Cutting – Processes – With preparatory or simultaneous ancillary treatment of work
Patent
1992-02-06
1997-03-11
Rada, Rinaldi I.
Cutting
Processes
With preparatory or simultaneous ancillary treatment of work
83 73, 83 767, 839155, G01N 106, B26D 520
Patent
active
056090838
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method for sectioning a specimen by means of a microtome, at least some of the essential sectioning parameters, such as clearance angle, sectioning speed (or force), type of knife, knife angle and specimen pretreatment, being systematically varied for achieving a sectioning-parameter choice providing an optimised sectioning function. The invention also relates to an apparatus for carrying out the method.
DESCRIPTION OF THE PRIOR ART
In biological and medical investigations and materials testing, use is generally made of microtomes for cutting thin sections of the specimens involved, these sections being examined by light- or electron microscopy.
Specimens that are not immediately sectionable are embedded in suitable media or frozen before sectioning. In the microtomes, the specimen, which is fixed to one end of a vertically movable arm, is generally engaged with a stationary knife. The feed, determining the section thickness, is applied to either the specimen arm or the knife holder.
Detailed information on microtomy and on how a microtome can be designed is given, e.g. in Science Tools, The LKB Instrument Journal, Vol. 7, No. 2, August 1960, pp 10-16, "The Ultrome Ultramicrotome--Basic Principles and Summarized Description of Construction".
Present-day microtomes are handled manually by the operator who tries to evaluate the section quality achieved and intervenes if it is not satisfactory. This evaluation is made with the aid of low-magnifying specimen microscopes. The researcher then makes the conclusive evaluation in his high-resolution light- or electron microscope prior to the actual task of analysing the section contents morphologically and/or analytically. If this latter evaluation shows that the sections are not satisfactory, which is not unusual, sectioning must be repeated with adjusted sectioning parameters. This, of course, means extra work, waste of time and increased costs. Further, particular problems arise if the specimen is not readily available for resectioning.
It has been suggested to vary the knife-angle parameter on the basis of a signal received from a sensor in the form of a load sensor or strain gauge arranged on the knife or the specimen holder. In this manner, the sectioning force can be minimised and so-called chatter eliminated without any examination of the section in an electron microscrope. This, however, provides no overall optimisation of the sectioning function as a whole.
OBJECT OF THE INVENTION
The object of the present invention is to provide improvements in microtomy so as to obviate the above-mentioned problems to a considerable extent while also conferring other advantages.
SUMMARY OF THE INVENTION
According to the invention, the object stated above is achieved by a method and an apparatus having the features stated in the accompanying claims.
The invention is thus based on the insight that, by using a number of sensors associated with the specially interference-protected microtome for detecting a number of selected variables dependent on the sectioning function, it is possible to generate signals the value of which, in a broad sense, is a measure of the sectioning function, i.e. a measure of how free from artefacts or distortions a resulting section is. The variation of the respective signal, when varying one or more sectioning parameters between successive cuts (without any examination of the respective section in a high-resolution microscope), is used as the basis of an optimising sectioning-parameter choice providing the optimum value of the respective signal and, hence, optimised sectioning function, within the limits of the conditions given. When varying the sectioning parameters, the operator may of course consider any preset sectioning-parameter limit values or reference values, like any knowledge gained from experience about suitable or unsuitable relationships between different sectioning-parameter values and signal values. The variation of the sectioning parameter or parameters can be ca
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KnifeMaker (Unique damping device gives more usable knife-edge) LKB, 7800 (4 pages), May 1984.
Ultratome III (The Wide-range Ultramicrotome) LKB, 8800 (8 pages), 1973.
LKB Ultratome V, 2088 (6 pages), Jun. 1978.
Ultrotome Ultramicrotome--Basic Principles and Summarized Description of Construction; Borje Hellstrom, Science Tools, The LKB Instrument Journal, pp. 10-16, Aug. 1960.
Dexter Clark F.
Glass Ultra Micro Trading Company
Rada Rinaldi I.
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