clinical records and electronic data processing

Clin. RadioL (1972) 23, 117-126

C L I N I C A L R E C O R D S A N D E L E C T R O N I C D A T A P R O C E S S I N G *

D E R E K N. EDWARDS

Regional Radiotherapy Centre, Clatterbridge Hospital, Bebington, Cheshire. L 63 4 J Y

Electronic data processing (E.D.P.) can facilitate the analysis of the clinical records of patients treated by radiotherapy. The structure of these records has been examined and related to the alternative methods of filing the data within the E.D.P. system. A description is given of the steps that were taken to create a system serving both a Regional Tumour Registry and a Regional Radiotherapy Centre. The accuracy of the data commonly recorded is discussed.

The Need.--When considering the application of electronic data processing (E.D.P.) to the clinical record it is best to begin at the end. (Edwards 1970). A long, hard look is required at the proposed output of the system. What will be done that has not been achieved before? Could it be done by methods other than E.D.P.? Is staff shortage the reason for using E.D.P.? Will the proposed system give answers to questions that could not be answered before ?

Setting up an E.D.P. system for clinical records is a long, hard slog not to be undertaken lightly. I t must be emphasized that any clinician about to be involved must be quite clear about his need for the system and the results it will achieve.

I t is possible that the Radiotherapist will find himself the initiator of such a system in his hospital. In this situation, it would be as well to bear in mind that clinical records for medicine, surgery and the specialties share a common structure upon which can be grafted the additional information required by the specialist interest. Thus, he would design the clinical record to suit himself and human nature being what it is, through sheer laziness, his clinical colleagues in medicine, surgery and the other specialties may accept his design.

On the other hand, a Radiotherapy record can be grafted onto a general clinical record, the contents of which have already been decided and which is already processed by an E.D.P system.

In Medicine generally, there has been an "information explosion" The record contains not only more information about the patient's habits and work but also the results of a detailed physical examination and extensive investigations This biological information has increased because many more facets are investigated and also because any

* Based on a paper read at a Symposium on 'Computers in Radiotherapeutics', held at the Royal College of Physicians and Surgeons, Glasgow, on llth September, 1970.

change in the facets with time has also been ir, vesti- gated. A change in one factor may be obvious to all; a link between 2 or 3 factors may be realised by some, but interaction between more than 3 factors, possibly linked also with the time that has elapsed between observations will be missed.

The realisation that such a situation exists will lead logically to the use of E.D.P. in clinical records. It, is, of course, true that in the past there have been mechanical methods of recording information such as punched cards, but such methods impose severe constraints on the user in the quantity of information that can be recorded before the system becomes impracticable. I t is a happy chance that the increased interest in reviewing the information in case notes has coincided with a means by which it can be done.

A system can be used to store every word that is written and every report that is made - - if this is considered necessary and if it can be paid for. Such a method of using E.D P. may be attractive to some, but it will prove difficult to use, if the need has been for a system to facilitate analysis of the accumulated data. I f this is the need (and for Radiotherapy it is), then the alternative system would be better. For this alternative system, some editing of the data in the notes is carried out and this abstracted record is then entered into the files of the E.D.P. system.

In addition to the interest of the clinician in the patients he has treated, there is the interest of the Regional Hospital Board, the Department of Health and the General Register Office. They require data for management and planning of the Health Services.

Recently some Radiotherapists in this country realised that there was a need to assess whether electronic data processing of the case notes of Radiotherapy patients offered advantages to the clinician. In this country, the two institutions

117

118 CLINICAL

concerned with Radiotherapy are the Faculty of Radiologists and the British Institute of Radiology. In 1967, the Joint Working Party on Computers in Radiotherapy was formed at the request of each Council. It has made two reports (Faculty of Radiologists, 1969) and a final report will be made in 1971.

