Introduction: Health professionals in paediatric medical imaging are routinely required to communicate radiation risks to carers and patients. Effective dose alone cannot be used to specify and communicate the radiation risk for an individual as risks are dependent on many factors including age and patient sex. In this study, we estimated typical effective doses for 20 commonly performed paediatric general radiography examinations using the weight-based imaging protocols employed at a major Australian specialist paediatric hospital. Effective doses were used to estimate and categorise associated age-based stochastic risks with commonly used risk terminology to facilitate communication of risk. Methods: Paediatric protocols for common general radiography examinations and World Health Organization 50th percentile weight-for-age data for females and males aged up to 18 years were used to estimate typical effective doses using Monte Carlo software and lifetime risk of cancer incidence using published data. Results were used to determine standardised levels of risk using the Calman risk model. Results: Effective doses, corresponding lifetime risk of cancer incidence and level of risk category from 20 general radiography examinations for paediatric patients were calculated and presented for ease of communication. Doses ranged from <0.001 mSv (negligible risk) to 1.6 mSv (low risk). Conclusion: Typical effective doses from common paediatric general radiography examinations, the associated lifetime risk of cancer incidence and level of risk have been established for our institution. This can be used to convey risks to health professionals, patients and carers in ways that are easy to understand and compare with other everyday risks.

Introduction: Effective dose alone cannot be used to specify and communicate the radiation risk for an individual as risks are dependent on many factors including age and gender. There are limited published data regarding agespecific effective doses and the associated lifetime risk of developing cancers for paediatrics. In this study, we have estimated the typical effective doses for six commonly performed paediatric nuclear medicine and positron emission tomography (PET) studies at the Royal Children's Hospital, Melbourne, Australia. Effective doses were used to estimate and categorise associated stochastic risks with commonly used risk terminology. Methods: Paediatric protocols for common nuclear medicine and PET studies and the World Health Organization (WHO) 50th percentile weight-for-age data for females and males aged up to 18 years were used to estimate typical organ and effective doses using ICRP dosimetric tables for radiopharmaceuticals and lifetime risk of cancer incidence using BEIR VII Phase 2 report data. Results were used to determine standardised levels of risk. Results: Organ doses, effective doses, corresponding lifetime risk of cancer incidence and level of risk category from six common nuclear medicine and PET studies for paediatric patients were calculated and presented for ease of communication. Conclusion: Typical effective doses from common paediatric nuclear medicine and PET studies and the associated lifetime risk of cancer incidence and level of risk have been established for our institution. This can be used to convey risks to health professionals, patients and carers in ways that are easy to understand and compare with other everyday risks.

Introduction: Carers and comforters frequently remain with children during paediatric general radiographic examinations. As well as improving the likelihood of overall success of the procedure, this can be important for minimising stress and anxiety of the child. Wearing lead aprons can contribute to additional stress and anxiety about the procedure for both carer and child, specifically due to radiation risk. It also introduces some practical challenges for radiographers. This study quantified a carers exposure to scattered radiation for general radiographic examinations when remaining with a child to assist in positioning or to comfort them. Methods: Scattered radiation was measured at four common locations where a carer may stand, with a range of tube potentials (40 kV p to 100 kV p ) and PMMA thicknesses of 2.5-22.5 cm. This was then matched to our clinical protocols to estimate the radiation dose a carer could be exposed to while assisting a patient during general radiographic examinations. Results: The effective dose received by a carer standing 20 cm from the centre of the patient varies from 11 min of Australian natural BERT for a finger radiograph on a patient <3 kg and up to 62 h for a swimmers view radiograph performed on a patient >70 kg. Conclusion: This dosimetric data allowed an evidence-based assessment of radiation protection requirements for the carer using the ALARA principle. At our institution, it was decided that a lead apron is not required if the carer is unlikely to receive more than 2 µSv. A new policy, presented here, was developed to implement this decision.

Across Australia and New Zealand, radiation use in medicine is regulated by differing governing bodies in each State and Territory. Although most heavily rely on the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) Codes of Practice, this is a broad guidance and the details of implementation vary between jurisdictions. This leads fundamentally to considerable differences in requirements for reporting, shielding design, quality assurance (QA) and quality control (QC). Additionally,

IntroductionThe vast majority of orthopaedic surgeons use C-arm fluoroscopy in the operating theatre when building a circular external fixator. In the absence of previous research in this area, we hypothesised that the surgeon who builds a circular external fixator is exposed to a greater amount of radiation purely as a result of the presence of the metallic fixator in the x-ray beam. The aim of our study therefore was to investigate how the presence of a circular external fixator affects the radiation dose to the surgeon and the surgical assistant.Materials & MethodsA simulated environment was created using a radiolucent operating table, an acrylic lower limb phantom (below knee segment), various configurations of metalic circular external fixation, and a standard size C-arm image intensifier.The variables investigated were 1. the amount of metal in the beam 2. the orientation of the beam (PA vertical vs lateral) 3. the horizonal distance of the person from the beam (surgeon vs assistant) and 4. the vertical distance of the various body parts from the beam (e.g. thyroid, groin).In terms of radiation dose, we recorded two things : 1. the dose produced by the image intensifier 2. the dose rate at standardised positions in the operating theatre. The latter was done using a solid-state survey sensor. These positions represented both where the surgeon and surgical assistant typically stand plus the heights of their various body regions relative to the operating table..ResultsThe effect of the presence of the circular external fixator : all frame constructs tested resulted in a statistically significant greater radiation dose both produced by the image intensifier and received by the surgical team.The effect of the beam orientation : the PA (vertical) orientation resulted in a statistically significant greater radiation dose for the surgeon than did the lateral orientation, but made no difference for the assistant.The effect of horizontal distance from the beam : unsurprisingly, the surgeon (who was closer to the beam) received a statistically significant greater radiation dose than the assistant. The effect of vertical distance from the beam : for the surgeon, the dose received was highest at the level of the phantom leg / frame, whilst for the assistant there was no statistically significant difference for any level.ConclusionsTo our knowledge, this is the first study investigating the radiation dose rate to the orthopaedic surgeon when building a circular external fixator. We found that the surgeon does indeed receive a ‘double whammy’ because the image intensifier puts out a greater amount of radiation plus the metalic frame scatters more of the x-ray beam. Whilst the amounts are relatively small, we think that it's important to quantify doses that orthopaedic surgeons receive to ensure optimal radiation practices.