Optimisation de la dose " patient " pour applications radiologiques spécifiques

The knowledge of effective dose can have a useful contribution to the optimization process of patient doses in vascular radiology and cardiology. For the determination of effective dose with computer codes like MCNP or MCNP-X, different available anthropomorphic phantoms were compared. In order to validate the calculations, the effective dose was also measured with the use of the Rando-Alderson (RA) phantom. Organ doses, normalized to the dose-area-product (DAP), are calculated for an abdomen PA irradiation with a spectrum composed by 75 kVp and 6,5 mm Al + 0,1 mm Cu. For 4 different phantoms: 1. the mathematical phantom BODYBUILDER; 2. the voxel phantom MAX; 3. a voxel model of the RA-phantom; 4. the experimental RA phantom. From these organ doses, effective doses were calculated of 0.151 mSv/Gy.cm² ; 0.141 mSv/Gy.cm² ; 0.295 mSv/mGy.cm² and 0.245 mSv/Gy.cm², respectively. We observed large differences between organ doses for the mathematical phantoms used frequently in the passed and the voxel models. The difference is smaller for the global effective dose factor. The organ doses were systematically higher for the Rando-Alderson phantom (experimental and calculated), compared to BODYBUILDER and MAX.