FI20176044A1

FI20176044A1 - An X-ray imaging unit for dental imaging

Info

Publication number: FI20176044A1
Application number: FI20176044A
Authority: FI
Inventors: Ari Metso
Original assignee: Palodex Group Oy
Priority date: 2017-11-22
Filing date: 2017-11-22
Publication date: 2019-05-23
Also published as: FI128099B; WO2019102067A1

Abstract

The invention relates to an X-ray imaging unit (100) for dental imaging. The X-ray imaging unit (100) comprising: a rotating part (112) comprising an X-ray source part (118) and an X-ray imaging detector part (120) configured to provide data for a dental image; a supporting part (110) for supporting the rotating part (112); and a moving part (200) for moving the rotating part (112) in a horizontal plane. The movement of the rotating part (112) is at least one of the followings: linear movement along the supporting part (110) and rotational movement around a rotation axis of the rotating part (112). The moving part (200) is further arranged to move the rotating part (112) in a vertical direction in order to adjust a field of view, FOV, in the vertical direction. The invention also relates to a method, a computer program, and a tangible non-volatile computer- readable medium for dental imaging.

Description

An X-ray imaging unit for dental imaging

TECHNICAL FIELD

The invention concerns in general the technical field of dental X-ray imaging. Especially the invention concerns an X-ray imaging device for dental imaging.

BACKGROUND

Traditionally a dental x-ray imaging device comprises a rotation unit having an X-ray source and an x-ray imaging detector. The X-ray source provides an Xray beam that travels through a patient’s head, for example, to the X-ray imaging detector. The X-ray beam forms a cylindrical field of view (FOV) around a 10 vertical rotation axis, when the rotation unit is arranged to rotate around the patient.

The size of the FOV in vertical direction and in horizontal direction may depend on at least one of the following: size of the X-ray imaging detector, relative distances of the X-ray source, the rotation axis and the X-ray imaging detector. In 15 order to fit both jaws of the patient inside the FOV the size of the X-ray imaging detector in vertical direction is required to be relatively large. Typically, a large size X-ray imaging detector means high costs.

According to one prior art solution a small X-ray imaging detector may be used and two imaging sequences or image sets at different points in vertical direc20 tion may be taken by moving the X-ray source and the X-ray imaging detector or the patient in vertical direction. The two image sets may be finally combined together by stitching them mathematically in order to provide programmatically a larger FOV. The movement of the X-ray source and the X-ray imaging detector in vertical direction may be implemented by moving the whole device by 25 means of a motor configured to move the device in vertical direction in order to adjust the FOV for different height patients. However, moving the whole device is not very accurate in stitching point of view because of a large mass of the device and several joints, for example rotation bearings, having tolerances.

Alternatively or in addition, the movement of the X-ray source and the X-ray 30 imaging detector in vertical direction may be implemented by moving the rotation unit by means of a separate motor for lifting the rotation unit only. However, moving the rotation unit by means of the separate mechanism requires an

20176044 prh 22 -11- 2017 additional motor, electronics, and mechanical guides and bearings, for example, causing at least complexity and additional manufacturing costs.

SUMMARY

An objective of the invention is to present an X-ray imaging unit, a method, a 5 computer program, and a tangible non-volatile computer-readable medium for dental imaging. Another objective of the invention is that the X-ray imaging unit, the method, the computer program, and the tangible non-volatile computer-readable medium for dental imaging enables adjustment of a field of view, FOV, in a vertical direction.

The objectives of the invention are reached by an X-ray imaging unit, a method, a computer program, and a tangible non-volatile computer-readable medium as defined by the respective independent claims.

According to a first aspect, an X-ray imaging unit for dental imaging is provided, wherein the X-ray imaging unit comprising: a rotating part comprising an 15 X-ray source part and an X-ray imaging detector part configured to provide data for a dental image; a supporting part for supporting the rotating part; and a moving part for moving the rotating part in a horizontal plane, wherein the movement of the rotating part is at least one of the followings: linear movement along the supporting part and rotational movement around a rotation axis of 20 the rotating part, wherein the moving part is further arranged to move the rotating part in a vertical direction in order to adjust a field of view (FOV) in the vertical direction.

Furthermore, the moving part may be configured to rotate the rotating part in a first imaging position around the rotation axis during the first radiation in order 25 to provide a first projection image set and to rotate the rotating part in a second imaging position around the rotation axis during the second radiation in order to provide a second projection image set, wherein the second imaging position differs from the first imaging position at least in the vertical direction.

Moreover, the moving part may be configured to move the rotating part from 30 the first imaging position to the second imaging position after the first radiation.

