2015 Research Grant

Dr Peter Kench, University of Sydney
Diagnostic Reference Levels for FDG PET/CT Studies in New Zealand

 

Background: The integration of positron emission tomography with computed tomography (PET/CT) hybrid systems has revolutionised clinical practise. However, PET/CT may contribute to a higher radiation burden among patients due to radiation exposure from both the PET and CT modalities. Diagnostic reference levels (DRL) allow the comparison of average patient radiation dose from clinical centres with a national standard. If local reference levels exceed the national DRL, there may be need for optimisation of the PET/CT protocol.

 

Aims: This survey aims to update the 2008 DRL values for fluoride-18 fluorodeoxyglucose (18F-FDG) published by the Australian and New Zealand Society of Nuclear Medicine (ANZSNM) (2009). It also aims to establish a new DRL value for CT component associated with whole-body PET/CT procedures in New Zealand (NZ).

 

Methods: A survey was sent to PET/CT centres in NZ. Data was collected prospectively for four weeks following the Australian Radiation Protection and Nuclear Safety Agency DRL protocol. The DRL and effective dose (ED) were calculated using the 75th percentile.

 

Results: Four of the five NZ PET/CT centres participated in this survey. The DRL for 18F-FDG has reduced from 385 MBq in 2008 to 301 MBq in 2016. The DRL for CT dose index volume (CTDIvol) and the dose length product (DLP) were 11.48 mGy and 1117.5 mGy.cm, respectively. The current DRL values for 18F-FDG were in good agreement with international published DRL data. However, the CT DRL was high in comparison to published data due to routine inclusion of a diagnostic CT and a chest breath hold CT in the PET/CT protocol. The 75th percentile ED was 18.88 mSv.

 

Conclusion: A revised national DRL for 18F-FDG PET imaging has been suggested. DRL for PET/CT in NZ have been recommended for the first time.

Applicants:
Peter L Kench, Principle Investigator, PhD, Senior Lecturer, Nuclear Medicine Science, Discipline of Medical Radiation Sciences, Faculty of Health Sciences, The University of Sydney,  Lidcombe, NSW, 2141
Essam M A Alkhybari, Master of Nuclear Medicine, Research Higher Degree Student
Kathy Willowson, PhD, Medical Physicist, Department of Nuclear Medicine Royal North Shore Hospital
Mark McEntee, PhD, Senior Lecturer, Diagnostic Radiography, Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney.