1. Positron Emission Tomography Research Centre; University of Hull; Cottingham Road Hull HU6 7RX UK
2. School of Mathematics and Physical Sciences; University of Hull; Cottingham Road Hull HU6 7RX UK
3. Current address: School of Earth and Environment; University of Leeds; Woodhouse Lane Leeds LS2 9JT UK
4. Department of Physics; University of York; Heslington York YO10 5DD UK
5. Current address: Faculty of Art and Science; Bitlis Eren University; Bitlis 13000 Turkey
6. School of Engineering and Computer Science; University of Hull; Cottingham Road Hull HU6 7RX UK