The very high dose gradients used in modern radiotherapy techniques means that a small error in the spatial dose distribution can lead to serious complication. To date, visualisation methods based on iso-contours (2D) and iso-surfaces (3D) have been used to visualise and evaluate dose conformity with tumour shape and location. While helpful, these methods display only a fraction of the data, constraining oncologists to scroll through several different iso-levels to develop a full understanding of the spatial relationship between patient anatomy and dose distribution. IRIS is software tool that employs advanced volume visualisation techniques (such as ray-casting) to solve this problem by rendering all data at once.
Direct volume rendering with ray-casting allows interactive viewing of datasets with multiple information channels, using transfer function to control the visibility and colour scaling of each channel. Due to the computationally expensive nature of this visualisation technique, we have employed a GPU-based implementation of ray-casting. GPU acceleration allows this analysis to be performed interactively and in real-time on a single computer.
IRIS provides an interactive 3D display of dose (or dose-difference) regions-of-interest, and CT anatomy. The tool provides a real-time qualitative evaluation of complex dose volumetric data better than other visualisation tools currently used in radiotherapy clinical practice. Using IRIS will establish a better and quicker visual validation of treatment plans. Improved information helps to refine therapeutic decisions and objectively choose between different strategies for treatment. This provides greater benefits to patient, in terms of higher safety and accurate treatment planning.
IRIS project was funded by STFC Impact Acceleration Account. We have delivered a series of interdisciplinary workshops, funded by the STFC Global Challenge Exploration Award, aimed to engage with clinicians and physicists in radiotherapy as potential users for the IRIS technology. The feedback collected from the workshops hasl enriched our practical knowledge on how IRIS technology can be utilised in the clinical practice. This will be reflected on a further development of the technology.