ORGAN DOSE ESTIMATES IN THORAX CT: VOXEL PHANTOM ORGAN MATCHING WITH INDIVIDUAL PATIENT ANATOMY
The main objective of this investigation was to modify existing three-dimensional (3D) voxel phantom models to resemble real patients, towards the personalized patient dosimetry concept. This work focused essentially in one of the most radiosensitive organs in the thorax, the lungs. Additionally, the variations of organ doses when a standard phantom is used instead were studied. A FORTRAN-based program was developed, which is able to semi-automatically modify the volumetric information of organs of interest in a standard voxel phantom (Female ICRP Adult Reference). Monte Carlo (MC) simulations were used to mimic CT scan conditions and access organ dose in both phantoms (ICRP standard and ICRP modified). Voxel models matched to patients’ size and overall anatomy allow increased accuracy in organ dose estimation, which can suffer from up to 20% underestimation and 40% overestimation. This study demonstrates that voxel phantoms developed using single patient data provide more precise organ dose assessments.