Room: Exhibit Hall
Purpose: Present a new patient positioning device and show first results from phantom experiments.
Methods: The classical patient setup for radiotherapy is limited to movements available on the treatment couch or technicians might do manual repositioning. Alternatively adaptive replanning can also be done. The new device might offer a way in between. It allows more degrees of freedom positioning the patient with a set of individually controllable air filled pillows. In general the device is MR compatible but first tests had to be done with a surface imaging system (Align RT, Vision RT) as monitor. Pillows, connected to a valve block and compressor can be adjusted manually or with a control system based on an arduino due micro controler (Arduino AG) and python software. With the actual prototype the workflow is like this: Generate a reference surface based on CT-data or Vision RT surface measurement, roughly align the patient/phantom, correct positions by adjusting the pillow filling by hand control or software to align accurate. Optionally the system can continuously correct for patient movements. The device with 10 pillows is capable of moving the patient up to 8cm with a force of 400 N with an iteration rate of about 1 second.
Results: Tests with an elastic phantom using the Vision RT system as surface detection system have been done. CBCTs were used to check for movements of the phantom based on the pillow fillings. The software tool allows for a repositioning of the surface within 2mm. Problems found, indicate that surface detection is not sufficient for position corrections of inner organs.
Conclusion: The Multi pillow device offers a new way of setting up a patient for RT. Designed being MR compatible, it might be worth thinking about using it in MR linacs offering high quality dose free imaging.