Monte Carlo simulation of radiation transport and dose deposition from locally released gold nanoparticles labeled with < sup > 111 < /sup > In, < sup > 177 < /sup > Lu or < sup > 90 < /sup > Y incorporated into tissue implantable depots.

We report here the three dimensional dose distribution resulting from a NPD incorporating AuNP labeled with electron emitters (&lt;sup&gt;90&lt;/sup&gt;Y, &lt;sup&gt;177&lt;/sup&gt;Lu, &lt;sup&gt;111&lt;/sup&gt;In) of different energies using Monte Carlo based voxel level dosimetry. &#13; The MCNP5 dose model was used to assess differences in dose distribution from simulated NPD and conventional brachytherapy sources, positioned in breast tissue simulating material. We further compare these dose distributions in mice bearing subcutaneous human breast cancer xenografts implanted with &lt;sup&gt;177&lt;/sup&gt;Lu-AuNP NPD, or injected i.t. with &lt;sup&gt;177&lt;/sup&gt;Lu-AuNP in suspension. The radioactivity distributions were derived from registered SPECT/CT images and time-dependent dose was estimated. &#13; Results demonstrated that the dose distribution from NPD reduced the maximum dose 3-fold when compared to conventional seeds. For simulated NPD, as well as NPD implanted in vivo, &lt;sup&gt;90&lt;/sup&gt;Y delivered the most homogeneous dose distribution. The tumor radioactivity in mice i.t. injected with &lt;sup&gt;177&lt;/sup&gt;Lu-AuNP redistributed while radioactivity in the NPD remained confined to the implant site. The dose distribution from radiolabeled AuNP NPD were predictable and concentric in contrast to i.t. injected radiolabeled AuNP, whic...

Source: Physics in Medicine and Biology - October 4, 2017 Category: Physics Authors: Lai P, Cai Z, Pignol JP, Lechtman E, Mashouf S, Lu Y, Winnik MA, Jaffray DA, Reilly RM Tags: Phys Med Biol Source Type: research