Microtome

Abstract

A microtome, comprising: a cutting tool; an actuator configured to cause relative movement between the cutting tool and a tissue specimen so as to cut the tissue specimen into multiple sections when the microtome is operating; a safety device, wherein the safety device is configured to be put in either a safety state in which the safety device is configured to inhibit risk of injury to a user from the microtome or an operational state in which the safety device allows operation of the microtome; a visual light system having one or more safety lights, wherein the / each safety light is configured to produce coloured light having a colour selected from a group of predetermined colours, wherein the visual light system is configured to change the colour of the coloured light produced by at least one of the one or more safety lights according to whether the safety device is in its safety state or its operational state.

Description

[0001] MICROTOME

[0002] Field of the Invention

[0003] The present invention relates to microtomes.

[0004] Background

[0005] A microtome is a device typically used to cut a tissue specimen into multiple sections, typically so that one or more of the sections can be subject to microscopic examination in the field of Histology. A “section” can be understood as a thin slice of tissue (e.g. having a thickness < 100pm).

[0006] Microtomes are available in a number of designs (e.g. rotary or sliding) and typically work either manually, semi automatically or fully automatic.

[0007] Typically, in a rotary microtome, the cutting tool (typically a cutting blade, sometimes referred to as a “knife”) is held in a fixed position whilst the specimen (typically mounted in a specimen chuck) is configured to move longitudinally and vertically relative to the (fixed) blade. Lowering the specimen to the knife blade is typically done by rotation of a flywheel, which may be rotated manually (e.g. via a handwheel which is rotated by a user) or automatically. For such a device, the rotary motion of a flywheel is typically translated into a vertical motion.

[0008] Many modern microtomes comprise one or more safety devices. However, these safety devices still typically rely, to some extent, on a user observing and following safety protocols.

[0009] An example safety device is a brake for inhibiting operation of an actuator of the microtome, and a guard for mitigating cutting of a user by a cutting tool of the microtome. For example, the brake may be manual or electronic, and may take the form of a handbrake for inhibiting rotation of a flywheel of the microtome (if the microtome is a rotary microtome).

[0010] Another example safety device is a guard for mitigating cutting of a user by a cutting tool of the microtome. The guard may, for example, be a knife guard for physically guarding a user’s hand from the blade of a microtome. In addition, it is recommended that the appropriate personal protective equipment (PPE) be used when working on Microtomes. For example, wearing cut proof gloves, especially when replacing a knife blade.

[0011] When safety protocols are not followed, there may be an increased risk of finger trapping and cutting hazard. For example, mounting a specimen into a specimen chuck when a handbrake is not applied may cause the chuck to move downwards and the user’s hands to come into close proximity of a knife blade. If the knife blade guard is in place, the risk of cutting is mitigated but a user’s finger may still be trapped.

[0012] The present invention has been devised in light of the above considerations. Summary of the Invention

[0013] In a first aspect, the present invention provides:

[0014] A microtome, comprising: a cutting tool; an actuator configured to cause relative movement between the cutting tool and a tissue specimen so as to cut the tissue specimen into multiple sections when the microtome is operating; a safety device, wherein the safety device is configured to be put in either a safety state in which the safety device is configured to inhibit risk of injury to a user from the microtome or an operational state in which the safety device allows operation of the microtome; a visual light system having one or more safety lights, wherein the / each safety light is configured to produce coloured light having a colour selected from a group of predetermined colours, wherein the visual light system is configured to change the colour of the coloured light produced by at least one of the one or more safety lights according to whether the safety device is in its safety state or its operational state.

[0015] In this way, the visual light system is able to provide a user with an easy-to-understand visual indication of the current safety state of the microtome, which may in use help to reduce the likelihood of user injury.

[0016] Herein, the term microtome may be understood as a device for sectioning a tissue specimen, i.e. cutting a tissue specimen into multiple sections. The term “sample” may be used interchangeably with “specimen” herein. The terms “section” and “sectioning” may be used interchangeably with “slice” and “slicing” herein.

[0017] The microtome may be a standalone device or integrated into a device configured to perform other functions (e.g. a cryostat).

[0018] The microtome may be configured to cut an embedded tissue specimen (e.g. a tissue specimen embedded in paraffin wax, e.g. at room temperature) or a frozen tissue specimen (e.g. that has been frozen in a cryostat).

