Injury, Int. J. Care Injured 45 (2014) 164–169

Radiation from CT scans in paediatric trauma patients: Indications,effective dose, and impact on surgical decisions

Michael H. Livingston a, Ana Igric a,c, Kelly Vogt a,b, Neil Parry a,c,d, Neil H. Merritt a,d,e,*a Division of General Surgery, Schulich School of Medicine and Dentistry, University of Western Ontario, London Health Sciences Centre, London, Ontario,

Canadab Acute Care Surgery and Surgical Critical Care, Los Angeles County and University of Southern California Medical Center, Los Angeles, CA, USAc Division of Critical Care, Schulich School of Medicine and Dentistry, University of Western Ontario, London Health Sciences Centre, London, Ontario, Canadad Trauma Program, London Health Sciences Centre, London, Ontario, Canadae Division of Paediatric Surgery, Schulich School of Medicine and Dentistry, University of Western Ontario, London Health Sciences Centre, London, Ontario,

Canada

A R T I C L E I N F O

Article history:

Accepted 9 June 2013

Keywords:

Paediatric

Trauma

Radiation

Computed tomography

Effective dose

A B S T R A C T

Objectives: The purpose of this study was to determine the effective dose of radiation due to computed

tomography (CT) scans in paediatric trauma patients at a level 1 Canadian paediatric trauma centre. We

also explored the indications and actions taken as a result of these scans.

Patients and methods: We performed a retrospective review of paediatric trauma patients presenting to

our centre from January 1, 2007 to December 31, 2008. All CT scans performed during the initial trauma

resuscitation, hospital stay, and 6 months afterwards were included. Effective dose was calculated using

the reported dose length product for each scan and conversion factors specific for body region and age of

the patient.

Results: 157 paediatric trauma patients were identified during the 2-year study period. Mean Injury

Severity Score was 22.5 (range 12–75). 133 patients received at least one CT scan. The mean number of

scans per patient was 2.6 (range 0–16). Most scans resulted in no further action (56%) or additional

imaging (32%). A decision to perform a procedure (2%), surgery (8%), or withdrawal of life support (2%)

was less common. The average dose per patient was 13.5 mSv, which is 4.5 times the background

radiation compared to the general population. CT head was the most commonly performed type of scan

and was most likely to be repeated. CT body, defined as a scan of the chest, abdomen, and/or pelvis, was

associated with the highest effective dose.

Conclusions: CT is a significant source of radiation in paediatric trauma patients. Clinicians should

carefully consider the indications for each scan, especially when performing non-resuscitation scans.

There is a need for evidence-based treatment algorithms to assist clinicians in selecting appropriate

imaging for patients with severe multisystem trauma.

� 2013 Elsevier Ltd. All rights reserved.

Contents lists available at SciVerse ScienceDirect

Injury

jo ur n al ho m epag e: ww w.els evier . c om / lo cat e/ in ju r y

Introduction

Computed tomography (CT) has become a fundamental part ofthe workup for patients with traumatic injuries. Some studies haveadvocated the use of ‘‘pan-scanning’’ in order to avoid missinginjuries in severely injured patients [1]. In some centres, thispractice has become routine for adult patients, and often carriesover to the management of paediatric trauma patients. There isevidence that paediatric trauma patients are scanned even more

* Corresponding author at: London Health Sciences Centre, Victoria Hospital,

Children’s Hospital of Western Ontario, 800 Commissioners Road East, London,

Ontario, Canada N6A 5W9. Tel.: +1 519 685 8454; fax: +1 519 685 8465.

E-mail address: neil.merritt@lhsc.on.ca (N.H. Merritt).

0020–1383/$ – see front matter � 2013 Elsevier Ltd. All rights reserved.

http://dx.doi.org/10.1016/j.injury.2013.06.009

liberally than adults, perhaps because of issues with communica-tion or confusion over the typical pattern of injuries in children [2].