20176044 prh 22 -11- 2017

In addition, the X-ray imaging unit may be configured to combine the first and the second projection image sets in order to provide a larger FOV in the vertical direction.

Alternatively or in addition, the X-ray imaging unit may be configured to com5 bine the first and the second projection image sets in order to provide a dental image.

The moving part may comprise: a first carriage; a second carriage to which the rotating part is attached; a motor configured to move the second carriage along the first carriage in order to move the rotating part in the horizontal direc10 tion; and at least two lifting parts having a vertically inclined surface and arranged a distance from each other in the horizontal direction, wherein the motor may further be configured to move the first carriage along the vertically inclined surfaces of the at least two lifting parts in order to move the rotating part at least in the vertical direction.

The moving part may further comprise at least two horizontal stopping means arranged between the two lifting parts a distance from each other in the horizontal direction, wherein the at least two horizontal stopping means may be configured to stop the horizontal movement of the rotating part.

Furthermore, each of the lifting parts may comprise at least two vertical stop20 ping means at different position of the lifting part in the vertical direction configured to stop the vertical movement of the rotating part.

The moving part may further comprise a guiding part arranged between the two horizontal stopping means for at least partly preventing the free dropping of the rotating part during the vertical movement of the rotating part.

The moving part may further comprise locking means for locking the rotating part to one of the two lifting parts.

According to a second aspect, a method for dental imaging is provided, which method is performed by an X-ray imaging unit as described above, which X-ray imaging unit comprises: a rotating part comprising an X-ray source part and an 30 X-ray imaging detector part configured to provide data for a dental image; a supporting part for supporting the rotating part; and a moving part for moving the rotating part in a horizontal plane, wherein the movement of the rotating

20176044 prh 22 -11- 2017 part is at least one of the following: linear movement along the supporting part and rotation movement around a rotation axis of the rotating part, wherein the method comprises: moving, by the moving part, the rotating part in a vertical direction in order to adjust a field of view (FOV) in the vertical direction.

According to a third aspect, a computer program for dental imaging is provided, which computer program is configured to perform the method described above, when it is run in the X-ray imaging unit, which comprises: a rotating part comprising an X-ray source part and an X-ray imaging detector part configured to provide data for a dental image; a supporting part for supporting the rotating 10 part; and a moving part for moving the rotating part in a horizontal plane, wherein the movement of the rotating part is at least one of the following: linear movement along the supporting part and rotation movement around a rotation axis of the rotating part, wherein the computer program comprises: moving code for moving, by the moving part, the rotating part in a vertical direction in 15 order to adjust a field of view (FOV) in the vertical direction.

According to a fourth aspect a tangible non-volatile computer-readable medium is provided, which tangible non-volatile computer-readable medium comprising a computer program for dental imaging configured to perform the method described, when it is run in the X-ray imaging unit, which comprises: a rotat20 ing part comprising an X-ray source part and an X-ray imaging detector part configured to provide data for a dental image; a supporting part for supporting the rotating part; and a moving part for moving the rotating part in a horizontal plane, wherein the movement of the rotating part is at least one of the following: linear movement along the supporting part and rotation movement around 25 a rotation axis of the rotating part, wherein the computer program comprises: moving code for moving, by the moving part, the rotating part in a vertical direction in order to adjust a field of view (FOV) in the vertical direction.

The exemplary embodiments of the invention presented in this patent application are not to be interpreted to pose limitations to the applicability of the ap30 pended claims. The verb to comprise is used in this patent application as an open limitation that does not exclude the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated.

20176044 prh 22 -11- 2017

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objectives and advantages thereof, will be best understood from the following 5 description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF FIGURES

The embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.

Figure 1 illustrates schematically an example of an X-ray imaging device for imaging according to the invention.

Figure 2A illustrates schematically an example of the X-ray imaging unit according to the invention in a first imaging position.

Figure 2B illustrates schematically an example of the X-ray imaging unit ac15 cording to the invention in a second imaging position.

Figure 3 illustrates schematically an example of a moving part of the X-ray imaging unit according to the invention.

Figures 4A-4D illustrate schematically examples of vertical movement of the rotating part of the X-ray imaging unit according to the invention.

Figure 5 illustrates schematically an example of the method according to the according to the invention.

Figure 6 illustrates schematically functional parts of the X-ray imaging unit according to the invention.

