NL2005898C2

NL2005898C2 - A mobile x-ray unit.

Info

Publication number: NL2005898C2
Application number: NL2005898A
Authority: NL
Inventors: Thamar Jacinthe Sarah Verhaar; Sander-Willem Schaik; Sebastiaan Willem Hekkenberg
Original assignee: Nucletron Bv
Priority date: 2010-12-22
Filing date: 2010-12-22
Publication date: 2012-06-25

Description

P91884NL00

Title: A mobile X-ray unit

FIELD OF THE INVENTION

The invention relates to a mobile X-ray unit comprising a base, a mast and an articulated displaceable arm mechanically coupled to the mast and supporting an X-ray applicator provided with an X-ray tube.

5 The invention further relates to a method of manufacturing the X- ray unit.

BACKGROUND OF THE INVENTION

Skin cancer, having increased incidence rate in the last decade of the 10 20th century, requires substantial effort from medical professionals in terms of early diagnosis, logistics and availability of suitable treatment. However, it is appreciated that over 1.3 million new skin cancers are diagnosed annually and are increasing at a rate of about 5 % per year. Increased exposure to the sun without skin protection and a decreased ozone layer are regarded as the main 15 causes of this increase - a problem estimated to be costing over 1 billion Euros in annual medical treatment expenses. Over 80% of skin cancers occur in the head and neck regions with 50% occurring in patients over 60 years of age. It is expected that a portion of the senior population will double in year 2025 compared to the present demographics.

20

Non proliferated cancers being substantially superficial lesions may be treated in different ways. First, surgery may be envisaged. However, such technique may be disadvantageous in terms of long waiting lists and complications related to post-treatment care. In addition, due to invasive 25 character of surgery contamination of the wound by infections may present an additional risk. Secondly, irradiation using electrons of soft X-rays may be envisaged. Such techniques have an advantage of being non invasive, wherein a treatment session may be as short as 2 or 3 minutes. It will be appreciated 2 that usually the integral treatment using radiotherapeutic techniques may comprise a number of sessions.

Accordingly, the growing incidence of skin cancer and increasing of a 5 share of the senior population in overall demographics pose substantial challenge on the cancer treatment logistics.

Recently, the use of a portable X-ray unit has been suggested, which may be used inside a hospital radiotherapy department. An embodiment of 10 such portable unit is described in US 5, 425, 069. The known device comprises a counterweighted articulated X-ray tube support arm allowing positioning of an attached X-ray tube in space substantially without the need of moving a supporting carriage. The articulated arm is arranged to be slidable along a mast rigidly connected to the support carriage. The known articulated X-ray 15 arm comprises a plurality of pivotable support appendages allowing an X-ray tube to be moved in planar motion substantially horizontal to the ground supporting the carriage.

It is a disadvantage of the known X-ray tube that for such apparatus 20 is bulky and supports a limited number of orientations of the X-ray tube in space. Such limited number of orientations may not be sufficient for enabling a proper alignment of the X-ray beam with respect to a tumor positioned in a patient’s skin.

25 SUMMARY OF THE INVENTION

It is an object of the invention to provide a substantially compact mobile X-ray unit having improved maneuverability of the X-ray applicator.

To this end in the mobile X-ray unit according to the invention 30 comprises a mast cooperating with the base and an articulated arm, the 3 articulated arm being mechanically coupled to the mast and supporting an X-ray applicator that is provided with an X-ray tube, the mast being displaceable along a substantially upright axis with respect to the base, the articulated arm having a ball joint at its one end portion and a rotating joint at its other end 5 portion.

It will be appreciated that the articulated arm may be provided with a rotational joint and the ball joint either directly at its end portion, or near the end portion. Those skilled in the art would readily appreciate that a 10 position of a joint along the articulated arm may be selected upon demand during manufacturing step.

It will be further appreciated that the substantially upright axis extends in a substantially vertical direction, which is generally upright.

15 However, it will be further appreciated that the terms ‘generally upright’ or ‘substantially vertical’ may relate to a direction substantially perpendicular (+-20 degrees) to a plane of the surface on which the mobile X-ray unit is sitting.