Over the last decade, there has been growing concern regardingthe risk of malignancy due to the ionizing radiation associated withCT [3–5]. In 2001, Brenner et al. [4] used historical data fromsurvivors of the atomic bomb to estimate the risk of fatal cancer tobe approximately 1 in 1000 for children undergoing CT scans. Thevalues reported varied significantly with age, such that the risk ofcancer in an infant was approximately 2–4 times as high as that ofan adolescent, and up to 10 times as high as that of an adult. Theattributable risk from a CT in a 1 year-old child was as high as 0.18%for scans of the abdomen and 0.07% for scans of the head. Whilethis represents a very small increase over the background rate ofmalignancy, it is important to note that there are 7 million CT scansperformed on children each year in the United States alone [6].

Table 1Summary of patient characteristics.

CT No CT Total

Total 133 24 157

Gender

Male 100 15 115

Female 33 9 42

Age

Mean 10y 7mo 3y 10mo 9y 7mo

Standard deviation 5y 9mo 4y 8mo 6y 1mo

Mechanism

Blunt 131 22 153

Penetrating 2 0 2

Burn 0 2 2

Presentation

Direct 43 5 48

Referred 90 19 109

Injury Severity Score

Mean 22.2 24.1 22.5

Standard deviation 8.5 9.5 9.6

Mortality

Survivor 121 21 142

Non-survivor 12 3 15

Fig. 1. Number of CT scans per patient.

M.H. Livingston et al. / Injury, Int. J. Care Injured 45 (2014) 164–169 165

Assuming a 1 in 1000 risk of malignancy, the number of futureexcess cancers due to CT scans may be as high as 7000 per year.

There are several reasons for the higher risk of malignancy inchildren [6]. First, tissues that are growing tend to be moresensitive to ionizing radiation compared to those that are in asteady state and mature. Second, children have a lifetime ahead ofthem to manifest the oncogenic effects of ionizing radiation,whereas an older adult may die from other causes before the dosehas a clinically significant effect. Finally, if CT scan parameters arenot appropriately adjusted for paediatric patients, the smaller-cross sectional area of a child results in a dose of radiation that isconcentrated in smaller amount of tissue. This can result in ahigher effective dose compared to the same scan in adults.

The most useful means of assessing the radiation risk to aparticular body area is the effective dose, expressed in milli-sieverts (mSv). The effective dose has been defined by theInternational Commission on Radiologic Protection as the singledose quantity reflecting the overall risk to a reference person fromany radiation exposure, where the risk is averaged over all agesand both sexes [7]. The effective dose from a single CT scan can bederived from scan parameters including scan length, pitch, tubecurrent, and tube voltage [8,9]. The dose length product (DLP) isa scan-specific measure reflecting the total dose delivered over aparticular scan length, and can be used to estimate effective dosethrough the use of conversion factors for body region and age ofthe patient [10–12].

The goal of this study was to quantify the total amount ofradiation from CT scans received by severely injured paediatrictrauma patients at our institution. Our institution is a Level Ipaediatric and adult trauma centre, which treats 70–80 paediatrictrauma patients with severe injuries per year (Injury Severity Scoregreater than or equal to 12). We hypothesized that paediatrictrauma patients are receiving significant doses of radiation,secondary to multiple scans, at the time of resuscitation, duringtheir hospital stay, and an outpatient. We also explored reasons foreach scan and determined, as accurately as possible, any follow-upaction taken as a result of these investigations.

Patients and methods

This study received approval from the Research Ethics Board atour institution (Study Number 16522E). All patients wereidentified through our centre’s prospectively collected traumadatabase.

We included all patients with: (1) age less than 18 years and (2)Injury Severity Score (ISS) greater than or equal to 12. Data wereretrieved from both the trauma database and each patient’selectronic medical record. We included all CT scans that patientsreceived at our centre during the initial resuscitation (defined asfirst 4 h after admission), the remainder of the hospital stay, and6 months following the trauma. Only scans performed at our centrewere included in the analysis.

The dose report accompanying each CT scan was used toidentify the DLP. Published conversion factors were used to convertthe DLP to effective dose (in mSv) [13–15]. The reason for each CTwas recorded as well as any action taken as a result of the scan. Alldata were analyzed using the Statistical Package for the SocialSciences (SPSS) Version 20.

