Optimization of SUV with Changing the Dose Amount in F18-FDG PET/CT of Pediatric Lymphoma Patients

Abstract

Aims: We aim to reveal an effect of residual activity leftover within the medical materials other than the empty syringe used for injection of the tracer on SUV measurements and, consequently, the effect on possible treatment response. Background: The staging and follow-up of pediatric lymphoma patients is mainly achieved with the help of PET/CT scans. Making an optimal imaging technique for interpreting individual images and assessing treatment response is crucial. Objective: Standardized uptake value measurement is an important quantification parameter in PET/CT scanning of childhood lymphomas. A low dose of activity in pediatric oncology patients makes them vulnerable to small input value changes for subsequent metabolic parameters Methods: Sixty-eight pediatric lymphoma patients below 50 kg were included in the study. SUVmax, and SUVpeak values of the most metabolically active lesions, along with liver and mediastinum, were recorded. Metabolic parameters of the lesions/lymph nodes, mediastinum and liver parenchyma were compared before and after counts from medical materials other than empty syringes were taken into account. Wilcoxon signed-rank test was used for non-parametric paired sampled tests for the groups. Results: There were statistically significant differences between the whole 6 above-mentioned groups confirming the importance of residual counts on metabolic parameters (p<0.001). Conclusion: Our study demonstrated residual radioactivity in medical materials such as serum line tubes, i.v. catheters, three-way stopcock and also butterfly needles used during intravenous injection should also be included for optimum quantitative metabolic parameter values and to minimize their adverse effect on treatment response evaluation, especially in borderline lesions.