GB2453320A

GB2453320A - Multiple compartment histology processing cassette

Info

Publication number: GB2453320A
Application number: GB0717315A
Authority: GB
Inventors: Philip Webber; Paul Webber
Original assignee: Cellpath Ltd
Current assignee: Cellpath Ltd
Priority date: 2007-09-06
Filing date: 2007-09-06
Publication date: 2009-04-08
Anticipated expiration: 2027-09-06
Also published as: GB0717315D0; GB2453320B

Abstract

A histology processing cassette 1 comprising a multiple compartment box 2 for holding biological tissue, the box 2 having a bottom face comprising a radiation transmissive material, and an open top face. Each compartment is defined by partitions 3 extending between the top face and the bottom face. An adaptor is also provided for insertion in a cassette base, in order to form a multiple compartment cassette. Multiple compartments allow improvements in throughput.

Description

CASSETTE

This invention relates to a cassette, in particular a histology processing cassette suitable for processing a plurality of biological tissue samples simultaneously and to a method of analyzing a plurality of biological samples simultaneously. The invention also relates to an adaptor for processing a plurality of biological samples which is inserted into a processing cassette base in use.

Biological materials for histological examination are processed in large quantities for a wide range of diagnostic purposes. Such processes may involve processing with fluids to dehydrate the tissue and to remove certain components from the tissue. The tissue may then be impregnated with wax to provide it with the rigidity necessary for further processing, for example microtome slicing. The processing usually involves placing the material in a small box-like plastics carrier, known in the art as a ucassetteu which generally is of a standard size as it is required to fit in other apparatus, for example fit standard specimen holders of microtomes.

Known cassettes for processing biological tissues typically comprise an open-topped box :**::: with a perforated bottom wall. The box may have a perforated top cover which is moveable relative to the box or a removable perforated cover. Typically, processing cassettes have e. : internal dimensions of 30 to 32 mm x 25 to 26 mm x 5 mm. Minor vanations in size may * . occur, dependent for example upon the wall thickness of the box. Processing cassettes with **** a plastics lid or top cover often have a continuous flange to provide rigidity which extends .. around the periphery of the lower face of the lid and is spaced from the peripheral edge of *:2 the lid so that the flange fits within the side wall of the box-like base.

The perforations of the box and cover are typically from I to 3 mm in diameter. Known processing cassettes are described in GB 1230913 and US 3674396. Such processing cassettes are used with the cover in place as a tissue processing capsule and with the cover removed for embedding a specimen in paraffin.

The processing cassette defines a cavity, which may be closed with the use of a perforated lid, into which the biological tissue is placed for processing. Genera'ly, processing cassettes define one cavity and process one sample at a time although cassettes having multiple cavities to allow processing of more than one sample are known.

I

Processing cassettes typically constructed of plastics material and the perforations are made in the plastic material which forms the bottom wall and, where employed, the plastics material forming the lid.

Whilst such cassettes are in widespread use, during processing it may be necessary to pass electromagnetic radiation, for example X-rays, through the cassette. The plastics material forming the bottom and optionally the lid are generally however not transparent to for instance X-rays.

A significant number of tissue samples are very small in size, for example having dimensions of less than 1 mm, and are generally too small to be processed in a standard processing cassette, since they would pass through the perforations of the lid and base.

Various approaches have been adopted to enable small specimens to be processed in standard processing cassettes. For example, stainless steel mesh 1 2 may be inserted in the cassette or the tissue may be wrapped in porous wrapping paper such as tea bag tissue, toilet tissue or cigarette paper, for example. In some areas of the world bags of woven polyamide (nylon) may be used. An alternative system has been developed using fine :. * filter sponges but these have been found to cause undesirable artefacts. **.* * S *5SI

Certain very thin tissue samples, for example skin, may have a tendency to curl up at the S...

: edges which may be problematic. Some of the approaches adopted, for example wrapping in porous paper, does help to control such curling. S...