It is found that by allowing the mast of the mobile X-ray apparatus 20 to travel along the substantially upright axis and by providing the articulated arm with substantial degrees of freedom, the X-ray applicator may be positioned almost in any position in space. It will be appreciated that the X-ray applicator may have a preferred alignment in space, such as an alignment which has a higher probability of being used. However, the rotatable 25 articulated arm comprising two joints is substantial and sufficiently robust for holding the X-ray tube in an angled displacement with respect to the said upright direction.

4

In an embodiment of the mobile X-ray device according to the invention the articulated arm is affixed to the mast using a rotating joint and the articulated arm is affixed to the X-ray application using a ball joint.

5 This arrangement is found to be advantageous as it provides improved stability of the X-ray applicator in space and enables improved maneuverability thereof.

Another advantage of the mobile X-ray unit according to the 10 invention may be found in that the X-ray applicator may be stored in a compact (non protruding) storage position, wherein the articulated arm is swung facing the mast using the rotational joint. More details on this embodiment will be discussed with reference to Figures la and lb.

15 The friction force in a suitable ball joint may be optimized for the ease of operation on the one hand, and the mechanical stability on the other hand. Because the total weight of the X-ray applicator may be as much as 3 - 4 kg, those skilled in the art will readily appreciate the benefits of such optimization and how the optimization may be carried out. In a particular 20 embodiment, the ball joint may be provided with a dedicated brake unit for holding the joint coupling in position when the X-ray applicator is in a treatment position. This feature may be particularly advantageous for the use of the X-ray applicator at more that 45 degrees with respect to a vertical direction. However, although the X-ray unit according to the invention allows 25 for such positioning, it will be appreciated that due to a combination of the rotation of the articulated arm with respect to the mast and the displacement of the segments with respect to each other, angulations of the X-ray applicator larger than 45 degrees may not be necessary inter alia because the patient may be easily positioned under the X-ray unit according to the invention with 30 the target region being substantially horizontal.

5

In order to improve maneuverability of the X-ray applicator to a greater extent, the mast is arranged to cooperate with a sliding carriage for enabling its displacement in the upward and/or the downward direction.

5

It is found to be particularly advantageous to provide a per se known sliding carriage for enabling a smooth displacement of the mast with respect to the base of the X-ray unit. The sliding carriage may be arranged to decrease a velocity of the mast when it approaches the extreme positions. For example, 10 resilient bodies, like a spring or an elastic cushion may be provided for enabling such moderation of the velocity of the mast. This feature is advantageous as undesirable mechanical shocks could possibly result in a loss of alignment of parts of the X-ray applicator and/or X-ray tube and so this may be avoided or at least mitigated. More preferably, the X-ray unit according to 15 the invention further comprises a counterbalance for the mast, wherein said counterbalance comprises one or more clock springs. Such configuration is found to be advantageous for improving mechanical stability of the X-ray unit when the mast is moved to its uppermost travel position. A clock spring is a per se known mechanism and will not be explained here in detail.

20

In a further embodiment of the X-ray unit according to the invention the first joint and/or the second joint are provided with corresponding sensors for detecting a position of the joint in space.

25 It is found to be particularly advantageous to provide the first joint and/or the second joint with sensors recording the position of the joint in space. Such feature is useful for recurrent treatments, when the patient undergoes a plurality of repeated irradiations. In order to increase efficiency of installation of the X-ray tube with respect to the patient, the recorded joint positions may 30 be reproduced, at least as a coarse setting. It will be appreciated that for such 6 procedure a stationary base may be required. Alternatively, the base may have a pre-determined position when moved towards the irradiation location.

The X-ray unit according to the invention may comprise a processor 5 for controlling the operation of the X-ray unit, including the settings of the X-ray tube, whereby the sensors may be arranged to communicate the detected position to the processor. The processor may be further arranged to store the joint locations in a patient file for retrieving during a following session.

10 In a still further embodiment of the X-ray applicator according to the invention, the X-ray applicator is counter-balanced for a preferred axial alignment along the vertical direction.

