Increased FDG uptake in the distal upper extremities of teenagers on FDG PET/CT scan: Are the mobile electronic devices culprit?

Objectives Increased FDG activity in the hand or forearm in adolescent patients can be sometimes seen. The purpose of this study was to determine how common an elevated FDG activity in the distal upper extremities in teenager patients could be observed and to see whether such activity was related to using mobile electronic devices.

Methods PET/CT images of the upper extremities from 174 adolescents between 13-19 years old were retrospectively analyzed. All of these patients had FDG PET/CT with their arms within the field of views. The pre-imaging questionnaire/interview records/technologist records were also reviewed and compared to the imaging findings.

Results The incident of some degree of elevated uptake in the muscles in the hand or forearm is unexpectedly high and was observed in 87 teenagers. Among those 87 patients, 24 had intense activity defined by more than 150% of SUVmax of the liver. Based on The pre-imaging questionnaire/interview records/technologist records, 9 teenagers were playing games heavily using either tablet or cell phones prior to the image acquisition. Interestingly, all these 9 teenagers who heavily used mobile electronic devices were among those 24 patients who had significantly increased FDG activity (>150% of hepatic SUVmax) in the hand and/or forearms. Among other 78 patients with increased forearm activity, although there were no definite records of heavily playing electronic games on tablet or cell phone, such behaviors could not be excluded because using tablet or smart phone was not specifically required to document.

Conclusions Increased FDG uptake in the muscles of the hand and/or forearm is common when FDG PET/CT scans are performed on teenagers. It is possible that playing electronic games on a tablet or a smart phone prior to image acquision plays a role of increased activity in the hand and forearm at least in some teenage patients.