New VoxTox animation illuminates radiotherapy treatment
The VoxTox Research Programme, funded by Cancer Research UK, focuses on reducing toxicity from radiotherapy by linking radiation dose at the ‘voxel’ level with toxicity. Specifically, we are developing methods to estimate the dose actually delivered to tissues during a course of radiotherapy as distinct from the dose that has been planned. Differences exist between these two for a number of reasons, including day to day variation in the shape and position of internal organs.
The animated film
The animation shows a man with prostate cancer who lies down on the treatment machine. On the treatment machine itself he will have a CT scan done each day and these scans are used in our VoxTox programme. The animation shows the prostate and the rectum within the pelvis. The prostate itself is quite ‘knobbly’ to represent the fact that it has prostate cancer within it. The rectum can be seen immediately behind the prostate.
Looking from the feet of the patient, we see the prostate and rectum. The treatment plan is then shown with dose represented by colour, superimposed on the planning CT scan done previously.
After a glimpse of the prostate a rectum, we see the daily treatment CT scan, with the rectum (and the hips) outlined, with the dose delivered that day shown in colour. The prostate gets the highest dose shown in a hot colour. The dose to the rectum can also be seen.
From one day to the next, for all 20 treatments, we see the dose move around within the patient, guided by the scan of the day, so that the prostate itself, which can move inside the patient, is always targeted. The size and position of the rectum changes each day, as does the dose delivered to it.
At the end of the treatment we once again see the prostate and the rectum from the side and prostate becomes smooth, representing the cancer having been killed by the radiotherapy.
Purpose of the VoxTox Research Programme
Within VoxTox we have developed a set of computer programmes, all managed by an overarching programme, which can perform a collection of the day by day CT scans, contouring of the rectum, and calculation of the delivered dose fully automatically. We are working to refine this process to improve its accuracy and ultimately we hope to be able to use this to alter a patient’s treatment as the result of watching the day by day accumulation of delivered dose.
Thanks to Preeti Deshpande for the production of the animation from real patient images and dose maps.
This animation may only be used with permission and for non-commercial purposes.
Published on 7 October 2016 by John