The Aim.--The reasons that will be given by an individual for setting up a system will depend on his interests. The clinician will wish to know whether one method of treatment is better than another, assessed by the survival or morbidity; the admini- strator will analyse different classes of patients and the length of stay; the radiobiologist will inspect the total dose, treatment volume and recurrence-free time; the epidemiologist will be interested in anatomical site, occupation and place of residence; the Registrar-General in the sex distribution and the changing rates of incidence of all patients whether treated or not. It should be realised that to justify the work and the cost involved in setting up such a system, there must be the assumption that it will have a life of at least five years, and that the through- put of records will be many thousands per annum rather than a few hundred.

The aim should be to facilitate the analysis of clinical data and the system will be designed for this purpose. However, the analysis may not be the paramount aim' Rapid transfer of information from one place to another may be considered of greater importance. In this type of system, the aim is to provide to any of several locations all the information available about a patient so that decisions on clinical management can be facilitated.

A clinical record would be identified by the personal details of the patient. This would then be followed by the history and examination. Each medical student has learnt the logical structure of a clinical record, and to facilitate handling of the file, the system should continue to use this sequence. However, this should not be regarded as a con- straint imposed by the system, but a clinical custom useful to the system. There is value in the term "clinical notes" rather than "clinical records", for use of a note-form rather than a lengthy sentence as a record should be encouraged. Medical termi- nology will be used, and E.D.P. systems have focused attention on the rather lax use clinicians make of medical words. Manuscript clinical records have the disadvantage that the writing often cannot be read if it can be deciphered, the choice of medical words to describe the same observation can vary widely.

I f the aim is to introduce a system that will file an exact copy of clinical notes as they are now written,

R A D I O L O G Y

then it follows that although analysis will be possible, it will be costly, The alternative method aims at filing an abstract which, by introducing a few constraints, will make subsequent analysis and assessment possible with simple techniques.

This process of abstraction can be performed in two ways. Either an agreed selection of details can by abstracted from each free-flowing clinical record of the clinician can record his observations according to a predetermined list using an agreed vocabulary.

Whether this format is remembered or whether printed stationery is used depends on local circumstances. The advantage of the printed list as a reminder of the possible clinical observations has been reeognised by many radiotherapists. It serves also as an insurance that observations are, indeed, recorded.

Whatever the method, the aim is to make available the clinical notes of a patient in a form which can assist in the management of that patient at that time, or in the future; to allow the notes of many patients to be analysed at the same time so that common features can be found; to enable unusual features to stand out from the common ones and thereby serve as a guide to the better management of future patients.

The Method.--The heart of the system will be a digital computer and the peripheral equipent. This is known as the "hard ware" and it will be housed in the data processing centre.

Several devices are used to convert the data so that it can be processed by the computer.

The simplest device is the key punch - a "typewriter" keyboard producing perforations on paper tape or punch cards. The combination of holes across the width of the tape or card is a code the computer program recognises as letters, digits or symbols. The more sophisticated tele-typewriter or flexowriter produces not only tape or cards, but also a typed record on paper. Another device, the lector, can automatically sense marks on documents made in predetermined positions. The presence of a mark indicates information in the same way as a hole on a punch card.

Of much greater potential as a method by which data can be entered directly from documents is the optical character reader. This will interpret printed characters if they belong to a special font. A document typed using this font can be passed through the optical character reader and each character is recognised and interpreted for entry into the data processing system.

The advantages of this method of data preparation is threefold:

I. It is quicker.

C L I N I C A L R E C O R D S A N D E L E C T R O N I C D A T A P R O C E S S I N G

2. The primary document can be used to create the input tape automatically, dispensing with with a human punch operator and the associated errors.

3. Preparation of a secondary document, if required, can be done automatically by the system.

These methods of input are relatively inexpensive when used to their maximum capability. There are others that are more expensive. In some institutions there may be advantages gained by putting in the data on-line using a visual display unit (V.D.U.). This is a device using a special cathode ray tube placed above the teletypewriter and both are con- nected directly to the E.D.P. system. The computer is programmed to display on the screen a facsimile of the clinical documentation. Instead of writing the observations on paper they are typed into the computer-file case notes using the teletypewriter. (Fig. 1).

