Abstract: A metrology apparatus including a body and a first member rotatable relative to the body about a first axis of rotation, said first axis being defined by first bearing and a first motor for actuating rotation of the first member relative to the body about the first axis of rotation. A surface sensing device is attachable to the first member such that the surface sensing device can move with the first member, relative to the body. The first motor may include a first magnet and at least one metal coil spaced apart along the first axis and mounted such that the first magnet and the at least one metal coil are moveable relative to one another.

Abstract: A method of fabricating a bearing surface for a gas or air bearing is described. The method comprises taking a bulk bearing portion having at least one bearing surface region and providing a coating on the bearing surface region to define at least one gas pocket. The at least one gas pocket has a depth substantially equal to the thickness of the coating. In one example, laser ablation is used to remove part of the coating to form the gas pockets. The coating may be an anodised coating and the bulk bearing portion may be formed from aluminium. An air bearing component formed using the method is also described.

Abstract: A method of fabricating a bearing surface for a gas or air bearing is described. The method comprises taking a bulk bearing portion having at least one bearing surface region and providing a coating on the bearing surface region to define at least one gas pocket). The at least one gas pocket has a depth substantially equal to the thickness of the coating. In one example, laser ablation is used to remove part of the coating to form the gas pockets. The coating may be an anodized coating and the bulk bearing portion may be formed from aluminium. An air bearing component formed using the method is also described.

Abstract: A guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate part having a composition of at least 80% tungsten carbide. The guide element may have a coating, such as a biocompatible plastics material which is more resilient than the elongate part.

Abstract: A head clamp for neurosurgery is described that includes a member for at least partially encircling the head of a subject. The first end and second end of the head clamp include first and second skull attachment portions for attaching the member to the head of a subject. A position setter, such as an indexing mechanism, is also provided that allows the member to be moved or indexed between at least two repeatable relative positions.

Abstract: Apparatus for imaging a body part of a subject, for example using MRI, is described. The apparatus includes a housing for at least partially surrounding a body part (e.g. a head) and a first fiducial marker assembly retained at least partially within the housing that includes one or more fiducial markers and a datum feature. The position of the datum feature is fixed relative to the one or more fiducial markers. The first fiducial marker assembly is moveable with respect to the housing and the datum feature is accessible from outside of the housing.

Abstract: A tomogram taken on an imaging path of a tomograph is corrected by using sets of tomogram correction data for neighbouring positions on that path, in an interpolative process. An error map of a tomograph is built up by comparing tomograms of a phantom with the expected appearance of the phantom at the tomogram positions. Also provided is a phantom having a body with one or more imaging fluid receptacles formed therein.

Abstract: A skull mount (50;150;170;200;300) is described that is attachable to a hole (60) formed in the skull. The skull mount (50;150;170;200;300) comprises an alignment guide (62;152;172;216;306) defining an alignment axis (22;210;312) along which neurosurgical instruments can be passed. The skull mount, when attached to a hole in a skull, is arranged such that it does not substantially protrude from the outermost surface of the skull and does not extend into the brain parenchyma. Also described is a neurosurgical alignment instrument (30,206) for aligning such a skull mount (50;150;170;200;300) that comprises an elongate shaft (32) and an element (34,36) protruding from the distal end of the elongate shaft (32) for engaging and aligning the alignment guide (62;152;172;216;306) of an associated skull mount (50;150;170;200;300).

Abstract: A neurosurgical catheter is described for insertion into the brain parenchyma of a subject. The catheter comprises a flexible tube and has a stiff, non-porous, tip comprising at least one fluid delivery aperture. The stiff tip of the catheter may be mechanically stiffer than the flexible tube. The stiff tip may be provided by a stiff tube attached to the distal end of the flexible tube. The stiff tube may comprise a ceramic (e.g fused silica) and/or a metal. A kit comprising the catheter and a guide tube is also described. Methods of catheter implantation are also outlined.