Results

157 paediatric trauma patients were identified during the 2-year period. Our patient population was predominantly male (73%)with a mean age of 9 years 7 months (range 1 month to 17 years 11months). Mechanisms of injury included blunt trauma (98%),penetrating trauma (1%), and burns (1%). The majority of our

patients were referred from other institutions (69%) rather thandirect presentations (31%). Mean ISS was 22.5 (standard deviation9.6) with an in-hospital mortality of approximately 10% (Table 1).Length of stay at our centre among the 142 survivors ranged from 1to 111 days (mean 10 days). Only one patient was observed in theemergency department for 6 h and was not admitted to hospital.

133 patients received at least one CT scan. The number of scansper patient ranged from 0 to 16 with an average of 2.6 (Fig. 1).Excluding patients who were not scanned (n = 24), the averagenumber of scans was 3.1. The most common type of scan was a CThead (104/133 patients, 78%), followed closely by scans of the body(73/133 patients, 55%). Body scans were defined as CT of the chest,abdomen, and/or pelvis. Other types of scans included CT spine(59/133, 44%), CT face (9/133, 7%), and CT of the extremities (3/133,2%). In our study, CT of the extremities included scans of the elbow,shoulder, and knee.

Total effective dose for all 157 patients ranged from 0 to 61 mSv(Fig. 2). The average radiation dose per patient scanned (n = 133)was 13.5 mSv (indicated by the black line in Fig. 2). Although thescan most frequently repeated scan was a CT head, the mostsignificant source of radiation was CT body (Table 2).

Indications for scans included initial resuscitation (56%),reassessment of injury without change in clinical status (30%),and change in clinical status (13%) (Table 3). Most scans resulted inno further action (56%) or additional imaging (32%). A decision to

Fig. 2. Total effective dose per patient in millisiverts (mSv). Solid black line indicates

the maximum recommended annual dose of 3.0 mSv.

M.H. Livingston et al. / Injury, Int. J. Care Injured 45 (2014) 164–169166

perform a procedure (2%), surgery (8%), or withdrawal of lifesupport (2%) was less common (Table 4a and b). Proceduresincluded the placement or adjustment of an external ventriculardrain (n = 8), placement of a subdural drain (n = 1), and splenicartery embolization (n = 1).

Discussion

Our study demonstrated that paediatric trauma patients arebeing exposed to significant radiation as a result of CT scans. Asshown in Fig. 2, the majority of patients included in this studyreceived more radiation than what a typical person living in theUnited States is exposed to in an entire year (3.0 mSv) [16]. Somepatients were exposed to a dose up to twenty times this amount.Among the 133 patients who had at least one CT scan, the averageeffective dose due to CT was 13.5 mSv. This is 4.5 times thebackground level.

Table 2Number of CT scans and average dose per patient.

Number of patients with

resuscitation scans

Number of patients with

non-resuscitation scans

M

o

Heada 104 43 2

Faceb 9 2 1

Spinec 59 2 1

Bodyd 73 20 1

Extremitiese 3 1 1

All scans 133 58 3

a Head, head/face, CT angiogram head/neck, head/cervical-spine.b Face.c Cervical-spine, thoracic/lumbar-spine.d Abdomen, pelvis, abdomen/pelvis, chest, chest/abdomen/pelvis.e Elbow, shoulder, knee.

Table 3Indications for CT scans.

Resuscitation Reassess inj

Heada 96 (44%) 79 (36%)

Faceb 5 (29%) 11 (65%)

Spinec 56 (93%) 4 (7%)

Bodyd 66 (70%) 22 (23%)

Extremitiese 1 (25%) 3 (75%)

All scans 224 (56%) 119 (30%)

a Head, head/face, CT angiogram head/neck, head/cervical-spine.b Face.c Cervical-spine, thoracic/lumbar-spine.d Abdomen, pelvis, abdomen/pelvis, chest, chest/abdomen/pelvis.e Elbow, shoulder, knee.