A modification of this system will present on the screen an agreed list of possible observations. The one to be entered into the file is identified, either by using the typewriter or by using the light pen or touch wire. Step by step, using a branching structured program, the results of history taking, examination, investigations and the details of treatment can be filed. The format and lists of terms can be as simple or as complex, as rigid or as free as required. However, greater freedom means greater cost in terms of money and time.

An alternative method is marketed as the "Medela" system (Brolin, 1969). In this system, the lists of alternatives presented to the clinician are not held electronically, but are projected optically from thirty-five ram. frames. This method has the advantage that complicated diagrams or photo- graphs can be reproduced for study by the clinician as an aid to selection of the correct item to be entered.

The use of a film medium must reduce the cost, but probably it will make the system less flexible than an electronic one. In the "Medela" system, the terms are identified by code numbers, and the record is built up by sequentially listing them.

Data within the computer is of no use to anyone unless it can be out-put. The method of presenta- tion of retrieved data will depend on the proposed use. For instance, the V.D.U. will be useful as the out-put terminal when the need is for a reminder during a follow-up clinic. Alternatively, a per- manent record of the data as filed will come from the teletypewriter, the line printer or the electro- static printer for using during the patient's stay in hospital.

119

(Photo courtesy LC.L.) FIG. ]

Visual Display Uni t

Thus, depending on the clinical interest, the print-out could be a complete set of" clinical notes for one patient as held in the file; a date-ordered list of white celt counts of one patient for the past two years; the dose-time-volume data for the 30 patients most recently treated for carcinoma of the antrum by megavoltage; or a survival table using actuarial analysis of all patients treated for a squamous carcinoma of the edge of the mid-third of the tongue, accompanied by a graphical representation of these results.

The System.---This term denotes all the equipment, forms and methodology used to create the clinical record within the computer. (Fig. 2).

The application of a system to the concept of a multi-hospital network inputting to a central bureau, or the internal communications of a big big hospital will not be considered here because few radiotherapists will be concerned withit during the next decade. There is no doubt, however, that many radiotherapists can create now a system for their own department that will be of value to them.

There are two main ways by which a system can be created. It can be (a) an added-on system, or (b) an integrated system.

In the added-on system, the method for handling and using the clinical record remains unchanged. In addition, all or some selected data are abstracted to form the computer file. A simple system would require that all clinical notes after completion of the first treatment are passed to an individual respon- sible for abstracting the required data. This is filed within the computer, either as words or as code numbers. The clinical notes are returned and batches of the abstracted records are sent to the computer centre for processing.

For the integrated system, the format of the clinical record will be designed to facilitate input

120 C L I N I C A L R A D I O L O G Y

SCHEMATIC SYSTEM CHART

"" [L.s','so~TE;" l "'''''''''.~?RR;ER~ [ ) [ INPUT . . - 1

(

FI~. 2

The sequence of actions for recording and retrieving data in a radiotherapy centre.

of data. In this country, an attempt at a uniform clinical record format has been made already with the H M R series, and an integrated system could be based on this format. In the majority of Radio- therapy Centres in this country, the clinical record in its final form is typed. This typed record would be divided into four basic sections; one each for administrative and personal data, diagnosis, treatment and follow-up. Each sheet would have a duplicate underneath of the "no-carbon-required" type. The copy would be passed to the Data Process- ing Centre. There would be an advantage in a layout which gave a list of selected terms one of which would be indicated. Alternatively, the term would be typed and this would be entered into the data file as it stood, or it would be coded to a number.

The details of the system would depend very much on the local circumstances, but the steps are clear. These are :-

1. Enter data into clinical record. 2. Cieate abstract record. 3. Code abstract record. 4. Input coded data. Step 3 can be eliminated by dictionaries held

within the system so that coding can be done internally. The advantage of a code is that it will take up less space in the file and can be manipulated more easily. To a certain extent, step 2 can be

eliminated or made only a small procedure by design of the clinical record format. In this way a system can be created, which will accept a structured clinical record upon a sheet of paper, written with an office typewriter using a character font acceptable to an optical character reader (Bruce et al., 1970). I f the facilities for rapid read back are available and circumstances justify the use of them, the original "hard" copy can be destroyed. There will be no need to file away clinical note folders or pull them out for clinics. This is the system which clinicians will desire and it is possible technically at the moment.

