1、BRITISH STANDARD BS ISO 5799:1991 Implementation of ISO5799:1991 Photography Direct-exposing medical and dental radiographic film/process systems Determination of ISOspeed and ISOaverage gradientBSISO5799:1991 This BritishStandard, having been prepared under the directionof the Consumer Products and
2、 Services Sector Board, was published under theauthority of the StandardsBoard and comesintoeffect on 15March1995 BSI02-2000 The following BSI references relate to the work on this standard: Committee reference CPM/10 Draft for comment89/43579DC ISBN 0 580 23907 1 Committees responsible for this Bri
3、tishStandard The preparation of this BritishStandard was entrusted by the Consumer Products and Services Sector Board to Technical Committee CPM/10, upon which the following bodies were represented: Association of Teachers of Printing and Allied Subjects British Association of Oral and Maxillo-Facia
4、l Surgeons British Dental Association British Kinematograph, Sound and Television Society British Photographic Association British Printing Industries Federation College of Radiographers Institute of Physics Institute of Practitioners in Advertising Lighting Industry Federation Ltd. Ministry of Defe
5、nce Oil and Colour Chemists Association PICON Periodical Publishers Association Ltd. Photogrammetric Society Pira International Royal Photographic Society University of Westminster Amendments issued since publication Amd. No. Date CommentsBSISO5799:1991 BSI 02-2000 i Contents Page Committees respons
6、ible Inside front cover National foreword ii Foreword iii Text of ISO 5799 1BSISO5799:1991 ii BSI 02-2000 National foreword This BritishStandard reproduces verbatim ISO5799:1991 and implements it as the UK national standard. It supersedes BS6358:1983 which is withdrawn. This BritishStandard is publi
7、shed under the direction of the Consumer Products and Services Sector Board whose Technical Committee CPM/10 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK inter
8、ests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI,389 Chiswick High Road, London W44AL. A British Standard does not purport to includ
9、e all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi
10、andii, theISO title page, pages ii to iv, pages1 to8 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.ISO5799:1991(E) ii BSI 02-2000 Contents Page Foreword iii Intro
11、duction 1 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Sampling and storage 1 5 Method of test 1 5.1 Principle 1 5.2 Safelights 2 5.3 Exposure 2 5.3.1 Film holders 2 5.3.2 Sampling conditions 2 5.3.3 Radiant energy quality 2 5.3.4 Scattered radiation 2 5.3.5 Modulation 2 5.4 Processing 2 5.4
12、.1 Conditioning of samples 2 5.4.2 Processing specifications 4 5.5 Densitometry 4 5.6 Evaluation 4 5.6.1 Sensitometric curve 4 5.6.2 Base plus fog density 4 6 Product classification 4 6.1 ISO speed determination 4 6.1.1 ISO speed of a product 5 6.1.2 Dental films 5 6.2 ISO average gradient determina
13、tion 5 6.2.1 ISO average gradient scale 5 6.2.2 ISO average gradient of a product 5 6.3 Accuracy 5 7 Product marking and labelling 5 7.1 ISO speed designation 5 7.2 ISO average gradient designation 5 7.3 General 6 Annex A (informative) Calibration parameters 7 Annex B (informative) Improvement of th
14、e reproducibility measurement of X-rays 7 Annex C (informative) Scattered radiation measurement 7 Annex D (informative) Units of measurement 7 Figure 1 Method for determining ISO speed and ISO average gradient 3 Table 1 ISO speed scale 4 Table 2 ISO speed scale 5 Table 3 ISO average gradient scale 5
15、ISO5799:1991(E) BSI 02-2000 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body inter
16、ested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
17、 Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. Inter
18、national Standard ISO5799 was prepared by Technical Committee ISO/TC42, Photography. This second edition cancels and replaces the first edition (ISO5799:1981), which has been technically revised. Annex A, Annex B, Annex C and Annex D of this International Standard are for information only.iv blankIS
19、O5799:1991(E) BSI 02-2000 1 Introduction This revision of ISO5799 has been primarily necessitated by the decision to adopt the recommendation of the International Commission of Radiation Units and Measurements to use the gray as a measure of X and * radiation in place of coulombs per kilogram of air
