moved to a location which substantially corresponds to the location at | which the visible light pattern was projected on the anatomy. |

According to another embodiment, adjusting the light field pattern | takes place via controls of the collimator construction 142 such that | when the opening the collimator construction 142 limits is adjusted, | the shape and size of the light field pattern gets adjusted according- | ly, as based on correlation information recorded in the control system | of the arrangement.

That is, in such embodiment, no separate input | means for adjusting the light field pattern is needed as control there- | of may take place via controls of the collimator construction 142. |

In both embodiments above, the control system of the apparatus may com- | prise information on which kind of an X-ray beam and light field pat- | tern correspond to each other under given circumstances, like in a con- |

Q text of a given imaging mode to be applied.

The imaging mode may be, | N for example, imaging a certain anatomy from a certain direction which | x means that, generally speaking, the surface of the anatomy will locate | © 30 at more or less the same distance from the X-ray detector 15 - and thus | x also more or less the same distance from the X-ray source 14 and the | & light emitting component 141 when being positioned at that same loca- | C tion in the support construction 12. When an imaging mode includes ro- | 3 tation about an anatomy, i.e. scanning the anatomy by an X-ray beam, | O 35 the light field pattern may be configured to show, instead of or in ad- | dition to showing location of the X-ray beam pattern at the initial po- | sition of the X-ray beam, the entire or at least part of the entire ar- | ea where the X-ray beam will travel during the scan.

In case of a to- | mography and especially a CBCT imaging mode, the area of an anatomy in- dicated by the visible light emitting component 141” may relate to the | volume of the anatomy which a given CT imaging mode, in case using a | given collimation setting of the X-ray beam, will cover. i Using the kind of arrangement shown in Figs. 4a - 4c, for example, de- | pending on the context it 1s not necessarily essential to have the | light field pattern and the X-ray beam pattern of precisely the same | shape and size.

For one, the focus or emission points of the diverging | visible light and X-ray beams need not to locate at exactly the same | distance from the X-ray detector 15, and their diverging angles need | not to be exactly the same.

Regarding differences there may be, they | can be taken into account when knowing the differences, and the dis- | tance to the location (i.e. surface of an anatomy) at which the pat- | terns should essential match.

Such correlation information can be rec- | orded in the control system of the arrangement and thus the pattern di- | mensions be configured to essentially correspond to each other under | given circumstances. | While Figs. 4a — 4c show an embodiment in which the components X-ray | source 14, X-ray beam collimator construction 142 and visible light | emitting construction 141’ are arranged to be moved as an integrated | assembly, which embodiment includes configuring the control system of | S the apparatus to provide for the X-ray beam collimator construction 142 | N the information of the size and shape of the light field pattern being | x generated, or vice versa, an alternative arrangement is to realize only | © 30 the X-ray source 14 and the light field indicator 141 as a fixed assem- | I bly, which would then be arranged to be moved in relation to the colli- | & mator construction 142. In such embodiment, the collimator construction | C 142 could be used to limit both the visible light beam and the X-ray | 3 beam. | N |

15 | As to the accuracy of correspondence of the beam sizes and shapes, or | the field pattern sizes and shapes, it is in view of certain aspects | more critical to get them closely match each other in the context of | using the imaging arrangement to take a single 2D radiograph, as com- | pared to 3D tomographic imaging.

In reference to Fig 5, according to one aspect, the support construc- | tion 12 comprises a ring-shaped gantry housing 121 which houses i) at | least one guiding construction 50 and optionally also ii) driving mechanism 16 arranged to move the X-ray imaging assembly 14, 15 about | the virtual or physical rotation axis 13, whereas the X-ray source 14 | and the image detector 15 are arranged to locate or extend outside the ring-shaped gantry housing 121. | According to one embodiment, the X-ray source 14 and/or the X-ray de- | tector 15 can include a housing for the X-ray source 14 and/or the X- | ray detector 15 which is so designed and dimensioned that in all posi- tions within the range of the lateral movement of at least either of | the X-ray source 14 and the X-ray detector 15, the housing covers the | opening 59 through which the mounting bracket 58 extends. | According to one aspect, in case of there being more than one guising | construction 50 they can comprise the same number of components having | the same functions so as to form similarly functioning assemblies.

As | an example, the guiding constructions may be identical while optionally | the mounting brackets 58 may be different, as adapted specifically for | S the X-ray source 14 and the image detector 15. | N | x According to one aspect when the housing 121 of the support construc- | © 30 tion 12 does not encase the X-ray source 14 and the X-ray detector 15, | I but functions primarily or solely as a housing för e.g. the ring-shaped | E gantry 122, to which the X-ray source 14 and the X-ray detector 15 are | R mounted, and for the structures arranged to the apparatus to drive the | 3 X-ray source 14 and the X-ray detector 15 about the rotation axis 13, | O 35 the support construction 12 can be realized to be lighter and to pro- |

16 | vide a possibility for better access for patients and personnel to the | imaging volume between the X-ray source 14 and the X-ray detector 15. | Such embodiment can also make it easier for the personnel to have a clear line of sight at the imaging volume inside the housing 121,

whereto the patient is to be positioned for an exposure. | Turning to Fig. 6 which shows, as an example and as a schematic general | side view, certain components of an embodiment in which, in addition to | what can be referred to as a first elongated frame part 11 discussed | above, there is a second elongated frame part 21 mechanically connected | to the first elongated frame part 11, of essentially the same length as | the first elongated frame part 11. | According to one aspect and still referring to Fig. 6, at the proximity | of the first end of the elongated frame parts 11, 12 is arranged an ar- | ticulated connection construction 22 to mechanically connect the first | and second elongated frame parts 11, 21, to allow for tilting of the | first elongated frame part 11 about at least one tilt axis in relation | to the second elongated frame part 21. The at least one tilt axis may | be an axis which is orthogonal to the direction in which the first and second elongated frame parts 11, 21 extend as well as to direction in | which the support construction 12 for the X-ray imaging assembly 14, 15 | extends - perpendicularly from the first longitudinally extending frame | part 11. |

| In the embodiments shown in Fig. 6, the at least one tilt axis is hori- |

Q zontal. | S | x According to another aspect, on the side of the second elongated frame | © 30 part 21, a mounting structure 23 not directly visible in Fig. 6 is ar- | r ranged in connection with the articulated connection construction 22. | E The mounting structure 23 is arranged movable along or alongside the | S second elongated frame part 21. |

17 |

According to another aspect, for example, in the proximity of the sec- | ond end of the second elongated frame part 21 is arranged a locking | mechanism 24 configured to enable connecting and disconnecting the | first and second elongated frame parts 11, 21. Particularly, the lock- | ing mechanism 24 may be arranged in the proximity of the second end of | the first and second elongated frame parts 11, 21 and as configured to | enable connecting together and disconnecting the first and second elon- | gated frame parts 11, 21 at the proximity of the second ends of the | first and second elongated frame parts 11, 21. |

When the second elongated frame part 21 is mounted stable and the lock- | ing mechanism 24 is not connecting the first and second elongated frame | parts 11, 21, the second end of the first elongated frame part 11 is | free to move laterally while the articulated connection 22 between the | frame parts 11, 21 allows for turning of the first elongated frame part |

11 about the horizontal tilt axis, at the proximity of the first end of | the first elongated frame part 11. In case of a vertical starting posi- | tion, such movably arranged mounting structure as discussed above al- | lows for descending and ascending of the first end of the first elon- | gated frame part 11. | While the construction allowing for tilting of the first elongated | frame part 11 and descending and ascending of the first end of the | first elongated frame part 11, as well as that of the locking mechanism |

24 discussed above may vary, examples of such are disclosed in more de- | tail in a co-pending patent application FI 20190054, which is incorpo- |

Q rated herein by reference. | x Fig. 6 shows the apparatus at a stage where the first end of the first | © 30 elongated frame part 11 has moved downwards and the second end of the | r first elongated frame part 11 has moved horizontally on a surface.

The | & apparatus of Fig. 6 may be configured to allow for descending of the | O first end of the first elongated frame part 11 all the way to the prox- | D imity of the second end of the second elongated frame part 21. |

18 |

According to yet another aspect, not directly visible in Fig. 6, in | functional connection with the second elongated frame part 21 is ar- | ranged a driving mechanism 27 to drive the mounting structure 23 along | or alongside the second elongated frame part 21. When being in mechani- | cal connection with the first elongated frame part 11, at the proximity | of the first end of it, the driving mechanism 27 can move the first end | of the first elongated frame part 11 in a direction in which the second | elongated frame part 21 extends. |

The driving mechanism 27 to drive the mounting structure 23 may be a | construction similar with the driving mechanism 17 driving the support | construction 12 of the X-ray imaging assembly 14, 15 along or alongside | the first elongated frame part 11. |

According to one aspect, the driving mechanism 27 to drive the mounting | structure 23 comprises a chain drive. |

Fig. 7 is a schematic general presentation of an apparatus, as an exam- | ple, extending in horizontal direction.

While not shown in Fig. 7, the | apparatus may comprise constructions as discussed in connection with Fig. |

6 which allows for changing the direction in which the elongated frame | part 11 extends.

The support construction 12 for the X-ray imaging assem- | bly 14, 15 in Fig. 7 is not similar with that of Fig. 6, while Fig. 7 | shows certain cömponents of the apparatus as driven to locations other | than their base position. |

Q That is, regarding e.g. the aspect of access to the volume between the | N X-ray source 14 and the X-ray detector 15, Fig. 7 illustrates how cer- | x tain components of the apparatus may be moved to various locations | © 30 within ranges of movements arranged for them.