[0019] The cutting tool may be a blade, a knife, or laser, for example.

[0020] The relative movement between the cutting tool and the tissue specimen may be generated, for example, by holding the cutting tool still whilst moving the sample (e.g. as in a rotary microtome) or by holding the sample still whilst moving the cutting tool (e.g. as in some types of sliding microtome).

[0021] The term “tissue” is intended to cover any form of biological tissue suitable for histological examination. For example, the tissue may be muscular, nervous, epithelial and / or connective. The tissue may be soft (e.g. skin) and / or hard (e.g. bone or teeth).

[0022] The safety device may inhibit operation of the microtome when in its safety state.

[0023] For avoidance of any doubt, if the microtome includes multiple safety lights, it is possible for just a subset (one or more) of the safety lights (not necessarily all safety lights) to change colour (i.e. change the colour of the coloured light produced by the safety light) according to whether the safety device is in its safety state or its operational state.

[0024] The microtome may be manually operated (e.g. by a handwheel). Alternatively, the microtome may be automatically operated, or semi-automatically operated. Note that semi-automated operated or even fully- automated device may still be hazardous to operate (e.g. there could be a cutting and / or trapping hazard) and may therefore incorporate safety devices as discussed herein.

[0025] In some examples, the / each safety light may be configured to illuminate a symbol relating to a safety issue associated with the microtome.

[0026] Whilst the use of symbols may in some examples be preferred, we note that in some examples, the microtome may include one or more safety lights which do not illuminate a symbol, e.g. a microtome with just one safety light where the colour of that safety light (without an illuminated symbol) indicates the overall safety status of the device (which is influenced by whether the safety device is in the safety state or the operational state), see e.g. Fig. 4, discussed below.

[0027] A safety issue associated with the microtome (to which a symbol relates) could be associated with whether a safety device included in the microtome is in its safety state or its operational state.

[0028] For example, a symbol configured to be illuminated by a safety light of the microtome could relate to whether or not a brake for inhibiting operation of the actuator is in its safety state or not.

[0029] A safety issue associated with the microtome (to which a symbol relates) could be a hazard associated with operating the microtome.

[0030] For example, a symbol configured to be illuminated by a safety light of the microtome could relate to a trapping hazard (e.g. a finger trapping hazard).

[0031] For example, a symbol configured to be illuminated by a safety light of the microtome could relate to a cutting hazard (e.g. a finger cutting hazard).

[0032] A symbol configured to be illuminated by a safety light of the microtome could be an opaque symbol on a transparent or semi-transparent background, or a transparent or semi-transparent symbol on an opaque background, for example.

[0033] In some examples, the visual light system may be configured to change the colour of the coloured light produced by at least one of the one or more safety lights according to whether or not the microtome is operating.

[0034] In this way, the visual light system can give an indication of safety not just based on whether or not the safety device is in its safety state, but can also give an indication of safety based on whether or not the microtome is operating, see e.g. the table discussed below with reference to Fig. 4.

[0035] For avoidance of any doubt, if the microtome includes multiple safety lights, it is possible for just a subset (one or more) of the safety lights (not necessarily all safety lights) to change colour (i.e. change the colour of the coloured light produced by the safety light) according to whether or not the microtome is operating. In some examples, the safety device may be a brake configured to inhibit operation of the actuator when the brake is in its safety state (which may correspond to the brake being ‘engaged’), and to allow operation of the actuator when the brake is in its operational state (which may correspond to the brake being ‘disengaged’).

[0036] The brake may, for example, be a handbrake for inhibiting rotation of a handwheel of the microtome (if the microtome is a rotary microtome).

[0037] In some examples, the safety device may be a guard configured to mitigate cutting of a user by the cutting tool when the guard is in its safety state (which may correspond to the guard being in a position where it physically obstructs user access to the cutting tool), and to allow operation of the microtome when the guard is in its operational state (which may correspond to the guard being in a position where it permits user access to the blade). The guard may inhibit cutting of a specimen by the cutting tool when in its safety state.

[0038] If the cutting tool is a knife, the guard may be a knife guard.

[0039] In some examples, the microtome may comprise a further safety device, wherein the further safety device is configured to be put in either a safety state in which the safety device is configured to inhibit risk of injury to a user from the microtome or an operational state in which the safety device allows operation of the microtome; wherein the visual light system is configured to change the one or more colours produced by the one or more safety lights according to whether the further safety device is in its safety state or its operational state.

