Antall József szerk.: Orvostörténeti közlemények 92. (Budapest, 1980)

TANULMÁNYOK - Miczbán Izabella: A sejtkép személetének alakulása a XX. században (magyar és angol nyelven)

In practice the results did not meet the expectations for among other reasons the inadequacy of biological programming. Thus the cytoanalyzer which was meant to make oncocytodiagnostic work more economic by allowing a pre-selection of big cell populations in several preparations, today must be regarded as surpassed. Despite all this, it should be included in a historical treatment of our view on the cell image. It was a milestone and turning point in the fields of optics and electronics, the right principles of its construction were made use of in further researches. [13] The purpose now was to direct the microscopic image itself into the computer. The basic idea was that if all the information in the microscopic image of a cell get into the computer, modern instruments allow to judge cells objectively according to their morphological character. Some of the research work was started to obtain more exact parameters which would more clearly divide the cellular types and to ameliorate technological processes. Now the goal was to transform the microscopic image into a series of numbers. The photocopying process served for technological analogy here. There the image is carried on a light-sensitive layer. The more or less local darkening of the film corresponds to areas of different optical density. Instead of darkenings, the different optical density points of the microscopic image are marked with number keys. Out of the arrangement of numbers is formed the digitized image ready for computer input (1968). [8] The functioning of the apparatus can be summed up as follows. The examinar picks out the cell to be examined more closely. Scanning takes place under electronic controll, taking a cathode ray tube for light source. Here also, the intensity of light is influenced by the object through which the light passes through, gets to the light multiplier and changes into electric sign. There is, however, another light multiplier which perceives the light of the cathode ray tube directly so this beam does not pass through the object. The difference in the intensity of the two beams of light represent the differences in optical density perceived in the preparation. This further analogous sign is translated into binary numbers. The binary digit, the bit is the unit of information. The above mentioned principles were first observed in the apparatus called CYDAC (Cytophotometric Data Conversion). (Fig. 3) Registrating point by point the optical densities in the visual fields concerned, the apparatus converts cytophotometric data into digital form, i.e. it quasi translates the microscopic image for the purpose of computer analysis. Figure 4 shows the digitized cell image of a leucocyte of polymorphous nucleus. After the biological, electrooptical and technological analogies mentioned so far, an historical analogy is at hand: Columbus chose a new way to reach India for practical reasons — and discovered a new world. The practical need of objectivity and work economy brought forth the digitized cell image which became the main subject of quantitative cytology and the starting point for a new field of research — that is for cytocibernetics. The CYDAC is able to convert the microscopic image into more then 100 000 bits. The computer processes this considerable amount of information on the principles of electronic digital computers. [20] The processing does not follow human visual perception so it is not an analogue computer to be preconditioned, from the memory of which information can be called associatively. The computer functions upon the