Article 

Radiation dose from ¹⁸F-FDG PET/CT procedures: influence of specific CT model and protocols

School of Chemistry & Physics, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

^* Corresponding author: chettyn3@ukzn.ac.za

Received: 18 July 2017
Accepted: 24 February 2018

Abstract

The increasing use of the integrated ¹⁸F-fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging modality in the management of tubercular lesions raises concerns about associated radiation exposure. This work aimed to study the effects of CT model and study protocols on the overall radiation dose from a PET/CT examination. Two PET/CT systems with five representative CT exposure protocols applied for clinical patients in PET/CT imaging following retrospective evaluation were studied. CT doses were calculated using the CT-Expo dosimetry software (version 2.4), while the PET component dose was estimated applying the International Commission on Radiological Protection (ICRP) 106 dose coefficients. The total effective dose ranged from 8.0 to 24.05 mSv for system I and 8.35 to 26.85 mSv for system II, resulting in differences of 4.3 to 15% for the low-dose scan and 4.1 to 11% for standard dose scans. The CT component contribution to the total dose was between 32 and 77% for system I, and 35 and 79% for system II. However, the contributions were not significantly different (p > 0.05) for all protocols. The observed variation in CT contribution represents a requisite pedestal on the need for a nation-wide dose assessment for further optimization of the imaging procedure to maximize benefit to patients.