Recent studies of paediatric trauma patients have revealedsimilar levels of radiation [17–21]. Kim et al. found a meaneffective dose of 14.9 mSv in their study of 506 paediatric traumapatients [17]. Their study considered a variety of radiologic studies,including plain film, fluoroscopy, angiography, nuclear medicine,and CT. Interestingly, 97.5% of the total effective dose was due toCT. Similarly, Brunetti et al. found mean effective dose of 12.8 mSv,of which 91% was due to CT [18]. In a study of 75 paediatric traumapatients, Tepper et al. reported a mean effective dose of 11.4 mSvfor CT scans done in the first 24 h as part of the resuscitation [19].On average, there was an additional 4 mSv of radiation for repeatCT scans done in the first 6 days following admission for a meantotal of 15.4 mSv. Mueller et al. reported a mean effective dose of17.4 mSv for scans performed during the initial evaluation [20].This study used dosimeters placed on the each patient todetermine the effective dose, and may account for the higherreported estimate. More recently, Kharbanda et al. [21] used theNational Trauma Data Bank to report a mean effective dose of12.0 mSv among 26,360 paediatric trauma patients who under-went CT.

The mean or median ISS in these five studies ranged from 5.1 to16 whereas ours was 22.5. We should also note that these studiesconsidered scans from different time intervals. Some studiesincluded scans from the first 24 h [20,21], some from the first 7days [19], and others considered scans from the entire admissionto hospital [17,18]. As mentioned previously, our study included CTscans from the initial resuscitation, hospital admission, and as anoutpatient up to 6 months after the initial injury. Despite thesedifferences, the values reported for effective dose were similar,ranging from 11.4 to 17.4. This is likely because the majority of theeffective dose from CT is delivered in the first 24 h following injury[19].

To the best of our knowledge, our study is the first to describethe indications and actions taken as result of all types of scans.Cook et al. looked at reasons for repeat CT scans of the abdomenafter transfer of paediatric trauma patients from other hospitals

ean number

f scans

Average dose per scan Average total dose per patient

.1 3.1 5.8

.6 1.6 2.2

.1 1.7 1.8

.4 9.8 13.8

.3 4.2 5.7

.1 4.7 13.5

ury Change in clinical status Total

44 (20%) 219

1 (6%) 17

0 (0%) 60

7 (7%) 95

0 (0%) 4

52 (13%) 395

Table 4(a) Action taken as a result of resuscitation scans. (b) Action taken as a result of non-resuscitation scans.

No Intervention Further imaging Surgery Procedure Withdrawal of life support Total

(a)Heada 41 (43%) 34 (35%) 12 (13%) 4 (4%)f 6 (5%) 96

Faceb 3 (60%) 1 (20%) 1 (20%) 0 (0%) 0 (0%) 5

Spinec 54 (96%) 2 (4%) 0 (0%) 0 (0%) 0 (0%) 56

Bodyd 41 (62%) 21 (31%) 3 (5%) 1 (2%)g 0 (0%) 66

Extremitiese 1 (100%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 1

All scans 139 (62%) 57 (25%) 16 (7%) 6 (3%) 6 (3%) 224

(b)Heada 52 (42%) 53 (43%) 11 (9%) 5 (4%)h 2 (2%) 123

Faceb 7 (58%) 5 (42%) 0 (0%) 0 (0%) 0 (0%) 12

Spinec 3 (75%) 1 (25%) 0 (0%) 0 (0%) 0 (0%) 4

Bodyd 20 (69%) 7 (32%) 2 (3%) 0 (0%) 0 (0%) 29

Extremitiese 1 (33%) 0 (0%) 2 (67%) 0 (0%) 0 (0%) 3

All scans 83 (49%) 66 (39%) 15 (9%) 5 (4%) 2 (1%) 171

a Head, head/face, CT angiogram head/neck, head/cervical-spine.b Face.c Cervical-spine, thoracic/lumbar-spine.d Abdomen, pelvis, abdomen/pelvis, chest, chest/abdomen/pelvis.e Elbow, shoulder, knee.f Placement of external ventricular drain.g Splenic artery embolization.h Placement or adjustment of external ventricular drain, placement of subdural drain.