According to that embodi- | I ment, while the embodiments discussed above to laterally move at least | & either of the X-ray source 14 and the X-ray detector 15 can be used to | C ease access of a patient inside the support construction 12 for the X- | 3 ray imaging assembly 14, 15, another similarly construed construction | S 35 or another similarly functioning construction may be arranged in the |

19 | apparatus to also laterally move the support construction 12 for the X- | ray imaging assembly 14, 15 itself, in relation to the elongated frame | part 11. By incorporating such linear movement mechanism 50” to the ap- | paratus, e.g. even more room may be provided for the patient to enter | the imaging area and then get properly positioned for an exposure.

Thus, according to one aspect, the apparatus further comprises a linear | movement mechanism 50’ arranged to enable moving the support construc- | tion 12 for the X-ray imaging assembly in relation to the longitudinal- | ly extending frame part 11 in a direction which is at right angles to | the direction in which the longitudinally extending frame part 11 ex- | tends.

A range of the linear movement of the support construction 12 | may comprise a base position in relation to the first longitudinally | extending frame part 11 and a first and a second extreme position. |

When the support construction 12 for the X-ray imaging assembly 14, 15 | extends in a direction at right angles to the longitudinally extending | frame part 11, the direction in which the linear movement mechanism 50” | moves the support construction 12 for the X-ray imaging assembly 14, 15 | in relation to the longitudinally extending frame part 11 is also at | right angles to that direction. i Concerning the base position provided by the linear movement mechanism |

50" for the support construction 12 for the X-ray imaging assembly 14, |

15, in embodiments either of the first and second extreme positions may | be the base position.

The same applies concerning the guiding construc- |

Q tion 50 for at least the X-ray source. | N | x According to yet another aspect and as shown in Fig. 8a, the connection | © 30 construction 19, 20 which mechanically connects the patient support 18 | T to the elongated frame part 11 may comprise a patient support adjust- | & ment mechanism 197, 20' configured to enable displacing the patient | S support 18 closer and further away from the (first) elongated frame | S part 11. | < |

20 |

According to another aspect, a patient support driving mechanism 19/', |

207 is arranged in functional connection with the patient support ad- | justment mechanism 197, 207. |

According to another aspect, the patient support adjustment mechanism |

197, 20" may comprise a first adjustment mechanism 19’ arranged togeth- | er with its driving mechanism 19'7 comprised in the patient support | driving mechanism 19’, 20'’ substantially at the first end of the | elongated frame part 11, and a second adjustment mechanism 20’ arranged | together with its driving mechanism 20'' comprised in the patient sup- | port driving mechanism 19'', 20'' substantially at the second end of | the elongated frame part 11. | According to one aspect, for example, the patient support adjustment | mechanisms 197, 20' is arranged in functional connection with the con- | trol system of the apparatus and the control system is configured to | control the patient support driving mechanism 19°", 20// of the patient | support adjustment mechanism 197, 207. |

According to one aspect, for example, the control system is configured | to control the connection construction 19, 20 comprising the first ad- | justment mechanism 19” with its driving mechanism 197/, arranged sub- | stantially at the first end of the (first) elongated frame part 11, and | the second adjustment mechanism 20’ with its driving mechanism 2077, | arranged substantially at the second end of the (first) elongated frame | part 11, to keep at the first and second ends of the elongated frame |

Q part 11 an identical distance between the (first) elongated frame part | N 11 and the patient support 18 when adjusting the distance between the | x two. | x According to another aspect; the distance between the ends of the | E (first) elongated frame part 11 and the patient support 18 can be ad- | S justed to be different. | S | |

21 |

According to one aspect, as shown in Fig. 8b, considering the above- | discussed first direction of the patient support 18, its cross section | as for its prevailing part is curved so as to better support a patient | against the concave surface of the patient support 18. |

| According to one other aspect, as shown in Fig. 8b, at the edges 181 of | that cross section of the patient support 18, the shape of the cross | section turns into being curved in the opposite direction. |

According to one other aspect and as further shown in Fig. 8b, near the | edges of the above-discussed cross section of the patient support 18 | and on the side opposite to the for its prevailing part concave sur- | face, is arranged a holding structure 182. The holding structure 182 | may be e.g. an elongated handle or an attachment structure to receive a | strap designed to extent on or over the concave side of the patient | support 18, to be used to provide further support to the patient and | thus to help keeping still during an imaging exposure. | According to one aspect, and as already generally mentioned aböve, the | various degrees of freedoms of movement of the components of apparatus, | including those that may be arranged for the patient support 18, may be | taken advantage of when positioning a patient, or to be more exact, an | anatomy for an exposure.

