A national survey of computed tomography doses in hybrid PET-CT and SPECT-CT examinations in the UK

• Published in: Nuclear medicine communications Vol. 38; no. 6; p. 459
• Main Authors: Iball, Gareth R, Bebbington, Natalie A, Burniston, Maria, Edyvean, Sue, Fraser, Louise, Julyan, Peter, Parkar, Nasreen, Wood, Tim
• Format: Journal Article
• Language: English
• Published: England 01.06.2017
• Subjects: Humans; Positron Emission Tomography Computed Tomography - standards; Positron Emission Tomography Computed Tomography - statistics & numerical data; Radiation Dosage; Reference Standards; Single Photon Emission Computed Tomography Computed Tomography - standards; Single Photon Emission Computed Tomography Computed Tomography - statistics & numerical data; Surveys and Questionnaires; United Kingdom
• ISSN: 1473-5628
• DOI: 10.1097/MNM.0000000000000672

The aim of this study was to conduct a nationwide survey of computed tomography (CT) doses for a wide range of PET-CT and single photon emission computed tomography-computed tomography (SPECT-CT) imaging procedures, with the aim of generating proposed UK national diagnostic reference levels (NDRLs). CT protocol and dosimetry data for three PET-CT and seven SPECT-CT examinations were gathered from centres across the UK. Data were divided according to CT purpose (attenuation correction, localization or diagnostic) and third quartile values of scanner average dose metrics were used to generate suggested NDRLs for a range of examination and CT purpose combinations. Achievable doses were also established from the median of the dose distributions. Data were obtained from 47 centres, allowing suggested NDRLs to be produced for fluorine-18-fluorodeoxyglucose half-body PET-CT, and parathyroid, post-thyroid ablation, meta-iodobenzylguanidine/octreotide, cardiac and bone SPECT-CT examinations.Variations in dose of up to a factor of 35 were observed for a given examination/CT purpose combination. For fluorine-18-fluorodeoxyglucose half-body PET-CT examination dose levels for the three CT purposes overlapped, which highlights the variability in the way in which CT purposes are interpreted across the UK. This lack of standardization is believed to be the largest contributor to the dose variations that were observed. The survey highlighted the need for targeted optimization work in many centres. Suggested UK NDRLs and achievable doses for six common PET-CT and SPECT-CT examinations have been established as a result of this study.