At regular intervals, routine analysis can be performed on the files held, such as tabulations of new patients seen or the survival and morbidity of different groups of patients. Special surveys will be produced by selection of a program from a library of output routines. For the regular follow-up clinics the E.D.P. file will produce lists of patients due to attend and an appointment reminder can be printed and posted. Any worthwhile system will also indicate any record that has not been updated for more than, say, three months, thus ensuring that patients are not lost sight of. The Clinical Record.

This has four sections :- 1. Identification and personal record.

C L I N I C A L R E C O R D S A N D E L E C T R O N I C D A T A P R O C E S S I N G 121

2. Diagnostic record. 3. Treatment record. 4. Follow up record.

This is the logical order that reflects the time sequence of events. Each section of the record is completed usually before events in the next part occur. Assuming that the ultimate objective for every Radiotherapy Department is the creation of an integrated system, each section will be dealt with in turn.

1. IDENTIFICATION.--To make sure that the clinical record is uniquely linked to an individual special attention is required in recording personal "labels". The "populat ion" attending a Radio- therapy Department is selected, therefore the problem is not as difficult as with a general record linkage scheme. However, some linkage will have to be made, for example with the G.R.O. cancer registration cards. The name and forenames are the main identifiers, but these may be transposed by mistake when the surname is one that can also be a forename, e.g., John JAMES.

To help identification all institutions use a reference number. Each patient will have a depart- mental number or hospital number, or possibly both. The National Health number could be used, but very few patients know it. The date of birth could be used also, but it is not infallible, as the elderly frequently get the year wrong.

These are "hard" facts. The name, forename, date of birth and department or hospital number are constant enough to be used, usually together, to identify uniquely a clinical record. Other identifiers can be used, but are liable to change with time - - the home address, the occupation and the diagnosis. Within this section the record can usefully contain other information, such as next of kin, and some of the requirements for cancer registration, such as place of birth and industry.

2. DIAGNOSIS.--this will be considered by most to have two parts :-

(a) The anatomical site involved. (b) The histological feature present.

I t would be as well to indicate the degree of validity of the diagnosis. Has it been made on clinical grounds alone or has the site been identified at operation with a biopsy to give the histology? Some might also wish as further criteria to identify the clinician and histologist !

Detailed results of investigations that led to the diagnosis might also be recorded. These might be biochemical tests with their values, or the reports of special diagnostic x-ray techniques such as an I.V.P. A decision will be required whether the

full text will be entered or only a summary entered as a code.

3. TREATMENT.--This will be the most complex part of the record. For radiotherapists the main requirement will be a full record of the technical details. Information possibly under a general title of "Radio-biological Data" must also be considered. Treatment combinations, for example with hor- mones or chemotherapy, can be recorded in detail by any E.D.P. system. The depth of detail will be linked directly to cost per record held, and this should be considered in relation to the value of the details. For the first time, the mechanics of a system will not limit the amount of data recorded, but this cannot justify the entry of multiple fields into the record in the hope that subsequent analysis may show something of interest. It is necessary to record and analyse the data which can be measured accurately and draw conclusions f rom this before exploring the fields where an observation is, at the moment, more qualitative than quantitative. In addition to Radiotherapy, the other forms of treatment such as surgery, medicine and chemotherapy, will be recorded.

Most of the abstracted clinical record so far considered will be entered as a summary of the event. A decision will have to be made locally about the depth of detail that is to be entered into the E.D.P. file. Are blood counts relevant? Can the effectiveness of radiotherapy to a painful secondary be measured by recording the daily amount of analgesics ?