As an example, considering a situation of a | patient's shoulder to be examined while lying on a patient support 18 | like the one discussed above, one can first drive the patient support |

18 to be located at a height position which is easiest for the patient |

N to get on the patient support 18. Then, when the patient is lying on | N the patient support 18, at least one of i) the height position of the | x patient support 18, ii) horizontal position of the support construction | © 30 12 for the X-ray imaging assembly 14, 15, and iii) position of at least | I either of the X-ray source 14 and the X-ray detector 15 within the i E range of the lateral movement provided therefor can be adjusted so that | R the desired anatomy will locate at the field of view of the apparatus. | 3 This, obviously, within the limits of the degrees of freedoms of move- | O 35 ment of the components of apparatus arranged therefor. |

22 |

Structures according to embodiments enable arranging to the apparatus various patient entry and positioning operations.

They can also be tak- | en advantage of to perform e.g. other than traditional kind CT imaging | and, in addition to CT imaging, also imaging modes with no rotation but mere linear movement of the X-ray imaging assembly may be deployed. | Specifically, embodiments may be applied in the context of positioning | an anatomy for an individual 2D imaging exposure. |

The operation modes such as those discussed above may include, as a | pre-exposure operation, driving the guiding construction 50 for the X- | ray source 14 to which is connected the visible light emitting con- | struction 141” such that the visible light emitting construction 1417 | will be moved to locate at essentially the base position of the X-ray | source 14, and adjusting the field pattern generated by the visible | light emitting construction 141” to be of a default shape and size.

The | default shape and size may be set according to an imaging mode, which | may be arranged to be selected from the user interface of the appa- | ratus. |

According to an embodiment, a selected imaging mode may include driving | the X-ray source 14 and the X-ray detector 15 a distance from their | base positions.

The apparatus may be configured to allow for, after | such pre-exposure operation, to adjust the light field pattern, and | thus the X-ray beam size and/or shape to be used during the imaging ex- | posiire, according characteristics of a given anatomy positioned for im- | aging. |

S | N In an embodiment, the arrangement is equipped with a component or com- | x ponents adapted to determine the location and/or the shape of the anat- | © 30 omy positioned for imaging, and the control system to then adjust the | r X-ray beam collimation and/or the projected visible light pattern on | & the anatomy using that knowledge.

Technologies to determine distance to | O and shape of a surface in a coordinate system exist, as well as to | 3 transfer information from one coordinate system to another - in this | O 35 case, when knowing the geometry of the (relevant components of the) im- |

23 | aging arrangement, and correlation of that to the coordinate system in | which the surface location and shape is determined.

In embodiments, in- | stead of determining the shape of the surface of the anatomy, e.g. just | a shortest distance from the said same location to the surface of the | anatomy may be determined.

Pre-exposure operations relating to mutual positioning of the anatomy | and the imaging assembly and adjusting the X-ray beam size and shape | according to a given imaging mode, and even according to the anatomy to | be imaged, may be applied in the context of various imaging modes ar- | ranged to the imaging apparatus.

Such an operation may include, in gen- | eral, the control system of the apparatus comprising geometric infor- | mation regarding mutual positions of the X-ray source, the light emit- | ting construction 141’, the X-ray detector and/or the patient support | such that for a given light field pattern and the location from where | it is cast, the control system comprises corresponding collimation in- | formation for limiting the X-ray beam when the X-ray beam is emitted at | a given location of the X-ray source, in a context of a given imaging | mode. |

|

An operation mode may include, as an example, a pre-exposure operation | of - prior to optionally driving the X-ray source 14 and the X-ray de- | tector 15 from their base positions, driving the guiding construction |

50 for the X-ray source 14 to which is connected the visible light | emitting construction 141’ such that the visible light emitting con- | struction 141’ will be moved to locate at essentially the base position |

S of the X-ray source 14, and adjusting the field light pattern generated | & by the visible light emitting construction 141 to be of a default | x shape and size.

The default shape and size may be pre-set according to | © 30 an imaging mode selected from the user interface of the apparatus. | & According to an embodiment, as an example, the selected imaging mode | 2 includes driving the X-ray source 14 and the X-ray detector 15 a dis- | 3 tance from their base positions.

The apparatus may be configured to al- | O 35 low for, after such pre-exposure operation, adjusting the light field | pattern, and thus the X-ray beam size and shape to be used during the imaging exposure, according characteristics of a given individual anat- omy positioned for imaging. | Concerning a given patient entry operation or patient entry mode, ac- | cording to one aspect, it includes the visible light emitting construc- | tion 141” being positioned at the same place as where the X-ray source will be positioned during, or at the beginning of a subsequent imaging | exposure. | | According to one aspect, then, the light field indicator 141 may be | configured to be able to project a light beam of the same shape as is | the shape of an X-ray beam the X-ray source 14 is configured to emit, | or can be adjusted to emit.

