This invention relates to an apparatus for coupling an ultrasound probe to an object. The apparatus is suitable for use in medical devices and other related fields although it is not restricted to use in those fields.
Ultrasound probes are well known and well used in medicine. For example, ultrasound imaging is used to provide expectant mothers with images of the foetus, to measure the blood flow in veins and arteries and when a medical practitioner wishes to inspect an internal cavity of a patient.
In most cases, the apparatus and techniques are very similar to those shown in
The gel, typically an aqueous gel, is applied either to the surface of the object 9 or to the probe head 5 in order to ensure effective acoustic coupling between the probe head 5 and the surface of the object 9. The gel is therefore required to provide a constant contact between the head 5 and the surface 9.
It is often the case that the probe 5 will be moved around over a significant area across the object 9 in order to obtain an image. Consequently, a large amount of gel is smeared across the surface of the object 9 which, in the case of a human, may be the abdomen, arm, leg or the like; this is unpleasant, messy and time consuming. In addition, the application of the gel is far from an exact science. It is often the case that the gel must be reapplied in order to obtain a good ultrasound signal.
Single layer gel pads are known to be used as coupling pads. However, these pads are prone to allow air into the path of the ultrasound signal which causes a degradation of the signal and hence the image.
It is therefore an object of an aspect of the present invention to provide a coupling apparatus for coupling an ultrasound probe to an object that obviates, or at least mitigates, one or more of the above described problems experienced by the coupling apparatus known in the art.
In accordance with a first aspect of the invention there is provided a coupling apparatus for coupling an ultrasound probe to an object, the coupling apparatus comprising:
a first coupler connectable to the probe;
a second coupler connectable to the object; and
an intermediate layer for acoustically connecting the first coupler and the second coupler, the intermediate layer being further adapted to provide structural strength to the apparatus,
wherein, the first coupler and the second coupler are adapted for direct acoustic coupling with the respective probe and object.
Preferably, the first coupler and the second coupler are made of a pliable material such that when in contact with the probe and/or object, the respective first coupler and second coupler deform to fit the shape of the probe and object, respectively.
Preferably, the first coupler and the second coupler exude an acoustic coupling liquid when in operative contact with the respective probe and object.
Preferably, the first coupler is shaped to accommodate the probe.
Preferably, the first coupler is made from a material that undergoes syneresis.
Preferably, the first coupler is semi-solid.
Preferably, the first coupler is a gel.
Preferably, the first coupler is a hydro-gel.
Preferably, the first coupler is a polyvinyl alcohol hydro-gel.
Preferably, the first coupler has a composition with less than six weight percentage of polyvinyl alcohol in water.
Preferably, the second coupler is made from a material that undergoes syneresis.
Preferably, the second coupler is a gel.
Preferably, the second coupler is a hydro-gel.
Preferably, the second coupler is a polyvinyl alcohol hydro-gel.
Preferably, the second coupler has a composition of less than six weight percentage polyvinyl alcohol.
Preferably, the intermediate layer has a similar, or identical, acoustic impedance to the first coupler and the second coupler.
Preferably, the intermediate layer has a higher density than the first coupler or the second coupler.
Preferably, the intermediate layer is a gel.
Preferably, the intermediate layer is a hydro-gel.
Preferably, the intermediate layer is a polyvinyl alcohol hydro-gel.
Preferably, the intermediate layer is a polyvinyl alcohol hydro-gel having a percentage composition of polyvinyl alcohol greater than six weight percentage.
Preferably, the intermediate layer is acoustically coupled to the first coupler and the second coupler.
Preferably, the acoustic coupling is achieved via a junction layer.
Preferably, the junction layer is defined by a discrete layer.
Optionally, the junction layer is defined by a transition layer of varying density.
Optionally, the transition layer is characterised by an increased density towards the intermediate layer.
Preferably, the coupler is formed in a single piece.
Optionally, the coupler is formed in three discrete layers.
Optionally, the discrete layers are bonded together.
Optionally, the discrete layers are bonded together using a heating and cooling cycle.
Preferably, the apparatus of the present invention is provided with a sterile cover for use in-vivo.
The cover is used to prevent the probe being contaminated, particularly when used in vivo.
Preferably, the cover is a sheath.
Preferably, the cover is integrally formed with the apparatus of the present invention.
Preferably, the cover is integrally formed with the intermediate layer of the present invention.
Optionally, the cover is connectable to the apparatus of the present invention.
Optionally, the cover is connectable by means of a channel.
Preferably, the channel is in the intermediate layer.
Preferably, the apparatus of the present invention further comprises a frame adapted to support the cover.
In accordance with a second aspect of the present invention there is provided a method for making a coupling apparatus for coupling an ultrasound probe to an object, the method comprising the steps of:
Following the above method results in the formation of a bonded structure comprising three layers of lower and higher density hydro-gels.
Most preferably the third density is selected so as to be equal to the first density.
Preferably the first hydro-gel is a polyvinyl alcohol hydro-gel. Preferably the first hydro-gel has a composition of less than six weight percentage polyvinyl alcohol in water.
Preferably the third hydro-gel is a polyvinyl alcohol hydro-gel. Preferably the third hydro-gel has a composition of less than six weight percentage polyvinyl alcohol in water.
Preferably the second hydro-gel is a polyvinyl alcohol hydro-gel. Preferably the second hydro-gel has a composition of greater than six weight percentage polyvinyl alcohol in water.
