GB2111794A

GB2111794A - Transillumination of tissue

Info

Publication number: GB2111794A
Application number: GB08134648A
Authority: GB
Inventors: David John Watmough
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-11-17
Filing date: 1981-11-17
Publication date: 1983-07-06
Also published as: GB2111794B

Abstract

Images of lesions (23) within tissues (25), normally regarded as optically opaque, are generated by projecting light from a powerful source, such as a slide projector, through the tissue and detecting the transmitted light with a television camera or photographic plate. The slide mount may contain filters to change the spectral content of the light, and suitably sized apertures. The tissue is flattened between transparent plates (12). <IMAGE>

Description

SPECIFICATION Device for transillumination of tissues A new device for imaging tumours in vivo is described which is non-invasive and which utilises non-ionising radiation.

The device permits immediate images of lesions within tissues, to be made provided they can be transilluminated, either on a television monitor or on photographic film. The instrument is relatively inexpensive. It permits the tissues to be interrogated rapidly with light of different wavelengths. Also light in narrow spectral bands can be arranged to match the absorption characteristics of blood in vessels (particularly around the neoplastic tumours). This gives maximum contrast permitting very small lesions to be observed.

The device consists of a table (see the accompany- ing Figures) into whose top (240) is recessed a plastic or glass section (9). Below the table is a "light guide" (21) of rectangular cross-section with an angled mirror (8) under the recess (9). Inside the guide (21) is a slide projector (3). Light from the lens (13) is shone onto the mirror and hence through the tissues (12). The (b) symbol is for breast which is the feature presently being interrogated for the presence oftumours. (10) is a slide holder to carry optical filters and suitable sized apertures. Atransparent plate (12) to flatten the tissues is necessary. In the expanded view a photographic casette may be attached forthe production of contact prints.Alternatively a television camera (1) may be utilised provided it has a detector sensitive out to the near infra-red. The camera may be wired to a monitor(s) via an a-numeric generator (2) and a video recorder (4). (27) represents power cables to each unit. The table requires to have a height adjustment (7).

The instrument permits a standard projector to be used for the transillumination and avoids stray light by the guide (21) and the mask (19) which must be suited to the anatomy of the patient. The television camera is attached to the rod (25) by the clamp (22) and to the table by a plate (20).

Spring-loading (28) on both sides of (12') (not shown) may be helpful in attaining uniform "slabs" of tissue.

The method does not significantly heat the tissues because of a slab of heat-absorbing glass interposed in the optical path within the projector. (6) is the button control to exchange slide holders containing optical filters and/or apertures.

Claims

1. It is claimed that lesions within normally opaque tissues can be observed directly or by a television camera or by photography using a new device which transilluminates tissues with a powerful light source.

2. By judicious use of a light guide situated beneath a table the light from a projector can be directed onto the skin and part passes through the tissues, usually sufficient to image lesions within.

3. The device prevents stray light reaching the camera or film or observer who must be dark adapted.

4. The instrument absorbs most of the heat from the bulb inside the projector thus protecting the patient from discomfort.

5. The device is elegant and cheap.

6. A major advantage is that the spectral content of the light can be changed at will by filters placed in the slide mounts.

7. The size of the exit pupil can be varied by placing a range of aperture diameters in the centre of modified slide mounts.

8. The instrument can be operated by either medical or para-medical staff because of its intrinsic simplicity.

9. The use of band pass filters matched to the absorbtron characteristics of either arterial or venous blood is an important feature of the instrument here described.

10. The projector could be replaced with a laser and beam expander (but this will be the subject of a separate and subsequent application).