Such light field indicator 141 may be | mounted to the same guiding construction 50 as the X-ray source 14, | e.g. as a component separate from the X-ray source 14, so as to be möv- | ably mounted in relation to the support construction 12. The range of | movement of the guiding construction 50 to which the X-ray source 12 | and the light emitting component may be mounted is then preferably so | configured that the X-ray source 14 and the light emitting construction | 141" can be positioned at the same location within the range of move- | ment the guiding construction 50 provides.

Such configuration provides | a novel arrangement by which one is able to cast a positioning light | pattern on the object to be imaged from the same location at which the | actual X-ray imaging exposure is to take place, or begin. | S Fig. 9 shows as a block diagram an example of components of a control | & system applicable for use in the arrangement.

The control system accord- | x ing to Fig. 9 is configured to enable controlling, first of all, opera- | © 30 tion of the X-ray source 14 and the X-ray detector 15 (imaging means, or | I assembly) during an exposure, according to an imaging mode.

Components | E controlling operation of the X-ray source 14 and the X-ray detector 15 | R can include components physically arranged to the X-ray source 14 and/or | 3 the X-ray detector 15 and/or elsewhere in the apparatus. |

25 |

The control system may further be configured to control various driving | means of the apparatus, such as those driving the one or more than one guiding construction 50 as well those moving the support construction 20 | for the X-ray imaging assembly 14, 15. A signal path can also be arranged | for controlling components discussed above relating to adjusting the shape and size of the field patterns, and positioning of those components in relation to the support construction 12. |

The control system of Fig. 9 further shows optional features of rotating | the X-ray imaging assembly 14, 15 as well as the patient entry mode fea- | ture, which may include controlling at least one of the above-discussed | driving means. |

Further shown in Fig. 9 is a signal path to the mounting structure 23 as | discussed further above and, in case of the apparatus comprising a mo- | torized locking mechanism 24 to connect and disconnect the first and | second elongated frame parts 11, 21 as discussed above, the control | system may also control driving of the locking mechanism 24. |

Overall, the control system may be arranged to control the above- | discussed operations or a portion thereof.

The structures and functional- | ities discussed above offer various possibilities to ease positioning and | performing imaging of a desired volume of a patient. |

Control signals for various operations may be triggered as a response to | a detected operation or input from the user interface of the apparatus. |

Q The memory of the control system may include various correlation infor- |

N mation of pattern shapes and dimensions as discussed above, and related |

S control protocols as discussed above, as well as protocols relating to |

2 30 one or more entry and/or imaging mode. |

While various embodiments are discussed above, an arrangement of this |

S disclosure can be described as a dental or medical X-ray imaging ar- |

S rangement which comprises an X-ray detector, an X-ray source configured |

G 35 to generate X-ray irradiation and comprising a collimator construction |

26 | functionally connected to the X-ray source, the collimator construction being configured to limit the X-ray irradiation generated by the X-ray | source into a beam to be aimed in the direction of the X-ray detector | and defining an X-ray irradiation field pattern, a light field indica- | tor comprising a visible light emitting construction and being config- | ured to project a visible light field pattern to be aimed in the direc- | tion of the X-ray detector, a support construction to which the X-ray | source and the visible light emitting construction are mounted, and a | control system comprising control information relating to an imaging | mode.

Further, the support construction may be configured to enable po- | sitioning the X-ray source and the visible light emitting construction at essentially the same location in relation to the support construc- | tion 12, so as to when at a given time locating at said essentially | same location, to direct a given field pattern in essentially the same | direction towards the X-ray detector. |

To add to, or summarize some of the features discussed above, embodiments | may include that the X-ray source 14, the collimator construction 142 | and the visible light emitting construction 141’ are arranged to be movable as a fixed assembly.

On the other hand, the X-ray source 14 and | the visible light emitting construction 141’ may be arranged to be mov- | able as a fixed unit in relation to the collimator construction 142. |

The light field indicator 141 may be configured to generate the visible | light field pattern such that the pattern is a substantially evenly il- | luminated area or comprises a pattern of light fields which as a combi- |

Q nation indicates an area.

Further, the light field indicator 141 may be | N configured to enable projecting visible light field patterns of differ- | S ent sizes and/or different shapes, and the collimator construction 142 | 2 30 to enable limiting X-ray irradiation field patterns of different sizes | z and/or of different shapes. | a | S The control system may comprise correlation information relating to di- | 2 mensions of the visible light field pattern and the X-ray irradiation | O 35 field pattern, at a given distance from the X-ray detector 15, and the | light field indicator 141 and the collimator construction 142 are con-

figured to enable adjusting dimensions and/or shape of their respective field patterns according to the correlation information such that the | field patterns cover essentially the same area at said given distance from the X-ray detector 15, and wherein the correlation information op- | tionally includes correlation information relating to a given imaging | mode.