DESCRIPTION OF SOME EMBODIMENTS

In this description we use the following vocabulary concerning different phases of an X-ray imaging process. The term radiating means the phase comprising merely the irradiation, i.e. the phase when the X-ray source is providing an Xray beam that travels to the X-ray imaging detector. During the radiating one or more parts of the X-ray unit may move. The term scanning, in turn, means the phase comprising the radiating and moving of one or more parts of the X-ray

20176044 prh 22 -11- 2017 imaging unit. The scanning does not comprise positioning of one or more parts of the X-ray imaging unit in a correct place for providing X-ray images. The term imaging means the whole process comprising radiating, scanning and positioning.

Figure 1 illustrates an example of an X-ray imaging unit 100 for providing X-ray images of an object, for example a dental or medical patient, in which the present invention may be implemented. While X-ray imaging is used as an example herein, it is understood that additional embodiments may be implemented in other image possibility. The imaging unit 100 according to the invention is 10 configured for, for example three-dimensional (3D) imaging of the dentomaxillofacial complex of the human skull. However, other configurations of devices for imaging of other portions of the anatomy of a patient may be employed with the concept of the present disclosure. The X-ray imaging unit 100 according to the invention may be configured to provide different types of imaging proce15 dures, including, but not limited to computed tomography (CT) imaging, panoramic imaging (standard, pediatric, orthozone, wide arch, orthogonal and/or the like), and/or cephalomatric imaging (cephalo pediatric lateral projection, cephalo lateral projection, cephalo postero-anterior, and/or the like). Fig. 1 illustrates only one example of an X-ray imaging unit 100 for use with the con20 cepts in the present disclosure.

The imaging unit 100 comprises a housing 102 that is moveably supported on a support column 104. The housing 102 may be moved up and down in the vertical direction V by means of a guide motor (not shown in Figure 1) that is configured to move the housing 102 vertically up and down along the support25 ing column 104. The supporting section 110 is configured to support a rotating part 112, which is rotatable in a horizontal plane H with respect to the stationary supporting section 110. The supporting section 110 and/or rotating part 112 may comprise a rotating motor (not shown in Figure 1) configured to rotate the rotating part 112. Alternatively or in addition, the imaging unit 100 may be 30 mounted to a supporting structure (not shown in Figure 1) exemplarily a wall to being supported by the column 104.

The imaging unit 100 comprises further an X-ray source housing 114 and an X-ray imaging detector housing 116, which are arranged opposite to each other and extending generally vertically from the rotating part 112. The source 35 housing 114 comprises an X-ray source 118. The X-ray source 118 is posi

20176044 prh 22 -11- 2017 tioned to emit X-rays from the X-ray source 118 through the object being imaged, e.g. the patient, to an X-ray imaging detector 120 locating in the X-ray imaging detector housing 116.

Furthermore, the imaging unit 100 may comprise a lower shelf 122 that ex5 tends from the housing 102. The lower shelf 122 may comprise a chin support

124 for positioning the object, for example a head of the patient, (not shown in Figure 1) between the opposed X-ray source 118 and the X-ray imaging detector 120. Alternatively or in addition, the imaging unit 100 may comprise a head support 126 extending from the horizontal supporting section 110 through the 10 rotating part 112. The patient support parts, i.e. chin support 124 and the head support 126, may be optional, and positioning of the patient may be carried out in other manners.

The X-ray source 118 is configured to project a beam (not depicted in Figure

1) of X-rays towards the X-ray imaging detector 120. The X-rays pass through 15 a portion of the object, for example the patient’s anatomy, e.g. patient’s head.

The anatomical structures through which the X-rays pass may absorb varying amounts of the X-ray energy. After passing through the object, the attenuated X-rays are received by the X-ray imaging detector 120. The X-ray imaging detector 120 is configured to convert the magnitude of the received X-ray energy 20 and to produce a digitized output, i.e. data, representative of the unabsorbed

X-rays at the X-ray imaging detector 120. The collection of digitized outputs from the X-ray imaging detector 120 that correspond to a single emission of a beam of X-rays from the X-ray source 118 may be referred to a projection image of the object being imaged, for example the patient’s head.

The rotating part 112 may be rotated by a rotating motor, for example. The rotation of the rotating part 112 rotates the X-ray source 118 and the X-ray imaging detector 120 around the object to be imaged, for example around a rotation axis. The rotation axis may be oriented with the center of the object to be imaged, for example. Alternatively, the rotation axis may be aligned with a partic30 ular anatomical feature of interest within the object, for example patient’s head.