4. FoLLow-up.--The information recorded here would be the date and an assessment of the state of the disease. The interval between records will usually be regular, but there is no reason for this. It has been a custom in the past to facilitate analysis and because the date of the record was not entered into the system, to make the report annually or for some other agreed interval. I f the date is included there is no reason why an assessment should not be entered each time the patient attends the clinic or is seen by the General Practitioner.

The information contained in the clinical record falls into several classes. If it is normally accepted and recognised as a number, no problems arise. I f it is normally a plain language term, there will be some advantage in converting this term to a number f rom a code, constructed in a logical fashion to cover a related group of terms. These classes are :-

1. The information is always one or more digits, e.g., the size of the tumour.

2. There is a limited number of variables, i.e., the dictionary or code will be small, as for example, marital state.


3. The variables are unlimited or very large, i.e., the dictionary or code will be large,for example anatomical site.

4. An extension of 3, i.e., the variables are not normally recognised as terms within a group, e.g., surname.

This classification is useful for constructing the input format of the system. Numbers represe'nting information are the simplest way in which data can be manoeuvred, both by the computer and the programmer. Therefore, they are preferred.

Information in class 1. is self-coding to digits. Information in class 2. can be self-coding if the

range of terms has been printed in the clinical notes so that the code number is identified by the clinician.

Class 3. will need to be coded. The inaccuracies that are associated inevitably

with the coding process when done by the human will not occur if either the system is designed to perform the coding step within the computer or else the plain language term is acceptable to the file.

The Liverpool System.--This system is designed for the Clinical and Pathological Registry, but radiotherapists will realise that, inevitably, it involves the clinical records of the Radiotherapy Centre. The Registry in Liverpool was started more than twenty-five years ago to record every new case of cancer in Merseyside, North Wales and the Isle of Man. It was established by the radiotherapists for the region, but soon recorded all new cancers, whatever the method of treatment, and also those which were not treated. The system was semi-mechanical based on 65 column punched cards. These have become obsolete together with the equipment processing them. In the last decade, new fields of clinical interest had arisen and the system could not expand to record this new interest.

These factors, together with the ~ delivery in 1967 of a computer for the Regional Board led to a decision to re-assess the organisation of the Registry and to base it in future on an E.D.P. system. It was decided to base, initially, any new processing system on a well-tried organisation that was already in existence; and that the data to be recorded would, for the present remain as an abstracted summary of items that were expected to be of some value on analysis, because the degree of validity for these items was known and acceptable.

Having decided the fields of data that would form the record on the E.D.P. system, the next planned stage was to design the clinical notes to ensure that the abstracted record is as complete as possible. This can be done for those patients who have received treatment in the Radiotherapy Centre,

but these patients total only one quarter of the new registrations each year. The format of the clinical notes has been planned for the possible extension of the system in which coding and abstraction will not be necessary. The final step, and this appears to be possible technically now, will allow a copy of the typed radiotherapy notes to be read by an O.C.R. in order to create the clinical file in the E.D.P. system.

The first step towards building a new system was to review the classes of information that had been routinely recorded in the Liverpool Registry over the past 25 years, in relation to the frequency of analysis and degree of validity. At the same time, the Joint Working Party was reviewing clinical records and recommended a Minimal List of Variates for the radiotherapy clinical notes. In Liverpool, it was decided to base the proposed system on the Minimal List, and to add Valiates which from previous experience were known to be useful. The record was designed to include not only the information that the General Register Office required for the cancer abstract card but also data that would make subsequent up-grading of the system as outlined earlier, quite painless. In other words, the eventual objective was to make it a total and integrated system.

Whilst the clinical decisions were being made about the content of the record, the O and M section of the Regional Board investigated the organisation of the Registry. The old system which had settled into a pattern over two decades was studied in detail and recommendations were made about modifications including the staff required, the grade and function of each of the staff and the cost. Happily, the conclusions were that staff could be reduced from 14 to 10.

At the same time, the Computer Centre staff were developing the method for dealing with the data when collected. This work included design of the abstract form which became a compromise between the requirements of punch operators and the logical sequence of clinical notes. None of this planning could take place in watertight compart- ments. The clinicians were required to specify where the record would contain plain language; the number of digits for a code number had to be decided; the frequency of complelion of data had to be assessed; a decision made about those fields which must always be completed. The abstract form was drawn and modified five times.

