Time of flight dual photon emission computed tomography

Chih-Chieh Chiang,Yu-Ching Ni,Hsin-Hon Lin,Meei-Ling Jan,Keh-Shih Chuang,Chun-Chao Chuang

doi:10.1038/s41598-020-76526-z

Abstract

Time-of-flight dual photon emission computed tomography (TOF-DuPECT) is an imaging system that can obtain radionuclide distributions using time information recorded from two cascade-decay photons. The potential decay locations in the image space, a hyperbolic response curve, can be determined via time-difference-of-arrival (TDOA) estimations from two instantaneous coincidence photons. In this feasibility study, Monte Carlo simulations were performed to generate list-mode coincidence data. A full-ring positron emission tomography-like detection system geometry was built in the simulation environment. A contrast phantom and a Jaszczak-like phantom filled with Selenium-75 (Se-75) were used to evaluate the image quality. A TOF-DuPECT system with varying coincidence time resolution (CTR) was then evaluated. We used the stochastic origin ensemble (SOE) algorithm to reconstruct images from the recorded list-mode data. The results indicate that the SOE method can be successfully employed for the TOF-DuPECT system and can achieve acceptable image quality when the CTR is less than 100 ps. Therefore, the TOF-DuPECT imaging system is feasible. With the improvement of the detector with time, future implementations and applications of TOF-DuPECT are promising. Further quantitative imaging techniques such as attenuation and scatter corrections for the TOF-DuPECT system will be developed in future.

Highlights

Time-of-flight dual photon emission computed tomography (TOF-DuPECT) is an imaging system that can obtain radionuclide distributions using time information recorded from two cascade-decay photons
The results show that the full width at half maximum (FWHM) values at 1500 sweeps can reach ~ 20 mm when the coincidence time resolution (CTR) is less than 50 ps
In the point source experiments, we found that the system spatial resolution in the central field of view (FOV) can achieve an FWHM of approximately 20 mm when the CTR is less than 50 ps

Summary

Introduction

Time-of-flight dual photon emission computed tomography (TOF-DuPECT) is an imaging system that can obtain radionuclide distributions using time information recorded from two cascade-decay photons. The potential decay locations in the image space, a hyperbolic response curve, can be determined via time-difference-of-arrival (TDOA) estimations from two instantaneous coincidence photons In this feasibility study, Monte Carlo simulations were performed to generate list-mode coincidence data. When photons in coincidence are detected, the source location can be determined as the intersection of line of response derived from collimated detector and hyperbola defined by the TOF information. We propose a time-of-flight dual-photon emission computed tomography (TOF-DuPECT) system to detect cascade photons without collimators and to reconstruct the distribution of radionuclides incorporating the time-difference-of-arrival (TDOA) technique[13]. The SOE approach is well suited to our preliminary feasibility study of TOF-DuPECT

Methods

Results

Discussion

Conclusion