Tridimensional dosimetry for prostate IMRT treatments using MAGIC-f gel by MRI

• Gel MAGIC-f was applied to real treatments plans.
• Proper application of MRI as scanning method.
• Great similarity between gel's and the TPS’ dose distributions.
• High rate of the gamma index in both patients.
• The results show that gel dosimetry allows tridimensional dose distribution determination for complex radiotherapy treatments.

Intensity-modulated radiation therapy is able to deliver complex dose distributions and a system able to determine tridimensional dose distribution during the quality assurance of the treatments would be of great interest. In this context polymeric gels can be a useful dosimeter. This work aims to apply this tridimensional dosimetry technique for two prostate IMRT treatments, using MAGIC-f as a gel dosimeter combined with the magnetic resonance imaging to determinate the dose distributions. Dose images obtained by the gel were compared with the treatment planning images and the gamma index was calculated as a quantitative comparison. In both plans a high pass rate was achieved in the gamma analyses (95.5% and 94.0% for plans 1 and 2 respectively) showing that they were approved in the tridimensional quality assurance.