Other techniques or alignments for the rotation axis may also be used as will be recognized by a person or ordinary skill in the art. As the X-ray source 118 and X-ray imaging detector 120 are rotated around the object, for example head of the patient, the imaging device 100 operates to acquire a plurality of 35 projection images of the object taken at incremental angles of rotation. As a

20176044 prh 22 -11- 2017 non-limiting example, projection images may be acquired about a 180°or 360° rotation. Furthermore, the X-ray imaging device 100 may capture, for example between 250-1600 projection images in an imaging operation, for example. However, this is not intended to be limiting on the present disclosure. Such in5 crements may represent fractions of a degree of rotation. Other angular increments and other total angles of rotation are contemplated within the scope of the present disclosure.

The X-ray imaging unit 100 according to the invention comprises a moving part 200 for moving the rotating part 112. The moving part 200 is configured to 10 move the rotating part 112 in the horizontal plane, wherein the movement of the rotating part 112 is at least one of the following: linear movement along the supporting part 110 and rotational movement around a rotation axis of the rotating part 112. The moving part 200 may comprise a rotating motor in order to rotate the rotating part 112 and a linear motor in order to provide the linear 15 movement of the rotating part 112. Alternatively, the moving part 200 may comprise one motor in order to provide the rotating movement and the linear movement of the rotating part 112.

In addition, the moving part 200 is further arranged to move the rotating part 112 in the vertical direction with the existing motor(s) of the moving part 200, 20 for example the linear motor. The movement of the rotating part 112 in the vertical direction enables that the field of view (FOV) may be adjusted in the vertical direction. In this application when referring CT imaging with the term FOV is meant three-dimensional (3D) cylindrical FOV.

The moving part 200 is configured to rotate the rotating part 112 in a first imag25 ing position around the rotation axis during the first radiation in order to provide a first projection image set. The first projection image set may comprise a plurality of projection images. Figure 2A schematically illustrates the X-ray imaging unit, when the rotating part 112 is in the first imaging position. The X-ray source part 118 provides an X-ray beam 202 that travels through an object 30 204, for example a patient’s head, to the X-ray imaging detector part 120. The

X-ray beam 202 forms a first cylindrical FOV 206a around a vertical rotation axis 208, when the rotating part 112 is arranged to rotate around the object 204 in the first imaging position. The moving part 200 is configured to move the rotating part 112 in the horizontal plane in order to move the rotation axis 35 208 on the horizontal plane to any point inside the object 204. The rotation axis

20176044 prh 22 -11- 2017

208 may be the same as the rotation axis of the rotating part 112 or the rotation axis 208 may be different than the rotation axis of the rotating part 112.

Additionally, the moving part 200 is configured to move the rotating part 112 from the first imaging position to a second imaging position after the first radia5 tion. The second imaging position differs from the first imaging position at least in the vertical direction. The X-ray source part 118 provides another X-ray beam 202 that travels through the object 204 to the X-ray imaging detector part 120. The X-ray beam 202 forms a second cylindrical FOV 206b around a vertical rotation axis 208, when the rotating part 112 is arranged to rotate 10 around the object 204 in the second imaging position. Furthermore, the moving part 200 is configured to rotate the rotating part 112 in the second imaging position around the rotation axis during the second radiation in order to provide a second projection image set. The second projection image set may comprise a plurality of projection images. Figure 2B schematically illustrates the X-ray im15 aging unit 100, when the rotating part 112 is in the second imaging position.

Furthermore, in order to provide larger FOV in the vertical direction the X-ray imaging unit 100 may be configured to combine the first and the second FOVs 206a, 206b. Moreover, the X-ray imaging unit 100 may be configured to combine the first and the second projection image sets by stitching them mathe20 matically in order to provide a dental image.

Figure 3 illustrates schematically the moving part 200 according to the invention. The moving part 200 comprises a first carriage 302, a second carriage 304 to which the rotating part 112 is attached, a motor 306, for example a linear motor, and at least two lifting parts 308. The at least two lifting parts 308 25 have a vertically inclined surface and arranged a distance from each other in the horizontal direction. The motor 306 is configured to move the second carriage 304 along the first carriage 302 in order to move the rotating part 112 in the horizontal direction. The motor 306 may be attached to the first carriage 302 and be configured to rotate a screw 307 or similar attached to the motor 30 306 and to the second carriage 304 in order to move the second carriage 304 along the first carriage 302. In order to provide smooth movement of the second carriage 304 along the first carriage 302 the second carriage 304 may comprise at least one linear bearing 305. The motor 306 is further configured to move the first carriage 302 along the vertically inclined surfaces of the at 35 least two lifting parts 308 in order to move the rotating part 112 at least in the

20176044 prh 22 -11- 2017 vertical direction. In order to provide smooth movement of the first carriage 302 along the surfaces of the at least two lifting parts 308 the first carriage 302 may comprise for example at least one lift bearing 303 for each lifting part 308.

