ORCID Profile
0000-0001-9991-757X
Current Organisations
Alfred Health
,
University of Melbourne
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Publisher: Wiley
Date: 19-02-2021
Abstract: More than half of the world’s population live in Asia‐Pacific. This region is culturally erse, with significant disparities in terms of socio‐economic status, provision of health care and access to advanced technology. The medical use of ionising radiation is increasing worldwide and similarly within the Asia‐Pacific region. In this paper, we highlight the current status in usage of ionising radiation in medicine in the region, and review the legal framework, implementation and activities in radiation protection. Asia‐Pacific countries are active in strengthening radiation protection by promoting education and training. Various projects and activities initiated by international organisations such as the IAEA, WHO and ICRP have provided stimulation in the region, but more work is needed to continue to improve protection practices.
Publisher: Wiley
Date: 26-07-2016
Publisher: Elsevier BV
Date: 05-2018
Publisher: Springer Science and Business Media LLC
Date: 07-03-2016
DOI: 10.1007/S00247-016-3563-5
Abstract: Despite the medical benefits of CT, there are concerns about increased cancer risks following CT scans in childhood. To assess Australian temporal trends in pediatric CT scans funded through Medicare over the period 1985 to 2005, as well as changes in the types of CT scanners used. We studied de-identified electronic records of Medicare-funded services, including CT scans, that were available for children and adults younger than 20 years between 1985 and 2005. We assessed temporal trends using CT imaging rates by age, gender and anatomical region. Regulators provided CT scanner registration lists to identify new models installed in Australia and to date the introduction of new technologies. Between 1985 and 2005, 896,306 Medicare-funded CT services were performed on 688,260 in iduals younger than 20 years. The imaging rate more than doubled during that time period. There were more than 1,000 CT scanners on registration lists during the study period. There were both a sharp increase in the availability of helical scanning capabilities from 1994 and significant growth in multi-detector CT scanners from 2000. Significant increases in the rate of pediatric CT scanning have occurred in Australia. This rate has stabilized since 2000, possibly a result of better understanding of cancer risks.
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.CANEP.2016.03.006
Abstract: Ionizing radiation is a cause of cancer. This paper examines the effects of radiation dose and age at exposure on the incidence of brain cancer using data from the Life Span Study (LSS) of atomic bomb survivors. The Radiation Effects Research Foundation website provides demographic details of the LSS population, estimated radiation doses at time of bomb in 1945, person years of follow-up and incident cancers from 1958 to 1998. We modelled brain cancer incidence using background-stratified Poisson regression, and compared the excess relative risk (ERR) per Gray (Gy) of brain dose with estimates from follow-up studies of children exposed to diagnostic CT scans. After exposure to atomic bomb radiation at 10 years of age the estimated ERR/Gy was 0.91 (90%CI 0.53, 1.40) compared with 0.07 (90%CI -0.27, 0.56) following exposure at age 40. Exposure at 10 years of age led to an estimated excess of 17 brain tumors per 100,000 person year (pyr) Gy by 60 years of age. These LSS estimates are substantially less than estimates based on follow-up of children exposed to CT scans. Estimates of ERR/Gy for brain cancers in the LSS and haemangioma cohorts seem much smaller than estimates of risk for young persons in the early years after exposure to CT-scans. This could be due to reverse causation bias in the CT cohorts, diagnostic error, measurement error with radiation doses, loss of early follow-up in the LSS, or non-linearity of the dose-response curve.
Publisher: AMPCo
Date: 07-2012
DOI: 10.5694/MJA11.11124
Abstract: • The system of radiation protection assumes a linear dose-response relationship with no threshold for low doses and dose rate exposures. This is based on epidemiological evidence at higher doses. • Hence there is a small theoretical risk of carcinogenesis attributable to low doses of ionising radiation. This risk is associated with any diagnostic imaging procedure involving radiation. • Radiosensitivity declines with age, so children are more susceptible to radiation risks than adults. Females are more radiosensitive than males. • The radiation protection system is based on the assumption that radiation risk is cumulative over a lifetime. • For an in idual, a justified, optimised computed tomography (CT) scan will result in more benefit than harm. A doctor must justify the necessity for a CT scan before referring an in idual for imaging.
