Australian Radiation Protection And Nuclear Safety Agency Research Articles

Community engagement programs on radiation and health: addressing public concerns.

Due to the negative connotations around radiation, there is a great deal of angst in the community regarding radiation exposure and health; especially electromagnetic radiation (EMR) sources such as powerlines, mobile phone towers and the rollout of the 5G network. As such, it is important for health authorities to provide the public with information and assurances regarding radiation safety. The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) set up community engagement programs to address community concerns. Type of program or service: From 2003 until April 2022, ARPANSA operated a Health Complaints Register, which collected reports of health complaints from members of the public related to possible EMR exposures. Collected data was used to produce annual statistical summaries on the nature and level of complaints received. Since 2016, ARPANSA has also run the Talk to a Scientist program, which allows the public to communicate directly with scientists on issues about radiation exposure, health and protection in Australia. Data is collected on the type of radiation and radiation source. There was a low level of interest in the Register, with only 180 reports received over the duration of its operation. Smart meters were the most common source of EMR exposure reported to be responsible for adverse health effects. The most common adverse health effect reported was headaches. The Register was closed in April 2022 due to a lack of interest. In contrast, the Talk to a Scientist program has responded to 6546 enquiries since 2016, most of which have been on EMR sources and the success of the Talk to a Scientist program, which rendered the Register obsolete. The EMR Health Complaints Register never received much interest from the public, potentially due to a perceived lack of engagement with authorities. The Talk to a Scientist program, which facilitated direct interaction with subject matter experts, has been much more successful in engaging with the public and addressing community concerns on radiation safety.

Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the ARPANSA, Australia and the BIPM in 60Co gamma radiation

Main textA new key comparison of the standards for air kerma of the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), Australia and the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in November 2020. The comparison result, based on the calibration coefficients for two transfer chambers and expressed as a ratio of the ARPANSA and the BIPM standards for air kerma, is 0.9986 with a combined standard uncertainty of 2.7 parts in 103. The result agrees within the uncertainties with the indirect comparison carried out in 2010. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Key comparison BIPM.RI(I)-K4 of the absorbed dose to water standards of the ARPANSA, Australia and the BIPM in 60Co gamma radiation

Main textA new key comparison of the standards for absorbed dose to water of the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), Australia and the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in November 2020. The comparison result, based on the calibration coefficients for two transfer chambers and evaluated as a ratio of the ARPANSA and the BIPM standards for absorbed dose to water, is 0.9995 with a combined standard uncertainty of 5.1 parts in 103. The result agrees within the uncertainties with the comparison carried out in 2010. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Updated Australian diagnostic reference levels for adult CT.

IntroductionIn 2018, ARPANSA published updated national DRLs for adult CT, which were first published in 2012, and augmented the national DRL categories. This paper presents the updated national DRLs and describes the process by which they were produced.MethodsExamine patient survey data submitted to the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) National Diagnostic Reference Level Service (NDRLS). Determine the quartiles of the distributions of median survey dose metrics with categorisation by procedure type. Engage a liaison panel representing the radiology professions to review procedure categories and recommend revised national DRLs. The revised NDRL procedure categories are: head (non‐contrast brain (trauma/headache)), cervical spine (Non‐contrast (trauma)), soft‐tissue neck (post‐contrast (oncology)), chest (post‐contrast (oncology)), abdomen–pelvis (post‐contrast (oncology)), kidney–ureter–bladder (non‐contrast (suspected renal colic)), chest–abdomen–pelvis (post‐contrast (oncology)) and lumbar spine (non‐contrast (degenerative pain)).ResultsThe existing six procedure categories were revised and refined. Updated Australian national diagnostic reference levels for adult CT were recommended and endorsed for eight procedure categories: head (52 mGy/880 mGycm), cervical spine (23 mGy/470 mGycm),soft‐tissue neck (17 mGy/450 mGycm), chest (10 mGy/390 mGycm), abdomen–pelvis (13 mGy/600 mGycm), kidney–ureter–bladder (13 mGy/600 mGycm), chest–abdomen–pelvis (11 mGy/940 mGycm) and lumbar spine (26 mGy/670 mGycm). The updated national DRLs are between 12 and 26% lower than the previous DRLs for dose‐length product and between 13 and 63% lower for volume computed tomography dose index.ConclusionsAustralian national DRLs for adult CT have been reviewed and revised. The revised national DRLs are lower, better reflecting current practice among imaging facilities in Australia. The revised Australian national DRLs are similar to those in other developed countries.