[0040] The further safety device may inhibit operation of the microtome when in its safety state.

[0041] For avoidance of any doubt, if the microtome includes multiple safety lights, it is possible for just a subset (one or more) of the safety lights (not necessarily all safety lights) to change colour (i.e. change the colour of the coloured light produced by the safety light) according to whether the further safety device is in its safety state or its operational state.

[0042] In some examples, the safety device may be a brake configured to inhibit operation of the actuator when the brake is in its safety state and to allow operation of the actuator when the brake is in its operational state, and the further safety device may be a guard configured to mitigate cutting of a user by the cutting tool when the guard is in its safety state and to allow operation of the microtome when the guard is in its operational state.

[0043] In some examples where the safety device is a brake and the further safety device is a guard, the visual light system may include: a first safety light relating to the brake of the microtome; at least one further safety light relating to a hazard associated with the guard of the microtome.

[0044] The at least one further safety light may include: a second safety light relating to a cutting hazard associated with the guard of the microtome (e.g. a finger cutting hazard caused by the guard being in its operational position); and / or a third safety light relating to a trapping hazard associated with the guard of the microtome (e.g. a finger trapping hazard caused by the guard being in its safety position).

[0045] For avoidance of any doubt, it would be possible for the visual light system to include the second safety light and not the third safety light or vice versa.

[0046] In some examples in which the safety device includes the first safety light and the at least one further safety light: the first safety light may be configured to illuminate a symbol relating to the brake of the microtome; the / each further safety light may be configured to illuminate a symbol relating to a hazard associated with the cutting tool of the microtome.

[0047] For example, if the visual light system includes the second safety light, the second safety light may be configured to illuminate a symbol relating to the cutting hazard.

[0048] For example, if the visual light system includes the third safety light, the second safety light may be configured to illuminate a symbol relating to the trapping hazard.

[0049] In some examples, the group of predetermined colours may include: a first colour corresponding to a safe condition; a second colour corresponding to a caution condition; a third colour corresponding to a danger condition.

[0050] The first colour may be green, the second colour may be yellow / amber / orange, and the third colour may be red. In this way, a “traffic light” colour scheme is achieved whereby microtome users may find it easier to interpret the coloured light produced by the / each safety light in the visual light system. Though other colour schemes could be envisaged.

[0051] In some examples, the visual light system may include multiple safety lights, wherein each safety light is configured to produce coloured light having a colour selected from the group of predetermined colours, wherein the visual light system is configured to change the colour of the coloured light produced by at least one of the safety lights according to whether the safety device is in its safety state or its operational state.

[0052] However, as exemplified in relation to Figs. 4 and 5 (discussed below), it is possible for the visual light system to include just one safety light, wherein the visual light system is configured to change the colour of the coloured light produced by the safety light according to whether the safety device is in its safety state or its operational state. In such an example, the visual light system may be further configured to change the colour of the coloured light produced by the (one) safety light according to whether or not the microtome is operating (see e.g. Fig. 4 and associated discussion) and / or according to whether a further safety device is in its safety state or its operational state (not shown).

[0053] In some examples, the microtome may be a standalone device configured to cut an embedded tissue specimen into multiple sections at room temperature. The embedded tissue specimen may be embedded in wax, e.g. paraffin wax, for example.

[0054] In a second aspect of the invention, there may be provided: A cryostat that includes a microtome according to the first aspect of the present invention, wherein the microtome is configured to cut a frozen tissue specimen into multiple sections when the microtome is operating.

[0055] The cryostat may be configured to generate a sub-zero (i.e. less than 0°C) temperature suitable for cutting a frozen tissue specimen into multiple sections.

[0056] The invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided.

[0057] Summary of the Figures

[0058] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which:

[0059] Fig. 1 shows an example microtome.

[0060] Figs. 2(a) and 2(b) show an example microtome.

[0061] Fig. 3 shows another example microtome.

[0062] Fig. 4 shows another example microtome.

[0063] Fig. 5 shows a cryostat that includes a microtome according to Fig. 1 , wherein the microtome is configured to cut a frozen tissue specimen into multiple sections when the microtome is operating.

[0064] Detailed Description of the Invention

[0065] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.

[0066] Fig. 1 shows an example microtome 100 in schematic form. The microtome 100 comprises a cutting tool 110, an actuator 120, a safety device 130, an optional further safety device 140, and a visual light system 150.

[0067] The actuator 120 is configured to cause relative movement between the cutting tool 110 and a tissue specimen (not shown) so as to cut the tissue specimen into multiple sections when the microtome 100 is operating.

[0068] The safety device 130 is configured to be put in either a safety state in which the safety device 130 is configured to inhibit risk of injury to a user from the microtome 100 or an operational state in which the safety device 130 allows operation of the microtome 100. The further safety device 140 (if present) is configured to be put in either a safety state in which the further safety device 140 is configured to inhibit risk of injury to a user from the microtome 100 or an operational state in which the further safety device 140 allows operation of the microtome 100.

[0069] The visual light system 150 has one or more safety lights 152, 154, 156, 158. The / each safety light 152, 154, 156, 158 is configured to produce coloured light having a colour selected from a group of predetermined colours. The visual light system 150 is configured to change the colour of the coloured light produced by at least one of the one or more safety lights 152, 154, 156, 158 according to whether the safety device 140 is in its safety state or its operational state.

[0070] If the further safety device 140 is present, the visual light system 150 is configured to change the colour of the coloured light produced by at least one of the one or more safety lights 152, 154, 156, 158 according to whether the further safety device 130 is in its safety state or its operational state.

[0071] Figs. 2(a) and 2(b) show an example microtome 200 which is an implementation of the microtome 100 of Fig. 1 . More specifically, Fig 2(a) shows a perspective view of the microtome 200, and Fig. 2(b) shows a side view of the example microtome 200. Where features differ from the microtome 100 of Fig. 1 , they have been given corresponding reference numerals (incremented by 100).

[0072] The structure and operation of the microtome 200 is similar to the Epredia™ HM 355S Automatic Microtome, except that the microtome 200 has been modified to include a visual light system 250, which includes three safety lights 252, 254, 256.

[0073] The microtome 200 of Fig. 2 is a standalone device configured to cut an embedded tissue specimen into multiple sections at room temperature. More specifically, the microtome 200 is an automatic rotary microtome which includes a knife 210, a specimen clamp 260, a flywheel (internal, so not shown), a handwheel 270, a handbrake 230, an operating panel 280, and an emergency stop button 290.

[0074] In this example, the knife 210 serves as the cutting tool, and the flywheel serves as the actuator. The flywheel is housed within a body of the microtome 200 and connects to both the handwheel 270 and a back side of the specimen clamp 260.

[0075] The handwheel 270 includes a handle 275 which in this example can be inserted into a body of the handwheel 270 when not in use (for packaging compactness and convenience). In other examples, the handle 275 may be fixed.

[0076] Before operation, a tissue specimen is placed into the specimen clamp 260, and the specimen clamp 260 is then adjusted to correctly position the tissue specimen relative to the knife 210. This positioning may include correctly orientating the tissue specimen relative to the knife 210, and / or positioning a front face of the tissue specimen close to the knife 210. When the microtome 200 is operated, the relative movement between the knife 210 and the tissue specimen (held in the specimen clamp 260) is generated by holding the knife 210 still whilst the sample is moved by the flywheel.

[0077] In this example, the flywheel is automatically operated by a motor (not shown), upon a user pressing one or more buttons located on the operating panel 280, which allows the user to control one or more functions and / or settings of the microtome 200. Additionally, the flywheel can also be operated manually, by turning the handwheel 270. Operation of the actuator can be ceased immediately using the emergency stop button 290.

[0078] In this example, the handbrake 230 serves as the safety device of the microtome 200. The handbrake 230 is configured to inhibit operation of the actuator (flywheel) when the handbrake 230 is in its safety state (which corresponds to the handbrake 230 being engaged) and to allow operation of the actuator when the handbrake 230 is in its operational state (which corresponds to the handbrake 230 being disengaged). This is a well-known safety device in the context of modern microtomes.

[0079] In this case, the handbrake 230 inhibits operation of the actuator mechanically. However, in other (e.g. automatic microtome) examples the handbrake 230 may instead inhibit the actuator by sending an electronic signal to the motor to stop further movement of the actuator.

