| Popis: |
High spatial resolution is essential to image small lesions in positron emission tomography. Traditional methods suggest using small crystals to obtain high resolution. In this study, a new method is introduced to achieve high spatial resolution by using scintillators with different decay times arranged in a checkerboard pattern. Pulse shape discrimination was implemented to determine which crystal the gamma energy was deposited. In this work, a 13/spl times/13 LSO crystal array and a 13/spl times/13 LSO-GSO checkerboard crystal array using 4/spl times/4/spl times/20 mm/sup 3/ crystals were built and optimized using light sharing techniques. Similarly, using 2.5/spl times/2.5/spl times/19 mm/sup 3/ LSO and LYSO crystals, a 17/spl times/17 LSO-LYSO checkerboard crystal array was built as a high-resolution application. The average pixel energy resolution for the 13/spl times/13 LSO was measured to be 14.5%. Similarly, the average pixel resolutions for the GSO part of the 13/spl times/13 LSO-GSO crystal array and the LSO part of the same array were measured to be 13.9% and 18.5%, respectively. The average crystal energy resolutions for the LSO and LYSO parts of the 17/spl times/17 LSO-LYSO crystal array were measured to be 23.5% and 24.2%, respectively. The average peak-to-valley ratios in the position profiles were measured to be 2.1 for the 13/spl times/13 LSO crystal array, 7.2 for the LSO part of the 13/spl times/13 LSO-GSO crystal array and 4.3 for the GSO part of the 13/spl times/13 LSO-GSO crystal array. Similarly, the average peak-to-valley ratios in the position profiles were measured to be 2.5 for the LSO part of the 17/spl times/17 LSO-LYSO crystal array and 2.7 for the LYSO part of the 17/spl times/17 LSO-LYSO crystal array. |
