Lead-Dust Contamination on Radiation Protection Apparel.

PURPOSE: To evaluate the prevalence of surface lead-dust contamination on radiation protection apparel (RPAs) in the radiology department and compare findings with those from other studies of RPA lead-dust contamination. MATERIALS AND METHODS: A survey of RPAs was conducted between June and December 2021 in radiology departments at a tertiary-care university hospital. A convenience sample of RPAs located on wall-mounted racks outside the angiography suite and emergency department was surveyed. Surface lead dust on RPAs was detected using a rapid qualitative test. RESULTS: A total of 69 RPAs included full-length frontal lead aprons (n = 11), full-length frontal lead aprons (n = 25) with thyroid collars (n = 25), and thyroid collars alone (n = 8). Garments consisted mainly of a lead/antimony composite core with a 0.5-mm lead equivalency. One RPA failed radiologic quality inspection, and 8 garments were in poor or worn condition. The overall prevalence of surface lead-dust contamination on RPAs was 60.9% (95% CI, 49.1%-71.5%) and was significantly (P = .0035) higher on thyroid collars (78.8% [95% CI, 62.2%-89.3%]) than on lead aprons (44.4% [95% CI, 29.5%-60.4%]). CONCLUSIONS: A high prevalence of surface lead-dust contamination was detected on RPAs using a rapid qualitative test. There is currently no established safe level of lead, and these findings suggest RPAs be monitored frequently not only for physical defects limiting radiation protection but also for lead-dust contamination.

The neurocognitive mechanisms underlying food cravings and snack food consumption. A combined continuous theta burst stimulation (cTBS) and EEG study.

Regulation of food cravings is thought to be critical for modulating eating behavior, yet we do not fully understand the mechanisms by which cognitive control operates in the eating context. The current study combined rTMS and EEG paradigms to examine the causal role of the left dorsolateral prefrontal cortex (dlPFC) in modulating visceral and behavioral responses to high calorie foods, and the mediational mechanisms underlying this relation. 28 right-handed female participants received both active and sham continuous theta burst stimulation (cTBS; a rTMS variant used to decrease cortical activity) targeting the left dlPFC in a counterbalanced order. Prior to and following each stimulation session participants completed a flanker and food-cue presentation (high and low calorie food) task. Following cTBS participants had the opportunity to consume both high and low calorie foods during a taste test. Findings revealed a reliable effect of cTBS on food consumption, such that participants selectively ingested significantly more calories from appetitive calorie dense snack foods following active relative to sham cTBS; this effect did not translate to control (low calorie) food consumption. In addition, attenuation of dlPFC activity resulted in the significant increase in N2 amplitude and P3b latency to incongruent flanker trials, and the selective significant increase in the P3a amplitude to and P3a amplitude bias for high calorie food stimuli. Results from the parallel mediation analysis revealed that only the indirect effect of flanker task performance was significant; the indirect effects of stimulation induced changes in the P3 bias for high calorie foods, the urge to consume high calorie foods, and the general liking ratings for high calorie foods were not significant. These findings confirm the causal role of the left dlPFC in the modulation of calorie dense food consumption via inhibitory control capacity.

Investigating Cortical Buffering Effects of Acute Moderate Intensity Exercise: A cTBS Study Targeting the Left Dorsolateral Prefrontal Cortex.

Background: The beneficial effects of both single-session bouts of aerobic exercise and therapeutic exercise interventions on the cortical regions associated with top-down attentional control [i.e., prefrontal cortex (PFC)] have been well documented. However, it remains unclear whether aerobic exercise can be used to buffer against suppressive influences on the dorsolateral PFC (dlPFC). Objective: The current study sought to determine whether a single session of moderate intensity aerobic exercise can offset the expected suppressive effects of continuous theta burst stimulation (cTBS) targeting the dorsolateral prefrontal cortex (dlPFC). Methods: Twenty-two right-handed participants (aged 19-30) completed a 20-minute movement-only control session [10% heart rate reserve (HRR)] and moderate intensity (50% HRR) exercise in a counterbalanced order. Following each exercise session, participants received active cTBS to the left dlPFC. Changes in executive functions were quantified using a Flanker paradigm employed at baseline, post-exercise and post-cTBS time points. Additionally, EEG was used to measure changes in event-related potential components related to inhibitory control (i.e., N2) and attentional control (i.e., P3) during the flanker task. Results: Behavioral results from the flanker task revealed a significant improvement in task performance following an acute bout of moderate intensity exercise. Furthermore, the effect of cTBS in both the movement-only control and moderate intensity conditions were non-significant. Similarly, EEG data from P3b and N2 ERP components revealed no changes to amplitude across time and condition. P3b latency data revealed a significant effect of time in both the moderate intensity and movement-only conditions, such that P3b latencies were significantly shorter across time points. Latency data within the N2 ERP component revealed no significant interactions or main effects. Conclusion: The findings of the current study provide tentative support for the hypothesis that both moderate and light intensity exercise promote cortical buffering against the suppressive effects of cTBS targeting the dlPFC. However, in the absence of a no-movement control, a lack of expected suppressive effects of cTBS cannot be ruled out.

The effects of theta burst stimulation (TBS) targeting the prefrontal cortex on executive functioning: A systematic review and meta-analysis.

Theta burst stimulation (TBS) is a highly efficient repetitive transcranial magnetic stimulation (rTMS) variant employed in experimental and clinical treatment paradigms. Despite widespread usage of TBS targeting the prefrontal cortex (PFC), there has been no systematic review of the evidence linking TBS protocols to changes in task performance on common measures of prefrontal function in general, and executive functions specifically. A systematic review of the literature was conducted using PsycINFO, PubMed, Web of Science and Scopus databases to identify articles examining the effects of TBS targeting the PFC on executive function task performance. Both the up-regulating (intermittent theta burst stimulation; iTBS) and down-regulating (continuous theta burst stimulation; cTBS) variants of TBS were considered. 32 (29 cTBS; 8 iTBS) studies met the inclusion criteria. Participants (n = 759; 51.41% female) were primarily young adults (Mage = 26), with one study examining the effects of cTBS and iTBS in older adults. Results from individual studies were converted to Hedge's g and random-effects models were used to estimate the overall effect size for each protocol. Age, biological sex, and control methodology were examined as potential moderators of the cTBS effect on executive function test performance. Findings indicated a- reliable attentuating effect of cTBS on executive function task performance (g = -.244, Z = -5.920, p < .001); this effect was relatively uniform across included studies (Q= 24.178, p = .838, I2 = 0). Although no significant moderators of the cTBS effect were identified, laterality sub analyses indicated that the magnitude of the effect was significantly higher (Mdiff = .213, Zdiff = 2.546, p = .011) for left-sided (g = -.358, Z = -5.816, p < .001) relative to right-sided (g = -.145, Z = -2.552, p = .011) PFC stimulation. A systematic review of iTBS studies revealed variability in reliability of effects though most were in the theorized direction. TBS protocols appear to be effective in modulating prefrontal cortical excitability in previously theorized directions.