Room: AAPM ePoster Library
Purpose: laboratory is in the process of building a new small animal irradiator with new features such as dual-energy cone beam CT functional imaging (PET) based image guidance, intensity modulated radiation delivery (IMRD) via a rectangular jaw collimator, a fast GPU-based Monte Carlo (MC) dose calculation. This study reports our development on an Imaging and Treatment Planning system (ITPS) associated with this irradiator.
Methods: ITPS was developed in C++, together with Qt, ITK and VTK, on a Windows-based workstation with two state-of-the-art GPU cards for MC dose calculations. The interface included 3D orthogonal views of anatomical structure, contours, and dose distribution, and DVH, beam placement etc. Major imaging and planning functions, such as image reconstruction and processing, contouring, MC based dose calculation, forward treatment planning, inverse planning, can be executed via the interface. An in-house developed MC package goMC was used for dose calculations. In the forward planning the user can define isocenters, beam angles, and collimator sizes. The inverse planning for IMRD was achieved by solving an optimization problem seeking for a series of rectangular apertures and corresponding beam-on time, as well as the most efficient delivery sequence for each beam angle.
Results: end-users can smoothly navigate through the ITPS for different functions and generate a plan. When IMRD plan and cone-based plan were normalized to the same target coverage, OARs are spared much more effectively in IMRD plans. Average dose can be reduced for OAR in water phantom case, lung in mouse case by 25.3%, 13.9%, respectively. We also compared measured and calculated percentage depth dose, which agreed within 4% for the 40 mm square, 10 mm circular collimators at all depths.
Conclusion: developed a dedicated ITPS for a new small animal irradiator currently under construction. Its use is expected to facilitate pre-clinical animal irradiation studies.