: ... As well as curling and the need to employ porous paper, the apparatus and materials used * 2 hitherto for transporting and processing small tissue samples present difficulties in sample handling.

GB 2278441A describes an adaptor for insertion into a histology processing cassette to enable the cassette to be used for processing small tissue specimens. The adaptor is of suitable dimensions to be fitted in a processing cassette and it comprises a base and a lid defining a chamber to hold a tissue sample. The perforations are defined by a mesh rather than being formed in a plastics material and X-rays may be transmitted through the adaptor.

However, the use of an adaptor does not allow full utilisation of the limited space within the processing cassette and is not suitable for processing multiple samples simultaneously.

The present inventors have devised a novel processing cassette which enables a plurality of samples to be processed simultaneously, allows X-rays to pass through the relevant part of the cassette for analysis of the tissue samples and which need not involve the use of an adaptor or insert in addition to the cassette.

In a first aspect, the invention provides a histology processing cassette comprising a multiple compartment box for holding biological tissue, the box having a bottom face comprised at least in part of a support transmissible to radiation, preferably a mesh, and an open top face wherein each compartment extends between the top face and the bottom face.

The compartment for holding biological tissue extends between the top face and the bottom face to define discrete compartments. The sides of the compartments are suitably defined by the box wall and a partition wall between adjacent compartments. As desired the sides of the compartments may be defined exclusively by partition walls where it is surrounded by other compartments.

In a second aspect, the invention provides a histology processing cassette comprising a box having side walls which define a bottom face and a top face, one or more partition walls in :**::: the box to define two or more sample compartments within the box and a support transmissible to radiation, preferably a mesh, disposed across at least a part of the bottom S...

*. : face such that each sample compartment has the support over at least a part of its bottom * S S...

... Advantageously, the invention enables several samples to be processed at once, suitably in 2 discrete compartments, thereby greatly improving throughput as compared to single sample cassettes and providing significant reductions in cost. Although processing of multiple samples in a single compartment in a conventional cassette is known, the present invention avoids the risk of contamination or tangling or damage to the samples in processing. The mesh cover for the bottom of the sample compartments renders the sample analysable by X-ray without Interference from the structure of the cassette as would be the case for cassettes having perforations in a plastics face.

The invention also provides a method of analysing or processing two or more biological samples simultaneously comprising: i) providing a histology processing cassette having two or more discrete sample compartments and the cassette being adapted to be received in apparatus for processing a biological sample; ii) loading a first biological sample into a first sample compartment and a second biological sample into a second sample compartment and optionally loading a further sample into a further sample compartment; iii) loading the cassette into apparatus for analysing or processing a biological sample; and iv) carrying out analysis or processing of the first and second sample simultaneously to provide analytical results from the first and second sample.

Suitably the first sample, second sample and any further samples being analysed comprise biological tissue samples.

The histology processing cassette is suitably of a shape, size and dimensions which are adapted to engage with a cassette receiving site in apparatus for histological examination, processing or analysis of a biological tissue sample.

Suitably, the partition walls are generally parallel to the internal face of the side walls and in a plane which is preferably generally perpendicular to the bottom face and top face. Suitably the partition walls extend between the top face and the bottom face. Suitably each sample compartment is discrete and contamination or damage of samples from other samples "S cannot occur. Preferably, the compartments are the full vertical depth of the cassette, that is S...

* : the bottom and top face define sides of the compartment *... S * S...

The cassette contains 2 and preferably at least 3 compartments. As the compartment needs : ... to be a certain size to accommodate the sample and as cassettes are generally produced with standard external dimensions, preferably the cassette comprises 6 or fewer and desirably 5 or fewer compartments. Preferably, the compartments are at least 5mm wide in their smallest dimension parallel to the top or bottom face.