[0080] In this example, a knife guard 240 serves as the further safety device. The knife guard 240 is configured to mitigate cutting of a user by the knife 210 when the knife guard 240 is in its safety state (which corresponds to the knife guard physically obstructing user access to the knife) and to allow operation of the microtome 200 when the knife guard 240 is in its operational state (which corresponds to the knife guard 240 exposing the knife 210). The knife guard 240 inhibits cutting of a specimen by the cutting tool when in its safety state, and so needs to be put in its operational state in order for the microtome 200 to be operated to cut a tissue specimen into sections. Again, a knife guard 240 is a well-known safety device in the context of modern microtomes.

[0081] In this example, the visual light system 250 includes: a first safety light 252 relating to the handbrake 230 of the microtome 200, wherein the first safety light 252 is configured to illuminate a symbol relating to the handbrake 230 of the microtome 200; a second safety light 254 relating to a finger cutting hazard associated with the knife guard 240 of the microtome 200, wherein the second safety light 254 is configured to illuminate a symbol relating to the finger cutting hazard; a third safety light 256 relating to a finger trapping hazard associated with the knife guard 240 of the microtome 200, wherein the second safety light 256 is configured to illuminate a symbol relating to the finger trapping hazard.

[0082] Each safety light 252, 254, 256 is configured to produce coloured light having a colour selected from a group of predetermined colours that includes red, amber, green, and the visual light system 250 is configured to change the colour of the coloured light produced by at least one of the one or more safety lights 252, 254, 256 according to:

[0083] • whether the handbrake 230 is in its safety state or its operational state

[0084] • whether the knife guard (240) is in its safety state or its operational state

[0085] • whether or not the microtome 200 is operating (manual or automatic operation) In this example, the visual light system 250 achieves this by being configured to control the safety lights 252, 254, 256 to produce coloured light having the colours shown in the table below:

[0086] Table 1 Comments on each of these states 1 -6 are provided as follows:

[0087] State 1 :

[0088] • Handbrake 230 is ‘ON’.

[0089] • Knife guard 240 is ‘In Place’.

[0090] • The microtome 200 is NOT operating. • This represents the expected state when switching on the instrument.

[0091] • All lights 252, 254, 256 are GREEN indicating it is safe to change the specimen block in the chuck.

[0092] State 2:

[0093] • Handbrake 230 is ‘OFF’. • Knife guard 240 is ‘In Place’.

[0094] • The microtome 200 is NOT operating.

[0095] • This is an intermittent state prior to operating the microtome 200.

[0096] State 3:

[0097] Handbrake 230 is ‘ON’. Knife guard 240 is removed

[0098] • The microtome 200 is NOT operating.

[0099] • This state is suitable for changing a knife blade.

[0100] State 4:

[0101] • Handbrake 230 is ‘OFF’.

[0102] • Knife guard 240 is removed

[0103] • The microtome 200 is NOT operating.

[0104] • This is another intermittent state prior to operating the microtome 200. One state on from #2.

[0105] State 5:

[0106] • A microtome 200 operating but with knife guard in place will cause damage so, whilst it is possible to generate this state, this is not recommended from an operation standpoint, as indicated by the RED, AMBER, RED lights 252, 254, 256.

[0107] State 6:

[0108] • Handbrake 230 is ‘OFF’.

[0109] • Knife guard 240 is removed

[0110] • The microtome 200 is operating.

[0111] • All lights 252, 254, 256 are RED, so operators need to be aware of moving parts and hands should be kept away from cutting area.

[0112] By operating in accordance with Table 1 , the visual light system 250 is able to provide a user with an easy-to-understand visual indication of the current safety state of the microtome 200, which may in use help to reduce the likelihood of user injury.

[0113] Of course, the mapping of safety lights 252, 254, 256 to the states of the safety devices and the operational state of the microtome 200 is exemplary, and other mappings may be chosen according to operational requirements.

[0114] In order to allow the visual light system 250 to control the safety lights 252, 254, 256 in this way, the microtome 200 is configured to determine the state of the first safety device (in this case handbrake 230), and the state of the second safety device (in this case knife guard 240) and the operating state of the microtome. Each of said states may be determined, for example, by the microtome 200 including one or more suitably configured sensors and / or by a control unit of the microtome 200 inferring the state from instructions directed to it by a user (e.g. using the control panel 280).

