In 2010, Maastro Clinic acquired a novel prototype micro-irradiation device for pre-clinical small animal radiotherapy studies: a combination of a precision irradiator and imaging system. Advances in clinical, radiation therapy, have continued to progress without real preclinical validation in animal models. These micro-irradiation devices are a major step forward compared to the current standard of animal experimentation in cancer radiobiology research. . The micro-irradiation device makes use of low energy radiation (40-225 kVp), the device can be used for both imaging and irradiation of small animals, e.g. a mice. A software program called DOSCTP, which is a Matlab-based program will be used as the treatment plan interface. This program uses CT-images and integrates with a Monte Carlo (MC) code, called DOSXYZnrc to perform an accurate dose calculation in the animal. The goal of this thesis is to generate 3-D dose-distributions in phantoms and validate the program in terms of its accuracy.
For this purpose, it is necessary to add several capabilities to DOSCTP. MC simulations are performed following irradiation, and measurements performed of the delivered dose distribution. Experiments have been carried out on a homogeneous as well as on a heterogeneous phantom. Such a phantom consists out of several material slabs such as solid water, breast, bone tissue and EBT2 Gafchromic dosimetry film. The absorbed dose to EBT2 film is compared with the MC simulation.
Six beams characterized by their collimator and angle of rotation were used in combination with 3 isocenters. Experimental results revealed a dose difference of 4.1 % between dose calculations and measurements in a homogenous phantom. In a more realistic heterogeneous geometry experimental results showed dose differences between dose calculations and measurements of 1.4 % for the field dose, 1.5% for the penumbra dose and finally 5.3% for the out of field dose. These dose differences were within the experimental uncertainty due to a combination of fixed uncertainties on the computer model and dosimetric film measurement.
If you want to cite this thesis in your own thesis, paper, or report, use this format (APA):
NIJST, S. (2012). Treatment planning for a novel small animal imaging device.
Unpublished thesis, Xios, TIW.