Liquid embolisation material reduces the delivered radiation dose: a physical experiment

To test a new hypothesis that the glue/contrast admixture used for embolisation reduces the dose delivered to AVMs using an experimental model. A model was created using a block of 'solid water' (6 x 5 x 2 cm) with twelve wells of different depths. Different concentrations of the glue admixture (Embucrilate + Lipiodol) were used. The model was irradiated using a 5MV beam with a clinical LINAC system and the dose was checked upstream and downstream. Dose was measured using Kodak XV film, a Vidar 16 bit film scanner and software for therapeutic film dosimetry measurements (RIT software). The radiation dose varied with the distance beyond the glue solid water interface. For distances of 0, 2 and 5 mm to the film, the mean reduction was 13.65% (SD = 2.94), 6.87 % (SD = 1.95) and 1.75 % (SD = 1.14), respectively. There was also correlation with the Lipiodol concentration in the mixture. The maximum reductions for 80, 50 and 20 % Lipiodol concentrations were 16.1 % (SD = 1.32), 14.85 % (SD = 0.98) and 10 % (SD 1.21), respectively. There was no correlation between the glue depth and the dose delivered. The hypothesis that the glue mixture used for embolisation reduces the radiation dose delivered was experimentally confirmed with this study. (author)