S values for voxel dosimetry


Simulations for obtaining the S values were performed with DOSxyznrc, a program based on the EGSnrc code for calculating the dose deposition in cartesian coordinates. Simulations were implemented by activating all the most advanced options available, such as the electron impact ionization, bound Compton scattering, photoelectron angular sampling, Rayleigh scattering, and atomic relaxations. Electron and photon transports were simulated in two different homogeneous tissues: soft tissue, having the elemental composition and physical density defined by Cristy and Eckerman, and bone tissue (namely, compact bone), as defined by ICRU Report 10b. Energy was scored in grids of cubic voxels with the chosen voxel size, with the sources uniformly dispersed in a voxel irradiating isotropically the surrounding ones. All simulations have been carried out with a cutoff energy of 1 keV and without using variance reduction techniques. The energy scored in each voxel has been converted in average dose to the target voxel per unit of cumulated activity [mGy/(MBq · s)] and associated with the target position in the Cartesian grid. A more complete description of the database of S values can be found in this paper.

If you use data from this database, please credit this website as the source of the data, and reference the following paper:

"A free database of radionuclide voxel S values for the dosimetry of nonuniform activity distributions", N. Lanconelli, M. Pacilio, S. Lo Meo, F. Botta, A. Di Dia, L. A. Torres Aroche, M. A. Coca Perez, M. Cremonesi, Physics in Medicine and Biology, Vol. 57, (2012) 517-533.

Here you can find the S values for some of the most common radionuclides at various voxel sizes. Should you need S values for other voxel dimensions (or other radionuclides), do not hesitate to send an email with your request at:

Choose the radioisotope:

Choose the Voxel size:

Choose the tissue: