DOSIS: An integrated computational tool for patient-specific dosimetry in nuclear medicine by Monte Carlo and dose point kernel approaches

P. PÉREZ; MAURO VALENTE

APPLIED RADIATION AND ISOTOPES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2019 vol. 150 p. 135 - 140

0969-8043

The use of radiolabeled molecules for tumor targeting constitutes a remarkable technique for the treatment ofsystemic malignancies. An accurate patient-specific dosimetry in nuclear medicine procedures should be a re-levant pre-requisite in order to achieve the required lethal damage to tumor cells while maintaining possibleside-effects to normal tissues at tolerable levels. It is desired to assessin vivothe radiopharmaceutical distributionfor further estimation of absorbed dose released to target and involved organs. In this context, it was developed acomputational toolkit, called DOSIS, in order to perform patient-specific dosimetry based on personalized pa-tient anatomy and biodistribution of radionuclides both obtained by currently available dual PET/CT or SPECT/CT facilities. This work is focused on comparing 3D dose distributions obtained by DOSIS performing full sto-chastic Monte Carlo simulations versus analogue distributions obtained with analytical approaches like dosepoint kernel convolution and local energy deposition, when considering non-homogeneous activity or densitydistributions at different scales. Mathematical virtual phantoms were created for this study in order to compareresults with other calculation methods. Some of the beta-emitters radionuclides commonly used for therapy (90Y,131I,177Lu) were investigated, and emissions of beta-particles, conversion electrons, gamma radiation, andcharacteristic X-rays were considered. DOSIS implements a novel code devoted to managing radiation transportsimulation by means of PENELOPE Monte Carlo general-purpose routines on voxelized geometries defined by 3Dmass and activity distributions. Both distributions can be defined through patients-specific images, or pre-de-fined virtual phantoms. Results preliminary confirmed DOSIS as a reliable and accurate toolkit for personalized internal dosimetry along with highlighting advantages/drawbacks of the different calculation schemes proposed.