It is found that the X-ray tube may be used most frequently when 15 aligned along a generally vertical axis, or with a small deviation from it (less than 20 degrees). Accordingly, it is found to be advantageous to provide the weight-balanced mechanical configuration, including the two-segmented articulated arm, so that substantially no net force is exerted on the mast in a radial direction. Such configuration is preferable as it further improves 20 mechanical stability of the X-ray unit as a whole. In addition, the X-ray unit may be securely maneuvered by pulling on the X-ray applicator.

In a still further embodiment of the X-ray unit according to the invention, the applicator is connected to a segment of the articulated arm in a 25 region near a distal portion of the X-ray applicator. It is found that such interconnection between the articulated arm and the X-ray applicator further improves angular maneuverability of the X-ray applicator. Preferably, the X-ray applicator comprises a window for emitting the X-rays at its proximal end portion.

30 7

According to an aspect of the present invention, there is provided a method for manufacturing a mobile X-ray unit comprising a base, a mast cooperating with the base, an articulated displaceable arm, mechanically coupled to the mast and supporting an X-ray applicator provided with an X-ray 5 tube, comprised the steps of: displaceably arranging the mast with respect the base in an upward direction; providing the articulated arm with a ball joint at its one end portion and a rotating joint at its other end portion; 10 - coupling the X-ray applicator to the articulated arm

These and other aspects of the invention will be discussed with reference to drawings wherein like reference numerals or signs relate to like elements. It will be appreciated that the drawings are presented for 15 illustration purposes only and may not be used for limiting the scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure la presents in a schematic way an embodiment of a mobile X-20 ray unit according to the invention.

Figure lb presents in a schematic way an embodiment of displacement functionality of the applicator of the X-ray unit according to the invention.

Figure 2 presents in a schematic way an embodiment of architecture 25 of the mobile X-ray unit according to the invention.

Figure 3 presents schematically an embodiment of the X-ray applicator according to an aspect of the invention.

Figure 4 presents a further schematic view of the articulated arm according to an aspect of the invention.

30 8

DETAILED DESCRIPTION OF THE DRAWINGS

Figure la presents in a schematic way an embodiment of a mobile X-ray unit according to the invention. The mobile X-ray unit 10 comprises a base 2 comprising at least a power supply unit, a cooling system and a control unit 5 for controlling an operation of the X-ray applicator 4 comprising an X-ray tube accommodated in an outer housing. The X-ray applicator 4 is electrically connected to the appropriate controls in the base using flexible cables 3 to the suitable controls, which may be at least partially received in a displaceable mast 5. The applicator 4 is supported by an articulated displaceable arm 4a, 10 which may comprise a rotatable joint 6a for connecting to the mast 5. The articulated arm 4 may comprise a ball joint 6b for connecting to the X-ray applicator 4 and thereby for altering angulation of the X-ray applicator in space.

15 Because the articulated arm is also mechanically connected to the displaceable mast 5, a range of vertical positions of the X-ray applicator 4 in space is possible. Preferably, the displaceable mast 5 is provided with a handle (not shown) enabling easy manipulation thereof. The displaceable mast 5 may be guided along suitable rails using a slidable carriage 18 for enabling a 20 substantially smooth and shock-free displacement thereof.

Preferably, the base 2 is provided with additional functionality, such as a display (not shown) for feeding-back suitable user information. The display may be arranged as a touch-sensitive screen for enabling suitable data 25 input into the system. For example, a sliding carriage may be further adapted for decreasing a velocity of the mast when it approaches the extreme positions. For example, resilient bodies, like a spring or an elastic cushion may be provided for enabling such moderation of the velocity of the mast. This feature is advantageous since undesirable mechanical shock could possibly cause 30 misalignment of parts of the X-ray applicator and/or X-ray tube and this 9 should be avoided. More preferably, the X-ray unit according to the invention further comprises a counterbalance (not shown) for the mast 5, wherein said counterbalance may comprise one or more clock springs. Such configuration is found to be advantageous for improving mechanical stability of the X-ray unit 5 when the mast is moved to the upper end of its travel position. A clock spring is a per se known mechanism and will not be explained here in detail.

Figure lb presents in a schematic way an embodiment of displacement functionality of the applicator of the X-ray unit according to the 10 invention. In accordance with an aspect of the invention mechanics of the mobile X-ray unit is developed and realized to support a broad range of translational and rotational movements for the X-ray applicator 4.

