Radiation protection in CT-guided interventions: does real-time dose visualisation lead to a reduction in radiation dose to participating radiologists? A single-centre evaluation.

AIM: To evaluate if real-time dose visualisation during computed tomography (CT)-guided interventions leads to a reduction in radiation dose to participating radiologists. MATERIALS AND METHODS: The individual radiation dose radiologists are exposed to during CT interventions was measured using dedicated dosimeters (RaySafe i2-system, Unfors RaySafe GmbH, Billdal, Sweden) worn over the usual radiation protective apron. Initially, only the total radiation dose was measured, without visualisation (control group). In the following study period, the radiation dose was shown to participants on a live screen in real-time (experimental group). In both groups, the dose was recorded in 1-second intervals. The results collected were evaluated by comparison using descriptive statistics and mixed-effect models. In particular, the variables experience, gender, role, and position during the intervention were analysed. RESULTS: In total, 517 measurements of 304 interventions (n=249 with and n=268 without live screen) performed by 29 radiologists acting as interventionalists or assistants were analysed. All CT-guided interventions were performed percutaneously, the majority of which (n=280) were microwave ablations (MWA). Radiation doses in the group without visualisation were comparable with usual dose rates for the corresponding intervention type. The mean total radiation dose was reduced by 58.1% (11.6 versus 4.86 µSv) in the experimental group (p=0.034). The highest reduction of 78.5% (15.55 versus 3.35 µSv) was observed in radiologists with the role of assistant (p=0.002). Sub-analysis showed significant dose reduction (p<0.0001) for the use of live screen in general; considering all variables, the role "assistant" alone had a statistically significant influence (p=0.002). CONCLUSION: The real-time visualisation of active radiation dose during CT interventions leads to a relevant reduction in radiation dose to participating radiologists.

Ras/MAPK Modifier Loci Revealed by eQTL in Caenorhabditis elegans.

The oncogenic Ras/MAPK pathway is evolutionarily conserved across metazoans. Yet, almost all our knowledge on this pathway comes from studies using single genetic backgrounds, whereas mutational effects can be highly background dependent. Therefore, we lack insight in the interplay between genetic backgrounds and the Ras/MAPK-signaling pathway. Here, we used a Caenorhabditis elegans RIL population containing a gain-of-function mutation in the Ras/MAPK-pathway gene let-60 and measured how gene expression regulation is affected by this mutation. We mapped eQTL and found that the majority (∼73%) of the 1516 detected cis-eQTL were not specific for the let-60 mutation, whereas most (∼76%) of the 898 detected trans-eQTL were associated with the let-60 mutation. We detected six eQTL trans-bands specific for the interaction between the genetic background and the mutation, one of which colocalized with the polymorphic Ras/MAPK modifier amx-2 Comparison between transgenic lines expressing allelic variants of amx-2 showed the involvement of amx-2 in 79% of the trans-eQTL for genes mapping to this trans-band. Together, our results have revealed hidden loci affecting Ras/MAPK signaling using sensitized backgrounds in C. elegans These loci harbor putative polymorphic modifier genes that would not have been detected using mutant screens in single genetic backgrounds.