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OPEAN GlON QUALITY CRITERIAFOR DIAGNOSTICRADIOGRAPHIC IMAGESIN PAEDIATRICS

EUR 16261 EN


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EU R O PEAN C O MMI SSI O NDirectorate-General XI I : Science, Research and De velop me nt

A great deal of additional information on the European Union is available on the Internet. It can be accessed through theEuropa server (ht tp: / /europ a.eu. in t ) .Cataloguing data can be found at the end of this publicationLuxembourg: Office for Official Publications of the European Communities, 1996ISBN 92-827-7843-6 ECSC-EC-EAEC, Brussels Luxembourg, 1996Reproduction is authorized, except for commercial purposes, provided the source is acknowledgedPrinted in Luxembourg


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These guidelines result from a European wide cooperation

The present report has been edited by the restricted Study

M.M. Kohn(D)B.M. Moores (UK)H. Schibilla (CEC)K. Schneider (D)H.St. Stender (D)F.E. Stieve (D)D. Teunen (CEC). Wall (UK)


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CONTENTS

PAGE

Preamble VII

C H A P T E R ' Qua lity Criteria for Diagno stic Radiographic Images inPaediatrics 1

C H A P T E R 2 Sum mary of the Evaluation of the European Trialsof Quality Criteria for Diagnostic Radiographic Imagesin Paediatrics 35

C H A P T E R 3 Quality Criteria Imp lem enta t ion and A ud it Guidelines 45

C H A P T E R 4 List of all those w ho contribute d to the Establishment,Testing and Evaluation of the Quality Criteria of this Report 57


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g


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OR DIAGNOSTIC RA DIOGRAPHIC IMAGES

med

2 and by participating in research for the imple

3 it was recognised that radi

k of late ma nifestation s of det rime ntal radiation effects is greater inesti for certain detrimental effects, to have an attributable l ifetime riskyears, and five to seven times greater w hen compared to exposures

4

Council Directive 84/466 EURATOM, Official Journal L 265/1,5.10.1994.Council Directive 93/42 EEC, Official Journal L 169/1, 12.7.1993.Report EUR 16260, 1996.UNSCEAR Report Sources, Effects and Risks of Ionizing Ra dia tion ,p. 433, 1988.

VII


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The Quality Criteria for paediatric radiology have been elaborated in a common effort bya European Group of paediatric radiologists, (the Lake Starnberg Group), together withradiographers, physicists, radiation protection experts, health authorities and professional national and international organisations.

The aim of the Quality Criteria is to characterize a level of acceptability of normal basicradiographs which could address any clinical indication. They have first been set up forconventional radiography, concentrating on examinations of high frequency or with relatively high doses to the patient.The follow ing freque nt paediatric radiographic examinations were selected as a first step:chest, skull, pelvis, full and segmental spine, abdomen and urinary tract. The age groupsand X-ray examinations using fixed X-ray installations were l imited to 10 month oldinfants for chest AP/, skull AP/, spine, lateral view, abdomen, AP supine position; and4 m ont h o ld babies for pelvis AP. The corresponding criteria fo r mobile X-ray equipm entwere for 10 month old infants, and premature babies with weight approximately 1 kgunderg oing a chest AP examination in supine pos ition. In a second and third step the agegroups of 5 and 10 year old children were added.The applicability of the Quality Criteria has been checked in European wide Trials involving about 160 paediatric X-ray departments in 14 Member States and other Europeancountries, and roughly 1600 radiographic fi lms and dose measurements.The results have been discussed at Workshops, by working parties and dedicated studygroups , as we ll as by indepe nden t experts all over the wo rld . The conclusions have beenintegrated in the present Guidelines and provided elements for the improvement of thelists of Quality Criteria.The European Guidelines on Quality Criteria for Diagnostic Radiographic Imagesin Paediatrics contain four chapters:The first chapter concerns the updated lists of the Quality Criteria for conventional paediatric examinations of chest, skull, pelvis, full and segmental spine, abdomen and urinarytract for different projections and, where necessary, specific criteria for newborns. Thisfirst chapter defines Diagnostic Requirements for a normal, basic radiograph, specifyinganatomical Image Criteria; indicates Criteria for the Radiation Dose to the Patient, as faras available, and gives an Example for Good Radiographic Technique by which theDiagnostic Requirements and the dose criteria can be achieved.The second chapter summarises the analysis of the findings of the European wide Trialsand explains the updating of the Quality Criteria as listed in Chapter 1.The third chapter outl ines a procedure for implementing and auditing the Quality Criteria;a model of t he scoring tables, and adapted questionnaires that have been developed during the evaluation of the Trials, are reproduced and can become tools for self-learning andperformance checking.

VIII


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radi

these Europe an Guidelines on Quality Criteria for D iagnostic Radiographic Images

-

Dr J. SinnaeveDirectorate GeneralScience, Research andDevelopment- Radiation Protection Research

IX


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TABLE OF CONTENTSIntroduction 3Objectives 4Gen eral Principles Associated w it h Goo d Ima ging Perform ance 6Guidance on Imp lem enta tion 13Description of Terms 14List of Referen ces 15List of Q uality Criteria for Diagnostic R adiographic Imagesin Paediatrics

C H E S T /AP Projec tion 18Lateral Projec tion 19AP Projection (Newbo rns) 20

S K U L L /AP Projec tion 21Lateral Projec tion 22

PELVIS AP Projection (Infants) 23AP Projection (Older Children) 24

FULL SPINE PA/AP Projec tion 25 PA/AP Projec tion 26

Lateral Projec tion 27A B D O M E N AP/PA Projection w it h Vertical Beam 28

U R I N A R Y T R A C T AP/PA Projection(W ithou t or before adm inistrat ion of contrast medium) 29AP/ Projection (After adm inistration of contrast med ium) 30Mic turat ing Cystourethrography (MCU) 31A P P E N D I X I Guidelines on Radiation Dose to the Patient 32


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~^N


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no diagnostic exposureis justifiable without a valid clinical indication, no mat ben

5

reli i.e. its results are reproducible and have sufficient sensitivity, specificity, accuracy, and tech

who must be suitably trained and experienced.

ect of diagnostic examinations ICRP does not recomm end th e ap plication of dose lim

both. The examinations are: chest, pelvis, full and segmental spine, abdomen and urinary tract on fixed X-ray installa

quality criteria have been drawn up for representative radiographs from the rou

H. Fendei et al. Efficacy of Diagnostic Use of X-Rays in Paed iatrics , 2nd Reportfor the Federal Ministry of Environment, Protection of Nature and Reactor Safety,Bonn, 1987, in German.


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OBJECTIVESThe objectives of the Guidelines presented in this document are to achieve:- adequate image quality, comparable throughout Europe;- accurate radiological interpretation of the image; and- reasonably low radiation dose per radiograph.The Guidelines are primarily directed at the technical and clinical staff involved in takingthe radiographs and in reporting on them. The Quality Criteria may provide the standardfor quality assurance programmes and also serve as a basis for self-education and training in good imaging practice. They will also be of interest to those responsible for thedesign of X-ray imaging equipment and for the maintenance of its functional performance. They wil l be helpful to those who have responsibil i ty for equipment specificationand purchase.The Guidelines represent an achievable standard of g oo d p ractice whi ch can be used as abasis for further development by the radiological community.TheImag e Criteria for paediatric patients presented for a particular type of radiograph arethose deemed necessary to produce an image of standard quality. No attempt has beenmade to define acceptability for particular clinical indications. The listed image criteria allowan immediate evaluation of the image quality of the respective radiograph. They are appropriate for the most frequent requirements of radiographic imaging of paediatric patients.Where necessary, specific clinical questions and situations are taken into account.The anatomical features and body proportions vary due to the developmental process ininfancy, childhood and adolescence. They are different in the respective age groups andare distinct from those of a mature patient. The Guidelines presuppose knowledge of thechanging radiographic anatomy of the developing child. The term consistent wit h ageindicates that the respective image criteria essentially depend on the age of the patient.The smaller body size, the age dependent body composition, the lack of co-operation andmany functional differences (e.g. higher heart rate, faster respiration, inability to stopbreathing on command, increased intestinal gas etc.) prevent the production of radiographic images in paediatric patients to which standard adult image criteria can beapplied. This, however, does not imply that all quality criteria are inappropriate; they mustbe adapted to paediatric imaging.Correct positioning of paediatric patients may be much more difficult than in co-operative adult patients. Effective immobilisation often necessitates the use of auxiliary devices.Sufficient skill and experience of the imaging staff and ample time for the particular investigation are the imperative prerequisites to fulfil this quality criterion in infants andyoun ger c hildren. No diagnostic radiation exposu re should be allow ed unless there is ahigh probabil i ty that the exact positioning wil l be maintained. Incorrect positioning is themost frequent cause of inadequate image quality in paediatric radiographs. Image criteria for the assessment of adequate positioning (symmetry and absence of tilting etc.) aremuch more important in paediatric imaging than in adults.The reasons for diagnostic imaging in paediatrics are often essentially different from thosein adult medicine. They vary in the different paediatric age groups. Image quality must beadapted to the particular cl inical problem.In paediatric diagnostic imaging, image quality must be a constant preoccupation; nevertheless, more often than in adults, a lower level of image quality may be acceptable forcertain clinical indications. An inferior image quality, however, cannot be justified unlessthis has been intentionally designed and must then be associated with a lower radiationdose. The fact that the X-ray was taken from a non-cooperative paediatric patient (anxious, crying, heavily resisting) is not an excuse for producing an inferior quality film whichis often associated with an excessive dose.


