# Positronium lifetime imaging using TOF PET

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2021 · $221,250

## Abstract

Project Summary/Abstract
Positron emission tomography (PET) is a high-sensitivity molecular imaging modality widely used in oncology,
neurology, and cardiology, with the ability to observe molecular-level activities inside a living body through the
injection of specific radioactive tracers with positron emitters. Recently it has been shown that the lifetime of
positronium, a metastable state formed by a pair of electron and positron, is sensitive to the microenvironment
of the surrounding tissue, such as oxygen pressure. Such information is valuable for cancer staging and
treatment planning. However, currently there is no practical method to imaging the positronium lifetime at a
spatial resolution matching that of PET due to the limited photon detection sensitivity and lack of proper image
reconstruction method. This proposal addresses these problems by developing a statistically based image
reconstruction method for positronium lifetime imaging (PLI) and combining it with the newly developed total-
body EXPLORER PET scanner at UC Davis. We will demonstrate the effectiveness of the method using
phantom experiments on the EXPLORER scanner. The advantage of the PLI is that the lifetime measurement
is independent of the tracer concentration and can be used together with standard PET imaging. The
combination of PLI and PET will add another dimension to current PET imaging and provide useful information
for understanding the microenvironment of the tissue for studying various human diseases.

## Key facts

- **NIH application ID:** 10288242
- **Project number:** 1R21EB032101-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** JINYI QI
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $221,250
- **Award type:** 1
- **Project period:** 2021-07-02 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10288242

## Citation

> US National Institutes of Health, RePORTER application 10288242, Positronium lifetime imaging using TOF PET (1R21EB032101-01). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10288242. Licensed CC0.

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