Medical Dosimetry is a key process in clinical practice to ensure patients’ safety during diagnostic and therapeutic applications of ionising radiation, particularly for radiotherapy cancer treatment. Diamond has been researched as medical dosimeter for several decades, due to the fact that its atomic number is similar to that of average human tissues, for its room temperature operation and its potential to achieve high spatial resolution.
Unfortunately, the mechanisms determining the electronically stable device performance are not yet fully understood and many reports in literature only report data from a small number of samples produced using a wide range of synthesis methods. The influence of imperfections in the devices (bulk material and surface effects – the latter depending on device fabrication (surface processing and metallisation)) on the performance and stability is still not very well understood. Furthermore, materials with higher atomic number than the diamond itself (for example within the metallisation and device mounting and packaging), may cause dose enhancement near the interface and hence modify the pumping and priming behaviour of devices.
Hence, this project will characterise the performance of high quality industrially reproducibly fabricated prototype diamond dosimeters in clinically relevant radiation fields. The work shall be complemented by fundamental charge transport studies and simulations in order to identify the underlying mechanisms determining device performance with the aim of defining the specifications for a commercial dosimeter. It is expected that a device design for a commercial macro-dosimeter will be determined throughout the duration of the project. If possible, the work shall then be expanded to micro-dosimetry devices, which is of particularly importance for the development of new treatment modalities coming online, namely proton and carbon therapy.
The project is a collaboration between the University of Surrey Radiation and Medical Physics Group and Micron Semiconductor Limited.