A Time-Walk Correction Method for PET Detectors Based on Leading Edge Discriminators

被引：38
作者：
Du J. [1 ]
Schmall J.P. [1 ,2 ]
Judenhofer M.S. [1 ]
Di K. [1 ]
Yang Y. [1 ]
Cherry S.R. [1 ]
机构：
[1] Department of Biomedical Engineering, University of California at Davis, Davis, 95616, CA
[2] University of Pennsylvania, Philadelphia, 19104, PA
来源：
IEEE Transactions on Radiation and Plasma Medical Sciences | 2017年 / 1卷 / 05期
基金：
美国国家卫生研究院;
关键词：
Leading edge discriminator (LED); PET; time of flight; time-walk correction; timing resolution;
D O I：
10.1109/TRPMS.2017.2726534
中图分类号：
学科分类号：
摘要：
The leading edge timing pick-off technique is the simplest timing extraction method for PET detectors. Due to the inherent time-walk of the leading edge technique, corrections should be made to improve timing resolution, especially for time-of-flight PET. Time-walk correction can be done by utilizing the relationship between the threshold crossing time and the event energy on an event-by-event basis. In this paper, a time-walk correction method is proposed and evaluated using timing information from two identical detectors both using leading edge discriminators. This differs from other techniques that use an external dedicated reference detector, such as a fast PMT-based detector using constant fraction techniques to pick-off timing information. In our proposed method, one detector was used as reference detector to correct the time-walk of the other detector. Time-walk in the reference detector was minimized by using events within a small energy window (508.5-513.5 keV). To validate this method, a coincidence detector pair was assembled using two SensL MicroFB SiPMs and two 2.5 mm × 2.5 mm × 20 mm polished lutetium-yttrium oxyorthosilicate crystals. Coincidence timing resolutions (CTRs) using different time pick-off techniques were obtained at a bias voltage of 27.5 V and a fixed temperature of 20 °C. The CTR without time-walk correction were 389.0 ± 12.0 ps (425-650 keV energy window) and 670.2 ± 16.2 ps (250-750 keV energy window). The timing resolution with time-walk correction improved to 367.3 ± 0.5 ps (425-650 keV) and 413.7 ± 0.9 ps (250-750 keV). For comparison, timing resolutions were 442.8 ± 12.8 ps (425-650 keV) and 476.0 ± 13.0 ps (250-750 keV) using constant fraction techniques, and 367.3 ± 0.4 ps (425-650 keV) and 413.4 ± 0.9 ps (250-750 keV) using a reference detector based on the constant fraction technique. These results show that the proposed leading edge-based time-walk correction method works well. Timing resolution obtained using this method was equivalent to that obtained using a reference detector and was better than that obtained using constant fraction discriminators. © 2017 IEEE.
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页码：385 / 390
页数：5
相关论文
共 32 条
  • [1] Abbiati R., Geraci A., Ripamonti G., A weighted least mean squares linear algorithm for energy and occurrence time measurement of pulse, IEEE Trans. Nucl. Sci., 54, 3, pp. 629-634, (2007)
  • [2] Kim H., Et al., A multi-threshold sampling method for TOF PET signal processing, Nucl. Instrum. Methods Phys. Res. A Accelerators Spectrometers Detectors Assoc. Equipment, 602, 2, pp. 618-621, (2009)
  • [3] Joly B., Et al., Test and optimization of timing algorithms for PET detectors with digital sampling front-end, Proc. IEEE Nucl. Sci. Symp. Med. Imag. Conf. Rec., pp. 4078-4085, (2008)
  • [4] Hua W., Et al., A simple and improved digital timing method for positron emission tomography, Nucl. Instrum. Methods Phys. Res. A Accelerators Spectrometers Detectors Assoc. Equipment, 622, 1, pp. 219-224, (2010)
  • [5] Monzo J.M., Et al., Digital signal processing techniques to improve time resolution in positron emission tomography, IEEE Trans. Nucl. Sci., 58, 4, pp. 1613-1620, (2011)
  • [6] Cho S., Grazioso R., Zhang N., Aykac M., Schmand M., Digital timing: Sampling frequency, anti-aliasing filter and signal interpolation filter dependence on timing resolution, Phys. Med. Biol., 56, 23, pp. 7569-7583, (2011)
  • [7] Seifert S., Et al., A comprehensive model to predict the timing resolution of SiPM-based scintillation detectors: Theory and experimental validation, IEEE Trans. Nucl. Sci., 59, 1, pp. 190-204, (2012)
  • [8] Yeom J.Y., Vinke R., Spanoudaki V.C., Hong K.J., Levin C.S., Readout electronics and data acquisition of a positron emission tomography time-of-flight detector module with waveform digitizer, IEEE Trans. Nucl. Sci., 60, 5, pp. 3735-3741, (2013)
  • [9] Derenzo S.E., Choong W.S., Moses W.W., Fundamental limits of scintillation detector timing precision, Phys. Med. Biol., 59, 13, pp. 3261-3286, (2014)
  • [10] Seifert S., Schaart D.R., Improving the time resolution of TOF-PET detectors by double-sided readout, IEEE Trans. Nucl. Sci., 62, 1, pp. 3-11, (2015)
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