Publisher: British Institute of Radiology
Date: 11-2012
DOI: 10.1259/BJR/28015185
Publisher: Elsevier BV
Date: 12-2011
Publisher: Wiley
Date: 04-2011
DOI: 10.1111/J.1754-9485.2011.02242.X
Abstract: The use of CT has rapidly increased since its introduction. Although an important medical tool for diagnosis and treatment, CT is recognised as being among the highest contributors to population radiation exposure. As the risks associated with exposure are higher for children than for adults, this study assessed the impact of paediatric CT in Australia by analysing imaging trends. CT imaging trends were derived from Medicare data. Comparable data from a dedicated paediatric hospital (Royal Children's Hospital Melbourne (RCH)) were analysed to determine the validity of utilising Medicare statistics in the younger age groups. The resulting trends reflect the situation for paediatric CT imaging in Australia. In 2009, 2.1 million CT services were billed to Medicare in Australia for children and adults. The average annual growth in the number of CT services provided since 1994 was 8.5%, compared with population growth of 1.4%. Comparison of RCH and Medicare data revealed that only one third of paediatric CT imaging is captured by Medicare. Combining the data sets showed that over the last 20 years, there has been an average annual increase of 5.1% in the CT imaging rate for 0 to 18-year-olds. However, in recent years, growth in the imaging rate for 11 to 18-year-olds has slowed, while for 5 to 10-year-olds the imaging rate has declined. The significant growth in CT services is attributable to increased demand from the adult demographic. Conversely, increases in the imaging rate for paediatric patients have slowed overall. In fact, for some age groups the rate has fallen.
Publisher: Oxford University Press (OUP)
Date: 21-11-2017
DOI: 10.1093/RPD/NCX258
Abstract: We report data for all Australians aged 0-19 y who underwent publicly funded nuclear medicine studies between 1985 and 2005, inclusive. Radiation doses were estimated for in idual patients for 95 different types of studies. There were 374 848 occasions of service for 277 511 patients with a collective effective dose of 1123 Sievert (Sv). Most services were either bone scans (45%) or renal scans (29%), with renal scans predominating at younger ages and bone scans at older ages. This pattern persisted despite a 4-fold increase in the annual number of procedures. Younger children were more likely to experience multiple scans, with the third quartile of scans per patient dropping from two to one with patient age. The median effective dose per patient ranged from 1.3 mSv (4-7 y old) to 2.8 mSv (13-16 y old). This large data set provides valuable information on nuclear medicine services for young Australians in the period 1985-2005.
Publisher: Wiley
Date: 11-2009
DOI: 10.1111/J.1445-5994.2009.01956.X
Abstract: In an emergency department (ED), computed tomography (CT) is particularly beneficial in the investigation of high-speed trauma patients. With the advent of multidetector CT (MDCT) scanners, it is becoming faster and easier to conduct scans. In recent years, this has become evident with an increasing number of CT requests. Patients who have multiple CT scans during their hospital stay can receive radiation doses that have an increased theoretical risk of induction of cancer. It is essential that the clinical justification for each CT scan be considered on an in idual basis and that due consideration is given to the radiation risk and possible diagnostic benefit. The current lack of a central State or Commonwealth data repository for medical images is a contributing factor to excessive radiation dosage to the population. The principles of justification and radiation risks are discussed in this study.