Evaluation of the IAEA-TRS483 protocol for the dosimetry of small fields (square and stereotactic cones) using multiple detectors.

The IAEA TRS 483 protocol1 for the dosimetry of small static fields in radiotherapy was used to calculate output factors for the Elekta Synergy linac at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Small field output factors for both square and circular fields were measured using nine different detectors. The “corrected” output factors (ratio of detector readings multiplied by the appropriate correction factor from the protocol) showed better consistency compared to the “uncorrected” output factors (ratio of detector readings only), with the relative standard deviation decreasing by approximately 1% after the application of the relevant correction factors. Comparisons relative to an arbitrarily chosen PTW 60019 microDiamond detector showed a reduction of maximal variation for the corrected values of approximately 3%. A full uncertainty budget was prepared to analyze the consistency of the output factors. Agreement within uncertainties between all detectors and field sizes was found, except for the 15 mm circular field. The results of this study show that the application of IAEA TRS 4831 when measuring small fields will improve the consistency of small field measurements when using multiple detectors contained within the protocol.

RESULTS OF THE JOINT IAEA/ARPANSA INTERCOMPARISON EXERCISE ON WHOLE BODY DOSEMETERS FOR PHOTONS IN ASIA AND THE PACIFIC REGION.

An intercomparison exercise (IC) on whole body dosemeters to determine the quantity personal dose equivalent Hp (10) in photon radiation fields was jointly organised and conducted by the International Atomic Energy Agency (IAEA) and the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) for individual monitoring services (IMS) in Asia and the Pacific region. This was arranged to help the IMS in the region to achieve a more accurate dosimetry service and to improve their performance. Twenty-four IMS participated in this IC. Four sets of dosemeters were irradiated using X-ray and gamma radiation qualities at 0° and 20° angle of incidence, respectively. All the IMS provided results that were within the acceptable limits defined by the IAEA. However, only a minority of participants reported confidence intervals that included the reference dose, for each exposure scenario. For few systems, the overall performance could be significantly improved by reviewing calibration procedures.

An Australian local diagnostic reference level for paediatric whole-body 18F-FDG PET/CT.

