Radiography (2004) 10, 15e21

Gonad protection for the antero-posteriorprojection of the pelvis in diagnosticradiography in Dublin hospitals

Aoife Doolan, Patrick C. Brennan), Louise A. Rainford, Jan Healy

UCD School of Diagnostic Imaging, Herbert Avenue, Dublin 4, Ireland

Received 19 September 2002; accepted 16 December 2003

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Abstract Gonad shielding during diagnostic X-ray procedures is an effective wayof reducing radiation dose to patients’ reproductive organs and reduces the riskof genetic effects in future generations. The utilisation of gonad shielding, theavailability of shields and the existence of written protocols for the use of radiationshielding for antero-posterior projections of the male and female pelvis were exam-ined in four major Dublin hospitals. A retrospective study of 198 pelvic radiographsrevealed that only 2% (n ¼ 4) of images had evidence of gonad shielding. All fourimages that demonstrated shielding showed that the shield was malpositionedwith either important bony anatomy obscured or gonads not sufficiently protected.Some of the hospitals surveyed had inadequate supplies of gonad shields in the gen-eral radiography rooms and no written protocols were available. The results of thisstudy indicate that patients in the hospitals investigated are receiving avoidable go-nad irradiation due to the omission, or malpositioning of gonad shields during pelvisexaminations. In line with recent EC recommendations appropriate shielding of thegonads during pelvis AP examinations should be encouraged.ª 2004 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

KEYWORDSReproductive organs;Radiation;Written protocols

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Introduction

The International Commission of Radiation Protec-tion (ICRP) deems the gonads to be the body’s mostradiosensitive organ at a weighting factor of 0.2where the potential for hereditary damage andmalignant changes exists following radiation expo-sure.1 The ICRP estimates the risk of serious hered-

) Corresponding author. Tel.: D353-1-2094424; fax: D353-1-2837425.

E-mail address: patrick.brennan@ucd.ie (P.C. Brennan).

1078-8174/$ - see front matter ª 2004 The College of Radiographedoi:10.1016/j.radi.2003.12.002

itary ill health within the first two generationsfollowing the irradiation of either parent to beabout 10 per million per millisievert.1 Genetic ef-fects, being stochastic events, mean that they donot have a threshold dose, so there is no such thingas a ‘‘safe’’ gonad radiation exposure and even thesmallest radiation dose can cause an effect.2

The sensitivity of cells following irradiation is indirect proportion to their reproductive activityand inversely proportional to their degree of differ-entiation. Therefore tissues and organs found with-in the reproductive system that support a large

rs. Published by Elsevier Ltd. All rights reserved.

16 A. Doolan et al.

amount of stem cell activity are extremely sensitiveto radiation.3 Potential health effects from the lowlevels of radiation exposure prevalent in diagnosticradiography may not be observed in the shortterm,2 and may not become apparent for severalgenerations. The probability of a fatal cancer be-ing induced in an individual patient from a singlepelvic examination exposed to a typical doseranges from 15 to 55 per million.4 Almost a millionpelvic radiographs were documented in the UK perannum following an NRPB survey.5 Exposures of thepelvis without appropriate shielding involve irradi-ating the gonads which lie in the primary beam,therefore the NRPB advocates the use of gonadshields in radiological examinations for patientsat or below reproductive age.6 Recent Irish legisla-tion requires written protocols for every type ofstandard radiological practice; this is to be estab-lished by the Medical or Dental Councils, howeverno information to this effect has been publishedto date.7 Godwin et al.8 also recommend that writ-ten departmental protocols for the correct use ofgonad protection should exist, with the aims ofavoiding confusion over when and how gonad pro-tection is applied and to reduce gonad dose with-out significant loss of radiographic information.

The effectiveness of gonad shielding has beenproven. An unshielded exposure of the pelvis re-sulted in a dose to the testis of 0.83 mSv and tothe ovary of 0.21 mSv.9 Following the applicationof shielding, the dose to the testis and ovary wasreduced to 0.06 mSv and 0.03 mSv which amountsto a 14 fold and 7 fold reduction, respectively.9

Previous researchers have advocated that gonadshields should be used in all routine examinationsof the pelvis, and in all but the first antero-poste-rior projection in emergency cases, since in the lat-ter, lead shields placed on the pelvis may obscureimportant structures that may be relevant to thecondition under investigation. Subsequent radio-graphs however, should include gonad shielding.10

Although guidance for the use of gonad shields isavailable, previous investigations have establishednon-optimal use. Investigations in the UK in 199211

and 200112 showed that gonad shielding was usedfor only a minority of patients and when it wasused it was poorly placed in the majority of cases.The practice of gonad shielding in Ireland has notbeen previously investigated and it is the aim ofthe current work, to explore the availability andusage of such shields for pelvic radiography ina number of major Dublin hospitals.