The moving part 200 may further comprise at least two horizontal stopping 5 means 310a, 310b arranged between the two lifting parts 308 a distance from each other in the horizontal direction. The at least two horizontal stopping means 310a, 310b are configured to stop the horizontal movement of the rotating part 112. The at least two horizontal stopping means 310a, 310b may be for example a column, a wall, a barrier or any similar means capable to stop 10 the horizontal movement of the rotating part 112. The distance between the at least two horizontal stopping means 310a, 310b in the horizontal direction may define the limits for the horizontal movement of the rotating part 112.

Furthermore, each of the lifting parts 308 may comprise at least two vertical stopping means 312a, 312b at different position of the lifting part 308 in the 15 vertical direction configured to stop the vertical movement of the rotating part 112. The at least two vertical stopping means 312a, 312b may be for example a pothole, a groove, a slot, a channel, a gutter or any similar means capable to stop the vertical movement of the rotating part 112 and/or to anchor the lift bearing 303 to the vertical stopping means 312a, 312b, when the rotating unit 20 112 is arranged in the first imaging position and/or in the second imaging position. The distance between at least two vertical stopping means 312a, 312b in the vertical direction may define the limits for the vertical movement of the rotating part 112.

The moving part 200 may further comprise a guiding part 314 arranged be25 tween the two horizontal stopping means 310 for at least partly preventing the free dropping of the rotating part 112 during the vertical movement of the rotating part 112. The guiding part 314 may be for example a column, a wall, a barrier or similar.

The vertical movement of the rotating part 112 is described more in detailed re30 ferring to Figures 4A-4B. In Figure 4A the rotating part 112 is arranged to the first imaging position. In this example the first imaging position is the upper imaging position. The moving part 200 is configured to rotate the rotating part 112 in the first imaging position around the rotation axis 208 during the first radiation in order to provide the first projection image set. Before the first radia

20176044 prh 22 -11- 2017 tion the moving part 200 is configured to move the rotating unit 112 to a first imaging position by means of the motor 306 and the guide motor that is configured to move the housing 102 vertically up and down along the supporting column 104.

After the first radiation the motor 306 is configured to continue the rotation of the screw 307 in order to push the second carriage 304 and the linear bearing 305 against first horizontal stopping means 310a towards which the linear bearing 305 is configured to move. This is illustrated in Figure 4B.

When the linear bearing 305 reaches the first horizontal stopping means 310a, 10 the horizontal movement of the rotating unit 112 stops, because the first horizontal stopping means 310a prevents the horizontal movement of the second carriage 304. Because the motor 306 is still configured to continue the rotation of the screw 307, the first carriage 302 begins to move substantially to the opposite direction (i.e. to the left in Figure 4B) along the inclined surfaces of the 15 lifting parts 308 thus causing the movement of the rotating part 112 in the vertical direction (down in this example). The angle of the inclined surfaces may be from 1 to 90 degrees. Preferably, the angle of the inclined surfaces is such that the vertical movement of the rotating part 112 in both directions may be controlled. The motor 306 may further be configured to limit the speed of the 20 movement.

Furthermore, the guiding part 314 at least partly prevents the free dropping of the rotating part 112 during the vertical movement of the rotating part 112, because the linear bearing 305 is configured to drop between the first horizontal stopping means 310a and the guiding part 314. This enables also that the ro25 tating part 112 moves only in vertical direction during the vertical movement of the rotating part 112, i.e. the rotating part 112 stays still in the horizontal direction during the vertical movement of the rotating part 112. The second vertical stopping means 312a is configured to stop the vertical movement of the rotating part 112 so that the vertical movement of the rotating part 112 and at the 30 same time the movement of the first carriage 302 along the inclined surface of the lifting parts 308 is configured to stop, when the at least one lift bearing 303 reaches the second vertical stopping means 312b. The vertical movement of the rotating part 112 is configured to stop at the second imaging position.

20176044 prh 22 -11- 2017

Figure 4C schematically illustrates the moving part 200, when the rotating part 112 is arranged to the second imaging position. In this example the second imaging position is the lower imaging position. The moving part 200 is configured to rotate the rotating part 112 in the second imaging position around the 5 rotation axis 208 during the second radiation in order to provide the second projection image set. The movements needed for the second radiation may be performed by moving the first carriage by means of the motor 306.