Abstract: A guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate ‘part having a composition of at least 80% tungsten carbide. The guide element may have a coating, such as a biocompatible plastics material which is more resilient than the elongate part.

Abstract: A method of fabricating a bearing surface (11,13) for a gas or air bearing (2) is described. The method comprises taking a bulk bearing portion (30; 44) having at least one bearing surface region and providing a coating (32; 42) on the bearing surface region to define at least one gas pocket (34; 40). The at least one gas pocket (34; 40) has a depth substantially equal to the thickness of the coating (32; 42). In one example, laser ablation is used to remove part of the coating (32; 42) to form the gas pockets (34; 40). The coating (32; 42) may be an anodised coating and the bulk bearing portion (30) may be formed from aluminium. An air bearing component formed using the method is also described.

Abstract: A rotary gas bearing is described that comprises a first part rotatable relative to a second part. The first part comprises a support member and a first portion and a second portion attached to the support member. The first portion comprises a first bearing surface and the second portion comprising a second bearing surface. Both the first portion and the second portion are attached to the support member by screw thread connections. The second part may comprise complimentary bearing surfaces. Epoxy may be used to fix the first and/or second portions to the support member. A method of determining the bearing working gap by measuring gas flow through the bearing is also described.

Abstract: A catheter assembly for insertion into the brain. The assembly comprises a first length of tubing made of a first material. A second material surrounds the first length of tubing, the second material being more flexible than the first material and having a hardness of less than 50 Rockwell E. The second material provides damping to the first length of tubing.

Abstract: An implantable fluid distribution device is described. The device includes a first inlet for receiving fluid under pressure from a remote pump. A plurality of outlets are also provided, each outlet being connectable to a fluid delivery catheter. A valve mechanism is arranged to control the passage of fluid from the first inlet to the plurality of outlets. Apparatus including the fluid distribution device, an implantable pump and a plurality of drug delivery catheters is also described. The fluid distribution device can be used to delivery drug to multiple regions in the body and the sequential delivery of drugs to different sites in the brain is disclosed.

Abstract: A metrology instrument, such as a probe, probe head, stylus or stylus arm, for mounting on a coordinate position apparatus. The metrology instrument is at least partially constructed from at least one sheet of thermally stable metallic material which is folded to form a three dimensional structure. The at least one sheet of thermally stable material is utilized in the metrology loop of the metrology instrument.

Abstract: A bearing arrangement for an articulatable support includes bearing assemblies. In one embodiment, the assemblies have a ball and aperture having sliding contact at discrete areas during relative rotation. In another embodiment, the sliding contact may be formed at a ball and a plastics (e.g. P.T.F.E. support). Resilient displacement of the bearing contact along a rotational axis is provided by planar spring supports and a rigid support is provided by supports.

Abstract: A bearing arrangement for an articulatable support (6) comprises bearing assemblies (20/28, 22/29, 24/30 and 26/32). In one embodiment the assemblies comprise a ball (20, 22, 24, 26) and aperture (40 FIG. 2) having sliding contact at discrete areas (36) during relative rotation. In another embodiment the sliding contact may be formed at a ball (20,22,24,26) and a plastics e.g. P.T.F.E. support (84, 85 FIGS. 10 and 11). Resilient displacement of the bearing contact along a rotational axis (A and B) is provided by planar spring supports (28, 32) and rigid support is provided by supports (29 and 30).

Abstract: A bearing arrangement for an articulatable support (6) comprises bearing assemblies (20/28, 22/29, 24/30 and 26/32). In one embodiment the assemblies comprise a ball (20, 22, 24, 26) and aperture (40 FIG. 2) having sliding contact at discrete areas (36) during relative rotation. In another embodiment the sliding contact may be formed at a ball (20, 22, 24, 26) and a plastics e.g. P.T.F.E. support (84, 85 FIGS. 10 and 11). Resilient displacement of the bearing contact along a rotational axis (A and B) is provided by planar spring supports (28, 32) and rigid support is provided by supports (29 and 30).