The aim of this study is to report a local diagnostic reference level (DRL) for paediatric whole-body (WB) fludeoxyglucose (18F-FDG) positron emission tomography (PET) CT examinations. The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) national DRL (NDRL) age category (0-4 years and 5-14 years), the International Commission on Radiological Protection age category (ICRP age) (<1, >1-5, >5-10, and >10-15 years), and European guideline weight category ( EG weight) (<5, 5-<15, 15-<30, 30-<50, and 50-<80 kg) were used to determine a local DRL for WB 18F FDG PET/CT studies. Two-structured questionnaires were designed to collect dose data, patient demographics, equipment details, and acquisition protocols for WB 18F-FDG PET/CT procedures. The local DRL was based on the median 18F-FDG administered activity (MBq), dose-length product (DLP), and the CT dose index volume (CTDIvol), values. The effective dose (E) was also calculated and reported. The local DRLs for 18F-FDG administered activity, CTDIvol and DLP values based on ARPANSA age and ICRP age were increased from lower to higher age categories. For the EG weight category, the local DRL for 18F-FDG administered activity, CTDIvol and DLP values were increased from the low EG weight category to the high EG weight category. The mean administered activity in our study based on ICRP age category >1-5, >5-10, and >10-15 years is 79.97, 119.40, and 176.04 MBq, which is lower than the mean administered activity reported in the North American Consensus guideline published in 2010 (99, 166, and 286 MBq) and European Association of Nuclear Medicine and Dosage Card (version 1.5.2008) (120, 189, and 302 MBq). However, the mean administered activity in our study based on ICRP age category <1 year was 55 MBq compared to the EANM Dosage card (version 1.5.2008) (70 MBq) and the NACG 2010 (51 MBq). Our study shows that the finding for ICRP age category <1 year was similar to the NACG 2010 value. The determined local DRL values for the radiation doses associated with WB 18F FDG PET/CT examinations are differed considerably between the ARPANSA and ICRP age category and EG weight category. Although, the determined 18F-FDG value for ICRP < 1 year is in good agreement with available publish data, it is preferable to optimise the 18F-FDG administered activity while preserving the diagnostic image quality. The local DRL value determined from WB 18F-FDG PET/CT examinations may help to establish the ARPANSA NDRL for WB FDG 18F-PET/CT examinations.

Survey of 5mm small-field output factor measurements in Australia.

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) held a comparison exercise in April 2016 where participants came to ARPANSA and measured the output factor of a nominal 5 mm cone attached to the ARPANSA Elekta Synergy (Elekta, Crawley, UK) linear accelerator. The goal of the exercise was to compare the consistency and methods used by independent medical physicists in measuring small‐field output factors. ARPANSA provided a three‐dimensional scanning tank for detector setup and positioning, but the participants were required to measure the output factor with their own detectors. No information regarding output factors previously measured was supplied to participants to make each result as independent as possible. Fifteen groups travelled to ARPANSA bringing a wide range of detectors and methods. A total of 30 measurements of the output factor were made. The standard deviation of the measurements (excluding one expected outlier from an uncorrected ionization chamber measurement) was 3.6%. The results provide an insight into the consistency of small‐field dosimetry being performed in Australia and New Zealand at the present time.

7Be and 210Pb wet/dry deposition in Melbourne, Australia and the development of deployable units for radiological emergency monitoring

A large stainless-steel collection tray (with a surface area of one square metre) was purpose built and mounted on the roof of the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) building at Yallambie, Victoria, Australia. Using this system two years’ worth of wet/dry deposition samples have been collected and analysed. Smaller portable units were also developed for deployment in an emergency and/or for environmental monitoring. The cosmogenic radionuclide 7Be and the naturally occurring terrestrial radionuclide 210Pb have been used to validate the systems. The data from the smaller units was successfully compared to the larger permanent collection unit for validation, thus finding the portable units fit for purpose.Monitoring of wet and dry fallout deposition is an important response to radiological emergencies. It can provide useful information in verifying predictive models of radionuclide atmospheric transport and dispersion, in addition to providing local deposition data.

Recommendations for radiographers and radiation therapists drawn from an analysis of errors on Australian Radiation Incident Registers.

IntroductionThe Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) collect reported incidents for inclusion in the Australian Radiation Incident Register (ARIR), a database of radiation incident reports that occur within Australia. While the information on previous radiation incidents is available, there is little information on the lessons that can be learned from those past incidents to help prevent the same errors reoccurring. The aims of the study were to investigate what radiation incident registers are publicly available in Australia and to utilise the information contained within the ARIR and any other state or territory radiation protection authority registers to make recommendations for radiographers and radiation therapists to prevent future adverse events.MethodsA search was conducted to locate what radiation incident registers within Australia were available to the public. All adverse events from 2003 to 2014 were compiled into a spreadsheet for analysis. An error‐type classification taxonomy was used to classify the adverse events. Conclusions were drawn from the determined causes to make recommendations to change work practices in an attempt to prevent similar adverse events reoccurring.ResultsIncident registers were located from New South Wales, South Australia, Tasmania, Victoria and Western Australia. Radiography represented 76% (243) of the adverse events. A vast majority of the incidents were a failure to comply with time‐out protocols (77%, 248).ConclusionThere are several radiation adverse event registers publicly available to utilise in Australia. All departments need to adopt and strictly adhere to time‐out protocols. This in conjunction with the other recommendations in this article has the potential to dramatically reduce radiation adverse events.