The objectives were to investigate:

� Whether departmental written protocols gov-erning the use of gonad shields exist

� Availability of gonad shields in rooms wheregeneral radiography is undertaken

� The use of gonad shields where appropriate inthe AP projection of the pelvis

� Whether gonad shields are correctly and opti-mally positioned when they are used.

Methodology

Four major Dublin hospitals were selected.The radiology service manager in each clinical

site was interviewed to ascertain the existenceand subsequent detail of written hospital protocolsconcerning the use of gonad protection for theantero-posterior (AP) projection of the pelvis.Following this, across the four clinical sites, allX-ray rooms in which pelvic radiographic exami-nations were undertaken were investigated todetermine:

� The availability of gonad shields� The completeness of gonad protection sets. A

gonad set was considered complete if shieldsof four sizes were available and these weresuitable for male and female patients.8

To establish the extent and accuracy of employ-ing gonad shields, AP pelvis images were assessedretrospectively. All images contained the completepelvic inlet, the ischial tuberosities and the proxi-mal quarter of the femurs. The application ofthese image criteria ensured that the male or fe-male gonads were always in the X-ray beam. Themost recent pelvic images from a minimum of 30patients (15 males, 15 females) of reproductiveyears were included in each clinical site. For thereasons outlined above, accident and emergency(A&E) patients were excluded.

Each pelvis image was assessed under the fol-lowing criteria:

� The presence of gonad shields� Position of shields if present

One assessor established whether gonad protec-tion was present on the images. Images with visibleprotection were then further assessed with regardto the accuracy of gonad shield positioning; thiswas performed by an experienced radiographerand a radiography lecturer using the following ac-ceptability criteria:

� Did the area of radiograph obscured by theshielding cover the gonad location? In malesthe gonads are enclosed within the scrotal sac,in females the gonads were considered to beadjacent to the ischial spine.10,13

Gonad shielding during pelvis radiography 17

� Was any bony anatomy obscured which couldhave been avoided by improved placement ofthe gonad shield?

Results

The results will be described under the followingheadings:

� Written protocols� Availability of gonad shields� The presence of gonad shields on AP pelvis

images� The positioning of gonad shields when em-

ployed

Written protocols

Written protocols for the use of gonad shields werenot in existence in any of the four hospitals inves-tigated.

Availability of gonad shields

The availability of gonad shields in X-ray roomsvaried between hospitals. In one hospital a com-plete set of shields was available in all five roomsinvestigated. In the second hospital a completeset was present in two of the four rooms examinedwith a partial set in a third room. In the third hos-pital a full set of shields was available in two of thefive rooms examined with a partial set in anotherroom. In the six rooms investigated in hospital 4,a complete set of shields did not exist; however,a single shield existed in one room. These dataare summarised in Table 1.

The presence of gonad shieldson AP pelvis images

A total of 198 radiographs were examined from120 patients. Four of the 198 images (2%) demon-strated the presence of gonad shielding. Thesefour images originated from one male (two images)and two females (one image each). The breakdownof shielding within each hospital is shown in Fig. 1.

The positioning of gonad shields whenemployed

Of the four images with evidence of gonad shield-ing, none of these were optimally positioned. Ontwo images the shields chosen were too small

and the gonads remained unprotected and ontwo further images bony landmarks were ob-scured. Examples are given in Figs. 2e5.

Discussion

The work presented is a small study resulting froman undergraduate dissertation. It describes the sit-uation in four Dublin hospitals and does not at-tempt to extrapolate the data gathered fromthese hospitals to the wider situation. As such itsscope is small, nonetheless it has identified someareas of concern regarding gonad shielding.

Examination of the pelvic images demonstratedthat gonad shields as a means of protecting the ra-diosensitive reproductive organs were rarely em-ployed in the hospitals investigated in this study.It was also identified that a patient can have asmany as five pelvic exposures without any gonadshielding. These results are worrying as the impor-tance of lead shielding has been described in theliterature12e14 and is recommended by the Euro-pean Commission.15 Of the four radiographs thatwere actually found to have gonad shields present,only two of these had the gonads completelyshielded, but even these images did not demon-strate ideal positioning of shields, as they obscuredimportant features of the bony anatomy. It should

Table 1 Availability and type of gonad shields inX-ray rooms

Hospital Room Gonad shields Type

1 1 Complete set Kings Lynn2 Complete set Kings Lynn3 Complete set Kings Lynn4 Complete set Kings Lynn5 Complete set Kings Lynn

2 1 Incomplete set Kings Lynn2 Complete set Kings Lynn3 Complete set Kings Lynn4 No shields n/a

3 1 Complete set Kings Lynn2 Complete set Kings Lynn3 Incomplete set Kings Lynn4 No shields n/a5 No shields n/a

4 1 Incomplete set Kings Lynn2 No shields n/a3 No shields n/a4 No shields n/a5 No shields n/a6 No shields n/a

18 A. Doolan et al.

Figure 1 Number of radiographs with/without shielding.

be acknowledged that the data presented here onshield usage should be considered as estimates,since there may be some downward bias due toshields being present for male examinations, butpoorly positioned so they were not visible on the

image, and some upward bias since no allowancewas made for the number of radiographs thatmay have been rejected and repeated withoutthe shield due to malpositioning of the shield onthe first radiograph. Also, although A&E patients

Figure 2 Gonad shield is too small.