A given imaging mode may be a CBCT imaging mode and the control | system be configured to enable indicating by the visible light field pattern an area at a given distance from the X-ray detector 15 relating | to a volume which, regarding a given CBCT imaging mode and in case us- | ing a given collimation setting of the X-ray beam, will cover. | The arrangement may further comprise a component or components config- | ured to determine location and/or shape of an anatomy positioned for | imaging, and the control system then configured to be able adjust the | X-ray beam collimation and/or the projected visible light pattern on | the anatomy using that knowledge, the location and/or shape then defin- | ing the given distance from the X-ray detector 15. | The control system may also be configured to receive information from | the light field indicator 141 on the characteristics of the visible | light pattern it projects and to convert said received information to | information on how to control operation of the collimator construction | 142 so as to adjust the X-ray irradiation field pattern to at least | substantially correspond to the size and shape of the area the project- | ed visible light pattern indicates. | N The control system may further be configured to receive information | x from the collimator construction 142 on the characteristics of the X- | © 30 ray irradiation field pattern it limits and to convert the received in- | I formation to information on how to control operation of the light field | E indicator 141 so as to adjust the visible light field pattern to at | S least substantially correspond to the size and shape of the X-ray irra- | S diation field pattern. | S |

28 |

The arrangement may comprise a first guiding construction 50 mounted to | the support construction 12, wherein the X-ray source 14 and the visi- | ble light emitting construction 141 are mounted together as a fixed | unit and the first guiding construction 50 is configured to enable mov- | ing that fixed unit, a range of that movement comprising a base posi- | tion and a first and a second extreme position.

The first guiding con- | struction 50 may comprise a carriage 51 mounted to said fixed unit com- | prising the X-ray source 14 and the visible light emitting construction |

141", a range of the movement of the carriage 51 comprising a base po- | sition and a first and a second extreme position. |

The first guiding construction 50 may comprise a at least one guiding | groove or rail 52 on a side of the support construction 12 and a mating i construction 52' on a side of the carriage 51. On the other hand, the | first guiding construction 50 may comprise a motorized construction 53 | in functional connection with the carriage 51, the motorized construc- | tion 53 providing the moving of the fixed unit comprising the X-ray | source 14 and the visible light emitting construction 141' within that | range comprising the first and second extreme positions.

The first |

— auiding construction 50 may also include a position sensor arrangement |

55 configured to acquire information relating to a position of the | fixed unit comprising the X-ray source 14 and the visible light emit- | ting construction 141” within that range of movement, the position sen- | sor arrangement 55 being configured to detect a position of the car- | riage 51 within the range of movement of the carriage 51. The first | guiding construction 50 may be configured to enable laterally moving |

Q said fixed unit and the motorized construction 53 may comprise a driv- | N ing screw 54, the driving screw 54 being aligned parallel with the at | S least one guiding groove or rail 52 and arranged in functional connec- | 2 30 tion with the carriage 51. | The position sensor arrangement 55 may comprise a magnetic component 56 |

S structurally connected to the carriage 51 and movably connected to a | S rod 57 extending in parallel with said at least one guiding groove or | Q 35 rail 52 and said driving screw 54 of the guiding construction 50. |

A mounting bracket 58 may be fixed to the carriage 51 and, on the other | hand, to the fixed unit comprising the X-ray source 14 and the visible | light emitting construction 141’, to mechanically connect the fixed | unit to the guiding construction 50.

| A signal path can be provided between the first guiding construction 50 | and the control system. The signal path may comprise a signal path be- | tween the position sensor arrangement 55 and the control system. | A signal path may also be provided between the collimator construction | 142 and the control system, and between the light field indicator 141 | and the control system, to enable controlling the collimator construc- tion 142 and the light field indicator 141 according to the correlation ; information. | Further, the X-ray detector 15 may be mounted to the support construc- | tion 12 to which the X-ray source 14 and the visible light emitting | construction 141’ are mounted. The arrangement may comprise a further | X-ray detector mounted elsewhere than to the support construction 1? to | which the X-ray source 14 and the visible light emitting construction 141” are mounted, and that mounting of the X-ray source 14 and the vis- | ible light emitting construction 1417 to the support construction 12 | may be realized as allowing for directing their respective field pat- | terns in essentially the same direction towards both of the X-ray de- | tectors. | S The support construction 12 to which the X-ray source 14 and the visi- | N ble light emitting construction 141’ are mounted may comprise a ring- | S shaped structure. The ring-shaped structure may comprise a ring-shaped | 2 30 gantry 122 and a housing 121 which houses at least said ring-shaped | I gantry 122 and the first guiding construction 50, The housing 121 may | + comprise a surface with at least one opening 59 for mounting by the | S mounting bracket 58 through the at least one opening 59 at least the X- | 2 ray source 14, wherein the at least one opening 59 is dimensioned so as | to allow for the range of movement of the X-ray source 14 as guided by | said guiding construction 50.