[0115] Here we note that there are not states in which the handbrake is in its safety state and the microtome is operating, because the handbrake is configured to prevent the microtome from operating when it is in its safety state (i.e. engaged). In operation, the microtome 200 may be operated by a user as follows, starting with the microtome 200 in state 1 as indicated in Table 1 (green-green-green):

[0116] • Load tissue specimen using a specimen clamp 260 of the microtome 200 [Note that adding this weight can cause weight of tissue sample to come down on someone’s hand and cause a finger trapping hazard if handbrake is not engaged]

[0117] • Take knife guard 240 off to expose knife 210, take handbrake 230 off (state 4: red-red-red) [Note that the order of taking the knife guard off or handbrake off is not significant here, though lights would light up differently according to the order, see states 2 and 3 in Table 1 ]

[0118] • Operate the microtome 200 [Note that in the case of microtome 200 this could be achieved by pressing a button (since the microtome is automatic) or by manual operation, since the microtome 200 allows both automatic and manual operation] so as to take some thick sections off the specimen so the user can access part of the sample which is of most interest (state-6-state 4: red-red-red)

[0119] • Operate the microtome 200 so as to take sections of interest (state 4: red-red-red)

[0120] • Stop operating (state 4: red-red-red)

[0121] • Put knife guard 240 back on, put handbrake 230 back on in either order (state 1 : green-green- green)

[0122] • Take sample out of specimen clamp 260

[0123] To replace the knife 210 of the microtome 200, the microtome 200 may be operated as follows, again starting with the microtome 200 in state 1 as indicated in Table 1 (green-green-green)::

[0124] • Take knife guard 240 off to expose knife 210 (state 3: green-red-amber)

[0125] • Change blade (state 3: green-red-amber)

[0126] • Replace knife guard 240 (state 1 : green-green-green)

[0127] Fig. 3 shows another example microtome 300, which is similar to the microtome 200 of Fig. 2. Note that corresponding features to the microtome 200 have corresponding reference numerals.

[0128] In this example, the visual light system 350 has been simplified to include only one safety light 352, which does not illuminate a symbol. The safety light 350 is configured to produce coloured light having a colour selected from a group of predetermined colours that includes red, amber, green, and the visual light system is configured to change the colour of the coloured light produced by the one or more safety light 352 according to:

[0129] • whether the handbrake (not shown in this example) is in its safety state or its operational state

[0130] • whether or not the microtome 300 is operating

[0131] In this example, the visual light system 350 achieves this by being configured to control the safety light 352 to produce coloured light having the colours shown in the table below: In this example, the microtome 300 still includes the knife guard 340, but the visual light system 350 does not change the colour of the coloured light it produces based on the knife guard 340 (e.g. there is no sensor to detect the state of the knife guard 340).

[0132] Table 2

[0133] In this way, the visual light system 350 is able to provide a user with an easy-to-understand visual indication of the current safety state of the microtome 300, which may in use help to reduce the likelihood of user injury.

[0134] Of course, the mapping of safety light 352 to the states of the safety devices and the operational state of the microtome 300 is exemplary, and other mappings may be chosen according to operational requirements.

[0135] Here we note that there is not a state in which the handbrake is in its safety state and the microtome 300 is operating, because the handbrake is configured to prevent the microtome 300 from operating when it is in its safety state (i.e. engaged).

[0136] In order to allow the visual light system 350 to control the safety lights in this way, the microtome 300 is configured to determine the state of the first safety device (in this case handbrake), and the operating state of the microtome 300. Each of said states may be determined, for example, by the microtome 300 including one or more suitably configured sensors and / or by a control unit of the microtome 300 inferring the state from instructions directed to it by a user.

[0137] Fig. 4 shows another example microtome 400, which is a manual rotary microtome.

[0138] In this example, the visual light system 450 includes only one safety light 452, which is configured to illuminate a handbrake symbol. The safety light is configured to produce coloured light having a colour selected from a group of predetermined colours that includes red, green, and the visual light system 450 is configured to change the colour of the coloured light produced by the one or more safety light 452 according to:

[0139] • whether the handbrake (not shown in this example) is in its safety state or its operational state

[0140] In this example, the visual light system 450 achieves this by being configured to control the safety light 452 to produce coloured light having the colours shown in the table below:

[0141] Table 3

[0142] Again, the visual light system 450 is able to provide a user with an easy-to-understand visual indication of the current safety state of the microtome 400, which may in use help to reduce the likelihood of user injury.