Gonad shielding during pelvis radiography 19

Figure 3 Gonad shield is obscuring the sacroiliac joints.

were not included in this work, there may be othercategories of patients defined by departmentalprotocol whereby gonad shields are not used.These categories should be specified in futurework.

The findings of this study are in broad agree-ment with previous workers. Kenny and Hill,10

who conducted a retrospective study of paediatric

radiographs, found that the gonads were notprotected in 71% of antero-posterior pelvicradiographs because the lead shielding had beenomitted or inadequately placed. Laikos et al.,12

studying female paediatric patients, showed thatlead shields, covering greater than 75% of the ova-ries, whilst not obscuring the necessary anatomi-cal detail, were only present for 1.6% of pelvic

Figure 4 Gonad shield not protecting the gonads completely and the left ischial tuberosity is obscured.

20 A. Doolan et al.

Figure 5 Bony anatomy is obscured by the gonad shield.

radiographs. Wainwright13 examined 200 imagesfrom patients of reproductive years as well asfrom children aged below 16 years. None of thepatients aged 16 or above had gonad shields whilst36% of patients below 16 achieved full coveragewith lead shielding.

Correct positioning of lead shields so that thegonads are completely obscured whilst not con-cealing important anatomical information is a deli-cate and difficult task. If in the first place oneexpects radiographers to use gonad protection inan effective way for all relevant patients, a com-plete set of protective devices needs to be avail-able in all rooms where pelvis X-rays can beperformed. This was the case in one of the fourhospitals examined. In two of the other hospitals,complete sets were only available in some of therooms, whilst in the fourth hospital a completeset did not exist anywhere. Secondly, once shield-ing devices are available, to encourage their em-ployment, it is important that proper directionsand protocols regarding their use are available toradiographers. This was not the case in any ofthe hospitals examined in this study. These defi-ciencies, where relevant, should be addressed asa matter of concern in the hospitals of this studyand highlight the importance of checking these pa-rameters in all X-ray departments. Once completeshielding and protocols are in place, along with theprovision of educational programmes if necessary,

radiographers should be expected and encouragedto employ gonad shielding for examinations of thepelvis.

It is interesting to consider the impact that go-nad shielding has on the collective dose of a popu-lation. A recent survey by our group showed that inone Dublin hospital, 3897 AP pelvic examinationswere performed in the year 2000.16 If this figureis typical for each of the hospitals involved in thecurrent investigation, this amounts to approxi-mately 15,000 examinations per year across thefour hospitals. Using the latest available entrancesurface dose data in Ireland for AP pelvis examina-tions (5.6 mSv),17 over 10 years (a conservative es-timate of the lifespan of a set of gonad shields),this would amount to a collective entrance surfacedose of 840 man-Sv, for the four hospitals, for thissingle projection. Using NRPB conversion coeffi-cients18 and assuming that equal numbers of malesand females were irradiated, this means a collec-tive dose to the testes and ovaries of 303.8 man-Sv and 82.5 man-Sv, respectively. Proper gonadshielding can reduce the radiation dose to the re-productive organs by up to a factor of 14 for malesand 7 for females,14 reducing the above testisand ovary doses to 21.7 man-Sv and 11.8 man-Sv,respectively. Using the NRPB estimates of2:4!10�2=Sv, the incidence of severe hereditarydisease would be reduced from 9.4 to 0.7.19 Inthe UK where the annual collective dose for the

Gonad shielding during pelvis radiography 21

AP pelvis is approximately 650 man-Sv, the bene-fits of employing gonadal shielding would be sub-stantially higher.20 A typical set of gonad shieldscosts 450 Euro (approx. £315/$520) and it seemsclear that their use is economically justified andin keeping with the principle of ALARA.

Conclusions

The results of this study demonstrate that gonadshielding is rarely used for antero-posterior projec-tions of the pelvis in four Dublin hospitals andwhen it is used it is not employed optimally.

The need for complete sets of gonad shieldingavailable to all relevant X-ray rooms and writtenprotocols for shielding have been highlighted.

Further work should investigate the usage of go-nad shields in a wider group of hospitals.

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