Application of HDMI? Cables as an MRI Compatible Single Cable Solution for Readout and Power Supply of SiPM Based PET Detectors

摘要

All PET detectors require cabling to supply power and transmit data, whether in analog or digital form. In this work we examine using High-Definition Multimedia Interface (HDMI~?) cables as a single cable solution to both supply power and transmit analog signals for a SiPM based PET detector that will be used in a hybrid PET/MRI imaging system. HDMI cables are designed for digital audio/video transmission, with each cable having four pairs of shielded 100 ohm differential signal lines, each rated for 3.4 Gbit/s, along with 7 additional signal lines and a braided shield around the entire cable. While designed as a digital signal cable, the lines are rated for 40V DC and 0.5A current. To test using HDMI? cables for application in PET, a silicon photomultiplier (SiPM) PET detector module with a single HDMI~? Type C ('mini) receptacle was built using a SensL SPMArray4 coupled to a dual-layer offset LYSO crystal array 1.67 mm crystal pitch. The 16 detector outputs were multiplexed to four signals using a simple resistor charge division network and driven using Analog Devices AD8132 op-amps. Detector bias of 30.2V and +/- 5V power for the op-amps was supplied through a 25' length HDMI? cable connected through a custom receiver card. The signals were processed using NIM electronics and digitized with a PC based analog to digital converter (ADC) card. The PET detector had an average energy resolution of 14.3% full-width at half-maximum (FWHM) and an average timing resolution of 2.50 ns. The performance of the PET detector was unaffected when operated inside a 7T MRI system. The MR images showed degradation in signal to noise ratio (SNR) of between 7 and 23%, which is believe to be due to coupling between the RF coil and the PET detector shielding. The results of this work suggest that HDMI~? cables with the Type C connector are a viable, cost effective and robust single cable solution for both analog signal and power/bias transmission for an MRI compatible PET insert system.