SIST ISO 9236-1:2011

INTERNATIONAL ISO
STANDARD 9236-1
Second edition
2004-02-01
Photography — Sensitometry of
screen/film systems for medical
radiography —
Part 1:
Determination of sensitometric curve
shape, speed and average gradient
Photographie — Sensitométrie des ensembles film/écran pour la
radiographie médicale —
Partie 1: Détermination de la forme de la courbe sensitométrique, de la
sensibilité et du contraste moyen

Reference number
©
ISO 2004
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2004
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 1
4 General requirements. 2
4.1 Storage and handling conditions. 2
4.2 Safelights . 2
4.3 X-ray equipment . 3
4.4 Air kerma meter. 3
4.5 Processing. 3
4.6 Densitometry . 4
5 Determination of sensitometric curve shape. 4
5.1 General. 4
5.2 Beam qualities. 5
5.3 Geometry for curve shape determination. 5
5.4 Exposure. 8
5.5 Evaluation . 8
6 Determination of average gradient. 8
7 Determination of speed . 10
7.1 Definition. 10
7.2 Beam qualities. 10
7.3 Geometry . 13
7.4 Exposure. 13
7.5 Evaluation . 13
8 Speed and average gradient determination without sensitometric curve. 16
9 Uncertainty . 16
10 Test report . 17
Annex A (informative) Rationale .18
Bibliography . 20

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 interested 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 Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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 least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9236-1 was prepared by Technical Committee ISO/TC 42, Photography.
This second edition cancels and replaces the first edition (ISO 9236-1:1996), which has been technically
revised to incorporate the following technical and major editorial changes:
 a spherical ionization chamber, or an equivalent detector, is required for dosimetry;
 only high frequency or 12-pulse high-voltage generators are allowed, 6-pulse high-voltage generators are
excluded;
 the allowed uncertainty for the density measurement has been increased in order to comply with the other
parts of the ISO 9236 series;
 the exposure times for the determination of speed and sensitometric curve shape have been reduced to
match the current state of the art;
 the phantom of Technique IV has been changed (leaving the beam quality unchanged) in order to reduce
the air kerma rate;
 the distances between the focal spot of the x-ray tube and the screen-film combination when determining
speed and average gradient may now be in the range from 1,5 m to 4,0 m;
 the use of a monitoring detector is no longer mandatory, because the precision of modern x-ray tubes and
high-voltage generators is often superior to that of monitoring detectors;
 the total uncertainty which can be reached has been changed;
 an informative annex has been added in order to describe the background of speed and curve shape
measurements, the choice of phantoms, and the energy dependence of speed values.
ISO 9236 consists of the following parts, under the general title Photography — Sensitometry of screen/film
systems for medical radiography:
 Part 1: Determination of sensitometric curve shape, speed and average gradient
 Part 3: Determination of sensitometric curve shape, speed and average gradient for mammography
The following part is under preparation:
 Part 2: Method for determining modulation transfer function (MTF)
iv © ISO 2004 – All rights reserved

Introduction
This part of ISO 9236 provides methods for determining the sensitometric curve shape, the average gradient
and the speed of radiographic screen/film/filmholder/processing systems used in medical radiography, except
in mammography and dental radiography.
The sensitometric curve shape, which is also needed for the determination of other properties (as, for
example, the modulation transfer function), is measured under low scatter conditions via intensity scale X-ray
sensitometry, preferably using an inverse square sensitometer. For the determination of the sensitometric
curve shape, as well as for a subsequent determination of the average gradient from the measured curve, but
not for speed, the irradiation of the screen/film/filmholder combination need to be measured only in relative
units.
Speed is measured in a separate way, under exposure conditions which simulate medical practice more
closely, including realistic fractions of scattered radiation. Different types of medical exposures are simulated
by using appropriate phantoms and X-ray tube voltages, and the screen/film/filmholder combination is
exposed behind the respective phantom. The irradiation is measured in absolute units of air kerma (gray, Gy)
in order to determine the speed.
Four different techniques are defined, differing in beam quality and fraction of scattered radiation, simulating
the imaging of extremities, skull, lumbar spine and colon, and chest. Speed may be measured for each
technique of interest. Owing to its dependence on X-ray energy and scatter, screen/film system speed varies
widely in medical practice. The four measurement conditions described in this part of ISO 9236 provide values
that are representative of those found under practical conditions.
INTERNATIONAL STANDARD ISO 9236-1:2004(E)

Photography — Sensitometry of screen/film systems for
medical radiography —
Part 1:
Determination of sensitometric curve shape, speed and average
gradient
1 Scope
This part of ISO 9236 specifies methods for the determination of the sensitometric curve shape, average
gradient and speed of a single sample of a screen/film/filmholder/processing system for medical radiography.
It is not applicable to special radiographic applications such as mammography, dental radiography and direct-
[3]
exposing medical radiographic systems (see for example ISO 5799 ).
The filmholder can be any means that ensures close screen/film contact and prevents the film from being
exposed to ambient light. In particular, the filmholder can be a light-tight vacuum bag, as often used in the
laboratory, or a radiographic cassette as used in medical radiography.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 5-2:2001, Photography — Density measurements — Part 2: Geometric conditions for transmission
density
ISO 5-3:1995, Photography — Density measurements — Part 3: Spectral conditions
ISO 554:1976, Standard atmospheres for conditioning and/or testing — Specifications
IEC 60522:1999, Determination of the permanent filtration of X-ray tube assemblies
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
screen/film system
radiographic imaging system consisting of screen(s), film, filmholder and film processing
NOTE Hereafter, screen/film/filmholder combinations will be referred to as “combinations” and will be referred to as
“systems” when the processing is included.
3.2
air kerma
K
sum of the initial kinetic energies of all charged particles (e.g., electrons) liberated by uncharged particles
(e.g., X-ray photons) from air molecules, divided by the mass of air in that volume where the charged particles
are liberated
NOTE The unit is the gray (Gy).
3.3
sensitometric curve
plot of the density of a processed photographic film as a function of the logarithm to the base 10 of the
exposure
3.4
speed
S
quantitative measure of the response of the screen/film system to radiant energy for the specified conditions
of exposure, processing and density measurement
3.5
average gradient
G
slope of the straight line joining two specified points on a sensitometric curve
3.6
net density
D
density of an exposed and processed film minus the density of an unexposed and processed sample of that
film
3.7
coverage factor
k
numerical factor, used as a multiplier of the combined standar
...