Publisher: Springer Science and Business Media LLC
Date: 16-01-2014
DOI: 10.1007/S13246-014-0244-2
Abstract: Although diagnostic and interventional fluoroscopic procedures are amongst the highest dose examinations performed in radiology, these procedures currently lack established national diagnostic reference levels (DRLs) in Australia. In this absence, local diagnostic reference levels (LDRLs) are proposed for a wide range of diagnostic and interventional angiographic and fluoroscopic procedures based upon data collected from 11,000 examinations, performed over a 2.5 year period at a major Australian public, teaching hospital. Each procedure type assessed included a minimum of 50 cases. LDRLs were defined for each procedure in terms of the 75th percentile of the dose area product and median fluoroscopic times have also been provided. The detailed categories of procedures used in this study may inform the Australian Radiation Protection and Nuclear Safety Agency when establishing national DRLs for angiographic and fluoroscopic procedures. Until national DRLs for these complex procedures are available, these LDRLs may provide guidance to other institutions on achievable dose levels.
Publisher: Springer Science and Business Media LLC
Date: 03-2012
Publisher: Springer Science and Business Media LLC
Date: 11-04-2012
DOI: 10.1007/S13246-012-0134-4
Abstract: Computed tomography (CT) is the single biggest ionising radiation risk from anthropogenic exposure. Reducing unnecessary carcinogenic risks from this source requires the determination of organ and tissue absorbed doses to estimate detrimental stochastic effects. In addition, effective dose can be used to assess comparative risk between exposure situations and facilitate dose reduction through optimisation. Children are at the highest risk from radiation induced carcinogenesis and therefore dosimetry for paediatric CT recipients is essential in addressing the ionising radiation health risks of CT scanning. However, there is no well-defined method in the clinical environment for routinely and reliably performing paediatric CT organ dosimetry and there are numerous methods utilised for estimating paediatric CT effective dose. Therefore, in this study, eleven computational methods for organ dosimetry and/or effective dose calculation were investigated and compared with absorbed doses measured using thermoluminescent dosemeters placed in a physical anthropomorphic phantom representing a 10 year old child. Three common clinical paediatric CT protocols including brain, chest and abdomen elvis examinations were evaluated. Overall, computed absorbed doses to organs and tissues fully and directly irradiated demonstrated better agreement (within approximately 50 %) with the measured absorbed doses than absorbed doses to distributed organs or to those located on the periphery of the scan volume, which showed up to a 15-fold dose variation. The disparities predominantly arose from differences in the phantoms used. While the ability to estimate CT dose is essential for risk assessment and radiation protection, identifying a simple, practical dosimetry method remains challenging.
Publisher: Oxford University Press (OUP)
Date: 14-01-2023
Abstract: Computed tomography (CT) scans make substantial contributions to low-dose ionizing radiation exposures, raising concerns about excess cancers caused by diagnostic radiation. Deidentified medicare records for all Australians aged 0–19 years between 1985–2005 were linked to national death and cancer registrations to 2012. The National Cancer Institute CT program was used to estimate radiation doses to the brain from CT exposures in 1985–2005, Poisson regression was used to model the dependence of brain cancer incidence on brain radiation dose, which lagged by 2 years to minimize reverse causation bias. Of 10 524 842 young Australians, 611 544 were CT-exposed before the age of 20 years, with a mean cumulative brain dose of 44 milligrays (mGy) at an average follow-up of 13.5 years after the 2-year lag period. 4472 were diagnosed with brain cancer, of whom only 237 had been CT-exposed. Brain cancer incidence increased with radiation dose to the brain, with an excess relative risk of 0.8 (95% CI 0.57–1.06) per 100 mGy. Approximately 6391 (95% CI 5255, 8155) persons would need to be exposed to cause 1 extra brain cancer. For brain tumors that follow CT exposures in childhood by more than 2 years, we estimate that 40% (95% CI 29%–50%) are attributable to CT Radiation and not due to reverse causation. However, because of relatively low rates of CT exposure in Australia, only 3.7% (95% CI 2.3%–5.4%) of all brain cancers are attributable to CT scans. The population-attributable fraction will be greater in countries with higher rates of pediatric scanning.
Publisher: IOP Publishing
Date: 2005
Publisher: BMJ
Date: 21-05-2013
DOI: 10.1136/BMJ.F2360
Start Date: 2015
End Date: 2019
Funder: National Health and Medical Research Council
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