The most difficult part was the content and design of the form that recorded the details of Radio- therapy. Eventually, a solution was reached that appeared to be able to cope with all the combina-


r~ 8

o

o

.<

124 CLINICAL RADIOLOGY

tions that could occur. A pilot run was made, a few modifications introduced and then it was accepted. However, further experience in routine use has shown that it is not yet perfect and there will have to be slight modifications made after a few years of use (Fig. 3).

Whenever records are filed with the intent of subsequent analysis of accumulated material, it is of paramount importance to ensure that the trans- cription has been accurate. Checking by the clerks removes a few errors, but this is far from infallible. The E.D.P. system has a very great advantage in this respect. Fairly simple programs can be written to carry out these checks. They can be used endlessly without any diminished accuracy. Further, the check is consistently performed.

The checks are of 2 types :- (a) Those that reveal invalid data. (b) Those that reveal inconsistent data.

Type (a). The program would, for instance, reject a record if a letter had been entered where a digit should appear, or where a code number was given that was out of the range specified; or where a field in which all 3 parts must contain data in fact only has data for 2. Type (b). The record would be rejected if, for example, the date of birth entered was greater than the date of treatment; or the anatomical site recorded could not occur in the sex given; or the T.N.M. categories had been recorded for an anatomical site such as a middle ear growth for which U.I.C.C. has not yet defined the categories.

This check on inconsistencies can lead to 2 stages of rejection of a record. Absolute rejection is required when the detected error can never occur. Relative rejection - - usually the record is accepted but is reported upon - - is required when the data as recorded can occur but normally it is so rare that there is a large chance that an error has been made. As an example, a minimum tumour dose of 10,000 rads. would be reported.

These checks have proved to be very worth while. They led initially to some very upset staff in the Registry, but they have come to be regarded as a very necessary and efficient way of ensuring that the quality of the record within the computer is maintained. This is essential because analysis of incorrect data can lead to incorrect deductions that can be to the detriment of the patients of the future. Up to 100 checks are made on each record of which 30 are on the details of radiotherapy.

The clinical record contains not only data about the patient, but also details of the hospitals associated with the diagnosis and the initial treatment of the patient. This detail was included because

clinicians are becoming more aware of the need to sit back from time to time and assess how the treatment they favour measures up to the general level. Thus, on request, statistics relating to one clinician can be sent to him; these can be in the simplest form as a list of case notes or they can be a full analysis that has been carried out for him.

A further use of this feature will enable notification to be sent to the hospitals which have been involved with a patient when death occurs so that the clinical notes can be taken out of file.

The follow-up record will be entered at the anniversary of the first definitive treatment. It will record an assessment of the state of the disease and whether further treatment was necessary during the past year. Of equal importance is an assessment of the quality of life of the patient following upon treatment, and an indicator if there is a new primary tumour. The usual data about death are also included.

Some of the follow-up reports have been sent regularly to the Registry by the hospital concerned but usually the information has to be abstracted by a registry clerk f rom the case notes. The system proposed will print out for each hospital a list of the patients whose anniversary is due, giving the identification details with the diagnosis and date last seen. Thus the hospital Records Officer will be warned of those patients due for follow-up. Just before the appointment, the identification data will be printed onto preprinted continuous stationery. This will be the request for the anniversary report and will be filled in with the anniversary data by the clinician. These reports will then be passed back to the Registry in order to up-date the clinical record.

In order to identify uniquely each patient, a Registry number is allotted. This includes a "check digit" which is obtained by a simple calculation upon the Registry number. Only when the number and the "check digit" are correctly quoted can any information be added to a record. This is the prime way of ensuring that correct linkage occurs because the computer repeats the calculation upon every registry number quoted.