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are not indicated in these

included in these Guidelines areressed in terms of a reference value for the entrance surface dose for a stan dard -paediatric patient. However, reference dose values are available only for the most

For reasons indicated there, the reference dose values given under the Criteria forpp endix I to th is C hapter.

included in these Guidelines have


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GENERAL PRINCIPLES ASSOCIATED WITHGOOD IMAGING PERFORMANCEThe following general principles are common to all radiographic X-ray examinations. Allthose who either carry out X-ray examinations or report on the results should be awareof them.Specific aspects of these principles are discussed in greater detail in a number of publications by national and international organisations, some of which are listed in reference (1)to (17) (see page 15).

1. I m a g e A n n o t a t i o nThe patient identification, the date of examination, positional markers and the name ofthe facility must be present and legible on the f i lm. These annotations should not obscurethe diagnostically relevant regions of the radiograph. An identification of the radiographers on the fi lm would also be desirable.

2 .Qua l i t y Con t ro l o f X- ray Imag ing Equ ipmen tQuality control programmes form an essential part of dose-effective radiological practice.Such programmes should be instigated in every medical X-ray facility and should cover aselection of the most important physical and technical parameters associated with thetypes of X-ray examination being carried out. Limiting values for these technical parameters and tolerances on the accuracy of their measurement wil l be required for meaningfulapplication of the Examples of Good Radiographic Technique presented in these Guidelines. BIR Report 18 (12) provides further useful information on this subject.

3 . L o w A t t e n u a t i o n Ma t e r i a l sRecent developments in materials for cassettes, grids, tabletops and front plates of f i lm-changers using carbon fibre and some new plastics enable significant reduction in patientdoses. This reduction is most significant in the radiographic-voltage range recommendedin paediatric patients and may reach 4 0 % . Use of these m aterials should be encourage d.

4. Pa t ien t Pos i t ion ing and Immob i l i sa t ionPatient positioning must be exact whether or not the patient co-operates. In infants, tod dlers and younger children immobil isation devices, properly applied, must ensure that;- the patient does not move- the beam can be centred correctly- the fi lm is obtained in the proper projection- accurate collimation limits the field size exclusively to the required area- shielding of the remainder of the body is possible.Immobil isation devices must be easy to use, and their application atraumatic to thepatient. Their usefulness should be explained to the accompanying parent(s).Radiological staff members should only hold a patient under exceptional circumstances.Where physical restraint by parents or another accompanying person is unavoidable, theymust know exactly what is required of them. They must be provided with protection fromscattered radiation and be absolutely outside the primary beam of radiation applied to th epatient. Pregnant women must not be allowed to assist.Even in quite young children the time allocation for an examination must include the timeto explain the procedure not only to the parents but also to the child. It is essential that


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ic examinations. Beyond the neonatal period, the tolerance for maximal field size

f i lm. This is of particular importance; beam-limiting devices automatically adjusting regu

f ield; special shielding has to be added for certain examinations to

gonads in ho t exa min ations , i .e. wh en they l ie wit hin or close (nearer than 5 cm)s and lead capsules for boys. They mus t be available in varied sizes. The testes mu st be

easi


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There is no reason to include the male gonads in the scrotum within the primary radiationfield for radiographs of the abdomen. The same applies, usually, for films of the pelvis andmicturating cystourethrographies. The tests should be protected with a lead capsule, butkept outside the f ield. In abdominal examinations gonad protection for girls is not pos-sible. In practice, the great majority of pelvic films show that female gonad protection iscompletely ineffective. The position of all sorts of lead material is often ludicrous. Thereare justifiable reasons for o m ittin g g ona d pro tection fo r pelvic films in girls, e.g. trau m a,incontinence, abdominal pain, etc.The eyes should be shielded for X-ray examinations involving high absorbed doses in theeyes, e.g. for conventional tomography of the petrous bone, when patient co-operationperm its. The absorbed dose in the eyes can be reduced by 5 0 % - 7 0 % . In any radiogra-phy of the skull the use of -projection rather than the AP-projection can reduce theabsorbed dose in the eyes by 95%. -projection, therefore, should be preferred as soonas patient age and co-operation permit prone or erect posit ioning.As developing breast tissue is particularly sensitive to radiation, exposure must be limited.The most effective m eth od is by using the -projection, rather th an t he AP. W hile this iswell accepted for chest examinations, the greatest risk is during spinal examinations, andhere -exa minations mu st replace AP.It should also be remembered that thyroid tissue should be protected, whenever possible,e.g. during dental and facial examinations.

7 . R a d i o g r a p h i c E x p o s u r e C o n d i t i o n sKnowledge and correct use of appropriate radiographic exposure factors, e.g. radi-ographic voltage, nominal focal spot value, filtration, film-focus distance is necessarybecause they have a considerable impact on patient doses and image quality. Permanentparame ters of the apparatus such as tota l tube filtr atio n an d grid characteristics sho uldalso be taken into consideration.

(a ) Nominal foca l spot va lueUsually a nom inal focal spot value betw een 0.6 and 1.3 is suitable for p aediatric pa tients.When bifocal tubes are available, the nominal focal spot value which allows the mostappropriate setting of exposure time and radiographic voltage at the chosen focus filmdistance should be used. This may not always be the smaller one.

(b ) A d d i t i o n a l f i l t r a t i o nThe soft p art of the ra diation spectrum wh ich is com pletely absorbe d in the pa tient is use-less for the production of the radiographic image and contributes unnecessarily to thepatient dose. Part of it is eliminated by the inherent filtra tion o f the tu be, tube housing,col-l imator etc., but this is insufficient. M ost tubes have a minim um inherent filtration of 2.5 mmAl. Additional filtration can further reduce unproductive radiation and thus patient dose.For paediatric patients, total radiation dose must be kept low, particularly when highspeed screen film systems or image intensifying techniques ar used. Not all generatorsallow the short exposure times that are required for higher kV technique. Consequently,low radiograph ic voltag e is frequ ently used for p aediatric pa tients. This results in com -paratively higher patient doses.Adequate addit ional f i l t rat ion allows the use of higher radiographic voltage with theshortest available exposure times, thus overcoming the limited capability of such equip-me nt for short exposures. This makes the use of high speed screen film systems and imageintensifier photography possible.


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An t i -sca t ter gr id

ecessary. The examples for g ood radiographic tech nique specify wh en grids are super suffi

grid,

115 cm for over-couch tubes w ith grid tables and 150 cm for vertical

radi

radise ge nerators canno t provide this. 12-pulse or high frequency multi-pulse (so-


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requires an exposure nearly 20-times longer and gives 2.15-times higher entrance surfacedose, when a1-pulse generator is used instead of a converter generator.The preset radiographic voltage and effective radiographic voltage may not be identical.In very short exposure times even small discrepancies may have an impact on image quality. When short exposure settings are inconstant, they will effectively influence film blackening and patient dose. Quality control programmes should be meticulous in this regardwhen assessing equipment for paediatric patients. Generators which do not fulfi l requirements for proper and stable calibration (within a tolerance range of about 10%) shouldnot be used for paediatric patients and should be replaced as soon as possible.The radiation emitted by the tube requires a certain time to reach its peak voltage. With thelonger exposures used in adult patients, this pre-peak time radiation is insignificant. Withthe very short exposure times in paediatric radiography, pre-peak times must be taken intoconsideration. Some old generators have pre-contact phases in which soft radiation may beemitted. Added filtration eliminates this which is another reason for advocating its use.

( f ) Au tomat i c exposure con t ro lAdult patients vary in size, but their variation is minimal compared to the range in paediatric patients: premature infants, weighing considerably less than a thousand grammes, toadolescents approaching 70 kg. Those investigating paediatric patients must be able toadapt to this range. One would expect that a device for automatic exposure control (AEC)would be helpful. However, many of the systems commonly available are not satisfactory.They have relatively large and fixed ionisation chambers. Neither their size nor their shapenor their position is able to compensate for the many variations of body size and body proportion in paediatric patients. In addition, the usual ionisation chambers of AECs are builtin behind agr id. Consequently, AEC-use may be associated with the use of the grid (wherethe grid is not removable) which as previously mentioned is frequently unnecessary.The optimal adaptation of the radiographic technique to the clinical needs requires theuse of screen film systems of different speeds and different switch-off doses at the imagereceptor. Screens and AEC cham bers are wave length depe ndan t, particularly in the lowerrange of radiographic voltage, but these dependencies do not correspond with eachother. AECs lengthen the minimal exposure times. All these factors must be consideredwhen AECs are used in paediatric patients. They are complicated to use and result in manyunsatisfactory examinations.Specially designed paediatric AECs have a small mobile detector for use behind a lead-freecassette. Its position can be selected with respect to the most important region of interest. This must be done extremely carefully, as even minor patient movement may be disastrous. The high speed of modern screens allows a minute dose at the cassette front.Consequently, the detector behind the cassette has to work in the range of a fraction of1 mGy. It is nearly impossible to provide constancy and reproducibility in this range.Much safer, easy-to-use and less expensive are exposure charts corresponding to radiographic technique and patient's weight the so-called body index when X-rayingthe trunk, or patient's age for the extremities. In the future, small and simple computersmay incorporate multifactorial parameters for this purpose. A learning inte ll igen t unitwould be deal for paediatric patients.The EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUE indicates when the AEC may beused and which chamber should be selected.

(g) Au tom at i c b r igh tness con t ro lAu tom atic brightness control has to be switched off du ring fluoroscopic exam inationswhere there are relatively large areas of positive contrast material to avoid excessive doserates, e.g. full bladders.