In view 11, not depicting the flexible cable 3 of Figure 1, a schematic 15 embodiment is presented wherein the X-ray applicator is in its parked position. Such position is enabled by rotating the articulated arm with respect to the mast 5. It is further found that it may be advantageous to provide the mast 5 as a curved body having curvature towards the X-ray applicator mounting position 5a and having length of a curved portion sufficient for 20 decking the X-ray applicator in its parked position. It will be appreciated that the parked position is a position wherein the X-ray applicator does not laterally protrude beyond the body of the mast 5.

Such parked position may be suitable for transporting the mobile X-ray unit towards a booth and/or for maneuvering the X-ray unit around the 25 patient. In order to retract the X-ray applicator as close as possible to the base 2, the articulated arm 4a may be bent under the outer portion 5a of the mast 5 using the rotational joint 6a, wherein the ball joint 6b may also be used for further positioning. However, the mast 5 may be designed with a curvature allowing parking of the X-ray applicator 4 in a single sweeping movement.

30 Those skilled in the art will appreciate that the exact geometry of the mast 5 is 10 dependent on the absolute dimensions of the X-ray applicator 4 and the length of the articulated arm 4a. For ensuring stability of the mobile X-ray unit during maneuvering thereof, a load block 2a close to a floor may be provided in the base 2 for lowering an absolute position of the point of gravity of the whole 5 assembly.

View 12 presents in a schematic way a further possibility, wherein the X-ray application 4 is in one of its working positions having an X-ray exit surface 8 of the X-ray applicator 4 to be oriented towards a patient P. In 10 accordance with the invention the X-ray applicator 4 is maneuvered in an easy yet reliable way wherein the ball joint 6b is adapted for maintaining the X-ray applicator 4 is the desired position.

In order to suitably position the X-ray applicator with respect to the 15 patient P, the mast 5 may be moved to a certain dwell position located between a pre-determine lowest position and a pre-determined highest position. The articulated arm 4a may be used for suitably rotating the X-ray applicator in space. Preferably, first the rotation joint 6a is used to coarsely position the articulated arm 4a after which the joint 4b is used for displacing the X-ray 20 applicator about a rotation axis. The rotation axis R is preferably selected to coincide with a direction of emission of the X-ray beam from the exit surface 8 for a vertically oriented X-ray applicator 4. Because the X-ray applicator is preferably affixed to the segment 4d at its distal portion 4’, rotation about the rotation axis R is simplified. An angle a between the rotation axis R and the 25 axis of the X-ray tube may be recorded automatically. For this purpose, the joints 6b, 6a may be provided with suitable sensors for automatically detecting the positions of the joints.

View 13 presents in a schematic way a still further possibility, 30 wherein the X-ray applicator 4 is to be used at a lowered position. For this 11 purpose the displaceable mast 5 may resume its lowest stand and the articulated arm 4a may be used for orienting the X-ray applicator in a preferred manner. In order to avoid mechanical shock when positioning the mast 5 in its lowest position, the sliding carriage guiding the displacement of 5 the mast 5 may be provided with a resilient means for cushioning purposes. It is also possible that the displacement of the mast 5 is carried out automatically using drive motors. A processor of the X-ray unit may be arranged to automatically decrease the velocity of the movement when approaching the end regions of the displacement trajectory.

10

It will be appreciated that although in the preferred embodiment the articulated arm 4a comprises a single segment, it is also possible that the articulated arm 4a is provided with two or more segments interconnected by respective pivots.

15

Figure 2 presents in a schematic way an embodiment of architecture of the mobile X-ray unit according to the invention. The mobile X-ray unit according to the invention comprises a high voltage power supply, preferably adapted to generate 50-75 kV X-rays in a suitable X-ray tube, a cooling 20 system for cooling the X-ray tube during use and a control system for controlling electronic and electric parameters of sub-units of the X-ray unit during use. View 20 schematically depicts main units of the control system 21 and of the X-ray applicator 22.

