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

Abstract

Objective: 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. Methods: 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. Results: 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. Conclusion: 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. Advances in knowledge: 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.

Revising and exploring the variations in methodologies for establishing the diagnostic reference levels for paediatric PET/CT imaging

“…The paediatric weight band is more appropriate for reporting paediatric DRLs when compared to the age band category, especially upon imaging the trunk [7]. This is because paediatric weight correlates strongly with dose more than paediatric age [28]. However, the use of the ICRP 135 age band category remains favourable and recommended in head studies or if the paediatric age band is the only available category during the NDRL audit; or for data comparison with previous published peer-reviewed data [7].…”

“…These were fixed in all studies. None of the identified NDRL reported the value of effective dose (ED), mAs, and scan length, except the LDRL implemented in Australia DRL [28]. The ED and the variable CT parameters (mAs and scan length) for each age and weight categories are provided in (Table 4).…”

“…As a result, the availability of paediatric weight in routine clinical practice enables for determining NDRL on the contingent of paediatric EG weight category [28]. In relation to the ICRP 135 age category, published guidelines report recommendations for paediatric patients based on age category for 18 F-FDG WB PET/CT scans [28]. These determined guidelines were derived by NM physicians and used by the NM community to administer a paediatric dose and CT dose for the paediatric population.…”

“…This review found only a few distinguishable DRL methods for paediatric PET/CT scans [28–31]. Only one LDRL method, implemented in Australia, reported the paediatric LDRL for fluoride-18 fluorodeoxyglucose ( 18 F-FDG) PET/CT whole-body exam, based on the ICRP 135 age category, European Guidelines (EG) weight category, and age band category implemented by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) (0–4 years and 5–15 years) for 18 F-FDG PET administered activity (AA) and CT dose used for AC-AL [28]. Another NDRL, in Pakistan, only derived DRL for 18 F-FDG AA using the age band category [31].…”

A dedicated paediatric [18F]FDG PET/CT dosage regimen

“…For performing paediatric nuclear medicine procedures, both the Society of Nuclear Medicine and Molecular Imaging (SNMMI) and European Association of Nuclear Medicine (EANM) recommend the EANM paediatric dosage card (version 5.7.2016) [6,7] or the 2016 North American Consensus guidelines (NACG) [7,8]. Both these guidelines have, however, several shortcomings as they are derived from adult-based protocols [9][10][11][12], and both focus on radiation dose without taking image quality into account [9][10][11][12][13]. Moreover, the EANM paediatric dosage card recommends even higher administered activities per kilogram than the adult 2015 EANM [ 18 F]FDG guidelines [14].…”