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under the Example of Good Radiographic Technique, exposure times are indicated for

the other for general use, they should be clearly marked.onship betw een th e speed class of the screen fi lm system, the dose requiremen t

stan

radi radiographic technique, image receptor sensitivity and fi lm processing. It determines f i lm. The range of the mean optical density (D) ofinical radiograph s hould norm ally l ie betw een D = 1.0 and D = 1.4 and the op tical den- 0.25 . For th e diagnostically relevant parts

l


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Whereas the total density above base and fog can be easily - and should be routinely -measured, objective measurement of the mean optical density of the fi lm of a patientrequires some expenditure and is not practicable in daily work. Even in external qualitycontrol programmes assessors usually base their judgement on subjective and globalimpressions rather than measurements. For a more precise assessment, the definition ofone or a few critical points of the particular radiographic projections would be desirablewhere the optical density of a specific anatomical feature and its contrast relative tothe surrounding mage could be measured.Film blackening is subject to the personal preference of the individual radiologist. A darker film may be associated with a relatively higher patient dose. In this respect the preference for darker fi lms should be supported by rational arguments. A fi lm which has beenfound too dark should be viewed with a bright spot l ight before a decision is made torepeat the examination.

10. Rad iograph ic Exposures Per Examinat ionThe number of radiographic exposures within one examination must be kept to a minimum consistent with obtaining the necessary diagnostic information.

11. Film ProcessingOptimal processing of the radiographic fi lm has important implications both for the diagnostic quality of the image and for the radiation dose to the patient. Film processorsshould be maintained at their optimum operating conditions as determined by regularand frequ ent (i.e. daily) quality con trol procedures. Consistent ima ging p erformanc e is notnecessari ly an indication of optimal performance, e.g. the developer temperature maywell be set too low.

12.V ie w in g C o n d i t io n sThe proper assessment of image quality and accurate reporting on the diagnostic information in the radiographs can best be achieved when the viewing conditions meet thefol lowing requirement:(a) The light intensity incident on the viewer's eye should be about 100 cd/m 2. To achievethis, the brightness of the fi lm i l luminator should be between 2000 and 4000 cd/m' forfilms in the density range 0.5 to 2.2.(b) The colour of the i l lumination should be white or blue and should be matchedthroughout a complete set of fi lm i l luminators.(c) Means should be available to restrict the illuminated area to the area of the radiographto avoid dazzling.d) Means for magnifying details in the displayed radiographic image should be available.These means should magnify by a factor of 2 to 4 and contain provisions to identify smallimage details of sizes down to 0.1 mm.(e) For viewing exceptionally dark areas in the radiographic image an additional spotlightwith iris diaphragm providing a brightness of at least 10 000 cd/m 2 should be available.(f) A low level of ambient light in the viewing room is essential.

13. Reject AnalysisRejected films should be collected, the reasons for rejection should be analysed and corrective action should be taken.

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ality Criteria are to be used by radiologists, radiog raphe rs, and med ical physicists as a

. D I A G N O S T I C R E Q U I R E M EN T S

radi

cri

. CRITERIA FOR RADIATION DOSE TO THE PATIENT

for the most frequently performed examinations in these Guidelines. The dose data collected during the Trials the values derived for the 5 year old child can tentatively be used as a reference dose value for all age groups

ref

E X AM P LE OF GO OD RAD IOGRA P HIC TE CHNIQUE

' ;


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DESCRIPTION OF TERMS USED ON FOLLOWING PAGES1 . DIAGNOSTIC REQUIREMENTSImage Cr i ter iaThese refer to characteristic features of imaged anatomical structures with a specific degree of visibility. At presenttime there are no internationally accepted definitions. For the purpose of this Document the degree of visibil i ty isdefined as follows:Visualisation:Characteristic features are detectable but details are not fully reproduced; features just visibleReproduct ion:Details of anatomical structures are visible but not necessarily clearly defined; details emergingVisually Sharp Reproduction:Anatomical details are clearly defined; details clear.

2 . CRITERIA FOR RADIATION DOSE TO THE PATIENTThe reference value for the entrance surface dose for a patient is expressed as the absorbed dose to air ^Gy) at thepoint of intersection of the X-ray beam axis with the surface of a paediatric patient, backscatter radiation included.For further information see Appendix 1.

3. EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUE3.0. Patient position upright, supine, prone or lateral.3.1. Radiographic device device supporting the fi lm-screen cassette and the anti-scatter grid.3.2. Nom inal focal spot value as indicated by the manufacturer.3.3. Total fi ltra tion the aluminium equivalence in mm of the inherent and added fi l tration.3.4. Anti-scatter grid described in terms of grid ratio r and numb er of absorb ing strips per cm for m oving grid.3.5. Screen film system the sensitivity of screen film systems is defined in terms of speed [see ISO 9236-1 , DIN6867- section 1, (1995)]. The speed of the screen film system is one of the most critical factors affecting theradiation dose to the patient. For convenience in these Guidelines only broad speed categories nominal speedclasses are indicated.3.6. FFD Focus-to-film distance (cm). If a focused grid is used, FFD must be within the range indicated by themanufacturers.3.7. Radiographic voltage expressed as the peak kilo-voltage (kV) applied to the X-ray tube, preferably 12-pulseor high frequency multi-pulse (so-called converter) generators.3.8. Automatic exposure control the recommended selection of the measurement chamber in the automaticexposure control device.3.9. Exposure time the time indicated for the duration of the exposure (ms).3.10. Protective shielding protection devices additional to existing standard equipment, in order to furtherreduce exposure of sensitive organs and tissues.Values in parentheses indicate options which are less desirable but acceptable for special conditions andindications.

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ICRP Publication 60, 1990 R ecomm endations of the Interna tional Comm ission on Radiological Protection, (PergamonPress, Oxford), 1 99 1.ICRP Pub lication 34, Protection of the Patient in Diagnostic Radiology, (Pergamon Press, Ox ford), 198 2.ICRP Publication 73, Ra diologic al Protection and Safety in M ed ici ne , in press.Council Directive of 3 September 1984 laying dow n basic measures for the radiation pro tection of persons undergoing medical examination or treatm ent (84 /466 EURATOM) O.J. Nr L 265 , p. 1 , 05 .10 .19 84, under revision: CO M95-560 f inal, 1995.WH O Technical Report 689 A Rational App roach to Radiographic Investigations , (World Health Organ isation,Geneva), 1986.WH O Technical Report 757 Rational use of Diagnostic Imaging in Paediatrics , (Wo rld Health Organ isation, Geneva),1987.Booklet on M ak ing th e Best Use of a Dep artmen t of Ra diology , (Royal College of Radiologists, London), 3rdEdition, 1995.Qu ality Criteria fo r Diagnostic Radiographic Images, (Office fo r Official Publications of the European Co mm unitie s,Luxembourg), Report EUR 16260, 1996.

Luxembourg), Report EUR 16263, in press.WH O R eport Q uality Assurance in Diagnostic Radiology , (World Health Organisation, Geneva), 1982.

and Appropriate Measuring Methods , BIR Report 18, 1989.Op tim isa tion of Image Qua lity and Patient Exposure in Diagnostic R adio logy , BIR Report 20 , 1989.

49, Nos 1-3, 1993.Q uality Con trol and R adiation Protection of the P atient in Diagnostic R adiology and N uclear Medicin e; R adiationProtection Dosimetry, Vol. 57, Nos 1-4, 1995.Na tional Co uncil on R adiation Prote ction and M easurem ents (NCRP). Radiation Protection in Pediatric R adiology.Report No 68. Bethseda: NCRP Publications 1981.

Ionising Radiation, Report 1988.

rztebl. 92. Heft 34-35, 1995.Schneider K, Fendei H, Bakowsk i C, Stein E, Kellner M, K ohn M M , Schw eighofe r K Cartagena G. Results of aEurope-wide Dosimetry Study on Frequent X-ray Examinations in Paediatric Populations. Radiation ProtectionDosimetry VOL.43, pp 31-36 (1992).

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CHEST/AP PROJECTIONBeyond the newborn period)For co-operative patients PA projection;AP projection for non-co-operative patients.

1 .

1.1.1.2.1.3.1.4.1.5.1.6.1.7.

DIAGNOSTIC REQUIREMENTSImage criteriaPerformed at peak of inspiration, except for suspected foreign body aspirationReproduction of the thorax without rotat ion and t i l t ingReproduction of the chest must extend from just above the apices of the lungstoT12 /L1Reproduction of the vascular pattern in central 2/3 of the lungsReproduction of the trachea and the proximal bronchiVisually sharp reproduction of the diaphragm and costo-phrenic anglesReproduction of the spine and paraspinal structures and visualisation of theretrocardiac lung and the mediastinum

CRITERIA FOR RADIATION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: 100 Gy

33.0.3 .1 .3.2.3.3.3.4.3.5.

3.7.3.8.

EXAMPLE OF GOO D RADIOGRAPHIC TECHNIQUEPatient positionRadiographic deviceNominal focal spot valueAddit ional f i l t rat ion

upright, supine position possibletable or vert ical stand, depending on age0.6


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CHESTn d th e n e wb o rn p e r i o d )

mus t no t be done rou t ine ly ,

DIAGN OSTIC REQUIREMENTSImage cri teria

Performed at the peak of inspirationTrue lateral proje ctionVisualisation of the trachea fro m the apices of the lungs do w n to and includingthe main bronchiVisually sharp reprod uction of the wh ole of both domes of the diaph ragmRe produ ction of the hilar vesselsReprodu ction of the sternum and the thoracic spine

CRITERIA FOR RADIATION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: 200 Gy

EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUEPatient positionRadiographic deviceNominal focal spot valueAddit ional f i l trat ionAnti-scatter gridScreen film systemFFDRadiographic voltageAu tom atic exposure controlExposure tim eProtective shielding

upright, supine position possibletable or vertical stand depending on age0.6 (1.3)up to mm Al + 0.1 or 0.2 mm Cu(or equivalent)r = 8; 40/cm; only for special indications and inadolescentsnominal speed class 400 - 8001 0 0 - 150 cm60 - 80 kV (100 - 150 kV with grid for olderchildren)chamber selected - lateral; preferably none ininfants and young children< 20 mslead-rubber coverage of the abdomen in theimmediate proximity of the beam edge

There are circumstances where the cervical trachea should be included (e.g.