After the second radiation the motor 306 is configured to continue the rotation of the screw 307 in order to push the second carriage 304 and the linear bear10 ing 305 against the second horizontal stopping means 310b towards which the linear bearing 305 is configured to move. This is illustrated in Figure 4D.

When the linear bearing 305 reaches the second horizontal stopping means 310b, the horizontal movement of the rotating unit 112 stops, because the second horizontal stopping means 310b prevents the horizontal movement of 15 the second carriage 304. Because the motor 306 is still configured to continue to rotate the screw 307, the first carriage 302 begins to move substantially to the opposite direction (i.e. to the right in Figure 4D) along the inclined surfaces of the lifting parts 308 thus causing the movement of the rotating part 112 in the vertical direction (up in this example). The motor 306 is configured to limit 20 the speed of the movement. The first vertical stopping means 312a is configured to stop the vertical movement of the rotating part 112 so that the vertical movement of the rotating part 112 and at the same time the movement of the first carriage 302 along the inclined surface of the lifting parts 308 is configured to stop, when the at least one lift bearing 303 reaches the first vertical stopping 25 means 312a. The vertical movement of the rotating part 112 is configured to stop again at the first imaging position as illustrated in Figure 4A. The X-ray imaging unit 100 is ready for providing new set of projection images.

Furthermore, the moving part 200 may comprise locking means 316 for locking the rotating part 112 to one of the at least two lifting part 308, when the rotating 30 part 112 is arranged to the first imaging position, i.e. the upper imaging position. The locking means 316 may prevent unintended dropping of the rotating part 112. Figure 4A schematically illustrates an example, wherein the rotating part 112 is locked to the lifting part 308 by means of the locking means 316. After the first radiation, when the rotating part 112 is configured to start the ver35 tical movement from the first imaging position to the second imaging position,

20176044 prh 22 -11- 2017 the locking means 316 is configured to be released in order to unlock the rotating part 112. Figure 4B illustrates schematically an example, wherein the locking means is released. The locking means 316 may be for example a lever, a hook, a hanger, a latch, a hasp, or similar.

Next an example of the method according to the invention is described by referring to Figure 5. Figure 5 schematically illustrates the invention as a flow chart. It is to be recognized that embodiments of the method may be carried out without each of the steps as disclosed herein or in conjunction with additional steps. As already discussed the moving part moves the rotating part 112 10 at the first imaging position for providing the first dental projection image set at the step 502. The step 502 may also be referred as positioning.

At the step 504 the moving part 200 rotates the rotating part 112 in the first imaging position around the rotation axis during the first radiation in order to provide the first projection image set. During the first radiation the X-ray source 15 118 projects a beam of X-rays towards the X-ray imaging detector 120. The Xrays pass through a portion of the patient’s anatomy and the attenuated X-rays are received by the X-ray imaging detector 120. The X-ray beam forms a first cylindrical FOV around the vertical rotation axis, when the rotating part 112 rotates around the patient.

After the first radiation the moving part 200 moves the rotating part 112 from the first imaging position to the second imaging position at the step 506. The vertical movement of the rotating part 112 is described above referring to Figures 4A-4D. The second imaging position differs from the first imaging position at least in the vertical direction.

At the step 508 the moving part 200 rotates the rotating part 112 in the second imaging position around the rotation axis during the second radiation in order to provide a second projection image set. During the second radiation the Xray source 118 projects a beam of X-rays towards the X-ray imaging detector 120. The X-rays pass through a portion of the patient’s anatomy and the atten30 uated X-rays are received by the X-ray imaging detector 120. The X-ray beam forms a second cylindrical FOV around the vertical rotation axis, when the rotating part 112 rotates around the patient.

At the step 510 the X-ray imaging unit 100 may combine the first and second FOVs in order to provide a larger FOV in vertical direction. The vertical move

20176044 prh 22 -11- 2017 merit of the rotating unit 112 enables that the FOV may be adjusted in the vertical direction. Moreover, the X-ray imaging unit 100 may combine the first image set and the second image set by stitching them mathematically in order to provide a dental image.

Figure 6 illustrates the functional parts of the X-ray imaging unit 100. The X-ray imaging unit 100 comprises a control part 670, the X-ray source part 118, the X-ray imaging detector part 120, and the moving part 200. The control part 670 is configured to control the X-ray unit 100, and its aforementioned movements and imaging processes. The control part 670 comprises a processor part 672, 10 a data transfer part 674, a user interface part 128, and a memory part 680.