The compartments may be any suitable shape, for example elongate and square and may be arranged in any desired manner in the cassette. Preferably, the compartments are arranged to extend across the full width of the cassette. Endoscopy biopsies for example, may be processed in compartments which are more square than elongate. The shape of the compartment may be relevant in the examination and diagnosis, for example in the examination of a prostate core. A prostate core is generally elongate, for example 20mm in length and 1mm in diameter and a cassette having a plurality of elongate channels is preferable in these cases. Elongate channels are preferable for biopsies using needle-shaped cores. In an especially preferred embodiment, the cassette has five identical channel-shaped compartments running across the width of the cassette.

In a preferred embodiment, at least a part of the top face of the box is covered by mesh so providing sample compartments which have mesh over the top and bottom faces. Suitably, the top face is covered by a lid comprising a peripheral frame which engages releasably with the box of the cassette with mesh covering at least part of the space defined by the frame.

Suitably, the lid is moveable relative to the box of the cassette. Preferably the lid is detachable and the lid and box have complementary engaging means, for example, recesses and lugs, to allow secure attachment of the lid to the box. If desired, the lid may be permanently attached to the box and pivotally mounted, for example through a hinge, to the box.

The lid may comprise bars across the peripheral frame to enhance structural rigidity.

Preferably the bars are located so as to align with the partition walls of the box and thereby not obstruct maintain the line of sight through the compartments from the top face to the bottom face. * *

:*::: Preferably the box and the partition walls of the cassette are constructed of a plastics **** material as is the frame part of the lid. Suitably these parts are constructed by injection S... . . .. : moulding a thermoplastics matenal around mesh parts such that a peripheral edge portion of . one mesh is embedded in the moulded box and of another mesh is embedded in the

SSS

moulded frame. The cassette is suitably made of a material which may be readily marked by n... cassette markers or is produced with identifying markers, for example numbers, for each *: compartment.

Preferably, the mesh has a pore size of not more than 5mm, more preferably not more than 1 mm and more preferably of not more than 500 microns. Desirably, the pore size is from to 400 microns. Preferably, the mesh is made of polyamide for example nylon.

The invention provides in a further aspect an adaptor for insertion in use in a histology processing cassette base which base comprises a box having side walls which define an open bottom face and an open top face, the adaptor comprising a base and a lid to engage the base to define a box having a plurality of compartments to hold tissue samples, at least one of the said base and the lid comprising a peripheral frame across at least part of which is disposed a support transmissible to radiation, preferably a mesh, secured to the frame, the adaptor being of suitable dimensions and being adapted to fit in a processing cassette base in use so as to form a histology processing cassette.

The histology processing cassette base is suitably of a shape, size and dimensions which are adapted to engage with a cassette receiving site in apparatus for histological examination, processing or analysis of a biological tissue sample.

The invention also provides a histology processing cassette kit comprising a histology processing cassette base and an adaptor according to the invention.

Suitably, the adaptor base and the lid each comprise a peripheral frame defining an area across which is disposed a fine mesh secured to the frame.

The invention provides in a further aspect an adaptor in the form of a capsule for transporting small tissue samples and for processing them in a processing cassette.

The invention further provides histology processing apparatus comprising, in combination, apparatus for processing or analysing a biological sample and a histology processing :..::: cassette according to the invention. *I..

:::: The apparatus for processing or analysing a biological sample may be semi-automatic or *. automatic. Examples of suitable apparatus include section cutting equipment, embedding equipment, X-ray apparatus and any other histopathology apparatus.

4 Suitably, the cassette or adaptor according to the invention is substantially transparent to X-rays or other radiation frequencies as desired to allow it to be employed in the examination of samples which are to be examined by irradiation, for example breast core biopsies.

Breast cores may typically be 10 to 20mm by 2 to 3mm in dimensions and elongate compartments dimensioned to accept such cores are preferred.

The invention further provides for the use of a cassette according to the invention in the analysis of a sample by irradiation, for example X-rays, to which radiation the mesh of the cassette is transparent.

