A Comparison of thermoplastic and 3D printed beam directional shells on viability for external beam radiotherapy and user experience
Robertson, Fiona Mary
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Robertson, F. (2017) A Comparison of thermoplastic and 3D printed beam directional shells on viability for external beam radiotherapy and user experience, no. 119.
Background: The precision of a patient's set-up for the accurate delivery of radiotherapy is paramount. For patients receiving radiotherapy for head and neck cancer it is particularly critical due to the need to prescribe the maximum therapeutic dose to the tumour while sparing normal tissue in very close proximity. Through advances in new technology three-dimensional printing gives the potential for creating an anatomically precise beam directional shell (BDS) directly from a three-dimensional computer model of the patient. Purpose: The aim of this study is to determine the viability of using three-dimensionally printed BDSs by comparing them to the currently used thermoplastic BDSs. Materials and methods: A direct comparison of three-dimensional and thermoplastic BDSs will be assessed. Seventeen healthy volunteers had both BDSs created and a retrospective isocentre positioned on the masks to be used as a baseline for set up. The retrospective isocentre mark allowed left-right, superior-inferior, anterior-posterior alignment and rotation to be assessed over four sessions. After each session of wearing the BDS, the volunteers immediately completed a State Trait Anxiety Inventory (STAI) Part 1 to assess their emotional experience of that particular BDS. Results and conclusion: The data was assessed for normality and homogeneity. If the data was considered normally distributed and homogeneous then a two-way repeated measures Analysis of Variance was performed. If it was not normally distributed then a non-parametric Friedman and Man Whitney U test was used. It was found that there was no significant difference in the external reproducibility of the 3D printed compared to the thermoplastic BDS for the Vertical, Longitudinal and Lateral couch parameters. There was however a statistically significant difference for the Rotational variable. The results obtained from the STAI Part 1 suggested that the thermoplastic BDS produced significantly higher scores in anxiety and distress compared to the 3D printed BDS. The results obtained give encouraging evidence to indicate that 3D printed BDSs could be a viable immobilisation device used for patients requiring EBRT to the head and neck region.