LIGHTING UNITS FOR SURGICAL AND MEDICAL USE

Abstract: A lighting unit for medical and surgical use comprises a head, preferably of materials which are non-magnetic and translucent to R.F. waves so as to be usable in conjunction with a Nuclear Magnetic Resonance imaging system, comprises a light projector, and means for forming a curtain of sterile air and for creating a supply of sterile air within the curtain.

Description: Lighting units for surgical and medical use This invention relates to lighting units for surgical and medical use, and provides such units which are particularly adapted for use in carrying out surgical and other medical procedures under sterile conditions. In accordance with the invention, there is provided a lighting unit for surgical and medical use, including a head having a light projector, characterized in that the head has inlet means for the supply of sterile air to the head, a first outlet for said sterile air at relatively high pressure to form an annular curtain of sterile air about an area illuminated by the head, and a second outlet for said sterile air at a relatively lower pressure, within said curtain. With this construction, the head may be posi¬ tioned to provide a localised, sterile atmosphere surrounding a part of the patient's body on which a treatment is to be performed. The head is preferably supplied with light and sterile air from remote sources and the unit as a whole may be readily portable so that it can be installed in, for example, treatment rooms, ambulances or other areas which are not purpose built to provide a total sterile atmosphere. Various minor surgical and cancer treatment procedures, among others, are currently conducted under X-ray observation, but prolonged and/or repetitive exposure to X-rays is, of course, hazardous. The use of NMR techniques offers an alternative to X-ray observation, without the hazards of radiation. However, it is normally impractical to house NMR units under conditions of sterility matching those of an operating theatre, and in a particularly advantageous embodiment of the invention, the head is constructed entirely of materials which will not interfere with the magnetic fields and R.F. transmitters of a Nuclear Magnetic Resonance (NMR) imaging system. Most synthetic plastics materials meet these requirements, being non- magnetic and translucent to R.F. waves and signals. A lighting unit in accordance with the invention is described below, by way of example, with reference to the accompanying drawing, which is a diagrammatic axial cross-section through the head. Preferably, a single cabinet (not shown) is provided, containing a light source, and a motorized fan drawing ambient air through a bacterial filter, e.g. a 5 micron paper filter element. Light is transmitted to the head by a bundle of lightweight, flexible optic fibres 5i or an equivalent light guide system, and sterile air by lightweight flex¬ ible tubing 6, such as "lay-flat" tubing which is rendered semi-rigid when inflated by the air flow through it. The head has a central duct 7 having a throttling restriction 8 downstream of a branch line 9 feeding air to an annular outer plenum 10 with an annular slit outlet 11 bounded by coanda curves for controlling and directing an annular curtain of sterile air generally axially of the head. The plenum 10 is maintained at a relatively high pressure, and the air issuing axially from the central duct is at relatively low pressure, due to the effect of the restriction 8, so that it is largely contained by the curtain. The optic fibres 5 are led through the head and have their ends cast into a lightweight plastics lens 12 which projects light generally axially, and focuses at about 1 metre from the head to a "shadowless" light. With this apparatus, a surgeon is able e.g. to direct light and sterile air at the point of entry into the patient of an operating catheter whose location and operation he can observe on a screen interpreting NMR imaging data. Although the above described apparatus is particularly adapted for use in an NMR environment, it could usefully be employed in other non-sterile situa¬ tions such as a doctors surgery, a treatment room or an ambulance. In such a case, the apparatus may, of course, be composed of metallic or other materials. Situations may also be envisaged in which the light source may be omitted.

Claims: - k - CLAIMS : 1. A lighting unit for surgical and medical use, including a head having a light projector, characterized in that the head (l) has inlet means for the supply of sterile air to the head, a first outlet for said sterile air at relatively high pressure to form an annular curtain of sterile air about an area illuminated by the head, and a second outlet for said sterile air at a relatively lower pressure, within said curtain. 2. A unit according to claim 1, characterized in that the head has a single inlet for the supply of sterile air at a source pressure, a connection (9) to the first outlet (ll) and a throttling connection (8) to the second outlet (7). 3. A unit according to claim 1 or 2, wherein the head is of generally circular shape, characterized in that the first outlet (ll) is formed as an annular slot adjacent the periphery of the head, the light projector and the second outlet both being positioned radially inwardly of the first outlet. k. A unit according to any preceding claim, characterized in that the head includes light guide means (5) conducting light to the head from a remote source and terminating at the head to form the said light projector. 5. A unit according to claim 4, characterized in that the light guide means are constituted by a bundle of flexible optic fibres terminating in the head at a lens (12). 6. A unit according to any preceding claim, characterized in that a remote source of sterile air is connected to the head by flexible ducting. 7. A unit according to any preceding claim, characterized in that the head is constructed entirely of materials which will not interfere with the magnetic fields and R.F. transmitters of a Nuclear Magnetic Resonance imaging unit.

Inventors: LONGMORE DONALD BERNARD, LONGMORE, DONALD, BERNARD
Applicants: LONGMORE DONALD BERNARD, LONGMORE, DONALD, BERNARD
Application year: 1987
Main classification: F21M1
IPC codes: F21S8, F21V8