In a further aspect, the invention provides a method of analysing a biological sample by irradiation which comprises providing a sample to be irradiated in a cassette or kit according to the invention, irradiating the sample and the mesh and detecting the radiation from the sample. The sample may be irradiated by passing radiation through the sample or by back scatter irradiation.

The method is particularly beneficial when employed to analyse a plurality of samples simultaneously in a single cassette.

The invention also provides a method of processing a tissue sample containing a component to be removed, preferably a plurality of such tissue samples simultaneously, comprising placing a plurality of tissue samples into either i) a processing cassette or kit according to the invention and contacting the processing cassette with a processing liquid to remove one or more components of the sample to provide a sample depleted in the component removed and optionally contacting the depleted sample with wax to provide a sample for further processing or study.

Suitably the tissue samples are infiltrated with wax in preparation for slicing and histological study.

:. The present invention is further described by way of example only with reference to the :..::: accompanying drawings, in which: Figure 1 shows a histology processing cassette with a closable lid according to the . : invention in a perspective view; Figure 2 shows a histology processing cassette without a lid *. according to the invention in a perspective view, S..

Figure 3 shows a lid of histology processing cassette according to the invention in a ... perspective view; * Figure 4 shows the bottom side of a histology processing cassette according to the invention in a perspective view; Figure 5 shows a histology processing cassette base and an adaptor for use with the base according to the invention in a perspective view.

Figure 1 shows a histology processing cassette (1) according to the present invention having a lid (4). The lid (4) is movable about hinge (15) so as to close the cassette (1). The lid (4) may be releasably closed using the releasable complementary engaging parts (14A and 14B). Cassette (1) has side walls (2) which together with partition walls (3) define the periphery of the cassette (1) and the sample compartments.

Figures 2 and 3 show a histology processing cassette (1) and a separate lid (4) for closing the cassette (1). The cassette (1) may be employed without the lid (4) or with it as desired.

In Figures 1 and 2, the bottom face of the cassette (1) is covered at least in part by a support which is transmissible to radiation, for example a mesh. The support extends over the bottom face of the sample compartments so providing a means of supporting the samples when placed in the compartments. The cassette (1) is dimensioned and shaped so as to be loadable in and removable from a sample processing apparatus.

Figure 4 shows the bottom side of a histology cassette (1) according to the invention and shows the support (5) and, through the support (5), the partition walls (3).

Figure 5 shows a histology processing cassette base (6) dimensioned and shaped to be loadable in and removable from apparatus for processing biological samples. The base (6) has side walls (2') which define an open top face and open bottom face. A retention lip (7) is provided for accepting an adaptor (8) in use and defines an opening (16) in the bottom of the base (6). The adaptor (8) has a base and a lid (10). Side walls (9) define the periphery of the base of the adaptor (8). The bottom side of the base is covered at least in part by a mesh (12) which together with walls (9) and partition walls (17) define discrete compartments (11). The adaptor (8) has a lid (10) which is closable on the base and is covered by a mesh (13). The lid is shown with partition waIls (18) spaced so as to align with :**::: partition walls (17) upon closure of the lid (10). In an alternative embodiment, the lid (10) e.

does not have partition walls (18) and suitably the partition walls (17) in the base extend * : : upwardly so that on closure of the lid (10), the walls(1 7) and the mesh (13) come into contact *. so closing the top of the compartments (11) and thereby reducing the risk of contamination U...

between samples in different compartments.

Claims

1. A histology processing cassette comprising a multiple compartment box for holding biological tissue, the box having a bottom face comprised at least in part of a support transmissible to radiation and an open top face wherein each compartment extends between the top face and the bottom face.

2. A histology processing cassette comprising a box having side walls which define a bottom face and a top face, one or more partition walls in the box to define two or more sample compartments within the box and a support transmissible to radiation disposed across at least a part of the bottom face such that each sample compartment has the support over at least a part of its bottom face.