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CHESTAP PROJECTION(Newborns)

1. DIAGN OSTIC REQUIREMENTSImage criteria

1.1. Performed at peak of inspiration1.2. Reproduction of the thorax w itho ut rotation and t i l t ing1.3. Reproduction of the chest must extend fro m the cervical trachea to T12/L1(part of the abdomen may be included for special purposes)1.4. Reproduction of the vascular pattern in central half of the lungs1.5. Visually sharp reprodu ction of the trachea and the proximal bronchi1.6. Visually sharp reprodu ction of the diaphragm and costo-phrenic angles1.7. Re produc tion of the spine and paraspinal structures and visualisation of theretrocardiac lung and the mediastinum

2. CRITERIA FOR RA DIAT ION DOSE TO THE PATIENTEntrance surface dose for newborns: 80 Gy

3. EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUE3.0. Patient position3.1. Radiographic device3.2. Nom inal focal spot value3.3. Addit ional f i l trat ion3.4. Anti-scatter grid3.5. Screen film system3.6. FFD3.7. Radiographic voltage3.8. Au tom atic exposure control3.9. Exposure tim e3.10 . Protective shielding

supinebedside (table), depending on clinical condition0.6 (1.3)up to mm Al + 0.1 or 0.2 mm Cu(or equivalent)nonenominal speed class 200 - 4008 0 - 100 (150) cm60 - 65 kVnone< 4 mslead-rubber masking of the abdomen in theimmediate proximity of the beam edge; if directplacement not possible, then masking on theincubator l id


33/78

SKULL

DIAGN OSTIC REQUIREMENTSImage cri teria

Symm etrical reprod uction of the skull, particularly cran ium , orbits and petrousbones2. Projection of the upper margins of the petrous tem poral bones into the low erhalf of the orbits in AP projection3. Reprod uction of the paranasal sinuses and structure of the tem pora l bonesconsistent with age4. Visually sharp reprod uct ion of the outer and inner tables of the entire cranial

vault consistent with age5. Visualisation of the lambdo id and sagittal sutures

CRITERIA FOR RA DIAT ION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: 1500 Gy

EXAMPLE OF GOOD RADPatient positionRadiographic deviceNominal focal spot valueAddit ional f i l trat ionAnti-scatter gridScreen film systemFFDRadiographic voltageAutomatic exposure controlExposure timeProtective shielding

supine, upright position possibletable, grid table, special skull unit or verticalstand with stationary or moving grid0.6 (


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SKULLLATERAL PROJECTION

1.

1 . 1 .1.2.1.3.1.4.

DIAGNOSTIC REQUIREMENTSImage criteriaVisually sharp reproduction of the outer and inner tables of the entire cranialvault and the floor of the sella consistent with ageSuperimposit ion of the orbital roofs and the anter ior part of the greater wings ofthe sphenoid bonesVisually sharp reproduction of the vascular channels and the trabecular structureconsistent with ageReproduction of the sutures and fontanelles consistent with age

2. CRITERIA FOR RA DIAT ION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: 1000 Gy

3.3.0.3 .1 .3.2.3.3.3.4.3.5.3.6.3.7.3.8.3.9.3.10.

EXAMPLE OF GOOD RADPatient positionRadiographic deviceNominal focal spot valueAddit ional f i l t rat ionAnti-scatter gridScreen film systemFFDRadiographic voltageAutomatic exposure controlExposure tim eProtective shielding

supine, upright position possibletable, grid table, special skull unit or verticalstand with stat ionary or moving gr id0.6


35/78

PELVIS

DIAGNO STIC REQUIREMENTSImage criteria

No ti l tin g: reproduction of the tri-radiate carti lages is in the same horizontal l ineas the 5th sacral segment or the upper margins of the ischial and pubic ossification centres superimposed2. No rotati on : a vertical line passing thr ou gh the middle of th e sacrum must passthrough the middle of the pubic symphysis or the i l iac wings and obturatorforamina must be perfectly symmetrical3. Reproduction of the necks of the femo ra in a standard position wh ich should

not be distorted by foreshortening or external rotation (patellae parallel to thetable top). If a functional study for instability is required, it should be taken infull internal rotation and 45 abduction of the thighs4. Visualisation of the peri-articular soft tissue planes

CRITERIA FOR RADIATION DOSE TO THE PATIENTEntrance surface dose for infants: 200 Gy

EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUEPatient positionRadiographic deviceNominal focal spot valueAdditional fi l trationAnti-scatter gridScreen film system

Radiographic voltag eAuto ma tic exposure controlExposure tim eProtective shielding

supinetable0.6 (1.3)up to mm Al + 0.1 or 0.2 mm Cu(or equivalent)r = 8;40/cm; only for special indications and inadolescentsnominal speed class 400 - 800100 cm60 - 70 kVnone< 10 msgonad capsules should be employed for malepatients and gonad masks or shields for femalepatients, when diagnostically possible


36/78

PELVISAP PROJECTIONOlder ch i ld ren)

1 DIAGNOSTIC REQUIREMENTSImage criteria

1.1 Symm etrical reprod uction of the pelvis1.2 Visualisation of the sacrum and its intervertebra l foram ina dep end ing on bow elcon ten t not to be considered in presence of female gon ad shielding)1.3 Rep roduction of the lower part of the sacroiliac joints not to be considered inpresence of female gonad shielding)1.4 Reproduction of the necks of the fem ora which should not be distorted byforeshortening or external rotat ion1.5 Rep roduction of spongiosa and cortex1.6 Visualisation of the trocha nters consistent w ith age1.7 Visua lisation of th e pe ri-articula r soft tissue planes

2 CRITERIA FOR RADIATION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: 900 Gy

3 EXAMPLE OF GOO D RADIOGRAPHIC TECHNIQUE3.03.13.23.33.43.53.63.73.83.93.10

Patient positionRadiographic deviceNominal focal spot valueAddit ional f i l t rat ionAnti-scatter gridScreen film systemFFDRadiographic voltageAutomatic exposure controlExposure timeProtective shielding

supinegrid table0.6 1.3)up to 1 mm A l + 0.1 or 0.2 m m Cuor equivalent)r = 8; 40/cmnominal speed class 400 - 800115 1 00 - 150) cm70 - 80 kVchamber selected - central or both laterals< 50 msgonad capsules should be employed for malepatients and gonad masks or shields for femalepatients, when diagnostically possible


37/78

FULL SPINE


Mu st include the base of the skull and the coccyx, and also the iliac crests2. Rep roduction of vertebra l bodies and pedicles3. Visualisation of th e posterior articular processes4. Rep roduction of the spinous and transverse processes consistent wit h age

CRITERIA FOR RADIATION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: no values as yet available

EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUEPatient positionRadiographic device

Nominal focal spot valueAdditional fi l trationAnti-scatter gridScreen film systemFFDRadiographic vo ltageAutomatic exposure controlExposure timeProtective shielding

supine or uprighttable, grid table or vertical stand with stationaryor moving gr id, or vertical stand with specialcassettes or special devices< 1.3up to mm Al + 0.1 or 0.2 mm Cu(or equivalent)r = 8; 40/cm or special cassettes; no grid forinfants < 6 months of agenominal speed class 600 - 8001 5 0 - 2 0 0 c m65 - 90 kVnone< 800 msgonad capsules should be employed for malepatien ts, (see also remarks)

-sensitive breast tissue. Edge filters sh ould be used wh en possible and are preferable


38/78

SEGMENTAL SPINE/AP PROJECTION

1. DIAGNO STIC REQUIREMENTSImage criteria

1.1. Rep roduction as a single line of the upper and lowe r plate surfaces in the centre of the beam1.2. Visualisation of the interve rtebra l spaces in the centre of the beam area1.3. Visually sharp reprodu ction of the pedicles, depe ndent on the anatom icalsegment1.4. Visualisation of the posterior articular processes (for lum bar spine examinations)1.5. Re produ ction of the spinous and transverse processes consisten t w it h age1.6. Visually sharp rep rodu ction of the cortex and trabec ular structures consistentwith age1.7. Re produ ction of the adjacen t soft tissues


3. EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUE3.0.3.1.3.2.3.3.3.4.3.5.3.6.3.7.3.8.3.9.3.10.

Patient positionRadiographic deviceNominal focal spot valueAddit ional f i l trat ionAnti-scatter gridScreen film systemFFDRadiographic voltageAutomatic exposure controlExposure timeProtective shielding

supine or uprighttable, grid table or vertical stand with stationaryor moving gr id, depending on age0.6 (


39/78

SEGMENTAL SPINE


Rep roduction as a single line of the upper and low er plate surfaces in the cen-tre of the beam2. Full supe rimpo sition of the posterior margins of the vertebral bodies3. Reprod uction of the pedicles and the intervertebral foram ina4. Visua lisation of the posterior articular processes5. Reprod uction of the spinous processes consistent w ith age6. Visually sharp reprod uction of the cortex and trabecular structures consistentwith age7. Re prod uction of the adjace nt soft tissues


EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUEPatient positionRadiographic deviceNominal focal spot valueAddit ional f i l t rat ionAnti-scatter gridScreen film systemFFDRadiographic voltageAutomatic exposure controlExposure timeProtective shielding

supine or uprighttable, grid table or vertical stand with stationaryor moving grid, depending on age0.6 (1.3)up to mm Al + 0.1 or 0.2 mm Cu(or equivalent)r = 8; 40/cm no gr id for infants


40/78

A B D O M E NAP/PA PROJECTION WITH VERTICAL/HORIZONTAL BEAM

1. DIAGNO STIC REQUIREMENTSImage cri teria

1.1. Reproduction of the abd om en, from the diaphragm to the ischial tuberosi ties,including the lateral abdominal walls1.2. Repro duction of the prope ritoneal fat lines consistent w ith age1.3. Visualisation of the kidney outl ines consistent w ith age and dep end ing on

bowel content1.4. Visualisation of the psoas out l ine consistent w ith age and dep end ing on bow el

content1.5. Visually sharp repro ductio n of the bones

2. CRITERIA FOR RAD IATION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: 1000 Gy

3.3.0.3.1.3.2.3.3.3.4.3.5.3.6.3.7.3.8.3.9.3.10.