25 The control system 21 preferably comprises a hard wired user interface 21a for enabling switching on and switching off of the high voltage supply 21b. Preferably, the high voltage supply 21b comprises a high voltage generator 21c with improved ramp-up and ramp-down characteristics. Preferably, the ramp-up time is of the order of 100 ms. The hard wired 30 interface 21a, may also be arranged to automatically switch on the cooling 12 system 2ld in the event the high voltage generator is switched on. In addition, the control system 21 may comprise a primary controller 21e arranged for controlling the dose delivery from the X-ray applicator in use. Such primary controller 21e may be provided with a primary counter adapted to register 5 time lapsed after the X-ray radiation is initiated. The primary counter may then automatically switch off the high voltage supply to the X-ray tube in the event a pre-determined dose is reached. It will be appreciated that the predetermined dose is at least dependent on the energy of generated X-rays and the dose rate, wherein such dependence may be calibrated in advance.

10 Provided corresponding calibrated data is made available to the primary controller adequate primary dose delivery control may be achieved. Preferably, a secondary controller 2 If is provided for enabling an independent loop of dose delivery control. The secondary controller may be connected to a dose meter accommodated inside the X-ray applicator in the X-ray field before the 15 collimator. Accordingly, the dose meter may provide real-time data on actual dose delivery taking into account dose variation during ramp up and ramp down of the high voltage source. Still preferably, the control system may further comprise a safety controller 21g adapted to compare readings from the primary controller 21e and the secondary controller 2 If for triggering 20 switching off of the high voltage generator 21c wherein a desired dose is delivered. In addition or alternatively, the safety controller 21g may be wired to guard emergency stop, door interlock and a generator interlock.

The X-ray applicator 22 may preferably comprise the following 25 features: an X-ray tube 22a, conceived to be housed in an outer housing (shielding) 22k. In accordance with the invention the X-ray tube is provided having a target-collimator distance of about 4-10 cm, preferably about 5 to 6 cm. The X-ray applicator may further comprise a beam hardening filter 22b selected to intercept low-energy radiation and a beam flattening filter 22c, 30 designed to intercept portions of X-ray radiation for generating a substantially 13 flat beam profile near the exit surface of the X-ray applicator. Further, the X-ray applicator 22 may comprise one or more collimators arranged to define treatment beam geometry. Preferably a set of collimators is used, for example, having diameters of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 cm. It will be appreciated that 5 although circular collimators are discussed, collimators of any shape, like square, elliptic or custom made collimators are possible. It is found to be advantageous to provide the X-ray applicator 22 with automatic collimator detection means 22f adapted to automatically signal which collimator is being used. Preferably, resistive sensing is used, wherein each collimator is provided 10 with at least a couple of projections for bridging a resistive path provided in a collimator receptacle. The resulting electrical resistance of the receptacle constitutes a signal representative of a collimator being used. The X-ray applicator 22 still further preferably comprises a built-in temperature sensor adapted to signal temperature of the X-ray tube and/or its shielding. The 15 signal from the temperature sensor is received by the control system which carried out analysis thereof. Should the measured temperature be elevated beyond an allowable level, an alarm signal may be generated. Optionally, a shut-off signal to the high voltage generator may be provided. The X-ray applicator 22 further comprises a radiation sensor 22h arranged inside the 20 outer housing 22k for detecting X-ray radiation which is actually being delivered by the X-ray tube. Preferably, for safety reasons the X-ray applicator 22 further comprises a non-volatile data storage 22i arranged for recording operational parameters at least of the X-ray tube. Further, to enhance radiation safety, the X-ray applicator 22 may be provided with a radiation 25 indicator 22j arranged for providing a visual and/or an audio output to the user and/or the patient regarding ON/OFF condition of the X-ray tube. It will be appreciated that the radiation indicator 22j may comprise a plurality of distributed signaling means. Preferably, at least one signaling means, for example a light emitting diode (LED) is associated with the X-ray applicator 14 22. More preferably, the signaling means is provided on the X-ray applicator 22.

The processor 21e may be adapted to store the values automatically 5 provided by the joint sensors for future use. In addition, when the displacement of the mast 5 is carried out automatically, the processor 21e may suitably control the driving motors to avoid mechanical shocks when the mast 5 arrives at an end position along its displacement trajectory.