3. A processing cassette according to claim 1 or claim 2 in which the plurality of compartments are defined by at least one partition wall which is generally perpendicular to the bottom face and top face.

:. 4. A processing cassette according to claim 3 in which the partition walls extend :: between the top face and the bottom face.

7: 5. A processing cassette according to any one of the preceding claims having at least 3 ... compartments. S.S*

6. A processing cassette according to any one of the preceding claims having 6 or fewer compartments.

7. A processing cassette according to any one of the preceding claims in which the compartments are at least 5mm wide in their smallest dimension parallel to the top or bottom face.

8. A processing cassette according to any one of the preceding claims in which the compartments are elongate in shape.

9. A processing cassette according to any one of the preceding claims in which the cassette has five identical channel-shaped compartments 10. A processing cassette according to any one of the preceding claims in which the compartments extend across the width of the cassette.

11. A processing cassette according to any one of the preceding claims in which the top face is covered by a lid comprising a peripheral frame which engages releasably with the box of the cassette with mesh covering at least part of the space defined by the frame.

12. A processing cassette according to claim 11 in which the lid is moveable relative to the box of the cassette and is detachable.

13. A processing cassette according to claim 11 in which the lid is moveable relative to and permanently attached to the box.

14. A processing cassette according to claim 13 in which the lid is pivotally mounted on the box.

16. A processing cassette according to any one of the preceding claims in which the support transmissible to radiation comprises a mesh and, optionally, the top face of the box is covered by mesh so providing sample compartments which have mesh over the top and bottom faces. * S

*:r: 17. A processing cassette according to claim 16 in which the mesh has a pore size of not ** morethan5mm. S...

:... 18. A processing cassette according to any one of the preceding claims in which the mesh comprises polyamide.

19. An adaptor for insertion in use in a histology processing cassette base which base comprises a box having side walls which define an open bottom face and an open top face, the adaptor comprising a base and a lid to engage the base to define a box having a plurality of compartments to hold tissue samples, at least one of the said base and the lid comprising a peripheral frame across at least part of which is disposed a support transmissible to radiation secured to the frame, the adaptor being of suitable dimensions and being adapted to fit in a processing cassette base in use so as to form a histology processing cassette.

20. A histology processing cassette kit comprising, in combination, a histology processing cassette base comprising a box having side walls which define an open bottom face and an open top face and an adaptor according to claim 19.

21. Histology processing apparatus comprising, in combination, apparatus for processing or analysing a biological sample and a histology processing cassette or kit according to any one of claims I to 18 and 20.

22. Use of a cassette, cassette kit or apparatus according to any one of claims 1 to 18, 20 and 21 in the analysis of a sample by irradiationto which radiation the mesh of the cassette is transparent.

23. A method of analysing or processing two or more biological samples simultaneously comprising: i) providing a histology processing cassette having two or more discrete sample compartments and the cassette being adapted to be received in apparatus for processing a biological sample: ii) loading a first biological sample into a first sample compartment and a second biological sample into a second sample compartment and optionally *2ô loading a further sample into a further sample compartment: iii) loading the cassette into apparatus for analysing or processing a biological sample: and I...

iv) carrying out analysis or processing of the first and second sample simultaneously to provide analytical results from the first and second sample. s S * . * S.

24. A method of analysing a biological sample by irradiation which comprises providing a sample to be irradiated in a cassette or kit according to any one of claims I to 18 and 20, irradiating the sample and the mesh and detecting the radiation from the sample.

25. A method of processing a biological sample containing a component to be removed comprising placing a tissue sample into either i) a processing cassette or kit according to any one of claims I to 18 and 20 and contacting the processing cassette with a processing liquid to remove one or more components of the sample to provide a sample depleted in the component removed and optionally contacting the depleted sample with wax to provide a sample for further processing or study.

26. A method according any one of claims 23 to 25 in which a plurality of samples are analysed or processed simultaneously in a single cassette or kit.