Design concepts and characterization of a next generation clinical PET detector

The future of positron emission tomography (PET) is systems with ultra-precise coincidence time resolution (CTR) to advance time-of-flight PET (TOF-PET) performance. Current state-of-the-art commercial PET systems have 350-800 ps fullwidth-at-half-maximum (FWHM) timing performance, constraining annihilation events to lie somewhere within a 5–12 cm region along system detector response lines (LORs). This constraint is applied during the image reconstruction process to enhance image SNR for improved lesion detectability, increased accuracy and precision of lesion uptake measurements, less sensitivity to errors in data correction techniques (normalization, scatter, and attenuation corrections), lower injected dose, or shorter scan time. The effect of these improvements on image quality and accuracy scales with system CTR performance, and a long-standing milestone for the TOFPET community is to drive system CTR towards 100 ps FWHM (1.5 cm localization along LORs). At this level of performance, a factor of five improvement in SNR can be realized compared to non-TOF imaging, with a transformational impact on quantitative PET imaging in many count starved and contrast-limited scenarios. Traditional PET detector designs are not able to achieve this level of CTR performance, and thus new detector concepts and signal processing methods should be explored to advance system CTR