EXAMPLE OF GOOD RADPatient positionRadiographic deviceNominal focal spot valueAddit ional f i l trat ionAnti-scatter gridScreen film systemFFDRadiographic voltageAutomatic exposure controlExposure timeProtective shielding

supine, prone or decubitustable, grid table0.6 (


41/78

URINARY TRACT


Reproduction of the area of the whole urinary tract from the upper pole of thekidney to the base of the bladder and the proximal urethra2. Visualisation of the kidney outl ines consistent w ith age and depend ing on bow elcontent3. Visualisation of the psoas outl ine consistent w ith age and depending on b ow elcontent4. Visually sharp repro duc tion of the bones

CRITERIA FOR RAD IATION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: no values as yet available

EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUEPatient positionRadiographic deviceNominal focal spot valueAddit ional f i l trat ionAnti-scatter gridScreen film systemRadiographic voltag eAut om atic exposure controlExposure tim eProtective shielding

supine or pronetable, grid table0.6 (


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U R I N A R Y T R A C TAP/PA PROJECTION( A f te r a d m i n i s t r a t i o n o f c o n t r a s t m e d i u m )Co n t r a s t m e d i u m s h o u l d r a r e ly b e a d m i n i s te r e d w i th o u t a p r e c e d i n g e v a l u a t i o nby a sono grap h ic ex am ina t ion . Image c r i te r ia re fe r to a sequence o f rad iog raph sd e te r m i n e d b y a n e x p e r i e n c e d q u a l i f i e d p h y s i c i a n wh o w i l l r e s t r i c t t h e i r n u m b e rto the m in imum necessary fo r so l v ing the c l i n i ca l p rob lem. There i s no need fo rc o n v e n t i o n a l t o m o g r a p h y .

1.1

1.2.1.3.1.4.1.5.

DIAGNOSTIC REQUIREMENTSImage cri teriaVisualisation of the outl ine of the kidneys by the increase in parenchymal density (nephrographic effect) in the early fi lm(s) which should be coll imated toinclude the whole of both renal areasVisually sharp reproduction of the renal pelvis and calyces (Pyelographie effect)Reproduction of the pelvi-ureter ic junctionVisualisation of the area normally traversed by the ureterReproduction of the whole bladder and the proximal urethra

2 . CRITERIA FOR RA DIAT ION DOSE TO THE PATIENTEntrance surface dose for standard five year old patient: no values as yet available

3.3.0.3.1.3.2.3.3.3.4.3.53.6.3.7.3.8.3.9.

EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUEPatient positionRadiographic deviceNominal focal spot valueAddit ional f i l trat ionAnti-scatter gridScreen film systemFFDRadiographic voltageAutomatic exposure controlExposure time3.10 . Protective shielding

supine or pronetable, grid table0.6 (


43/78

URINARY TRACT

fill

DIAGNOSTIC REQUIREMENTSImage criteria

True lateral or steep obliqu e projection is recom men ded for bladder outlet andurethraRep roduction at the peak of voiding of the bladder ou tlet and proximal urethraand of the entire male urethra in cases of flow disturbances or other penilepathologyVisualisation of any vesico-ureteric reflux for grad ingVisualisation of any intrarenal refluxRep roduction of the refluxing uretero-vesical jun ctio n in app ropriate obliqu eprojectionsVisualisation of the ureter for evaluation of ureteric fun ctio n after voidingReproduction of the wh ole extent of any duplication


EXAMPLE OF GOOD RADIOGRAPHIC TECHNIQUEPatient positionRadiographic deviceNominal focal spot valueAdditional fi l trationAnti-scatter gridScreen film system

intensifier distanceRadiographic voltag eAut om atic exposure controlExposure tim e

filling phase in supine position, voiding phase insupine, lateral or upright positionti l ting fluoroscopic table0.6 (


44/78

CHAPTER 1APPENDIX IGUIDELINES ON RADIATION DOSE TO THE PATIENT

Ob j e c t i v eThe Criteria for Radiation Dose to the Patient which are given for some of the more common radiographic projections in these Guidelines are expressed in terms of a referencevalue of the Entrance Surface Dose for a standard five year old patient. It is intended thatthis reference dose value is used as an aid to the optimisation of radiation protection ofthe patient by identifying those situations in most urgent need of investigation and possible corrective action. If the reference dose value is signif icantly exceeded then immediate investigations should be made to justify this relatively high level of patient exposureor, if it cannot be justif ied, to reduce it.The reference dose value does not signify an optimum level of performance and reduction of doses below the reference level should always be pursued in l ine with the ALARA(As Low As Reasonably Achievable) principle but with due attention to the potential lossof clinical information with any dose reduction. This objective is in l ine with the recommendation in paragraph 180 of ICRP Publication 60 (1 ) tha t conside ration sh ould be givento the use of 'dose constraints or investigation levels' for application in some commondiagnostic procedures.The reference dose values have been derived from th e observed distributions of paediatricpatient doses in European Trials of the Quality Criteria conducted over the past six yearswhich are described in Chapter 2. They have been set at approximately the level of thethird quarti le in the dose distributions seen for f ive year old patients. The reasons forchoosing patients of this age are described in Chapter 2, Part 2. The third quarti le valuewas chosen as an appropriate investigation level on the grounds that if 75% of X-raydepartments can operate satisfactorily below this dose level, then the remaining 25%should be made aware of their considerably less than optimal performance and should beencouraged to alter their radiographic equipment or techniques to bring their doses inline with the majority. At the same time adherence to the Diagnostic Requirements foreach radiographic projection will ensure that diagnostic effectiveness does not suffer fromany dose reduction.

M e t h o d s o f D o se M e a s u r e m e n tto Check Compl iance w i t h t he Cr i t e r iaTo check compliance with the Criteria for Radiation Dose to the Patient it is necessary toobtain a reliable indica tion of the Entrance Surface Dose tha t w ou ld be delivered to astandard five year old patient using the radiographic techniques and equipment that arebeing tested against the Quality Criteria. For the chest examinations the entrance surfacedoses will often be below 100 Gy and will require particularly sensit ive dosemeters foraccurate measurement. Special thermoluminescent dosemeters or ionisation chamberdosemeters can be used.Thermoluminescent dosemeters (TLDs) have the advantage of measuring the requiredentrance surface dose directly (including backscattered radiation) when attached to thepatient's skin at a point coincident with the centre of the incident X-ray beam. For chestexaminations in particular they probably need to be of higher sensit ivity than the commonly available l ithium fluoride or l ithium borate material. CaF2:Dy TLDs were successfully used during the European Trials of the Quality Criteria. Uncertainties in the measurements due to the pronounced energy dependence of this material were not found to be

32


45/78

ain a reliable m easureme nt of th e entranc e surface dose associated w ith typical

ay tube as a func tion of the exposure factors. The outpu t can be measured w ith

scatter factors calculated using Mo nte Carlo techniques in a mathem atical pha ntomng a 5 year old patie nt vary betw een a bou t 1.2 an d 1.4 for the p rojections an d

con

:


46/78


47/78

2

M M AR Y OF THE EVALUATION OF THE EUROPEAN TRIALSQU ALITY CRITERIA FOR DIAGNOSTIC RADIOGRAPHIC

Part 1 deals with the radiographic technique. Part 2 the patient dose and Part 3 the

1of these Gu idelines.