Some patients are aged or unwell. They remain under the care of their General Practitioners and may not attend any Clinic. Completion of the anniversary report then falls to the G.P. Typing the letter requesting the information becomes a burden on any Radiotherapy Records Office staff. It is believed that this problem has been solved with the use of specially printed continuous stationery for the E.D.P. system. The computer record already contains the personal details of the patient, his address and the diagnosis. It also has the prac-


titioner's name and address or that of the Consul- tant and hospital. The stationery is known under the brand-name of " D A T A M A I L E R " . Each unit of stationery consists of a top file copy of full print-out and an envelope addressed to the G.P. This contains a letter giving the name, address and diagnosis of the patient. The back of the letter is used for the report completed by the doctor which is returned in. the enclosed prepaid envelope. This type of continuous stationery is already on the market for other purposes. There is no doubt that it is the answer to the problem of lack of staff. The shortage of clerks will not improve over the coming years. Initial costings suggest the use of this method will produce savings, not only in the staff required, but also in money.

Present and Future.--There is no doubt that the E.D.P. system will make the handling and retrieval of information very easy, but to achieve this requires thousands of man-hours of work. The design of the system ensures rapid retrieval of information which can be related in a statistical way to any one of the other items of information. But what of the quality of the information that is being processed? Some comment is justified.

Some of the medical data is "hard", "valid", in a word factual. Dates are in this class and so are most measurements. At the other end of the scale are data which are "qualitive" or "intangible". Examples are "pain," "nausea," "vertigo". The means for measuring some of them can and have been evolved, but are not carried out often. Perhaps this is significant implying insufficient interest to record them accurately. Thus, errors due to inaccurate mensuration may be present. To these must be added errors due to the interpretation of the observer. These difficulties are recognised by all and they are mentioned again to remind the reader that each item of data within the record must be assessed with this in mind. How accurate is the data within the record? How many recognis- able divisions can be found in that condition? Are there only 3 divisions, each of which slides imper- ceptibly into the other as a continuous sliding scale or can a hundred sub-divisions be easily and accurately recognised ?

This "sliding scale" may be thought to be applicable only to "sensations" such as pain but perhaps it is also true for "diagnosis". The useful- ness of a nomenclature of sub-divisions is directly related to the clarity of definition of the sub- division and the ease with which all those concerned with using the nomenclature, code or phrase can recognise the margin between one sub-division and another sub-division (Fig. 4).

NO

OF

OPINION~

ALTERNATIVE DIAGNOSIS

FIG. 4

A crude graphical representation of how poor definition of 'boundaries' may be associated with

difficulty in the use of nomenclature.

Consider how this is applied to diagnosis, using the anatomical site. An example of one nomenclature is based upon the systems: the G.I., the Respiratory and the Uro-Genital tract, etc., with a further breakdown to individual organs and parts of the organ. It is the identification of the smaller parts of organs that may not be accurate. The advantage, however, of a branching structure in the nomenclature is obtained when doubt is cast on the accuracy of classifcation within the last sub-division. It is possible in that instance to use the division above for classification.

The same concept applies to histology, but in this field there is less agreement about the boundaries of the classification. Further, it must be recognised that an observer factor is present.

This subject has been introduced deliberately, for it is considered that insufficient attention has been given to it. Great efforts will be made to file away a mass of information about patients. Much of that information will belong to classes of data which, even with a benign outlook, must be considered suspect.

In other fields it is realised that there is a different type of error, i t has been pointed out that numerical data is factual but consider the radiation dose. The measurement of a single level of isodose in a water phantom has an error of plus or minus 2 ~ . After the fields are planned, a summated isodose may have an error of plus or minus 4 ~ . At the moment, only a few centres can make a correction for tissue inhomogeneity. In addition, there are the accepted tolerances associated with the output of the treatment machine. How close is the dose received by the patient to the nominal dose set on the console of the treatment machine? Could it be that the figures entered in the record as a "hard" fact in digits are somewhere in a range of, at the best 10 and at the worst, perhaps 20 ~ ?


