No description available.

No description available.

No description available.

No description available.

A system for visual guidance in patient set-up for external-beam radiotherapy procedures was developed using augmented reality. The system uses video cameras to obtain views of the linear accelerator, and the live images are displayed on a monitor in the treatment room. A 3D model of the patient's external surface, obtained from planning CT data, is superimposed onto the treatment couch in the camera images. The augmented monitor can then be viewed, and alignment performed against the virtual contour. The system provides an intuitive method for set-up guidance, and allows non-rigid deformations to patient pose to be visualised. It also allows changes to patient geometry between treatment fractions to become observable, and can remain in operation throughout the treatment procedure, so that patient motion becomes apparent. Coordinate registration between the camera view and the linac is performed using a cube which is aligned with the linac isocentre using room lasers or cone-beam CT. The AR tracking software detects planar fiducial tracking markers attached to the cube faces, and determines their positions in order to perform pose estimation of the 3D model on-screen. Experimental results with an anthropomorphic phantom in a clinical environment have shown that the system can be used to position a rigid-body with a translational error of 3 mm, and a rotational error of 0.19 degrees, 0.06 degrees and 0.27 degrees, corresponding to pitch, roll and yaw respectively. With further developments to optimise the system accuracy and its interface, it could be made into a valuable tool for radiotherapy clinics. The outcome of the project has been encouraging, and has shown that augmented reality for patient set-up guidance has great potential.

No description available.

The linear attenuation coefficient and buildup factor are a few of the important characteristics that need to be studied and determined prior to using a material clinically in radiation treatment and protection. The linear attenuation coefficient and buildup factor, as well as several other properties, will be determined for MCP-96 alloy to assess its use in radiation therapy. A narrow collimated beam of γ-rays from sources with varying energies will pass through various thicknesses of MCP-96 alloy. The attenuation in the intensity of the beam will be determined for each varying thickness of the alloy. Plotting the thickness of the alloy versus the corresponding logarithmic intensity of the beam will allow calculation of the linear attenuation coefficient. The narrow beam geometry will then be replaced by the broad beam geometry to determine the buildup factor. Additional radiation is obtained through the broad beam geometry as a result of scattering and secondary radiation. Comparing the broad beam geometry to the narrow beam geometry allows determination of the buildup factor. Since the buildup factor depends upon the thickness of the MCP-96 attenuator, the energy of the beam, and the source-to-attenuator (STA) distance, it will be calculated using three parameters. It will be calculated as a function of thickness of MCP-96 alloy by using various thicknesses of the alloy; as a function of the energy of the incident radiation beam by using several sources with different beam energies; and finally, as a function of the source-to-attenuator distance by changing the position of the MCP-96 attenuators. / Department of Physics and Astronomy

The goal of this research is to present a framework to accelerate the execution of software legacy systems without having to redesign them or limit future changes. The speedup is accomplished through hardware acceleration, based on a semi-automatic infrastructure which supports design decisions and simulate their impact. Many programs are available for translating code written in C into VHDL (Very High Speed Integrated Circuit Hardware Description Language). What is missing is simpler and more direct strategies to incorporate encapsulatable portions of the code, translate them to VHDL and to allow the VHDL code and the C code to communicate through a flexible interface. SHARP is a streamlined, easily understood infrastructure which facilitates this process in two phases. In the first part, the SHARP GUI (An interactive Graphical User Interface) is used to load a program written in a high level general purpose programming language, to scan the code for SHARP POINTs (Portions Only Including Non-interscoping Types) based on user defined constraints, and then automatically translate such POINTs to a HDL. Finally the infrastructure needed to co-execute the updated program is generated. SHARP POINTs have a clearly defined interface and can be used by the SHARP scheduler. In the second part, the SHARP scheduler allows the SHARP POINTs to run on the chosen reconfigurable hardware, here an FPGA (Field Programmable Gate Array) and to commu- nicate cleanly with the original processor (for the software). The resulting system will be a good (though not necessarily optimal) acceleration of the original software application, that is easily maintained as the code continues to develop and evolve. / Graduate

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Intensity modulated radiotherapy (IMRT) can potentially increase the dose delivered to liver tumours while sparing normal tissues from dose. More complex IMRT, with more modulation of the radiation beam is more susceptible to geometric and dosimetric uncertainties than simpler radiotherapy plans. Simple breath-hold liver IMRT using few radiation beam segments (<30) was investigated in 27 patients to determine the quality of treatment in terms of tumour dose coverage and normal tissue sparing as compared to index IMRT using >30 segments. In all 27 plans number of segments was reduced to <30 without compromising tumour coverage or normal tissue dose constraints, at the expense of dose conformity. Delivered tumour and normal tissue dose did not differ statistically between IMRT plans when accounting for treatment residual geometric error. This research supports considering the use of simple IMRT for treatment of liver cancer, except when loss of dose conformation is undesirable (i.e. very high doses).