35


48/78

Part 1 - Radiographic TechniqueThe fol lowing information on radiographic technique was col lected:Type and make of X-ray equipmentTube fi l tration and nominal focal spot valueAutomatic or manual exposure controlExposure time and tube currentGrid, moving or stationaryFocus-to-film distance (FFD)Manufacturer/type of screen fi lm systemSpeed class of screen film systemPatient age, weight and heightRadiographic voltageFilm size

Resu l ts and D iscuss ionGeneral Aspects of Survey DataThe response rate by the X-ray departments for a number of technical parametersem ployed is sho wn in Figure 1. In particular the tube fi l t ratio n and n om inal focal spotvalue were generally less frequently reported. In general the fi l tration was reported by lessthan 3 0 % of departme nts w ith a less than 2 0 % response rate for bo th the chest examinations of the 1 kg neonate and for mobile X-ray examinations. This is surprising giventhat both European and International Standards [IEC (1979)] require that both pieces ofinformation should be indicated on the X-ray tube housing. Consequently ei ther manufacturers are not providing this information as required or users of the equipment are notaware that it is readily available. Since both parameters have a direct bearing on eitherpatient dose (fi l tration) or image quality (nominal focal spot value) this lack of informationis a serious omission.The response rate for information on the speed class of screen fi lm systems also showeda general lack of awareness by the user. In particular for the infant chest examination performed on a mobile X-ray unit a response rate of only 36% was noted and even for thechest /AP, w ith the highest response rate, a figure o f 8 2 % w as no ted . Article 3 of theEURATOM Directive 84/466 laying down basic measures for the radiation protection ofpersons undergoing medical examination or treatment, requires the drawing up of inventories of medical radiological equipment as well as the strict surveil lance of all installations. Awareness and knowledge of the technical in format ion on X- ray equipment should be an integral component of such act ions.

percent of X-ray departments

80604020

0

F

Abd om en Skull Chest Spine Hip Chest 1kg Chest 10m onthmobi lekV-setting gene rator type gene rator age focal spot size add itional f i l tratio n

Question-response rates for technical parameters in the first European Trial 1989

6


49/78

on thetypeof X-ray generator presently in useindicates tha t12-themost commo n typeof generator with over 50% of respondents

of equipment. However,it would appear thatthe use of high frequen-(converter) generatorsisincreasing wi th roughly 2 5% employing this tech-is of significant importance giventheextremely sh ort exposure times

in paediatric X-ray examinations.forSpecific Ex am ination s

of generator types employedindifferent radiographic exam inationsandin the1989/91and 1994/95 TrialsispresentedinFigure2.A l thoughthemost

for all examinations wereof the 12-pulseor mul t i - -,2-and 6-pulse generators were still employe d. Also, althoug h rou ghly 5 0 %ons we reofthe 12-pulse variety approxim ately 5 0 %of f ixed installations were more years old.Themo bile X-ray units were generally newer, especially thosein

of typesofX-ray g enerators observedin the later Trial and also shownin2, indicates that therehasbeenageneral move tow ardstheuse of more modern

in paediatric examinations.for the different examinations are showninTable1.of kVsettingsfor the 10montholdinfant em ployed were above60 kV for

of examinationonf ixed installations except thoseof the pelvis and thoseon

entto higher kilovoltage settingsfor 5year and 10year old child reninFigures3a and 3b forboththechest and pelvis e xaminations. However,in

of thepelvis almost 4 0 %of examinationson 5yearoldchildren employedkV-< 60 andsimilarly, 1 7 %of this typeof low kVexaminationon 10yearoldchil-

ofspeed classofscreen film systems observedin the 1989/91 Trial showsofdepa rtmen ts emp loyed speed classesof2 00orlessforall exa minations .


50/78

The use of additional tube fi l tration has been recommended in the 1992 Quality CriteriaWorking Document for paediatric X-ray examinations. The distribution of responses to theque stion do you em ploy additional fi l tra tio n? is sho wn in Figure 4. Results indicate thatthe majority do not employ additional fi l tration. However, here also the origin of additional fi l tration in paediatric examinations may have come about in past by the need toartificial ly increase the mAs value employed in order to permit i ts selection on the generator control , wi thout the need to lower the kV sett ing.ConclusionsThe results of the EC Trials of the CEC Quality Criteria for Paediatrics highlighted a number of important aspects concerning radiographic practice in Europe.1. Inform ation concerning the technical aspects of radiographic equ ipme nt, such asfi l tration, nominal focal spot value etc., was sti l l in many cases not sufficientlyknown by staff in X-ray departments. For example 50% of departments did notknow the speed class of screen fi lm systems employed in abdomen examinations.Availabil i ty and awareness of this information forms an integral part of fulfi lmentof Article 3 of the EURATOM Directive 84/466. Every effort should be made bymanufacturers and X-ray department staff to ensure this information forms part ofthe technical database of an X-ray department. All 1979 IEC guidelines concerningpresentation of nominal focal spot value and total tube f i l trat ion on the tube hous

ing should be ful ly implemented.2. An extremely high propo rt ion of departm ents employ lower than recomm ended kVvalues even for the 5 year old child. Settings of appropriate kV to make full use ofthe speed of more modern rare earth screen fi lm systems is imperative.3. The use of X-ray generators w hic h perm it the use of the low mAs values ofte nrequired in paediatric examinations is crucial i f in order to control X-ray output the possible lowering of the kV settings is to be eliminated.4. A signi ficant propo rt ion (54 % ) of examinations employed screen f i lm systems w itha nominal speed class of 200 or below. The prevalent recommended range is400 - 800 so that further consideration should be given to this fact.Part 2 - Patient DoseIn this section the results of measurements of the entrance surface dose (ESD) valuesencountered during the three EC Trials are presented. These results indicate the factorswhich play an important role in determining the patient dose and highl ight some of theproblems encountered when trying to define meaningful reference dose values for paediatric X-ray examinations.D is t r i b u t i o n o f I n d i v i d u a l D o se sIn all three of th e EC Trials, inform ation was collected and dose m easuremen ts m ade o nonly one patient at each hospital for each type of examination studies. The total numbersof dosimetric measurements undertaken during the three Trials are shown in Table 2. Asummary of the entrance surface dose measurements performed during the 1989/91 and

yes 41,3 %no 3,6 %

Vmissing 55,1 %Figure 4 Response rates to the quest ion do you employ addi t ional f i l t rat ion?All X-rav examinations of the 5 year old child

8


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Trials is sho wn in Table 4. For the chest and skull exa minations there is a rema rk

stud

les of hospitals from t hro ugh out Europe w ith of ten q uite different radiographic tech

examinations in paediatrics patients

AP (1 00 0 g new born )Infant77

724266564 453

dosimetric Trials on frequenl5 year98

467467685563

10 year10734755661594242535564

X-rayTotal282721221491891291704442425355180

percent of X-ray departments10 month infant 5 year old child 10 year old child

0 0-50 50-100 100-200 200-300 300-400 400-500 500-600 600-700 700-80(ESD (nG y)

Entrance surface dose distributions (ESD) for 10 mon th old infan t, 5 year old and 10 year old children for chest PA/AP examin ation900-1000 1000-1500

39


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Derivat ionof thereference dose va luesThe derivation of reference dose values for paediatric patients is not as straightforward asfor adult patients. Patient doses for the same type of examination are expected to varysignificantly throughout the paediatric age range because of the wide variation in patientsize and composition and the corresponding image requirements. However, it is important

Table3a Entrance surface dosesn u m b e roff r e q u e n tX-i

Chest AP (1000 g newborn)Chest PA/AP(10m onth)ChestAP (10mon th) mobi leSkull PA/AP(10 month)PelvisAP (4 month)Spine Lateral(10month)Abdomen AP/PA(10month)

measuredin the1 989/91 CEC Tr ia lof infantsfora*ay examinationsmin11213415218

10777

EntranceS1stquarti le254555

600100450260

median457590

930260880440

urface Dose(pGymean

68132129

12603981128651

3rdquarti le80

135150

16906401500700

Table3b Entrance surface doses measured in the 1992CEC Tr ialof 5yeara num ber offrequ ent X- ray exam inat ions

Chest PA/APChestAR mobi leChest LateralSkull PA/APSkull LateralPelvisAPAbdomen AP/PA

min1829372421388656

EntranceS1stquarti le4549102691396282340

median6768140967703

485588

urface Dose(pGymean102891701248827707796

3rdquarti le10086213154010789241000

max386979718

4514136943513210

old child

max13473335544 6 2 62 3 5 82 7852917

ratio1111111

354 72130764142

re nfor

ratioI111111

71111519173252

le 4 Variation of entrance surface dose pGy) observed in the three CEC paediatric Trialsmedian, minimum-maximum values and corresponding ratio min:max) of frequentpaediatric patients

1989/91,1992, 1994/95):X-ray examinations in

of X-ray examinationAP(1000g newborn)AP(mobile)

AP

AP

AP

457590

930

260867

440

Infant11- 38621-97 93 4 - 7 1 8

15 2-451 4

1 8 - 1 3 6 9

1 0 7 - 4 3 5 1

7 7 - 3 2 1 0

1:351:471:21

1:30

1:761:41

1:42

6768140967703485

588

5 year

1 9 -134729- 33337- 554

242- 46261 3 8 - 2 3 5 886- 2785

5 6 - 2 9 1 7

111111

711115191732

1:52

7191

1531036577812

887162911462427729

10 year

1 7 - 1 1 5 729- 760

39- 1 9761 3 0 -52101 1 3 - 37878 9 - 4 1 6 7

2 0 4 - 4 3 1 2303 -6 66013 1-5 685

249- 23 4651 4 8 - 3981

1:681:261:511:401:331:47

1:211:221:431:941:27


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he thre e Trials on the infan t, 5 year old and 10 year old child, it has not been

er 1 . However, in presenting these values it is clearly understood that:Every effort should be made by staff und ertaking paediatric X-ray exam inations toensure that entrance dose values for infants and children less than 5 years old arelower than these values.Entrance surface dose values fo r children older tha n 5 years of age are, if possible,no higher than the values indicated in this document, allowing for variations inweight and patient thickness.Further w ork is und ertaken to develop a rational and consistent fram ew ork forcomparing entrance surface doses employed in paediatric X-ray examinations onchildren of different stages of development.

r examp le Figure 6 shows the m ean ESD encou ntered both w ith and wit ho ut a grid for grid, a large dose saving is possible. There is, generally, no need for ant i-

4 --

0 -8 -6 -4 -2 -0

ESD (jiGy)-

- M

o oo om M-1

o oo o^f LO1

o oo om io'

o oo o3 r-~

o oo or~- co1

o oo oco en

o oo oen o'

o oo oO LD* *o oo oLD O r\l

O Oo oO LOrsl rsjO OO OLT Org m

ooLnm< 200 200 - < 400 400 - < 600 > 600Distribution of entrance surface dose with screen film system nominal speed classes for the skull PA/AP child; = number of X-ray departments