[0143] In order to allow the visual light system 450 to control the safety light 452 in this way, the microtome 400 is configured to determine the state of the safety device (in this case handbrake). Said states may be determined, for example, by the microtome 400 including one or more suitably configured sensors.

[0144] Fig. 5 shows a cryostat that includes a microtome 100 according to Fig. 1 , wherein the microtome 100 is configured to cut a frozen tissue specimen into multiple sections when the microtome 100 is operating.

[0145] ***

[0146] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0147] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention. For example, the invention may be used with rotary microtomes (as above) or other forms of microtome (e.g. a sliding microtome).

[0148] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0149] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0150] Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0151] It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / - 10%.

Claims

Claims:1 . A microtome, comprising: a cutting tool; an actuator configured to cause relative movement between the cutting tool and a tissue specimen so as to cut the tissue specimen into multiple sections when the microtome is operating; a safety device, wherein the safety device is configured to be put in either a safety state in which the safety device is configured to inhibit risk of injury to a user from the microtome or an operational state in which the safety device allows operation of the microtome; a visual light system having one or more safety lights, wherein the / each safety light is configured to produce coloured light having a colour selected from a group of predetermined colours, wherein the visual light system is configured to change the colour of the coloured light produced by at least one of the one or more safety lights according to whether the safety device is in its safety state or its operational state.

2. A microtome according to claim 1 , wherein the / each safety light is configured to illuminate a symbol relating to a safety issue associated with the microtome.

3. A microtome according to claim 1 or 2, wherein the visual light system is configured to change the colour of the coloured light produced by at least one of the one or more safety lights according to whether or not the microtome is operating.

4. A microtome according to any previous claim, wherein the safety device is a brake configured to inhibit operation of the actuator when the brake is in its safety state, and to allow operation of the actuator when the brake is in its operational state.

5. A microtome according to any previous claim, wherein the safety device is a guard configured to mitigate cutting of a user by the cutting tool when the guard is in its safety state, and to allow operation of the microtome when the guard is in its operational state.

6. A microtome according to any previous claim, wherein: the microtome comprises a further safety device, wherein the further safety device is configured to be put in either a safety state in which the safety device is configured to inhibit risk of injury to a user from the microtome or an operational state in which the safety device allows operation of the microtome; the visual light system is configured to change the one or more colours produced by the one or more safety lights according to whether the further safety device is in its safety state or its operational state.

7. A microtome according to claim 6, wherein the safety device is a brake configured to inhibit operation of the actuator when the brake is in its safety state and to allow operation of the actuator when the brake is in its operational state, and the further safety device is a guard configured to mitigate cuttingof a user by the cutting tool when the guard is in its safety state and to allow operation of the microtome when the guard is in its operational state.

8. A microtome according to claim 7, wherein the visual light system includes: a first safety light relating to the brake of the microtome; at least one further safety light relating to a hazard associated with the guard of the microtome.

9. A microtome according to claim 8, wherein the at least one further safety light includes: a second safety light relating to a cutting hazard associated with the guard of the microtome; and / or a third safety light relating to a trapping hazard associated with the guard of the microtome.

10. A microtome according to claim 8 or 9, wherein: the first safety light is configured to illuminate a symbol relating to the brake of the microtome; the / each further safety light is configured to illuminate a symbol relating to a hazard associated with the cutting tool of the microtome.

11. A microtome according to any previous claim, wherein the group of predetermined colours include: a first colour corresponding to a safe condition; a second colour corresponding to a caution condition; a third colour corresponding to a danger condition.

12. A microtome according to claim 11 , wherein the first colour is green, the second colour is yellow / amber / orange, and the third colour is red.

13. A microtome according to any previous claim, wherein the visual light system includes multiple safety lights, wherein each safety light is configured to produce coloured light having a colour selected from the group of predetermined colours, wherein the visual light system is configured to change the colour of the coloured light produced by at least one of the safety lights according to whether the safety device is in its safety state or its operational state.

14. A microtome according to any previous claim, wherein the microtome is a standalone device configured to cut an embedded tissue specimen into multiple sections at room temperature15. A cryostat that includes a microtome according to any of claims 1 to 13, wherein the microtome is configured to cut a frozen tissue specimen into multiple sections when the microtome is operating.

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