The processor part 672 is configured to perform user and/or computer program (software) initiated instructions, and to process data. The processor part 672 may comprise at least one processor. The memory part 680 is configured to store and maintain data. The data may be instructions, computer programs, 15 and any data files. The memory part 680 may comprise at least one memory.

The memory part 680 may further comprise at least a data transfer application 684 in order to control the data transfer part 674, a user interface application 688 in order to control the Ul part 128, and a computer program (code) 689 in order to control the function of the X-ray unit 100.

The data transfer part 674 may be configured to send control commands to at least one of the X-ray source part 118, the X-ray imaging detector part 120, and the moving part 200. In addition, the data transfer part 674 may receive data from measuring parts or other detection parts that detect the function of the X-ray imaging unit 100. In addition, the data transfer part 674 may receive 25 information from at least one of the parts 118,120, 200.

The user interface (Ul) part 128 may be configured to input control commands, to receive information and/or instructions, and to display information. The Ul part 128 may comprise at least one of a touchscreen, at least one function key, a wired or wireless remote controller, and a separate tablet computer. The Ul 30 part 128 may be attached to the housing 102.

The moving part 200 may comprise motors, drivers, or other parts that may cause the movements of at least one of the part 110, 118, 120, 112.

The computer program 689 may control at least one of the moving part 200, the X-ray source part 118, and the X-ray imaging detector part 120. In addition,

20176044 prh 22 -11- 2017 the computer program 689 may control imaging parameters, imaging sizes, and imaging modes. The memory part 680 and the computer program 689, with the processor part 672, may cause the X-ray imaging unit 100 at least to provide actions presented in context of the figures.

Such action may be moving the rotating part 112 by means of at least one of the above presented movements to the first imaging position, where the irradiation of the patient will be started. In addition, such action may be rotating the rotating part 112 by means of the moving part 200 in the first imaging position around the rotation axis during the first radiation in order to provide the first 10 projection image set. In addition, such action may be moving the rotating part

112 by means of the moving part 200 from the first imaging position to the second imaging position in vertical direction. In addition, such action may be rotating the rotating part 112 by means of the moving part 200 in the second imaging position around the rotation axis during the second radiation in order 15 to provide the second projection image set. In addition, such action may be moving the rotating part 112 by means of the moving part 200 from the second imaging position to the first imaging position in vertical direction. In addition, such action may be combining the first FOV and the second FOV in order to provide larger FOV. In addition, such action may be combining the first projec20 tion image set and the second projection image set in order to provide a dental image.

The computer program 689 can be a computer program product that comprises a tangible, non-volatile (non-transitory) computer-readable medium bearing a computer program code 689 embodied therein for use with a computer (con25 trol part 670).

The present invention described above enables that the rotating part 112 of the X-ray imaging unit 100 may be moved in vertical direction in order to adjust the FOV in vertical direction by means of the existing moving part 200 of the Xray imaging unit 100 together with the at least two lifting parts 308. Thus, addi30 tional motor for moving only the rotating part 112 in the vertical direction, large detector, and/or moving the whole housing of the X-ray imaging unit in vertical direction, is not needed. The present invention enables high positioning accuracy that depends only on the accuracy of machinery of the lifting parts 308. Furthermore, the present invention enables that the first and the second pro35 jection image sets may be obtained with one positioning of the patient position16 ing, because the patient support parts are not moved during the scanning. Furthermore, the number of the individual parts of the X-ray imaging unit 100 may be reduced by manufacturing the at least two lifting means 308, at least two horizontal stopping means 310a, 310b, and the guiding part 314 as a part of 5 the supporting part 110. Preferably, the present invention is suitable, but not limited, for CT X-ray imaging.

The specific examples provided in the description given above should not be construed as limiting the applicability and/or the interpretation of the appended claims. Lists and groups of examples provided in the description given above 10 are not exhaustive unless otherwise explicitly stated.

Claims

1. An X-ray imaging unit (100) for dental imaging comprising:

a rotating part (112) comprising an X-ray source part (118) and an X-ray imaging detector part (120) configured to provide data for a dental image,

5 a supporting part (110) for supporting the rotating part (112), and a moving part (200) for moving the rotating part (112) in a horizontal plane, wherein the movement of the rotating part (112) is at least one of the followings: linear movement along the supporting part (110) and rotational movement around a rotation axis of the rotating part (112),

10 characterized in that the moving part (200) is further arranged to move the rotating part (112) in a vertical direction in order to adjust a field of view, FOV, in the vertical direction.

