  A new approach to three-dimensional (3D) dosimetry based on
optically-stimulated luminescence (OSL) is presented. By embedding OSL-active
particles into a transparent silicone matrix (PDMS), the well-established
dosimetric properties of an OSL material are exploited in a 3D-OSL dosimeter.
By investigating prototype dosimeters in standard cuvettes in combination with
small test samples for OSL readers, it is shown that a sufficient transparency
of the 3D-OSL material can be combined with an OSL response giving an estimated
>10.000 detected photons in 1 second per 1mm3 voxel of the dosimeter at a dose
of 1 Gy. The dose distribution in the 3D-OSL dosimeters can be directly read
out optically without the need for subsequent reconstruction by computational
inversion algorithms. The dosimeters carry the advantages known from
personal-dosimetry use of OSL: the dose distribution following irradiation can
be stored with minimal fading for extended periods of time, and dosimeters are
reusable as they can be reset, e.g. by an intense (bleaching) light field.
