Multi-Channel Fpga-Based Time-To-Digital Converter for Low-Complexity Time-Based Positron Emission Tomography System (Pet) Applications

In this study, multi-channel time-to-digital converter (TDC) is proposed to apply to the time-based position emission tomography (PET). The time-based PET is proposed by using the all-digital TDC instead of traditional analog-to-digital converter (ADC) to compute the trigger energy. For this reason, the PET can be implemented using all-digital circuit except the sensor readout circuit. Recently, many components will be designed or implemented in digital circuit as possible as they can. Therefore, this work focuses on the TDCs, which are the most important components in the time-based PET system, in the field-programmable gate array (FPGA) platform. This work employs histogram method to calibrate the non-linear effect in the FPGA-based TDC design. The proposed self-calibration method can improve the differential nonlinearity (DNL) values hugely. The extra delay line is included in the proposed TDC to achieve a run-time calibration, and the same idea can be adapted by the implementation of the multi-channel TDCs. The proposed multi-channel TDCs can robustly cope with the temperature and voltage effect. To conclude, this work aims to cope with the high time-resolution and hopefully to save the area cost as much as possible in PET system. Therefore, self-calibration and run-time calibration TDC, multi-channel TDCs and multi-hit TDC are proposed to achieve linear, high-resolution and low-cost designs.

Project ID:PB10507-2962
External Project ID:MOST105-2221-E182-032