20、. This has required changing the speed constant. The International Standard now includes updated references, and speed and average gradient tables compatible with the format of other radiographic film standards. 1 Scope This International Standard specifies methods for determining the ISO speed and
21、ISO average gradient of the film/process combinations used in medical and dental radiography other than mammography. Sensitometric procedures are described for films exposed directly to X-rays. Thepurpose of this International Standard is to provide a method for the measurement of ISO speed and ISO
22、average gradient so that the characteristics of the film/process system can be obtained reproducibly and can also be compared with those of other systems. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this Internatio
23、nal Standard. At the time of publication, the editions indicated were valid. Allstandards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Membe
24、rs of IEC and ISO maintain registers of currently valid International Standards. ISO5-1:1984, PhotographyDensity measurementsPart1: Terms, symbols and notations. ISO5-2:1985, PhotographyDensity measurementsPart2: Geometric conditions for transmission density. ISO5-3:1984, PhotographyDensity measurem
25、entsPart3: Spectral conditions. ISO4037:1979, X and gamma reference radiations for calibrating dosemeters and dose ratemeters and for determining their response as a function of photon energy. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 air ker
26、ma, K the energy, which is transferred by ionizing radiation (for instance X-rays) to air molecules, divided by the mass of air in that volume where the energy is released 3.2 speed a quantitative measure of the response of the photographic material to radiant energy for the specified conditions of
27、exposure, processing, and image density measurement 3.3 average gradient the slope of the straight line joining two specified points on a sensitometric curve 3.4 gray, Gy 1) the absorbed dose of X and/or * radiation in1kg of air which produces charged particles and imparts1J of initial kinetic energ
28、y to those charged particles 4 Sampling and storage In determining the ISO speed and ISO average gradient of a product, it is important that the samples evaluated yield the average results obtained by users. This will require evaluating several different batches periodically under conditions specifi
29、ed in this International Standard. Prior to evaluation, the samples shall be stored according to the manufacturers recommendations for a length of time to simulate the average age at which the product is normally used. Several independent evaluations shall be made to ensure the proper calibration of
30、 equipment and processes. The basic objective in selecting and storing samples as described above is to ensure the film characteristics are representative of those obtained by a consumer at the time of use. 5 Method of test 5.1 Principle Samples are exposed and processed as specified below. Measurem
31、ents are obtained from the resultant images to produce a sensitometric curve from which values are taken and used to determine ISO speed and ISO average gradient. 1) 1Gy=1J/kg of air is equivalent to114,5R or is equivalent to0,0295 C/kgISO5799:1991(E) 2 BSI 02-2000 5.2 Safelights To eliminate the po
32、ssibility of safelight illumination affecting the sensitometric results, all films shall be handled in complete darkness during exposing and processing. 5.3 Exposure 5.3.1 Film holders Films shall be exposed in holders which provide less than2% absorption of the radiation specified (without lead scr
33、eens). Dental films shall be exposed in the original packet or a wrapping of equivalent absorption. 5.3.2 Sampling conditions The sample shall be at a temperature of23 C 5 C and be equilibrated with air at a relative humidity of (50 20)% during exposure. If the film packet contains two films, the fi
34、lm towards the side with the radiation source shall be used. If the packet contains lead backing, the backing shall be away from the radiation source. 5.3.3 Radiant energy quality The tungsten target X-ray tube shall fulfil all reproduction conditions for radiation as specified in ISO4037. Inherent
35、filtration of the tube plus an additional aluminium 2)filter located as close to the target as possible shall provide a total filtration equivalent to7,0mm 0,5mm of aluminium. The kilovoltage 3)of the X-ray tube shall be adjusted until the half value in aluminium is3,0mm 0,2mm, i.e.the exposure rate
36、 of the X-ray beam with a total filtration equivalent to10,0mm aluminium shall be one-half the value obtained with the total filtration equivalent to7,0mm of aluminium. The3,0mm aluminium half-value layer absorber shall be placed at a maximum from the target of one-half the distance between the X-ra
37、y target and the ion chamber. 5.3.4 Scattered radiation To minimize scattered radiation when exposing test films, X-ray beams shall be collimated to as small a size as will permit a uniform exposure field for the films (and the measuring device, if included). The amount of scattered radiation reachi
38、ng the film and measuring device shall be no greater than5% of the primary radiation. Constructing the supports for the film, filters, and ion chamber from low atomic number materials and making such structures as light in mass as possible will minimize scattered radiation (seeAnnex C). 5.3.5 Modula
39、tion The film shall be given a graduated series of exposures such as will result in a series of densities above base plus fog from0,2 to2,3. The exposure over the useful area of each exposure step shall be uniform to within3%. The log 10of the exposure increments shall not exceed0,15. Each exposure
40、shall be measured, in grays, by using an ionization chamber calibrated for the radiant energy quality and intensity used for exposing the film 4) . Aseparate sample of the film shall be left unexposed for measuring inherent base plus fog density. 5.4 Processing 5.4.1 Conditioning of samples In the t
41、ime interval between exposure and processing, the samples shall be kept at23 C 5 C and be equilibrated with air at a relative humidity of(50 20)%. The processing shall be started between30min and8h after exposure. 2) Any grade in Table 1 of ISO209-1:1989, Wrought aluminium and aluminium alloysChemic
42、al composition and forms of productsPart1: Chemical composition, may be used (the ISO symbols are Al99,0Al99,5Al99,7Al99,8). 3) In constant potential equipment, a value between50kV and55kV is required. In equipment without electrical smoothing, approximately60kV is satisfactory. 4) If the instrument
43、 can be calibrated only at certain half-value layers close to but not identical with those specified in5.3.3, then interpolation at the specified half-value layer from a plot of the calibrations over a bracketing range of half-value layers is permissible. Annex A lists suitable radiant energy.ISO579
44、9:1991(E) BSI 02-2000 3 Figure 1 Method for determining ISO speed and ISO average gradientISO5799:1991(E) 4 BSI 02-2000 5.4.2 Processing specifications No processing specifications are described in this International Standard in recognition of the wide range of chemicals and equipment used. ISO spee
45、d and ISO average gradient data provided by the film manufacturers generally apply to the film when it is processed in accordance with their recommendations to produce the photographic characteristics specified for the process. Process information shall be available from the film manufacturers or ot
46、hers who quote ISO speed and ISO average gradient. This shall specify the chemicals, times, temperatures, agitation, equipment, and procedure used for each of the processing steps, and any additional information required to obtain the sensitometric results described. The values for speed and average
47、 gradient obtained using various processing procedures may differ significantly. Although different speeds and average gradients for a particular film may be achieved by varying the process, the user should be aware that other sensitometric and physical changes may also accompany the speed and avera
48、ge gradient changes. 5.5 Densitometry ISO standard visual diffuse transmission density of the processed images shall be measured using a densitometer complying with the geometric requirements specified in ISO5-2 and spectral requirements specified in ISO5-3. A minimum aperture of7mm 2shall be used.
49、Reading shall be at least1mm from the edge of the exposure. 5.6 Evaluation 5.6.1 Sensitometric curve The ISO standard visual diffuse transmission density values shall be plotted against the logarithm to the base10of the corresponding air kerma, expressed in grays, to obtain a sensitometric curve similar to that shown in Figure 1. 5.6.2 Base plus fog density The combination of base plus fog density shall be determined from an unexposed sample of the same film processed simultaneously with the sample exposed for determining the sens