M.H. Livingston et al. / Injury, Int. J. Care Injured 45 (2014) 164–169 167

and found that 80% of these scans were unnecessary or preventable[22]. In our study, we were concerned to discover that many CTscans were repeated to ‘‘reassess injury,’’ rather than because of achange in clinical status. This happened most frequently in scans ofthe head.

We were also concerned how frequently CT scans resulted in nofurther action or additional imaging (87% total). A decision toperform a procedure, surgery, or withdrawal of life support wasmuch less common (13% total), even though these scans wereperformed on patients with severe injuries. There were noapparent differences in this trend when comparing imagingperformed during the course of resuscitation (Table 4a) and inhospital or as an outpatient (Table 4b).

One of the strengths of this study is that we considered CT scansup to 6 months after the traumatic event. As mentioned previously,other studies only considered CT scans performed during the firstweek of admission [19] or during the initial evaluation [20,21].Patients with severe injuries may have long and complicated staysin hospital as well as an outpatient. We therefore thought it wouldbe important to extend our collection period to include scansperformed during the initial resuscitation, hospital stay, and as anoutpatient.

Another strength of our design is the relatively short timeperiod of 2 years. Practise patterns are unlikely to have changed insuch a short period of time and our findings likely give an accurateestimate of true practice at our centre. Finally, we should note thatthe effective dose was calculated using the DLP for each scan andapplying age-adjusted factors. This more accurately captures thedose of each scan, rather than using a standard ‘‘estimated dose’’and applying it to all patients who had this type of scan. Forexample, we did not assume an effective dose of 3.1 mSv for all CTscans of the head and apply it to all patients who had thisinvestigation. We calculated a unique effective dose for all 395scans included in our review. This is the same approach used by insimilar studies by Kim et al. [17] and Tepper et al. [19].

There are several limitations to our study. First, we onlyconsidered radiation from CT. As mentioned previously, CT hasbeen reported to contribute over 90% of the effective dose due toimaging in paediatric trauma patients [17,18,21], so our focus onCT is appropriate. Second, since our study did not capture CT scansperformed outside our centre, the cumulative dose of radiationthat these children were exposed to may be even higher than that

reported here. This is important for the reader to consider, sinceonly 31% of our patients were direct presentations.

Finally, and most importantly, we were unable to determinehow many surgeries were prevented because of negative findingson these scans. This is probably impossible to tell because there isno way of knowing how many patients who would have beenconsidered for an exploratory laparotomy or some other invasiveprocedure in the absence of a negative CT scan. We also did notassess the degree to which scans with positive findings may haveimpacted medical management. For example, we did not deter-mine whether a CT scan of the head showing increased intracranialpressure resulted in the administration of mannitol or hypertonicsaline.

Up until recently, the evidence for CT scans leading to cancerwas based mainly on data from survivors of the atomic bombs inHiroshima and Nagasaki [4]. The validity of this methodology hasbeen debated extensively in the medical literature [23]. One of thechief criticisms is that: ‘‘Cancer risks at very low doses areuncertain and depend on extrapolating risks from atomic-bombsurvivors who were exposed to high doses.’’ The authors of thesurvivor study agree that estimating the risk of cancer from very

low doses of radiation (less than 5 mSv) is uncertain, but haveprovided direct evidence that low doses (5–100 mSv) areassociated with a small but statistically significant increase inthe risk of cancer [4,23]. Despite this positive finding, otherconcerns remain: (1) the dose estimates from the atomic bombitself are uncertain; (2) survivors of the atomic bomb were exposedto mainly gamma rays rather than x-radiation; and (3) there aredifferent background rates of cancer in Japan compared to otherparts of the world. These issues are discussed in detail elsewhere[24].