In accordance with a third aspect of the present invention there is provided a method for making a coupling apparatus for coupling an ultrasound probe to an object, the method comprising the steps of:
Optionally the second and third steps are carried out simultaneously.
Aspects and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the following Figures in which:
In this example of the present invention, the first and second couplers 14 and 18 provide a means for directly coupling an ultrasound probe to the apparatus 10 and the apparatus to a body without requiring the application of a coupling gel to the body 26 or the probe 24. In this example the direct coupling is provided by selecting a pliable material of the first 14 and/or second coupler 18 such that the material deforms around the probe 24 and/or body 26. The coupler therefore fits around or conforms to the shape of the probe 24 and/or body 26 to provide good acoustic coupling. In this example, the probe 24 is pressed into the first coupler 14, and the second coupler 18 is pressed against the body 26.
In this example the entire arrangement of the first and second couplers, 35 and 39, along with intermediate layer 37 are made from a hydro-gel. In addition, in this example, the density (as measured by the weight percent of polyvinyl alcohol (PVA)) of the first coupler 35 and the second coupler 39 are substantially identical. The density of the intermediate layer 37 is higher than that of the first coupler 35 and the second coupler 39. The intermediate layer 37 is designed to be a harder and more resilient structure in order to provide mechanical strength to the overall structure.
Couplers 35 and 39 are designed to be pliable such that they deform on contact with the probe 33 or body 49, respectively, and conform to the shape of the probe 33 or body 49.
The apparatus 31 may be designed to be disposable after a single use.
Couplers 55 and 59 are designed to exude a liquid when in operative contact with the probe 53 and the object 69, respectively. The purpose of the liquid is to provide a physical coupling between the probe 53 and first coupler 55 and between the object 69 and second coupler 59. The purpose of this coupling liquid is to remove the need for applying a gel to the object surface.
The couplers 55 and 59 have composition that readily allows a liquid 65, 67, in this example water, to be exuded onto the probe 53 and object 69. The process by which a liquid is exuded in this manner is known as syneresis and the extent to which, or the amount of, liquid that is exuded is dependant upon the density of the gel.
In one respect the couplers 55 and 57 can be viewed as liquid reservoirs where the liquid 65, 67 is held in a semi-fixed state and which can be released from the reservoir during operative contact with a probe 53 and object 69. The presence of the layers of liquid 65, 67 provide a good coupling and because the gel contains a significant amount of liquid the coupling is maintained when the probe apparatus is moved across the object surface, because liquid is continuously exuded during use.
In this example the interfaces 61 and 63 between the first coupler 55 and intermediate layer 57 and the intermediate layer 57 and second coupler 59 are not discrete. This means there is a change in density as measured by a change in the weight percentage of PVA in the hydro-gel across the layer. It is believed that this type of structure is likely to occur where the apparatus is formed using the heating/Cooling cycled described below.
Arrow 58 shows the distance through the apparatus and a graph of density 75 as measured by weight percentage of the hydro-gel against distance D 73 is shown in
As outlined above, the apparatus of the present invention can be made using PVA hydro-gels in the following manner. A first mixture containing a lower concentration of PVA is added to a container where it is first frozen and then thawed until a hydro-gel is formed in the bottom of a container (usually the container is shaped like a column).
A second mixture containing a higher concentration of PVA is added to the container where it is first frozen and then thawed until a hydro-gel is formed on top of the first formed hydro-gel. During the freezing and thawing process the second, higher density, hydro-gel fuses, bonds or mixes with the first formed hydro-gel to form a continuous hydro-gel with an area of higher concentration and an area of lower concentration of PVA.
Thereafter, a third mixture is added to the container. This third mixture contains a lower concentration of PVA similar or identical to the concentration of the PVA in the first mixture. Once again, a freezing and thaw cycle is performed until a hydro-gel is formed from the mixture. As with the first and second mixtures this third mixture, upon formation of a hydro-gel is fused, bonded or mixed with the second hydro-gel to form a larger, continuous hydro-gel with a lower density similar to the density of the first hydro-gel.
In an alternative embodiment the coupling apparatus of the present invention can be made by initially carrying out the second step so as to form the high density intermediate hydro-gel layer. Thereafter the first and second steps can be carried out in order to form the lower density hydro-gel layers on different sides of the intermediate layer. It will be appreciated that the first and second steps may be carried out simultaneously in order to speed up the production process.
In this embodiment of an aspect of the present invention the integrated sheath 187 provides a ready made hygienic and sterile sheath which, as with the previous embodiment, that does not present any part of the sheath 157 or 187 to the path of the ultrasound as it goes from the probe, 143 or 173, to the object, 155 or 185. In addition, the embodiment of
The above described apparatus provides an improved means for coupling an ultrasound probe to an object and particularly a medical ultrasound probe to a patient. This is achieved without the need to deploy layers of gel to the object or patient or to employ hydro-gel pads. Since the described apparatus comprises a multi layered hydro-gel structure it provides an elegant and cost effective solution for improving the coupling of ultrasound to an object. In some or the above described embodiments, a sheath is employed that provides for a cost effective disposable device thus significantly reducing the risk of cross contamination between patients.
The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form enclosed. The described embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilise the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore, further modifications or improvements may be incorporated without departing from the scope of the invention as defined by the appended claims.
Number | Date | Country | Kind |
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0619322.1 | Sep 2006 | GB | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/GB07/03712 | 10/1/2007 | WO | 00 | 12/21/2010 |