Absolute dosimetry on a dynamically scanned sample for synchrotron radiotherapy using graphite calorimetry and ionization chambers

The absolute dose delivered to a dynamically scanned sample in the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter anticipated to be established as a primary standard for synchrotron dosimetry. The calorimetry was compared to measurements using a free-air chamber (FAC), a PTW 31 014 Pinpoint ionization chamber, and a PTW 34 001 Roos ionization chamber. The IMBL beam height is limited to approximately 2 mm. To produce clinically useful beams of a few centimetres the beam must be scanned in the vertical direction. In practice it is the patient/detector that is scanned and the scanning velocity defines the dose that is delivered. The calorimeter, FAC, and Roos chamber measure the dose area product which is then converted to central axis dose with the scanned beam area derived from Monte Carlo (MC) simulations and film measurements. The Pinpoint chamber measures the central axis dose directly and does not require beam area measurements. The calorimeter and FAC measure dose from first principles. The calorimetry requires conversion of the measured absorbed dose to graphite to absorbed dose to water using MC calculations with the EGSnrc code. Air kerma measurements from the free air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. The two ionization chambers are secondary standards requiring calibration with kilovoltage x-ray tubes. The Roos and Pinpoint chambers were calibrated against the Australian primary standard for air kerma at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Agreement of order 2% or better was obtained between the calorimetry and ionization chambers. The FAC measured a dose 3–5% higher than the calorimetry, within the stated uncertainties.

Point/Counterpoint. Calibration of radiotherapy ionization chambers using Co-60 is outdated and should be replaced by direct calibration in linear accelerator beams.

Point/Counterpoint. Calibration of radiotherapy ionization chambers using Co-60 is outdated and should be replaced by direct calibration in linear accelerator beams.

Evidence of dose saving in routine CT practice using iterative reconstruction derived from a national diagnostic reference level survey.

To assess the influence and significance of the use of iterative reconstruction (IR) algorithms on patient dose in CT in Australia. We examined survey data submitted to the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) National Diagnostic Reference Level Service (NDRLS) during 2013 and 2014. We compared median survey dose metrics with categorization by scan region and use of IR. The use of IR results in a reduction in volume CT dose index of between 17% and 44% and a reduction in dose-length product of between 14% and 34% depending on the specific scan region. The reduction was highly significant (p < 0.001, Wilcoxon rank-sum test) for all six scan regions included in the NDRLS. Overall, 69% (806/1167) of surveys included in the analysis used IR. The use of IR in CT is achieving dose savings of 20-30% in routine practice in Australia. IR appears to be widely used by participants in the ARPANSA NDRLS with approximately 70% of surveys submitted employing this technique. This study examines the impact of the use of IR on patient dose in CT on a national scale.

SU‐E‐P‐03: The Australian Clinical Dosimetry Service, a Bespoke National Solution