An arrangement as discussed above may then comprise a first frame part | 11 extending in a first direction and comprising a first end and a sec- ond end, and the support construction 12 may extend from the first | frame part 11 in a second direction essentially at right angles to the | first direction. The positioning of the X-ray source 14 and the visible light emitting construction 141’ at essentially the same location may include arranging the X-ray source 14 and the visible light emitting | construction 141” movable in a direction at right angles to both those | first and second direction. | N | O i S | < | <Q | 00 , | © | I | a | - | I | O | O | oO i N | O | N |

Claims (25)

31 | CLATMS |

1. A dental or medical X-ray imaging arrangement, comprising: | an X-ray detector 15; | an X-ray source 14 configured to generate X-ray irradiation and com- | prising a collimator construction 142 functionally connected to the X- | ray source 14, the collimator construction 142 configured to limit the | X-ray irradiation generated by the X-ray source 14 into a beam to be | aimed in the direction of the X-ray detector 15 and defining an X-ray | irradiation field pattern; | a light field indicator 141 comprising a visible light emitting con- | struction 141’ and configured to project a visible light field pattern | to be aimed in the direction of the X-ray detector 15; | a support construction 12 to which the X-ray source 14 and the visible | light emitting construction 141’ are mounted; | a control system, the control system comprising control information re- | lating to an imaging mode; | characterized in that the support construction 12 is configured to | enable positioning the X-ray source 14 and the visible light emitting | construction 1417 at essentially the same location in relation to the | support construction 12, so as to when at a given time locating at said | essentially same location to direct a given irradiation / light field | pattern in essentially the same direction towards the X-ray detector |

2. The arrangement according to claim 1, characterized in that the | Q X-ray source 14, the collimator construction 142 and the visible light | & emitting construction 141’ are arranged to be movable as a fixed assem- | 3 bly. | I

3. The arrangement according to claim 1, characterized in that the | E X-ray source 14 and the visible light emitting construction 1417 are | S arranged to be movable as a fixed unit in relation to the collimator | 2 construction 142. |

4. The arrangement according to any of the claims 1 - 3, character- | ized in that the light field indicator 141 is configured to generate the visible light field pattern such that the pattern is a substantial- | ly evenly illuminated area or comprises a pattern of light fields which as a combination indicates an area. |

5. The arrangement according to any of the claims 1 - 4, character- | ized in that the light field indicator 141 is configured to enable | projecting visible light field patterns of different sizes and/or dif- | ferent shapes, and the collimator construction 142 is configured to en- | able limiting X-ray irradiation field patterns of different sizes | and/or of different shapes. |

6. The arrangement according to any of the claims 1 - 5, character- | ized in that the control system comprises correlation information re- | lating to dimensions of the visible light field pattern and the X-ray | irradiation field pattern, at a given distance from the X-ray detector | 15, and the light field indicator 141 and the collimator construction | 142 are configured to enable adjusting dimensions and/or shape of their | respective field patterns according to the correlation information such | that the field patterns cover essentially the same area at said given | distance from the X-ray detector 15, and/or wherein the correlation in- | formation optionally includes correlation information relating to a | given imaging mode. | |

7. The arrangement according to claim 6, characterized in that the | S given imaging mode is a CBCT imaging mode and the control system is | & configured to enable indicating by the visible light field pattern an | x area at a given distance from the X-ray detector 15 relating to a vol- | © 30 ume which, regarding a given CBCT imaging mode and in case using a giv- | I en collimation setting of the X-ray beam, will cover. | a | R 8. The arrangement according to claim 6 or 7, characterized in that | D the arrangement comprises a component or components configured to de- | O 35 termine location and/or shape of an anatomy positioned for imaging, and |

33 | the control system is then configured to be able adjust the X-ray beam | collimation and/or the projected visible light pattern on the anatomy | using that knowledge, said location and/or shape then defining said | given distance from the X-ray detector 15. |

9. The arrangement according to any of the claims 1 - 8, character- | ized in that the control system is configured to receive information | from the light field indicator 141 on the characteristics of the visi- | ble light pattern it projects and to convert said received information | to information on how to control operation of the collimator construc- | tion 142 so as to adjust the X-ray irradiation field pattern to at | least substantially correspond to the size and shape of the area the | projected visible light pattern indicates, and/or that the control sys- | tem is configured to receive information from the collimator construc- | tion 142 on the characteristics of the X-ray irradiation field pattern | it limits and to convert said received information to information on | how to control operation of the light field indicator 141 so as to ad- | just the visible light field pattern to at least substantially corre- | spond to the size and shape of the X-ray irradiation field pattern. |

