Apparatus for supporting a radiation transmitter

An apparatus for supporting a radiation transmitter has a first C-arm carrying the radiation transmitter at one end thereof, which is mounted so as to be movable within a holder, the holder in turn being mounted so as to be movable along a second C-arm. The second C-arm is adjustably mounted within an installation room.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention is directed to an apparatus for supporting a 
radiation transmitter, of the type wherein the radiation transmitter is 
mounted at one end of a C-arm. 
2. Description of the Prior Art 
It is well-known to attach a radiation transmitter, such as an x-ray 
radiator in an x-ray diagnostics apparatus, at one end of a C-arm, with a 
radiation receiver disposed at the opposite end of the C-arm. Such an 
arrangement is described, for example in German OS 14 66 880. The C-arm is 
mounted in the installation room so as to be height-adjustable along its 
circumference by means of a vertical column, as well as being pivotable 
around a horizontal axis. The vertical column is mounted so as to be 
displaceable in a plane along ceiling rails. The spatial adjustment of the 
unit formed by the x-ray radiator and the radiation receiver is 
accomplished by appropriate motor drives, which can be operated by a 
control device. 
Since the C-arm is displaceable along its circumference within its holder, 
oblique projections of an examination subject can be made by swiveling the 
unit formed by the x-ray radiator and the image receiver on the C-arm, 
thereby producing exposures of an examination subject from different 
directions. If the C-arm is in the form of a semi-circle, swiveling 
through approximately .+-.90.degree. can be achieved. Although the C-arm 
could be lengthened, for example, to form three-quarters of a circle, 
which would increase the swiveling range, such a lengthening of the C-arm 
degrades the manipulability of the apparatus. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an apparatus for 
supporting a radiation transmitter of the type employing a C-arm with the 
radiation transmitter mounted at one end thereof, wherein the swiveling 
range of the radiation transmitter is optimally large, without having a 
disadvantageous influence on the manipulability of the apparatus. 
The above object is achieved in accordance with the principles of the 
present invention in an apparatus for supporting a radiation transmitter 
wherein the radiation transmitter is mounted at the end of a first C-arm, 
which is mounted in a holder, and the holder is mounted so as to be 
movable along a second C-arm. 
The structure of this apparatus achieves the advantage that the radiation 
transmitter is not only movable in a manner corresponding to the 
circumference of the first C-arm, but us additionally movable 
corresponding to the circumference of the second C-arm. This results in an 
apparatus which is easy to manipulate, and which occupies a space which 
relatively small. 
Preferably a radiation receiver is disposed at the opposite end of the 
first C-arm, so that the apparatus can be employed in an x-ray diagnostics 
installation. 
If the imaging scale is to be variable, the radiation receiver is 
preferably adjustable along a central axis of the radiation transmitter. 
The spatial adjustability of the radiation transmitter and/or the radiation 
receiver is enhanced in an embodiment wherein the second C-arm is 
adjustable around a vertical axis as well as being height-adjustable, 
either by means of a ceiling rail arrangement or a floor rail arrangement, 
or a combination of both. 
If the second C-arm has a free end, i.e., if only a floor rail arrangement 
or only a ceiling rail arrangement is employed, a locking mechanism can be 
provided at the free end for stabilizing the apparatus in an exposure 
position, after being moved to that position. 
Preferably a control device is provided for facilitating operation of the 
apparatus by spatially displacing one or both of the C-arms, as well as 
all other mechanisms which are employed for spatially displacing the 
supported components of the radiation transmitter and / or the radiation 
receiver.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in FIG. 1, an apparatus for supporting a radiation transmitter 1 
includes a first C-arm 2 with the radiation transmitter 1 mounted at one 
end thereof. The radiation transmitter 1 may be of any type, and it is of 
no consequence to the invention whether the radiation transmitter 1 emits 
ionizing radiation or electromagnetic radiation or acoustic waves. 
The first C-arm 2 is carried by a second C-arm 3 by means of a mount or 
holder 4, so that the C-arm 2 is a movable along its circumference within 
the holder 4, as indicated by the double arrow in the drawing on the C-arm 
2. The range of movement of the radiation transmitter 1 is enlarged if the 
mount 4 is also adjustable along the circumference of the second C-arm 3, 
as indicated by the double arrow in the drawing on the holder 4. The 
holder 4 is moveable along the circumference of the second C-arm 3 so that 
the holder 4 is pivotable through at least 90.degree.. When the holder 4 
is moveable the radiation transmitter 1 can be moved not only through the 
circumference of the first C-arm 2, but also through the circumference of 
the second C-arm 3. The range of movement is thus enlarged, while 
preserving a compact structure and a good manipulability of the apparatus. 
Preferably one end 5 of the C-arm 3 is held by a suitable mount 15 for 
displacing the C-arm 3 in a plane along a ceiling rail arrangement 6, as 
indicated by the double arrow on the mount 15. The mount 15 also permits 
the second C-arm 3 to be pivoted around a vertical axis 7, as indicated by 
the double arrow curved around the vertical axis 7. Both C-arms 2 and 3 
can thus be moved around the vertical axis 7, so that the apparatus, for 
treatment or examination of a subject, can be displaced to a location at 
which it does not impede access to the subject. It will be understood that 
the apparatus could be mounted at its lower end by means of a floor rail 
arrangement similar to the ceiling rail arrangement 6, or by a combination 
of floor and ceiling rails. 
The mount 15 is preferably adjustable in steps, automatically or under the 
control of an operator, by means of a control unit 14, so that the C-arms 
2 and 3 and the radiation transmitter I are moved step-by-step along the 
longitudinal axis of a patient support 8. The patient support 8 is shown 
for clarity as simply extending into the opening of the C-arm 2, however, 
it will be understood that suitable supporting elements, which are not 
shown in the drawing, will be provided for the support table 8. During the 
step-by-step adjustment of the position of the radiation transmitter 1, 
the holder 4 is adjusted via the control unit 14 so that insofar as 
possible, the center of mass of the overall apparatus substantially 
coincides with the center of gravity, or is optimally close thereto. 
Vibrations of the apparatus which may otherwise occur during the 
step-by-step adjustment are thus reduced. 
If a subject on a patient support 8 is to be examined or treated, the free 
end 9 of the second C-arm 3 can be locked in a specific position on the 
floor 11 by means of a locking mechanism 10. The locking mechanism 10 may 
be, for example, a hydraulic telescoping leg, with one end attached to the 
free end 9 of the second C-arm 3 and the other end coming to rest on the 
floor 11. The actuation of the locking mechanism 10 can ensue on the basis 
of suitable control from the control unit 14 as soon as the overall 
apparatus reaches the specified position. 
In the embodiment of FIG. 2, the second C-arm 3 is mounted on floor rails 
6a on which a mount 15a can slide, the second C-arm 3 being rotatable 
around the vertical axis 7 on the mount 15a. A locking mechanism 10a is 
mounted at an upper free end 9a of the second C-arm 3, so as to support 
the second C-arm 3 against the ceiling of the installation space. Movement 
of the individual components in the embodiment of FIG. 2 takes place in 
the same manner as described in connection with the embodiment of FIG. 1, 
under the control of the control unit 14. 
If the radiation transmitter 1 is an x-ray radiator, a radiation receiver 
in the form of an x-ray image intensifier 12 may be disposed at the 
opposite end of the first C-arm 2. The apparatus is then suitable for use 
in an x-ray diagnostics installation. It is preferable that the x-ray 
image intensifier 12 be adjustable along the central ray 13 of the x-ray 
radiator, as indicated by the vertical double arrow in the drawing on the 
x-ray image intensifier 12. This enables the magnification scale of an 
image of an examination area, produced from the signals of the image 
intensifier 12, to be varied. Oblique projections can be obtained by 
moving the C-arm 2 and/or the holder 4 in the directions of the double 
arrows respectively indicated thereon, which cause a rotation of the 
entire unit formed by the x-ray radiator and the image intensifier 12 
through angles greater than .+-.90.degree., due to the fashioning of the 
apparatus of the invention. 
In order to avoid damage to the x-ray radiator and/or to the x-ray image 
intensifier during movement thereof, known anti-collision sensors can be 
provided at the exposed faces of one or components, which will immediately 
stop further adjustment of the apparatus when actuated. 
Although modifications and changes may be suggested by those skilled in the 
art, it is the intention of the inventors to embody within the patent 
warranted hereon all changes and modifications as reasonably and properly 
come within the scope of their contribution to the art.