2. The X-ray imaging unit (100) according to claim 1, wherein the moving 15 part (200) is configured to rotate the rotating part (112) in a first imaging position around the rotation axis during the first radiation in order to provide a first projection image set and to rotate the rotating part (112) in a second imaging position around the rotation axis during the second radiation in order to provide a second projection image set, wherein the second imaging position differs

20 from the first imaging position at least in the vertical direction.

3. The X-ray imaging unit (100) according to claim 2, wherein the moving part (200) is configured to move the rotating part (112) from the first imaging position to the second imaging position after the first radiation.

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4. The X-ray imaging unit (100) according to any of claims 2 to 3, wherein the X-ray imaging unit (100) is configured to combine the first and the second dental image sets in order to provide a larger FOV in the vertical direction.

5. The X-ray imaging unit (100) according to any of claims 2 to 4, wherein the X-ray imaging unit (100) is configured to combine the first and the second

30 projection image sets in order to provide a dental image.

6. The X-ray imaging unit (100) according to any of the preceding claims, wherein the moving part (200) comprises:

a first carriage (302), a second carriage (304) to which the rotating part (112) is attached,

20176044 prh 22 -11- 2017 a motor (306) configured to move the second carriage (304) along the first carriage (302) in order to move the rotating part (112) in the horizontal direction, and at least two lifting parts (308) having a vertically inclined surface and ar5 ranged a distance from each other in the horizontal direction, wherein the motor (306) is further configured to move the first carriage (302) along the vertically inclined surfaces of the at least two lifting parts (308) in order to move the rotating part (112) at least in the vertical direction.

7. The X-ray imaging unit (100) according to claim 6, wherein the moving 10 part (200) comprises further at least two horizontal stopping means (310a,

310b) arranged between the two lifting parts (308) a distance from each other in the horizontal direction, wherein the at least two horizontal stopping means (310a, 310b) are configured to stop the horizontal movement of the rotating part (112).

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8. The X-ray imaging unit (100) according to any of claims 6 to 7, wherein each of the lifting parts (308) comprises at least two vertical stopping means (312a, 312b) at different position of the lifting part (308) in the vertical direction configured to stop the vertical movement of the rotating part (112).

9. The X-ray imaging unit (100) according to any of claims 6 to 8, wherein 20 the moving part (200) comprises further a guiding part (314) arranged between the two horizontal stopping means (310a, 310b) for at least partly preventing the free dropping of the rotating part (112) during the vertical movement of the rotating part (112).

10. The X-ray imaging unit (100) according to any of the preceding claims, 25 wherein the moving part (200) comprises further locking means (316) for lock- ing the rotating part (112) to one of the two lifting parts (308).

11. A method for dental imaging, which method is performed by an X-ray imaging unit (100) of any of the preceding claims, which comprises:

a rotating part (112) comprising an X-ray source part (118) and an X-ray 30 imaging detector part (120) configured to provide data for a dental image, a supporting part (110) for supporting the rotating part (112), and a moving part (200) for moving the rotating part (112) in a horizontal plane, wherein the movement of the rotating part (112) is at least one of the

20176044 prh 22 -11- 2017 following: linear movement along the supporting part (110) and rotation movement around a rotation axis of the rotating part (112), characterized in that the method comprises:

moving (506), by the moving part (200), the rotating part (112) in a verti5 cal direction in order to adjust a field of view, FOV, in the vertical direction.

12. A computer program for dental imaging configured to perform the method of claim 11, when it is run in the X-ray imaging unit (100), which comprises:

10 a supporting part (110) for supporting the rotating part (112), and a moving part (200) for moving the rotating part (112) in a horizontal plane, wherein the movement of the rotating part (112) is at least one of the following: linear movement along the supporting part (110) and rotation movement around a rotation axis of the rotating part (112),

15 characterized in that the computer program comprises:

moving code for moving (506), by the moving part (200), the rotating part (112) in a vertical direction in order to adjust a field of view, FOV, in the vertical direction.

13. A tangible non-volatile computer-readable medium comprising a comput20 er program for dental imaging configured to perform the method of claim 11, when it is run in the X-ray imaging unit (100), which comprises:

a rotating part (112) comprising an X-ray source part (118) and an X-ray imaging detector part (120) configured to provide data for a dental image, a supporting part (110) for supporting the rotating part (112), and

25 a moving part (200) for moving the rotating part (112) in a horizontal plane, wherein the movement of the rotating part (112) is at least one of the following: linear movement along the supporting part (110) and rotation movement around a rotation axis of the rotating part (112), characterized in that the computer program comprises:

30 moving code for moving (506), by the moving part (200), the rotating part (112) in a vertical direction in order to adjust a field of view, FOV, in the vertical direction.