ESD ijiG yl)3 5 0 / ~

~3002502001501 0 0 ^

50

* (n)

Use of gridno yes

Figure 6Mean entrance surfacedose (ESD) with and without a gridfor th e chest PA/AP examinationson 10 month infant, 5 year and10 year old children; = number of X-ray departments

Table 5 Percentage ofchildren's hospitals inGermany fu lfilling the CECCriteria for GoodRadiographic Technique forchest X-ray examinations innewbornsExposure tim ekV-setting

12%2 1 %

Additional filtration 3 0 %Focus-filmdistanceScreen filmsystem speed

6 7 %6 6 %

13/9421/10026/10671/10666/100

41


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employed. Clearly demonstrated is the fact that practically only nominal speed classes of> 400 were used for those examinations with an ESD below 700 pGy. Examinations withhigher dose had a speed class of mostly 200 some even less. Two departments hadhigher ESD despite the use of high nominal speed classes (> 600). However, this may bedue to the fact that speed class decreases at lower kV settings and/or lower kV values areemployed in order to compensate for the inabi l i ty of the generator to provide a lowenough mAs value.In order to explore the role of radiographic technique on patient dose the number of individual radiographic technique factors, e.g. kV, fi l tration, speed class, recommended in theQual i ty Cri ter ia Document which were ful f i l led was investigated together with the corresponding ESD values. Table 6 presents results for the 5 year old child for different examinations and clearly demonstrates that the greater the number of recommended radiograp hic techn ique fac tors whic h are met the lo we r the me an ESD value for all exam inations. As shown in Part 3 of this Chapter, this lower dose does not lead to loss of imagequality.Conc lus ions1. The roun ded thir d qua rti le dose values presented in Table 3b for the 5 year old child

should be taken as reference dose values for paediatric patients.2. Every effo rt should be mad e to reduce doses for children less tha n 5 years of ageto below the values presented.3. Strict adherence to all the radiograp hic tech niqu e factors reco mm end ed can leadto signi f icant dose reduction.4. X-ray generators em ployed in paediatric exam inations should be capable of selecting the low mAs values required to ensure that the recommended kV values can beemployed.5. Screen fi lm systems w ith nom inal speed classes > 40 0 should always be emp loyed

together with the appropriate kV sett ings.

Frequency of fulf i lm ent of th e criteria for Good R adiographic Technique in the 5 year old child (num ber o f X -raydep artmen ts [n] and corresponding mea n ESD values [pGy] only criteria direct ly affect ing dose are considered)

zerocriterian pGy

Ful i lment of Criteria of anonecriterion

n1

1

pGy1201085

twocriterian832192

pGy14327314224351307386

Examph of Good Radiographicthreecriteria

n139147102410

pGy193131246

135811495331171

fourcriterian

40193024261125

pGy8088

2141637865851769

: Techn quefivecriteria

n181317191959

pGy5 488103881771302470

sixcriterian6

4465

pGy2553

654464270


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five EU coun tries. The first 1989 /91 Trial involved 8 radiolog ists,

Trial. Following th e first Trial the Image Criteria were mo dified since i f cri

< 1.3 mm .< 4 mm Al equivalentUsednominal speed class > 400> 1 0 0 c m>6 5 k Vction of the n umber of radiographic techniqu e factors fulfi l led for th chest lateralchild. Clearly the more technique factors fulfi l led the lower

ESD (jiGyl) %(n = 66) (3) (4) (24) (21)

-

-

(14) 80

60

40

20

ESD^Gy l ) %

2 3 4 5Total num ber of criteria fu lf i l led

35

3

25

2

15

1

5

(n = 84) (1) (14) (30) (27) (12) 100

, '.?>//

80

60

40

20

2 3 4 5Total number of criteria fulf i l ledDose Image Q uality

Impact of good radiographic technique on entranceace dose and image quality: Chest lateral examina tion child; n = number of X-ray departments

Dose Image QualityFigure 9 Impact of good radiographic technique on entrancesurface dose and mage qu ality: Chest AP/PA exam inationfor 10 year old child; n = number of X-ray departments

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Fendei H., Schneider K., Schofer H., Bakowski C. and Kohn M .M . (1985). Optim ization in paediatr ic radiology: arethere specific proble ms for qua lity assurance in paed iatric radiology? BJR (Suppl.) 1 8:1 59 -16 5.. Fendei H., Schneider K., Kohn M .M . and Bakowski C. (1989 ). Specif ic pr inciples for opt imiz atio n of image quality andpatient exposure in paediatr ic diagnostic imaging. BIR Report 20 :91-101 .

Schneider K., Fendei H., Bakow ski C , Stein E., Koh n M .M ., Kellner M ., Sch we igho fer K., Cartag ena G., Padovani R.,Panzer W., Scheurer C , Wall B. (1992). Results of a dosime tr ic study in the European C om m un ity o n freq uen t X-rayexaminations in infants. Radiation Protection Dosimetry 43: 31-36.. Schneider K., Koh n M. M ., Bakow ski C , Stein E., Freidhof C , H orw itz A.E., Padovani R., Wa ll ., Panzer W., FendeiH. (1993) Im pact of radiograp hic im aging cr iter ia on dose and ima ge quality in infants in an EC-wide survey. RadiationProtection Dosimetry 49:73-76.

Schneider K., Koh n M .M ., En dem ann ., Ernst G., Panzer W., Padovani R. an d W all . (199 5). Varia tion in radia tiondose and mage quality of common X-rays of the f ive year old chi ld. A European wide survey in children's clinics.Supplement to Vol. 5. European Radiology, p. 192 (abstract, detailed publication in preparation).CEC 1 992 : Quality Criter ia for Diagnostic Radiographic Images in Paediatr ics, Draft Wo rkin g D ocu me nt, CECXII /307/91, June 1992.IEC 1979 , Marking of accom panying d ocum ents for X-ray tubes and X-ray tub e assemblies for me dical use,International Electrotechnical Commission, Publication 637, 1979.

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page but one, and a means of m easuring or estimating th e dose to the p atient. They

Set standardsCheck complianceCorrect bad practiceSet new standardsRepeatQu ality Criteria essentially provide the initial stan dar ds for mage qua lity andaud it; a special case of me dica l au di t .

Choose type of radiograph frequen tly taken on 4-6 year old patients in the X-rayfacil i ty to be audited.Take a random sample of at least 10 patients aged 4-6 years, weight 1 5-25 kg.Take chosen type of radiograph on each patient using established techniques.Record all the technique and equipment parameters for each radiograph. (Seeexample que stionnaire in App endix I to this chapter for relevant details to record).Measure or estimate the entrance surface dose for each radiograph using themethods described in Appendix I of Chapter 1. Compare the mean value for thesample of at least 10 average sized patients with the corresponding reference dosein the Quality Criteria.At least two observers check compliance of each radiograph with the ImageCriteria independently. Appendix II to this chapter contains a copy of the ImageQuality Assessment form similar to those used by the panel radiologists for scoringfilms in the Trials of Quality Criteria. Observers taking part in this audit processmight find this form useful. The form can be adopted for each type of radiographfor which Quality Criteria are provided in these Guidelines. As well as providing asystem for scoring compliance with the Image Criteria these forms also include asystem for scoring more general aspects of the image such as film blackening, fieldsize and diagnostic acceptability; other aspects such as contrast and sharpness mayalso be considered.To help in judging these features, both during this audit process and moregeneral ly at any t ime. X-ray departments should consider having avai lable

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a set of idea l f i lms in wh ich al l these aspects are opt im ised and ag ainstwh ich a ny o ther f i lms can be direct ly visual ly com pare d. I t is essen t ial , ofcourse, tha t the ideal f i lm can be produced w i th a dose to the pat ientbelow the corresponding reference value.7. Identify wh ere the standard (image quality or dose criteria) is not being met.8. Investigate the cause(s) of any consistent non com pliance w ith the criteria. TheExam ple of Good Radiographic Techniqu e may be useful to help identify those

aspects of the established technique or equipment which are responsible.9. Take corrective action by chan ging technique s or eq uipm en t in a ma nner l ikely toremedy the noncompl iance.10 . Afte r a short period of using the revised techn iques or eq uip me nt, repeat steps2-7.11. If no imp rovem ent, repeats steps 7-10 .12 . If initial standard s (criteria) are no w bein g me t in fu l l , consider improving standards,for example, by setting lower reference doses in l ine with the ALARA principle.To help establish a more uniform and more widespread level of performance in diagnostic radiology it would be desirable to extend the audit process to include independentobservers, external to the X-ray department being audited, and to progressively apply theprocess to larger groupings than individual X-ray departments.Optimisation of radiographic techniques in paediatric radiology is often restricted by thefact th at th e eq uipm ent is not designed specifically for use on small children. A l ist of basicrequirements for radiographic equipment suitable for paediatric radiology may bededuced from discussions which took place within the European Study Group under contract No 91/ET005, DG XI-C-1/1992.For further guidance this l ist is presented below:Guidel ines on basic requirements for radiographic equipment in paediatric radi ology as an aid to fulf iment of the qual i ty cri teria for diagnost ic radiographicimages in paediatrics1 . GeneratorsWaveform:Power:Tube voltage:mA settings:Exposure time:2. TubeNominal focal spot value:Extra-focal radiation:3. FiltrationMinimum inherentf i l trat ion:Addit ional f i l trat ion:

preferably 12-pulse or high frequency multi-pulse converter> 30 kW (f ixed generator equipment)> 10 kW (mobi le equipment)45 to 120 kV (150 kV for special conditions and indications)(constancy of tube voltage (kV) < 5%)adjustable, lowest possible mAs value < 0.5shortest exposure time nominal 1 msseparate display of exposure time (ms) and mAs

