Abstract
Rationale: The International Atomic Energy Agency (IAEA) instituted a Coordinated Research Project (CRP) on the “Evaluation and Optimization of Pediatric Imaging” addressing the lack of consistency in this field. The purpose was to develop and test an optimization schema for the practices of pediatric radiology and nuclear medicine. Methods: A 5-step optimization schema was developed. Once a protocol optimization is identified, the steps are: 1) identification of the imaging situation, 2) collection of administered activity data and evaluation of the diagnostic image quality at baseline, 3) comparison of baseline administered activity data to published standards or other benchmarks, 4) identification of intervention, if necessary, 5) implementation of intervention and evaluation. Results: Within the CRP, two institutes considered optimization projects regarding nuclear medicine. In this work, renal imaging using 99mTc-DMSA projects are presented as examples. Site 1 acquired their standard 300-s static 99mTc-DMSA studies as 5-frame dynamic studies in 29 children. Frames were added to simulate different levels of administered activity. Image quality was subjectively judged on a 3-point Likert scale. A 30% reduction in administered activity with increased imaging duration (350-s) across all age groups was shown to be acceptable. This reduction was implemented and evaluated in 31 subsequent children yielding administered activities significantly lower than baseline (mean relative difference of 30% (age group 0-5 y), 37% (5-10 y) and 38% (10-15 y)). Site 2 performed a phantom study to determine the impact of lowering administered activity on image noise, indicating that administered activities could be significantly lowered if longer imaging times were used. This led to a 50-70% reduction from baseline with no loss in image quality. Conclusion: A dose optimization approach was applied successfully for several procedures commonly performed in pediatric nuclear medicine. Results are reported for renal cortical imaging using 99mTc-DMSA, leading to significant reductions in administered activity (and thus radiation dose). This optimization schema can be successfully implemented by nuclear medicine clinics seeking to improve their approach to imaging children.
- Copyright © 2020 by the Society of Nuclear Medicine and Molecular Imaging, Inc.