Medical Compton cameras based on semiconductor detectors

The work presented in this thesis is aimed at the study of Compton scatter as an alternative method of collimating gamma-rays in nuclear medicine applications. Conventional approaches to radioisotope medical imaging and their current limitations are examined. The theory of electronic collimation based on Compton scatter is introduced and it is shown that in principle its application could provide an advantageous imaging method, with both high spatial resolution and high sensitivity. The current status of research in the field, of Compton cameras is assessed and potential niches for applications of clinical interest are suggested. The criteria for the design of a Compton scatter camera are examined. A variety of semiconductors are considered for the construction of an electronic collimator and results from Monte Carlo computer simulations are presented for photon energies of clinical interest. It is concluded that the most viable approach is to design a silicon collimator for the imaging of high-energy (511 ke V) photons. A computer model of a Compton camera is developed in order to study the phenomena that affect the angular resolution and the sensitivity of the system. This simulation tool is applied to select the optimum characteristics of the silicon scatter detector. Such results are employed to design and initiate the construction of an experimental prototype of Compton camera, based on the use of double-sided silicon microstrip detectors. The development of special readout electronics required for the camera operation is described. Experimental tests are performed for the characterisation of the silicon strip detectors and the results are presented. Predictions are made on the performance of the designed system. Finally, the current stage of system development is assessed and the main areas for future work are identified. (author)Available from British Library Document Supply Centre- DSC:DXN058876 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo