CT apparatus with cooling system

A CT system is disclosed for generating tomographic recordings of an examination object. In an embodiment, the CT system includes at least a gantry with a rotatable support for receiving components of the CT system, and a cooling system for cooling the components secured to the gantry with at least one air duct. In at least one embodiment, an incoming-air duct of the cooling system is divided into at least two segments to ensure uniform pressure distribution in the incoming-air duct.

PRIORITY STATEMENT

The present application hereby claims priority under 35 U.S.C. §119 to German patent application number DE 102014205739.6 filed Mar. 27, 2014, the entire contents of which are hereby incorporated herein by reference.

FIELD

At least one embodiment of the invention generally relates to a CT system for generating tomographic recordings of an examination object, at least having a gantry with a rotatable support for receiving components of the CT system, and a cooling system for cooling the components secured to the gantry with at least one air duct.

BACKGROUND

During operation, the system components arranged on the gantry of a CT system produce between 12 kW and 17 kW of heat. In an X-ray tube of the CT system, by way of example, the majority of the energy used is converted into heat during generation of X-ray radiation. This heat must be removed from the gantry in order to protect the system components, in particular a radiator-detector system. For this purpose it is necessary to supply the system components on the rotating support with sufficient cooling air at all times.

It is known to cool individual components with additional fans attached to the rotating support. These fans are very susceptible to the accelerations during rotation of the support, however. These additional fans are therefore often omitted for reliability reasons, in order to avoid maintenance. However, in this case the uniform air supply of the components, viewed over the circumference of the gantry, cannot always be ensured. Temperature problems can therefore occur when the support is stationary since the waste heat cannot be adequately removed.

It is also known to locally correct the pressure by way of baffles in the incoming-air ducts and an adjustment of the air outlets out of the incoming-air duct to the components in order to generate an optimally uniform pressure in the incoming-air duct and thus ensure optimally uniform cooling along the circumference of the gantry.

In the case of non-uniform cooling along the circumference, in particular during operation when the gantry is stationary, it is also necessary to operate the gantry cooling at a higher power. A higher noise level is also generated therewith, however.

SUMMARY

At least one embodiment of the invention is directed to an improved cooling system for a gantry of a CT system which enables uniform and reliable cooling of the gantry and the system components located thereon, primarily also when the support is stationary.

Advantageous developments of the invention are the subject matter of subordinate claims.

In at least one embodiment, the CT system includes at least a gantry with a rotatable support for receiving components of the CT system, and a cooling system for cooling the components secured to the gantry with at least one air duct such that an incoming-air duct of the cooling system is divided into at least two segments to ensure a uniform pressure distribution in the incoming-air duct.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The inventors recognized that by dividing the incoming-air duct into a plurality of segments, which can be individually supplied with air and in which the pressure can therefore be individually adjusted, a uniform pressure can be achieved in the incoming-air duct. The uniform pressure in turn enables uniform and position-independent cooling of the system components along the circumference of the gantry. This is ensured even when the support is stationary. The individual segments of the incoming-air duct are supplied with cooling air centrally and are decoupled from each other as a result, so there are no interactions between the segments. The segments of the incoming-air duct are connected to the waste-air duct by the components to be cooled.

By segmenting the incoming-air duct a pressure and volume flow can be easily and reliably adjusted for all regions along the circumference of the gantry. The pressure in the individual segments can consequently be adapted to each other, resulting in a uniform or consistent pressure distribution. The cooling of the system components along the circumference of the gantry is no longer position-dependent therefore when the support is stationary. Cooling is consequently reliable even when the support is stationary.

The cooling system can also be operated with less power so the noise level is reduced in the incoming-air ducts compared to the known solution with baffles.

The inventors accordingly propose improving a CT system for generating tomographic recordings of an examination object, in particular a patient. In at least one embodiment, the CT system includes at least a gantry with a rotatable support for receiving components of the CT system, and a cooling system for cooling the components secured to the gantry with at least one air duct such that an incoming-air duct of the cooling system is divided into at least two segments to ensure a uniform pressure distribution in the incoming-air duct.

The CT system of at least one embodiment comprises a gantry housing in which the gantry is arranged. The gantry has a rotatable support on which a plurality of system components of the CT system is arranged. These system components are primarily at least one radiator-detector system and further electronic components.

The cooling system comprises at least one air duct. An air duct is designed as an incoming-air duct for conveying the cold fresh or cooling air. A further air duct is designed as a waste-air duct for the removal of air heated during cooling of the system components.

According to at least one embodiment of the invention, the incoming-air duct of the cooling system is divided into at least two segments. In one embodiment, the incoming-air duct is divided into exactly two segments. In a further embodiment the incoming-air duct is divided into more than two, by way of example three, four or five, segments.

The at least two segments are preferably each individually supplied with air, i.e. are decoupled from each other. In other words, the air flows in the segments are not connected to each other, so no interactions occur between them. The segments of the incoming-air duct are preferably then connected in parallel, i.e. the entire incoming air flow is distributed among the plurality of segments.

The segments are connected to a shared incoming air supply. The segments advantageously have at least one inlet opening each, through which the incoming air flows into the individual segments. In one embodiment a segment has exactly one inlet opening. Other embodiments have segments with more than one inlet opening, by way of example two or more.

The pressure and thus the volume flow in the segments can preferably be adjusted by the size of the inlet openings in each case. On the one hand, the larger the inlet opening is, the greater the volume flow is in the segment. On the other hand, the lower the flow speed is in the segments, the greater the pressure is. Therefore, in order to reduce the pressure the inlet openings are advantageously reduced in size, and vice versa.

The flow speed of the air in the segments is greatest immediately behind the inlet opening(s). In the case of a segment with just one inlet opening the flow speed decreases during passage through the segment, so the pressure increases as the distance from the inlet opening increases.

In one embodiment of a segment with two inlet openings, the inlet openings can be arranged on the segment so as to oppose each other. The inlet openings are each arranged for example on the opposing ends, i.e. on a leading end and on a trailing end of the segment, viewed in the flow direction. A segment of this kind is designed for example in a C shape. The inlet openings are preferably each formed on the ends of the C legs. The air then flows from the two C legs toward each other, so the flow speed is at its lowest and the pressure is at its greatest at the point where the opposing air flows meet.

In a further embodiment a plurality of inlet openings of a segment may also be arranged side by side.

The shape of the individual segments is advantageously different, in particular the segments are arranged in different ways in the gantry. Shape and course of the segment can be adjusted using flow simulations in order to achieve the desired pressure ratios. One embodiment of the incoming-air duct provides for the segments to be arranged at least in part concentrically to each other.

The at least two segments are advantageously connected to the waste-air duct by the components to be cooled. Once the incoming air has passed through the inlet openings into the individual segments, it flows out of the incoming-air duct via a large number of air inlets into the gantry, where it flows through and cools the system components. From there the heated waste air passes through air outlets into the waste-air duct.

The air inlets in the system components on the gantry are advantageously arranged over the entire length of the individual segments. More than one segment can be associated with one air inlet, i.e. the air from a plurality of segments can flow into a system component through a shared air inlet. The pressure along the circumference of the gantry can be adjusted to a uniform value by the improved and simplified pressure adjustment, so the air always flows out of the segments into the rotating part of the gantry at constant pressure.

Air-impermeable partitions are advantageously arranged between the segments, and these separate the segments from each other. The rigidity of the structure of the entire incoming-air duct is also advantageously increased by the partitions.

The gantry cooling system can have different designs. In one embodiment the cooling system has an air cooling system. Here the hot waste air is given off to the surroundings of the CT system, by way of example an examination room, so the waste air is cooled again by an air conditioning unit of the building. The cooling circuit is open in this case. In a further embodiment the cooling system has a water cooling system. The cooling circuit is closed in this embodiment. The hot waste air is cooled again for example by means of a cooling unit such as a heat exchanger.

FIG. 1shows an example CT system C1. The CT system C1comprises a gantry housing C6in which a gantry (not shown in greater detail here) having a rotatable support is located, to which a first X-ray tube C2having an opposing first detector C3is secured. A second X-ray tube C4having a second opposing detector C5is optionally provided. The CT system C1also has a cooling system for removing the waste heat from the electrical components out of the gantry housing C6, seeFIGS. 2 to 7.

A patient C7is located on an examination table C8which can be moved in the direction of the system axis C9, and with which he can be pushed continuously or sequentially during the scan with the X-ray radiation along the system axis C9through a measuring field between the X-ray tubes C2and C4and the respectively associated detectors C3and C5. This process is controlled by an arithmetic and control unit C10with the aid of computer programs Prg1to Prgn.

FIG. 2shows a schematic view of a known example gantry housing C6. A plane of intersection A-A extends through the gantry housing C6and the X-ray tube C2attached to the support. The air ducts of the cooling system of the CT system are also shown. The known cooling system comprises an incoming-air duct Z for introducing cold fresh air. The cooling system also comprises a waste-air duct A for removing the air heated by the system components on the support1.

