Effective doses and associated age‐related risks for common paediatric diagnostic nuclear medicine and PET procedures at a large Australian paediatric hospital

Abstract

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.

Effective doses for common paediatric diagnostic general radiography examinations at a major Australian paediatric hospital and the communication of associated radiation risks

“…This mirrored the approach used by the authors in their earlier publication for estimating age-dependent organ and effective doses and the associated lifetime risk of cancer incidence and level of risk for the six most commonly performed nuclear medicine and PET procedures at RCH for children aged 0-18 years using published organ and effective dose coefficients and commonly used risk terminology. 10 As noted in ICRP Publication 128, effective dose can be a useful tool for comparing doses related to stochastic effects from other radiological procedures, similar or otherwise, performed at other institutions provided that the populations involved are of similar age and patient sex. 25 Using age-and patient sex-specific risk factors such as those provided in BEIR VII allow us to estimate the risk of developing a cancer from a particular procedure, additional to the lifetime baseline risk.…”

“…23 The median weight for male and female children was used to estimate the typical kVp and mAs used for each patient sex as per Table 2. For example, a chest anterior-posterior radiograph of a newborn female weighing 3.2 kg would have the lower exposure parameters of 70 kVp and 0.71 mAs, a 20 kg male or female 6 year old would use Using the same approach as the authors' previous publication, 10 the lifetime attributable risk of cancer incidence was estimated using the calculated effective doses and data provided in the Biological Effects of Ionising Radiation VII (BEIR VII) report, linearly interpolating for risk estimates for the in-between ages. 2 BEIR VII provides lifetime risk estimates for cancer incidence and cancer mortality resulting from a single dose of 0.1 Gy (100 mSv) at several specific ages for males and for females (Tables 12D-1 and 12D-2 in the BEIR VII report).…”

“…As previously discussed by the authors, 10 effective dose alone cannot be used to specify and communicate the associated stochastic risk for an individual examination due to differences in risk due to age and patient sex. In an earlier publication, the authors established typical effective doses from common paediatric nuclear medicine and positron emission tomography (PET) studies performed at the RCH and the associated lifetime risk of cancer incidence and level of risk for female and male children from 0 to 18 years old 10 .…”

“…As previously discussed by the authors, 10 effective dose alone cannot be used to specify and communicate the associated stochastic risk for an individual examination due to differences in risk due to age and patient sex. In an earlier publication, the authors established typical effective doses from common paediatric nuclear medicine and positron emission tomography (PET) studies performed at the RCH and the associated lifetime risk of cancer incidence and level of risk for female and male children from 0 to 18 years old 10 . Various methods are in use to categorise relative risks, with the classifications and terminology proposed by Calman being frequently used by State and National authorities such as the Australian Radiation Protection and Nuclear Safety Agency information sheets and Codes 11–14 .…”

Quantifying and communicating radiation dose and risk from imaging procedures

“…5,6 In a research study published in this issue, Earl et al 7 have computed radiation doses for commonly performed general radiography procedures at a major paediatric hospital and similar work by the same group has been published previously for nuclear medicine procedures. 8 These are excellent examples of a facility building a good understanding of patient exposures arising from their standard techniques. Other facilities are encouraged to do the same since practice may vary for a range of reasons such as equipment capabilities, patient cohort, disease presentation and the resources available for optimising technique factors.…”