< 1.3 (according to IEC 336, 1993)minimise by use of focusing lead strips

beam quality of first half value layer equal to 2.7 mmAl at 100 kV(according to EN 606 01 -1-3, 1994)1 mm Al and 0.1 mm Cu or more (selected settings should bevisually displayed)


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removable (automatically or manually, visual display)high primary beam transmission (carbon fibre covers and interspace material or better)moving grids with strip density > 36 lines/cm and grid ratio 8;multi-line grids with strip density > 60 lines/cm (according toIEC 627, 1978)

Au tom atic Exposure Control Systemrequirem ents: particularly adap table for infants

inal speed class: 40 0 - 800 (200 for special cond itions)

Ancillary Eq uipm ent

Measurement and display of dose area product, dose, and,optionally, dose area product rate and dose rate

table top with low attenuation materialimmobilisation board or chairimmobilisation devicescompression bandslead contact shields or shadow masks for girlsshaped lead gonadal capsules for boysspecial organ'shaped filters and shadow shieldslead rubber contact shieldsorgan shaped sponges (2 5 cm diameter)

on limit: > 1.4 Ip/mmdigital spot imaging 10242 matrixadaption of field size to the size of the image intensifier system

. Digital Image processing (storage phosphor screens) 576 1976 pixels with 24 cm 30 cm cassette (> 3 Ip/mm)1770 2370 pixels with 18 cm 24 cm cassette (> 4 Ip/mm)reading grey scale > 8 bit

Fluoroscopyer inpu t dose rate: For standard 25 cm diam eter image inten sifier field size

Low dose fluoroscopy: 0.1 mGys1

0.2 mGys 10.6 mGys 11.0 mGys 1

infantschildrenmaximum'High Level Control'Fluoroscopy: maximum(not needed if other options provided)vo ltag e: > 70 kV (w ith override available to allow setting for infant studies)

requirements: autom atic brightness controlpreferably pulsed fluoroscopylast image holdfluoroscopy only with an additional fi l tration of 0.2 mm Cu ormoremulti leaf diaphragm and/or iris diaphragmminim um field size at the image recording system < 4 cm 4 cm

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EN 60 60 1-1 -3, 1994 = IEC 601-1 -3, 19 94, part 1: General requirements for safety 3. Col lateral stand ard: Generalrequirements for radiation protection in diagnostic X-ray equipment IEC 62 7, 197 8; Characterist ics of anti-scatter grids used in X-ray equ ipm ent .

IEC 33 6, 199 3; X-ray tu be assemblies fo r medical diagnosis C haracteristics of foca l spots.


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DIX I

Chest PA/AP questionnaire.

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FOR THE S T U D Y O F EN TR AN C E SU R FAC E D O S E V A R I A B I L I T Y I N PED IAT R IC R A D I O L O G Y

- 5 year old childDosemeter N.:IMPORTANT Please fil l in the dosemeter N used for thisexam inat ion and the cl inical informa tion in the left box.Name of the study center

I n f o r m a t i o n o n t h e p a t i e n tExposure Date

/ /D

Sex femaleQ male

Date o f B i r th/ /

D M Y

W e i g h t

kg

H e ig h t

cmTLD placement

always place the TLDon the beam entrance

side of the patient)

. I n f o r m a t i o n o n e q u i p m e n t

ManufacturerModel/TypeConstruct. YearPower

Generator

kW

Generator Type

1 or2-Pulse 6-Pulse 12-Pulse converter, multipulse condensator discharge direct-current generator

Automatic exposurecontrol used?

no yes

infronto fcassette behind cassette

X-ray device

table stand bed side otherspecify:

wh at is the inherent f i l t rat ion of the X-ray tube used for this exam inat ion?:was addit ional f i l tration used for this exposure? no yes, please specify material Cu, Mo , Fe, etc.) and thickness mm Al + .

mm Al-equivalent

e.g. 1 mmA I + 0.1 m m Cu)

I n f o r m a t i o n o n r a d i o g r a p h i c t e c h n i q u e: mAs : Anti-sc atter grid used?: no yes: nominal focal spot val.: mm stationa ry grid: focus-f i lm-dist . : cm Q moving grid

dose area pro duc t : Rcm2or Gy cm2 grid cassettesradiat ion protect ion measures taken? Q no yes

ovarian shields Q testicular capsules others , specify ovarian masks testicular shields

ManufacturerModelXTypeLight emission

Film

green blue

Screen

green blue

Ma terial of cassette fro nt aluminium plastic carbon fibre kevlar

Nominal speed class of screen fi lm system:e.g. 100, 200, 400, 600, 800, etc.)

Base optical density fog) of the f i lm: e.g. 0.20)


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Diagrams for TLD-placementfor the respective examinationaccompanying instruct ion:

(always place the TLD on thebeam entrance side of the patient)

CHEST PA/APstationary unit5 year old child

ST AP CHEST Lateralstationary unit5 year old child

r ^i SKULL Lateral5 year old child

ABDOMEN PA/AP5 year old child

THORACIC SPINE Lateral5 year old child

TLD-position = T6-T7LUMBAR SPINE Lateral5 year old child

TLD-position = L351


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3

hindA few examples are l isted below w hich may prove useful for people attem pting this

The TLDs we re not always visible on the films. To con firm correct pos itioning it isuseful to ask the radiographer who placed the TLD to indicate its position on thediagram in the questionnaire.All edges of the beam must be visible on the film so tha t correct pos itioning canbe checked. Sometimes the patient identification details had been removed by cutt ing off a complete edge of the fi lm together with the corresponding edge of thebeam. Patient details should be masked rather than cut off.Num bered stickers should be supp lied to indicate the order of the films take n in theIVP series, for example.A processed but unexposed film is useful for assessing fo g level.The patie nt pos ition (supine, pron e, up righ t, etc.) is not always appare nt fro m thefilm and should be indicated on the questionnaire.Useful if the name of the person (and telephone or fax number) wh o took fi lms andcompleted the questionnaire is indicated so that they can be easily contacted ifdetails are not clear.All l ight boxes used for viewing the fi lms should be from the same manufacturerand of the same colour and brightness.

Each observer (film reader) should have their ow n light box and w or k inde pen dently of other observers.Experience should be gained in observing films and filling in the assessment form sbefore starting on the real tr ial. Judgements have been seen to change during theearly stages of the learning process.

Chest PA/AP follows on the next page. Assessmentreplace the Image C riteria, rows 1 to 7 on th e sample scoring sheet for Chest

fol

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CHEST PA/AP

Performed at peak of inspira tion, except forforeign body aspiration Reproduction of the thorax a: w i th ou t rotation

b: and wi tho ut t i l t ingReproduction of the chest must extend from justabove the apices of the lungs to T12/L1

. Repro duction of the vascular pat tern incentral 2/3 of the lungsRepro duction of a: the trachea

b: and the proximal bronchiVisually sharp a: the diaph ragmreproduction of

b: and costo-phrenic anglesRep roduction of a: the spine

b: and paraspinal structuresand visualisation of c: the retrocardiac lung

d: and the mediastinum

Film - No.

lm acceptable for the given clinical question * * *

1 = yes+ = op t imum+ = op t imum1 = fully acceptable

Name of radiologist and hospital code

0 = no= too much / too high = su b-opt imum2 = only acceptable under special conditions = too l i tt le / too low0 = unacceptable3 = unacceptable (give reasons)


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III Survey: ESPR Lake Starnberg Group on the right is similar to the previous feedback you had

in thepast.Thedose values and image quality scores mea in your depar tment are shown as a profile in relation to the

of all theother values m easured for the respective examina(thestatistical ranking procedure yields values slightly belowthe

for the extreme scores).Achest PA /AP dose value extremely close to 0 (e.g.4pGy for chest PA/AP) means that your dose value lies near to or

at themedian of all values;a value extremely nearto or at -0 % (50%) means, your value equalledtheminimum ( maximum)or,

the lowest (highest) percentileof all dose measuremen ts .for image qualitycan beinterpreted similarly.Allvaluesare asdeviations from the median; optimal values should be as

as possible (minimum dose ormaximum image quali ty) .The andmaximum and your individual scores for the

aregiven in the Table below.is a very rough indicatorof the image quali

on thedefinitions in theDocu ment Quality criteriafordiagin paediatrics .Apanelof nine paediatric

radiologists rated each film in respect to fulfilment of the criteriadefined inthis docum ent and, inaddit ion,to three general image criteria, i.e. appropriate f ilm-blackening and field sizeandwhetherthefilm is acceptablefor thegiven clinical question. For comparisonsandto simplify theanalysis , the score for the IVP-series is an averagescorefor all allX-ray films d uringthe contrast phaseof theIVP;thescore for the plain film alone is given under abdom en . A score(mean scoreof all nine raters) of 100% means that all of the criteriawere ratedas fulfilled. Youmayfind some,and in a fewcasesallvalues missingon theprofile. There was then either no X-ray madeforthe respective examinationor thedose m easurements werenotpossib le or misleading (occasionally theTLD s were placedon the beamexit side of the patient yielding a low exit dose). When patientage/weight was not within the requested range, we have still listedyour dose valuesand image quality scoresand thecorrespon ding percentile graphs (highlighted inyellow) showin g your percentiles for adata analysis wherenoexclusions for age and weight were made.

A s

quality criteria image 3

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