FIG. 3shows a schematic cross-section along the plane of intersection A-A through the gantry housing C6known per se. The plane of intersection A-A extends through the X-ray tube C2arranged on a rotatable support1of the gantry. The air flows through an air inlet2.1out of the incoming-air duct Z into the system components, therefore inter alia also into the X-ray tube C2shown here, and flows through this. As it continues, the now heated air flows through air outlets2.2out of the system components into the waste-air duct A. As it passes through the X-ray tube C2the air absorbs the waste heat thereof and therefore cools it. The course of the colder incoming air is symbolically illustrated here as broken-line arrows and the course of the hotter waste air as solid-line arrows.

FIG. 4shows a schematic view of the air circuit in the gantry according toFIG. 2along a plane of intersection B-B. The plane of intersection B-B divides the gantry housing C6parallel to a plane perpendicular to the system axis C9and extends according toFIG. 3between the incoming-air duct Z and the waste-air duct A. In the region of the air intake into the incoming-air duct Z the waste-air duct A is arranged in a different drawing plane to the incoming-air duct Z and is therefore shown with a broken line. For a better overview an illustration of the system components on the support that are to be cooled has been omitted. The cooling system shown by way of example and known from the prior art has an air cooling system.

The air inlets2.1out of the incoming-air duct Z into the system components are also shown in this view. The air inlets2.1are uniformly spaced apart here and are arranged along the entire circumference of the gantry. For local pressure correction and to achieve optimally uniform cooling along the circumference of the gantry a plurality of baffles4are arranged in the incoming-air duct Z between the air inlets2.1.

FIGS. 5 to 7each show a schematic view of the gantry according toFIG. 2along the plane of intersection B-B with different embodiments of the inventive air circuit. Basically the gantry and the cooling system correspond toFIGS. 5 to 7of the embodiment shown inFIG. 4. Only the differences from the prior art and the details essential to the invention will be discussed below therefore. Identical components are identified by identical reference characters.

According to an embodiment of the invention the incoming-air duct Z is divided into a plurality of segments Z1to Z4. The individual segments Z1to Z4are separated from each other by air-impermeable partitions5. All segments Z1to Z3are constructed independently of each other, i.e. are not connected to each other. In the embodiments inFIGS. 5 to 7the segments Z1to Z4each have a different design.

The segments Z1to Z4each have at least one inlet opening6through which the cold incoming air flows into the segments Z1to Z4. The incoming air flows in parallel through the segments Z1to Z3. The pressure in the segments Z1to Z4is individually adjusted. The size of the inlet opening(s)6can be varied for this purpose.

In the embodiment shown inFIG. 5, the incoming-air duct Z is divided into three segments Z1, Z2and Z3. The two segments Z1and Z2are designed approximately in the shape of a C and are arranged in part concentrically. The third, middle segment Z3is designed approximately in the shape of a truncated cone.

The two C-shaped segments Z1and Z2each have an inlet opening4at the ends of the C legs, through which the cold incoming air flows. The truncated cone-shaped, smallest segment Z3has just one inlet opening6. By adjusting the sizes of the inlet openings6a virtually uniform pressure is achieved over the entire length of the segments Z1to Z3, so the air flows along the entire circumference of the gantry at uniform pressure into the cooled system components and cools the system components independently of position. This cooling process is ensured during rotation of the support and also when it is stationary.

FIG. 6shows a further embodiment of the inventive air circuit. The incoming-air duct Z is divided here into four segments Z1to Z4. An outermost C-shaped segment Z1and two symmetrically arranged, bent segments Z2and Z3and one middle, truncated cone-shaped segment Z4are formed. The segment Z1has two inlet openings6, i.e. one inlet opening6on one end of the C leg respectively. The further segments Z2to Z4have just one inlet opening6.

The air flows from the two opposing ends into the outermost C-shaped segment Z1. Strong eddies consequently result in a central region of the segment Z1, here opposite the inlet openings6, if the air flows collide. As a result it is more difficult to adjust a uniform pressure in this segment Z1than in the remaining segments Z2to Z4.

FIG. 7shows a further embodiment. Here the C-shaped segment Z1is divided by a further partition5into two segments Z1.1and Z1.2. The two segments Z1.1and Z1.2are separate and can be adjusted independently of each other.

Although the invention has been illustrated and described in more detail by the preferred example embodiment, it is not restricted by the disclosed examples and a person skilled in the art can derive other variations herefrom without departing from the scope of the invention.