Abstract Book

S162

ESTRO 37

Results The positional correlation between humeral head and node level is high in the medio-lateral (ML) direction for all node levels (0.67

OC-0309 Impact of environmental factors on IGRT image interpretation: RTTs’ opinions and perceptions L. Fitzpartick 1 , G. Menezes 1 , E. Forde 1 , L. Mullaney 1 1 Trinity College Dublin, Discipline of Radiation Therapy- School of Medicine, Dublin, Ireland Purpose or Objective The impact of environmental factors on error, efficiency and accuracy in image interpretation is widely addressed in diagnostic imaging (DI) by the provision of guidelines outlining the optimal environment under which image interpretation should occur; this is currently lacking for the Radiation Therapy environment. The aim of this research was to identify the opinions and perceptions of radiation therapists (RTTs) regarding the impact of environmental factors on image guided radiation therapy (IGRT) image interpretation. Material and Methods A mixed methods survey based on relevant DI literature was developed and distributed to RTTs worldwide. The survey was designed to collect qualitative and quantitative data regarding opinions and perceptions of the impact of environmental factors on IGRT image interpretation. Results Four hundred and thirty four RTTs fully completed the survey. 82% of RTTs identified environmental factors as having an impact on image interpretation. Figure 1 demonstrates the perceived impact of specific environmental factors on image interpretation. 10% of RTTs reported their work environment was unsuitable for image interpretation and 34% of respondents felt that changes were needed to facilitate image interpretation, these included provision of a designated room, or imaging workstation, removal of distractions/interruptions and lighting improvements. 69% surveyed identified that they believe the provision of guidelines would be beneficial to their image interpretation. Figure 1. Distribution of RTTs perceptions on the impact of specific environmental factors on their image interpretation

Conclusion There is a rather strong correlation between the position of the humeral head and the node levels. This correlation is strongest in the medio lateral direction. In cranio caudal and ventro dorsal direction the correlation is strongest for level I, and less prominent for levels II – IV. For 95% of all set ups, the displacement of a node level is within 5 mm of the displacement of the humeral head. For accurate dose coverage of node levels I to IV, an additional margin of 1 to 2 mm is required on top of the margin needed for the clinical match.

Conclusion A wide range of environmental factors impact on RTTs’ ability to interpret images during IGRT. The introduction of guidelines outlining the optimal environment under which image interpretation should occur is needed based on the opinions and perceptions of RTTs and the literature identified from DI to improve image interpretation in Radiation Therapy.