Purpose:The Australian Clinical Dosimetry Service, (ACDS) was a pilot program to enable the Australian Government to determine whether a locally designed audit program was suitable for mitigating dosimetric error risk to radiotherapy patients within Australia. The outcomes from four years of operations will be presented and discussed with a focus why and how the pilot requirements were met. The consequnces of success will be considered, the lessons learnt from the pilot program and how they are impacting the future ACDS design, operation and engagement with stakeholders.Methods:The ACDS was designed over 2010/11 by experts drawn from the three professions in consultation with the national Department of Health. The list of outcomes required over a three year pilot was expressed in a Memorandum of Understanding, (MoU) between Health and the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) which hosted the ACDS.Results:The ACDS has achieved all the MoU requirements. This paper describes how the staff within the ACDS engaged with the professional clinical workforce and provided a successful and functioning audit service. It identifies the strengths and weaknesses within the MoU and the ACDS structure and how the ACDS resolved a number of conflicting issues. It identifies the successes within the ACDS and how these were achieved. It provides details to assist and advise those seeking to design or modify national or regional auditing programs. Finally the paper reviews potential futures for the ACDS.Conclusion:The raw number of audits and outcomes indicate that the ACDS has met the MoU auditing requirements. The reasons for the ACDS’ success are highly dependent on: attracting quality staff who can respond with agility to changing situations, a high level of communication with the professional community, a high level of engagement by the community and an interested and engaged Federal Department.The Australian Clinical Dosimetry Service is a joint initiative between the Australian Department of Health and the Australian Radiation Protection and Nuclear Safety Agency.

Maintaining the accuracy of the (60)Co calibration service at the ARPANSA post source replacement in 2010.

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) maintains a (60)Co teletherapy source primarily for the calibration of therapy dosemeters. The source and encapsulating head were replaced in early 2010 with an Eldorado 78 head and new (60)Co source. In this article we present the results of ongoing accuracy and stability measurements since the replacement. A number of formal and informal indirect comparisons have been carried out with laboratories holding primary and secondary standards for (60)Co. ARPANSA chambers have also been calibrated at international primary standard laboratories allowing comparison of calibration coefficients and thus (60)Co absorbed dose standards. (60)Co calibration coefficients supplied by manufacturers of chambers were compared to those measured at the ARPANSA when this calibration was traceable to a primary standard. ARPANSA also participates in an annual international mailed dosimetry audit conducted by the International Atomic Energy Agency. The results thus far demonstrate that the absorbed doses to water delivered by the new ARPANSA (60)Co source are consistent with international doses within the stated uncertainties.

Direct calibration in megavoltage photon beams using Monte Carlo conversion factor: validation and clinical implications

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) has established a method for ionisation chamber calibrations using megavoltage photon reference beams. The new method will reduce the calibration uncertainty compared to a 60Co calibration combined with the TRS-398 energy correction factor. The calibration method employs a graphite calorimeter and a Monte Carlo (MC) conversion factor to convert the absolute dose to graphite to absorbed dose to water. EGSnrc is used to model the linac head and doses in the calorimeter and water phantom. The linac model is validated by comparing measured and modelled PDDs and profiles. The relative standard uncertainties in the calibration factors at the ARPANSA beam qualities were found to be 0.47% at 6 MV, 0.51% at 10 MV and 0.46% for the 18 MV beam. A comparison with the Bureau International des Poids et Mesures (BIPM) as part of the key comparison BIPM.RI(I)-K6 gave results of 0.9965(55), 0.9924(60) and 0.9932(59) for the 6, 10 and 18 MV beams, respectively, with all beams within 1σ of the participant average. The measured kQ values for an NE2571 Farmer chamber were found to be lower than those in TRS-398 but are consistent with published measured and modelled values. Users can expect a shift in the calibration factor at user energies of an NE2571 chamber between 0.4–1.1% across the range of calibration energies compared to the current calibration method.

Direct megavoltage photon calibration service in Australia.