There is emerging epidemiological evidence that should also beconsidered. In 2012, Pearce et al. reported an excess risk ofleukaemia and brain tumour in a cohort of 178,604 children whounderwent CT scans in the United Kingdom between 1985 and2002 [25]. This was the first human epidemiological study todemonstrate that CT scans increase the risk of cancer. In the 10-year follow-up, there was one excess case of leukaemia and oneexcess case of brain tumour per 10,000 CT scans of the head. Thus,the risk of developing a fatal cancer was estimated to beapproximately 1 in 5000. This is comparable to the estimate of1 in 1000 obtained from the atomic bomb data, which involved a

M.H. Livingston et al. / Injury, Int. J. Care Injured 45 (2014) 164–169168

longer follow-up (approximately 50 years instead of 10) and alltypes of malignancies (not just leukaemia and brain tumour).

More recently, Matthews et al. reported increased rates ofcancer in 680,211 people in Australia who underwent a CT scanduring childhood and adolescence between 1985 and 2005 [26].The risk of malignancy was compared to the general population ofover 10 million people. Interestingly, there were not only higherrates leukaemia and brain tumour, but also melanoma, lymphoma,and tumours of the soft tissue, gastrointestinal system, urinarytract, thyroid, and female reproductive system. The excess risk wasestimated to be approximately 1 in 2000. As expected, the reportedrisk is higher than that from the study from the United Kingdombecause more cancers were considered. In light of these recentstudies, there is now definitive evidence that CT scans cause asmall but significant increase in cancer. This is also suggests thatthe estimates provided by the atomic bomb survivor data areaccurate.

There are several ways to reduce the radiation associated withCT scans. First, clinicians and radiologists should be aware of theprinciples of the ‘‘Image Gently’’ campaign [27]. These includedecreasing the voltage and current to a ‘‘child-size’’ dose,performing a single phase scan whenever possible, and scanningonly the indicated area. They should also strive to keep radiationdoses ‘‘as low as reasonably achievable’’ (ALARA) [28]. Strategiesinclude developing weight-based protocols, improve shielding,performing focused or limited-view studies, discouraging repeatstudies, and considering imaging modalities with less or noradiation, such as ultrasound and magnetic resonance imaging.

Future research should focus on developing treatment algo-rithms to guide decision making for determining which scansshould be performed. The Paediatric Emergency Care AppliedResearch Network (PECARN) performed a prospective cohort studyof over 42,000 children to develop prediction rule for identifyingchildren at very low risk of intracranial injury [29]. For thoseyounger than 2 years, negative predictive value and sensitivitywere 100%. In patients 2–18 years old, negative predictive valuewas 99.95% and sensitivity was 96.8%.

Similar decision rules are available for cervical spine injuries[30,31]. The National Emergency X-ray Utilization Study (NEXUS)decision rule for cervical spinal injuries has a sensitivity of 100% inchildren greater than 8 years old [30]. Anderson et al. [31]developed a protocol to rule out cervical spine injuries in childrenaged 0–3 years. This approach uses CT and MRI selectively and didnot miss any injuries in a sample of 575 young children withtraumatic injuries. A rule for identifying intra-abdominal injurieshas also been developed [32]. The sensitivity approached 95% andshowed encouraging results.

Unfortunately, these rules are not always applicable topaediatric patients with severe multisystem injuries. Consequent-ly, clinicians are forced to use the adult-style ‘‘pan scan’’ (whichresults in increased radiation) or revert to an ad hoc approach ofselective scanning (which may result in missed injuries). There isclearly a need for an all-encompassing screening tool to guideclinicians through these challenging decisions. Several studieshave advocated for increased use of ultrasound, especially for theworkup of abdominal injuries [32–35]. This imaging modality hasno radiation and can be brought into the trauma bay to at the timeof the patient’s presentation. When combined with evidence-based clinical decision tools and laboratory investigations,ultrasound has great potential to decrease our reliance on CT ina way that is safe and evidence-based.

Conclusions

CT scans are a significant source of radiation exposure inpaediatric trauma patients. Clinicians should carefully consider the

indications for each scan, especially in cases of repeat imaging.They should also think carefully about how the results of theseinvestigations may or may not impact patient management, sincethe majority of scans in this study resulted in no further action orfurther imaging. Finally, there is a need for evidence-basedtreatment algorithms to assist clinicians in selecting appropriateimaging for paediatric patients with severe multisystem injuries.