I t is impor tan t to realise that much of the infor- mat ion that is recorded for analysis is, and probably always will be, an approximation. If this is remembered, clinicians will no t be "led up the garden path" by subsequent analysis of details which are no better than educated approximations. The collection of hundreds of thousands of observations in this category is a poor substitute for fewer but more accurate values. Al though those clinicians who are directly concerned will realise the second class value of such data, there is the danger that others will not, and will be led into spurious deductions.

In the future, the effort required to improve the quality of the data by a t tent ion to nomenclature, classification and mensura t ion will be worth while because E.D.P. has removed the chore of data retrieval.

Systems which will accept the plain language term rather than code numbers will be the logical development. For a few, such a system is available already. Time and money must be available to develop similar systems, particularly those using an optical character reader, for general use.

Finally, so that there can be no misunders tanding the sections of the system working now at Clatter- bridge are listed.

(1) The input and the checks on it for new registrations.

(2) Inpu t and the checks for follow-up of both pre- and post-1970 registrations.

(3) Successful t ranslat ion of the 160,000 old registrations to the new format.

In the pipeline for October, 1970, is a simple

analysis program and for December, the automatic follow-up system, with suites of analysis programs for early in 1971.

Aeknowledgements.--I must express my gratitude to the Staff of the Liverpool Regional Hospital Board's Computer Centre for the work done on the technical side of the system; to the secretarial staff of the Radiotherapy Centre for typing the manuals; to the staff of the Clinical Registry for accepting the change in their ways with grace - and to my colleagues for taking over some of my clinical work when I was buried under code-books and print out. One of the illustrations was supplied by I.C.L.

Addendum.--During the 3rd International Conference on Computers in Radiotherapy in Glasgow in September, 1970~ Dr. W. R. Bruce confirmed that, in the experience of the Ontario Cancer Institute, it was considered economical overall to use a plain language input from a typewriter using a font which is then read by an O.C.R. For several months the Institute has used this system routinely and without regrets.

REFERENCES BROLIN, I. M. (1969). Medela System of Transmitting

Consultation Reports. Proceedings of the XI1 International Congress of Radiology (Tokyo, 1969).

BRUCE, W. R., JENKIN, R. D. & GORDON, S. (1970). A physician-orientated medical index for hospital or clinic use. Canadian Medical Association Journal, 102, 1080- 1084.

EDWARDS, D. N. (1970). The Radiotherapeutic Record. Proceedings of the International Symposium on Computers in Radiology (Brussels, 1969). Pub. Karger of Bgde & New York.

FACULTY OF RADIOLOGISTS (1969). Computers in Radio- therapy. A report of the Joint Working Party of tbe Faculty of Radiologists and the British Institute of Radiology.

B O O K

A Radiographic Index. By MYER GOLDMAN and DAVID COPE. Published by John Wright & Sons Ltd., Bristol. Price £0.90.

This is the 4th edition of this small handbook, originally produced in 1960.

It is still proving to be an excellent pocket-book for both radiographers and radiography students. It contains a surprising amount of information, it is simple to use, each section being alphabetically arranged and it is a most useful size.

Appendix V on named skull views is a worthwhile addition and will be appreciated by many radiographers, but these eponyms are not often taught in schools of radiography.

Appendix III on common abbreviations is very useful since these seem to be used more and more on request cards and create an increasing practical problem in the Depart- ment.

R E V I E W

One criticism; it is stated that A.P. tomography is the only satisfactory method of radiography of the larynx, but surely the soft tissue lateral is important.

It is gratifying that the authors have noted our criticism in the review of the 3rd edition in 'Clinical Radiology' concerning the Appendix on Contrast Media. This has now been completely re-written: it is much more informative and up to date but two comments seem appropriate, 1. Biligrafin should not be recommended for direct (as opposed to Intravenous Cholangiography) and 2. Hypaque 65 per cent actually contains (surprisingly and paradoxically) 75 per cent W/V of salts not 65 per cent as might be expected and as is reported in this index.

This is a comprehensive and very informative book for its size, and can be strongly recommended to both students and trained radiographers.

J. OSBORNE R. G. GRAINGER

clinical records and electronic data processing

Documents