10. The arrangement according to any of the claims 1 - 9, character- | ized in that the arrangement comprises a first guiding construction | 50 mounted to the support construction 12, and wherein the X-ray source | 14 and the visible light emitting construction 141' are mounted togeth- | er as a fixed unit and the first guiding construction 50 is configured | to enable moving said fixed unit, a range of said movement comprising a | S base position and a first and a second extreme position. | x 11. The arrangement according to claim 10, characterized in that | © 30 the first guiding construction 50 comprises a carriage 51 mounted to | I said fixed unit comprising the X-ray source 14 and the visible light | a emitting construction 141’, a range of said movement of the carriage 51 | S comprising a base position and a first and a second extreme position. | S |

34 |

12. The arrangement according to claim 11, characterized in that | the first guiding construction 50 comprises at least one guiding groove | or rail 52 on a side of the support construction 12 and a mating con- | struction 52’ on a side of the carriage 51. | s |

13. The arrangement according to claim 12, characterized in that | the first guiding construction 50 comprises a motorized construction 53 | in functional connection with the carriage 51, the motorized coristruc- | tion 53 providing said moving of the fixed unit comprising the X-ray | source 14 and the visible light emitting construction 1417” within said | range comprising the first and second extreme positions. |

14. The arrangement according to any of the claims 11 - 13, charac- | terized in that the first guiding construction 50 includes a posi- | tion sensor arrangement 55 configured to acquire information relating | to a position of said fixed unit comprising the X-ray source 14 and the | visible light emitting construction 141" within said range of movement, | the position sensor arrangement 55 being configured to detect a posi- | tion of the carriage 51 within said range of movement of the carriage | — 51. |

15. The arrangement according to any of the claims 11 - 14, charac- | terized in that the first guiding construction 50 is configured to | enable laterally moving said fixed unit and the motorized construction | 53 comprises a driving screw 54, the driving screw 54 being aligned | parallel with said at least one guiding groove or rail 52 and arranged | S in functional connection with the carriage 51. | 3 16. The arrangement according to claim 15, characterized in that | 2 30 the position sensor arrangement 55 comprises a magnetic component 56 | I structurally connected to the carriage 51 and movably connected to a | = rod 57 extending in parallel with said at least one guiding groove or | S rail 52 and said driving screw 54 of the guiding construction 50. | N |

35 |

17. The arrangement according to any of the claims 11 - 16, charac- terized in that a mounting bracket 58 is fixed to the carriage 51 | and, on the other hand, to the fixed unit comprising the X-ray source 14 and the visible light emitting construction 141/, to mechanically | connect said fixed unit to the guiding construction 50. |

18. The arrangement according to any of the claims 10 - 17, charac- | terized in that a signal path is provided between the first guiding | construction 50 and the control system, the signal path comprising a | signal path between the position sensor arrangement 55 and the control | system. |

19. The arrangement according to any of the claims 6 - 18, character- | ized in that a signal path is provided between the collimator con- | struction 142 and the control system, and between the light field indi- | cator 141 and the control system, to enable controlling the collimator | construction 142 and the light field indicator 141 according to the | correlation information. |

20. The arrangement according to any of the claims 1 - 19, character- | ized in that the X-ray detector 15 is mounted to the support con- | struction 12 to which the X-ray source 14 and the visible light emit- | ting construction 141, are mounted. |

21. The arrangement according to claim 20, characterized in that | the arrangement comprises a further X-ray detector mounted elsewhere | Q than to the support construction 12 to which the X-ray source 14 and | N the visible light emitting construction 141” are mounted, and that | 3 mounting of the X-ray source 14 and the visible light emitting con- | S 30 struction 141” to the support construction 12 is realized as allowing | I for directing their respective field patterns in essentially the same | E direction towards both X-ray detectors. | 2 22. The arrangement according to any of the claims 10 - 21, charac- | O 35 terized in that the support construction 12 to which the X-ray |

36 | source 14 and the visible light emitting construction 141’ are mounted | comprises a ring-shaped structure, said ring-shaped structure compris- | ing a ring-shaped gantry 122 and a housing 121 which houses at least | said ring-shaped gantry 122 and the first guiding construction 50. | |

23. The arrangement according to claim 22, characterized in that | the housing 121 comprises a surface with at least one opening 59 for | mounting by the mounting bracket 58 through the at least one opening 59 | at least the X-ray source 14, wherein the at least one opening 59 is | dimensioned so as to allow for the range of movement of the X-ray | source 14 as guided by said guiding construction 50. |

24. The arrangement according to any of the claims 1 - 23, character- | ized in that the arrangement comprises a first frame part 11 extend- | ing in a first direction and comprising a first end and a second end, | and the support construction 12 extends from the first frame part 11 in | a second direction essentially at right angles to the first direction. |

25. The arrangement according to claim 24, characterized in that | said positioning of the X-ray source 14 and the visible light emitting | construction 141” at essentially the same location includes arranging | the X-ray source 14 and the visible light emitting construction 141’ | movable in a direction at right angles to both said first and second | direction. | o | N | O | N | < | <Q | 00 | O | I | oc | - | ™ | N | O | 0 | oO N i O | N |