Conflict of interest

Each author certifies that he or she has no commercialassociations that might pose a conflict of interest in connectionwith the article.

Acknowledgements

This work was supported by the Trauma Program at LondonHealth Sciences Centre and by the Division of General Surgery atthe University of Western Ontario. We dedicate this project to thememory of Dr. Murray Girrotti, who was an incredible teacher, aninspiring leader, and will be greatly missed by his friends andcolleagues.

References

[1] Huber-Wagner S, Lefering R, Qvick LM, Korner M, Kay MV, Pfeifer KJ, et al.Effect of whole-body CT during trauma resuscitation on survival: a retrospec-tive, multicentre study. Lancet 2009;373:1455–61.

[2] Jindal A, Velmahos GC, Rofougaran R. Computed tomography for evaluation ofmild to moderate pediatric trauma: are we overusing it? World Journal ofSurgery 2002;26:13–6.

[3] United Nations Scientific Committee on the Effects of Atomic Radiation.Sources and effects of ionizing radiation. New York, NY: United NationsScientific Committee on the Effects of Atomic Radiation; 2000.

[4] Brenner DJ, Elliston CD, Hall EJ, Berdon WE. Estimated risks of radiation-induced fatal cancer from pediatric CT. American Journal of Roentgenology2001;176:289–96.

[5] Chodick G, Ronckers CM, Shalev V, Ron E. Excess lifetime mortality riskattributable to radiation exposure from computed tomography examinationsin children. Israel Medical Association Journal 2007;9:584–7.

[6] Brody AS, Frush DP, Huda W, Brent RL, the Section of Radiology. Radiationrisk to children from computer tomography. Pediatrics 2007;120:677–82.

[7] The 2007 recommendations of the International Commission on RadiologicalProtection: ICRP publication 103. Annals of the International Commission ofRadiological Protection 2007;37:1–332.

[8] Van Unnik JG, Broerse JJ, Geleijns J, Jansen JT, Zetelief J, Zweers D. Survey of CTtechniques and absorbed dose in various Dutch hospitals. British Journal ofRadiology 1997;70:367–71.

[9] Jones DG, Shrimpton PC. Survey of the CT practice in the UK. Part 3: Normalisedorgan dose calculated using Monte Carlo techniques. NRPB Report R250.Chilton, United Kingdom: NRPB; 1991.

[10] Aldrich JE, Bilawich AM, Mayo JR. Radiation doses to patients receivingcomputed tomography examinations in British Columbia. Canadian Associa-tion of Radiologists Journal 2006;57:79–85.

[11] Mayo JR. Radiation dose issues in longitudinal studies involving computedtomography. Proceedings of the American Thoracic Society 2008;5:934–9.

[12] Shrimpton PC. Doses from computed tomography examinations in the UK –2003 review. Chilton, United Kingdom: NRPB; 2004.

[13] Ulzheimer S, Leidecker C, Endt H. Dose parameters and advanced dosemanagement on SOMATOM scanners. Forcheim, Germany: Siemens; 2011.

[14] Huda W, Ogden KM, Khorasani MR. Converting dose-length product to effec-tive dose at CT. Radiology 2008;248:995–1003.

[15] American Association of Physicists in Medicine. The Measurement, Reporting,and Management of Radiation Dose in CT. Report of AAPM Task Group 23 ofthe Diagnostic Imaging Council CT Committee; 2008.

[16] National Council on Radiation Protection and Measurements. Ionizing radia-tion exposure of the population of the United States. NCRP Report No. 93.Bethesda, MD: National Council on Radiation Protection and Measurements;2009.

[17] Kim PK, Zhu X, Houseknecht E, Nickolaus D, Mahboubi S, Nance ML. Effectiveradiation dose from radiologic studies in pediatric trauma patients. WorldJournal of Surgery 2005;29:1557–62.