10 Figure 3 presents schematically an embodiment of the X-ray tube for use in the X-ray applicator according to an aspect of the invention. The X-ray tube 100, has a body 102 enclosing at one end an end window 104 through which the x-rays pass. The end window is made from a thin sheet of Beryllium metal. Covering the end window 104 to provide protection against the damage 15 of the window and protection against the toxic effects of the metal is an applicator cap 106. Applicator cap 106 is preferably made from a plastics material.

In the tube body 102 a target 108 is located at between 4 -10 cm 20 from an exit surface 124, and preferably at 4-6cm from the exit surface. The target is made from Tungsten metal to provide the desired X-ray spectrum.

The tungsten tip of the target is mounted on a large anode assembly 110 which also serves to conduct away the heat created from the generation of the x-rays in the target. Most of the anode assembly is made from copper. The cathode 25 112 is located slightly off-axis near the end window. Electrons emitted from the cathode are accelerated across the gap by the potential difference between the cathode and anode, in this case set at about 70kV, to the target which they impact and cause the generation of x-rays in a known manner. X-rays emitted from the target 108 pass through a beam hardening filter 122 before passing 15 through a collimator 130 and an exit surface 124 on an applicator 106. The collimator 130 may be housed in a suitable collimator receptacle 128.

The anode assembly 110 is mounted in the body 102 and electrically 5 insulated from it. One of a number of known techniques and materials can be used to provide the desired level of insulation between the anode and the body 102.

As is also well known in the art, the production of X-rays generates large amounts of waste heat, with the result that it is necessary to cool the 10 tube in order to maintain it at a safe temperature. Various cooling mechanisms are known and used in the art. In this embodiment, the tube is cooled by means of cooled water forced around the anode region. Cooled water enters the back of the tube by means of conduits 116 and leaves by means of a second conduit 118. The water cooling circuit is a closed loop circuit, with the 15 water leaving the tube assembly to be cooled by a remote cooler (not shown) before returning to the tube. Alternatively oil or another liquid could be used as the cooling medium. It is also known that a pressurized gas is used as an effective coolant in some applications.

20 As is known in the art, X-rays are generated and emitted in all directions, but the shielding by the body of the tube 102 and other internal components will tend to reduce the amount of radiation emitted from the body of the tube to a minimum, with most of the radiation emitted from the end window. The thickness of the shielding provided by the body is designed such 25 that it provides at least the minimum level of shielding required for safe use by the operator.

A high voltage cable assembly 120 is connected to the anode assembly 110. The high voltage cable assembly is connected to flexible cable 30 means (not shown) which in turn is connected to a high voltage power supply.

16 A radiation detector 114 is placed outside the path of the x-ray beam emitted from the target 108 and passing through the end window 104. This detector can be any known form of radiation detector. In this embodiment it is 5 a known form of suitably radiation hardened semi-conductor connected to an amplifier. The radiation detector 114 detects when the tube 102 is working and emitting x-ray energy. Output from the detector is connected to a control unit, the output signals from which may be used to provide an optical indication to a user of whether the tube is operating or not. By this means an 10 X-ray detector is provided which can be used to detect whether the tube is on or off.

With further calibration of the radiation detector 114, it is possible to determine and calculate the x-ray dose administered to the patient during 15 the treatment. By this means it is possible to have a real time dosimetry measurement system, in which the precise amount of radiation dose administered can be determined. Once the dose rate is known, a treatment plan can be modified during treatment. This is advantageous because it enables a very accurate and carefully controlled dose of x-rays to be 20 administered.

In order to enable the tube 102 to be placed accurately over a tumour, a tumour illumination means is used. The tumour illumination means comprises a plurality of lights 126 placed around the circumference of the tube near the end window. When in use, the lights shine onto the skin of 25 the patient. Since the lights 126 are positioned around the circumference of the tube body 102, at a short distance from the end of the tube they create a circle of light with a sharp cut off of the inner part of the circle. In this way, the position of the lights on the tube body 102 creates a shadow. This shadow circle is used to indicate the region which will be subject to irradiation when 30 the X-ray tube is turned on. It should be appreciated the area within the circle 17 will not be completely dark; the ambient light will be able to enter the shadow region.

Preferably the lights 126 are white LEDs which can be bright enough to clearly illuminate the target region but do not generate amounts of 5 heat and have very long lives. The lack of heat generation is important because the lights will be in close proximity to the skin of the patient, and so it is important to minimise the risk of burning or other damage to the skin.

Other colours of LEDs could be used. Alternatively, other light sources could be used, such as known filament lamps or even a remote light source connected 10 to the ring by fibre optic cables.

Figure 4 presents a further schematic view of the articulated arm 4a, according to an aspect of the invention, comprising a rotation joint 6a and a ball joint 6b. In this particular embodiment, the end portions 4a’, 4a” of the 15 articulated arm 4a are thickened, wherein the intermediate portion 4am is provided with a diameter convenient to be handled by a human hand. Preferably, the diameter of the intermediate portion 4am of the articulated arm is in the range of 4 - 7 cm.

20 In this particular embodiment the ball joint 6b is provided at the end of the articulated arm. However, it is possible that the ball joint 6b and/or the rotational joint 6a (as shown) are provided near the end of the articulated arm 4a.

25 The X-ray applicator 4 having an exit window 8 for passing the X- rays generated by an internal X-ray tube may comprise an additional rotatable sleeve 9, for allowing fine adjustment of a downward position of the X-ray tube when its position is set using the articulated arm 4a. Preferably, the rotatable sleeve 9 is adapted to adjust an axial translation of the X-ray applicator 4 as a 30 whole using, for example, a screw mechanism. However, any other suitable 18 mechanism for enabling the axial translation of the X-ray applicator may 4 be used including, but not limited to a telescopic mechanism.

While specific embodiments have been described above, it will be 5 appreciated that the invention may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. For example, the X-ray device according to the invention maybe used with the X-ray applicator accommodating an X-ray tube having a side X-ray exit window. Thus, it will be apparent to one skilled in the art that modifications may be 10 made to the invention as described in the foregoing without departing from the scope of the claims set out below.

Claims

A mobile X-ray unit, comprising a base, a mast that cooperates with the base and an articulated arm, the articulated arm being mechanically coupled to the mast and supporting an X-ray delivery unit which is provided with an X-ray tube, the mast being relative to the base can be moved along a substantially upright axis, the articulated arm having a ball joint on its one end part and a rotatable connecting piece on its other end part.

2. A mobile X-ray unit according to claim 1, wherein the articulated arm is connected to the mast using a rotatable connecting piece.

The mobile X-ray unit according to claim 1, wherein the articulated arm is connected to the X-ray delivery unit with the aid of a ball joint.

4. A mobile X-ray unit according to any one of the preceding claims, wherein the ball joint comprises a braking mechanism.

A mobile X-ray unit as claimed in any one of the preceding claims, wherein the mast is adapted to cooperate with a slide for enabling movement in said direction.

6. Mobile X-ray unit according to claim 5, wherein the carriage is provided with a spring-back means for reducing the speed of the mast as it approaches an end of the moving position.

7. A mobile X-ray unit according to any one of the preceding claims, wherein the rotatable connecting piece and / or the ball joint are / are provided with sensors for detecting a position in the space of the connecting piece / joint.

The mobile X-ray unit according to claim 7, further comprising a processor, wherein the sensors are arranged to transmit the detected position to the processor.

9. A mobile X-ray unit according to any one of the preceding claims, wherein the X-ray delivery unit is counterbalanced for a desired axial alignment along the upward direction.

The mobile X-ray unit according to any of the preceding claims, wherein the X-ray delivery unit is connected to the articulated arm in an area near a distal part of the X-ray delivery unit.

A mobile X-ray unit according to any one of the preceding claims, further comprising a counterweight for the mast, wherein the counterweight comprises a clock spring.

12. A method of manufacturing a mobile X-ray unit comprising a base, a mast cooperating with the base, and an articulated movable arm mechanically coupled to the mast and supporting an X-ray delivery unit provided with an X-ray tube, the method comprising the steps of of: - placing the mast displaceable in an upward direction relative to the base; 45. providing the articulated arm with a ball joint on its one end portion and with a rotatable connector on its other end portion; and - coupling the X-ray delivery unit to the articulated arm.