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) maintains the Australian primary standard of absorbed dose. Until recently, the standard was used to calibrate ionisation chambers only in (60)Co gamma rays. These chambers are then used by radiotherapy clinics to determine linac output, using a correction factor (k Q) to take into account the different spectra of (60)Co and the linac. Over the period 2010-2013, ARPANSA adapted the primary standard to work in megavoltage linac beams, and has developed a calibration service at three photon beams (6, 10 and 18 MV) from an Elekta Synergy linac. We describe the details of the new calibration service, the method validation and the use of the new calibration factors with the International Atomic Energy Agency's TRS-398 dosimetry Code of Practice. The expected changes in absorbed dose measurements in the clinic when shifting from (60)Co to the direct calibration are determined. For a Farmer chamber (model 2571), the measured chamber calibration coefficient is expected to be reduced by 0.4, 1.0 and 1.1 % respectively for these three beams when compared to the factor derived from (60)Co. These results are in overall agreement with international absorbed dose standards and calculations by Muir and Rogers in 2010 of k Q factors using Monte Carlo techniques. The reasons for and against moving to the new service are discussed in the light of the requirements of clinical dosimetry.

Key comparison BIPM.RI(I)-K6 of the standards for absorbed dose to water of the ARPANSA, Australia and the BIPM in accelerator photon beams

A comparison of the dosimetry for accelerator photon beams was carried out between the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) and the Bureau International des Poids et Mesures (BIPM) in September and October 2012. The comparison was based on the determination of absorbed dose to water for three radiation qualities at the ARPANSA. Following receipt of the provisional comparison results, the ARPANSA decided to verify the geometry of the jacket and calorimeter core. This resulted in a change in the conversion factors applied by the ARPANSA to convert from absorbed dose to graphite to absorbed dose to water which was implemented after the comparison. The results for the revised standard, reported as a ratio of the ARPANSA and the BIPM evaluations, are 0.9965 at 6 MV, 0.9924 at 10 MV and 0.9932 at 18 MV, with a combined standard uncertainty of 5.5 parts in 103, 6.0 parts in 103 and 5.9 parts in 103, respectively. This result is the fifth in the on-going BIPM.RI(I)-K6 series of comparisons, and the first to be based solely on graphite calorimetry.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

An Australian secondary standard dosimetry laboratory participation in IAEA postal dose audits

For over 30 years, the International Atomic Energy Agency (IAEA) and the World Health Organization (WHO) have jointly monitored activities of secondary standard dosimetry laboratories (SSDLs) through postal dose audits with the aim of achieving consistency in dosimetry throughout the world. The Australian Nuclear Science and Technology Organisation (ANSTO) maintains an SSDL and is a member of the IAEA/WHO SSDL Network. Postal dose audit results at this Australian SSDL from 2001 to 2011 demonstrate the consistency of absorbed dose to water measurements, underpinned by the primary standard maintained at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).

Australian diagnostic reference levels for multi detector computed tomography

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) is undertaking web based surveys to obtain data to establish national diagnostic reference levels (DRLs) for diagnostic imaging. The first set of DRLs to be established are for multi detector computed tomography (MDCT). The survey samples MDCT dosimetry metrics: dose length product (DLP, mGy.cm) and volume computed tomography dose index (CTDIvol, mGy), for six common protocols/habitus: Head, Neck, Chest, AbdoPelvis, ChestAbdoPelvis and Lumbar Spine from individual radiology clinics and platforms. A practice reference level (PRL) for a given platform and protocol is calculated from a compliant survey containing data collected from at least ten patients. The PRL is defined as the median of the DLP/CTDIvol values for a single compliant survey. Australian National DRLs are defined as the 75th percentile of the distribution of the PRLs for each protocol and age group. Australian National DRLs for adult MDCT have been determined in terms of DLP and CTDIvol. In terms of DLP the national DRLs are 1,000 mGy cm, 600 mGy cm, 450 mGy cm, 700 mGy cm, 1,200 mGy cm, and 900 mGy cm for the protocols Head, Neck, Chest, AbdoPelvis, ChestAbdoPelvis and Lumbar Spine respectively. Average dose values obtained from the European survey Dose Datamed I reveal Australian doses to be higher by comparison for four out of the six protocols. The survey is ongoing, allowing practices to optimise dose delivery as well as allowing the periodic update of DRLs to reflect changes in technology and technique.