[18] Brunetti MA, Mahesh M, Nabaweesi R, Locke P, Ziegfeld S, Brown R. Diagnosticradiation exposure in pediatric trauma patients. Journal of Trauma 2011;70:E24–8.

[19] Tepper B, Brice JH, Hobgood CD. Evaluation of radiation exposure to pediatrictrauma patients. Journal of Emergency Medicine 2012 [Epub ahead of print].

M.H. Livingston et al. / Injury, Int. J. Care Injured 45 (2014) 164–169 169

[20] Mueller DL, Hatah M, Al-Senan R, Cohn SM, Corneille MG, Dent DL, et al.Pediatric radiation exposure during the initial evaluation for blunt trauma.Journal of Trauma 2011;70:724–31.

[21] Kharbanda AB, Flood A, Blumberg K, Kreykes NS. Analysis of radiation expo-sure among pediatric trauma patients at national trauma centers. Journal ofTrauma and Acute Care Surgery 2013;74:907–11.

[22] Cook SH, Fielding JR, Phillips JD. Repeat abdominal computer tomographyscans after pediatric blunt abdominal trauma: missed injuries, extra costs,and unnecessary radiation exposure. Journal of Pediatric Surgery 2010;45:2019–24.

[23] Letters to the Editor and authors’ reply. Computed tomography and radiationexposure. New England Journal of Medicine 2008;358:850–3.

[24] Wakeford R. The risk of childhood leukemia following exposure to ionisingradiation—a review. Journal of Radiological Protection 2013;33:1–25.

[25] Pearce MS, Salotti JA, Little MP, McHugh K, Lee C, Kim KP, et al. Radiationexposure from CT scans in childhood and subsequent risk of leukaemia andbrain tumours: a retrospective cohort study. Lancet 2012;380:499–505.

[26] Matthews JD, Forsythe AV, Brad Z, Butler MW, Goergen SK, Byrnes GB, et al.Cancer risk in 680 000 people exposed to computed tomography scans inchildhood or adolescence: data linkage study of 11 million Australians. BMJ2013;346:2360.

[27] Goske MJ, Applegate KE, Boylan J, Butler PF, Callahan MJ, Coley BD, et al. The‘Image Gently’ campaign: increasing CT radiation dose awareness through anational education and awareness program. Pediatric Radiology 2008;38:265–9.

[28] Shah NB, Platt SL. ALARA: is there a cause for alarm? Reducing radiation riskfrom computed tomography scanning in children. Current Opinion in Pediat-rics 2008;20:243–7.

[29] Kuppermann N, Holmes JF, Dayan PS, Hoyle Jr JD, Atabaki SM, Holubkov R,et al. Identification of children at very low risk of clinically-important braininjuries after head trauma: a prospective cohort study. Lancet 2009;373:1160–70.

[30] Viccellio P, Simon H, Pressman BD, Shah MN, Mower WR, Hoffman JR. Aprospective multicenter study of cervical spine injury in children. Pediatrics2001;108:E20.

[31] Anderson RCE, Kan P, Vanaman M, Rubsam J, Hansen KW, Scaife ER, et al.Utility of cervical spine clearance protocol after trauma in children between 0and 3 years of age. Journal of Neurosurgery Pediatrics 2010;5:292–6.

[32] Holmes JF, Mao A, Awasthi S, McGahan JP, Wisner DH, Kuppermann N.Validation of a prediction rule for the identification of children with intra-abdominal injuries after blunt torso trauma. Annals of Emergency Medicine2009;54:528–33.

[33] Fenton SJ, Hansen KW, Meyers RL, Vargo DJ, White KS, Firth SD, et al. CT scanand the pediatric trauma patient—are we overdoing it? Journal of PediatricSurgery 2004;39:1877–81.

[34] Scaife ER, Rollins MD. Managing radiation risk in the evaluation of thepediatric trauma patient. Seminars in Pediatric Surgery 2010;19:252–6.

[35] Jimenez RR. Radiographic evaluation of the pediatric trauma patient andionizing radiation exposure. Clinical Pediatric Emergency Medicine 2010;11:22–7.