# PET-enabled Dual-energy CT

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2021 · $196,250

## Abstract

PROJECT SUMMARY
Positron emission tomography (PET) fused with X-ray computed tomography (CT) is a molecular imaging
modality that uses radiolabeled tracers, for example 18F-fluorodeoxyglucose (FDG), to image biochemical
processes in the living body. On the other hand, dual-energy CT (DECT) employs two different X-ray energies
to obtain energy-differential attenuation information of tissue properties. DECT allows quantitative
characterization of tissue composition by material basis decomposition that cannot be easily achieved by
standard PET. Thus, DECT and PET may complement each other to enable a new multiparametric imaging
solution. This complementarity has important implications in clinical diagnosis and therapy assessment.
However, integration of DECT with PET would require either costly scanner hardware upgrade or significant
modifications of imaging protocols to allow two X-ray CT scans, which is associated with increased radiation
dose and scan cost. This project proposes a novel dual-energy CT imaging methodology that is enabled by the
PET data in PET/CT instead of a second X-ray CT scan. The new method does not require any change of
scanner hardware or add additional radiation dose or scan time except a standard time-of-flight PET/CT scan
that is already available on most modern PET/CT scanners. We hypothesize that a quantitatively accurate 511
keV gamma-ray attenuation image can be obtained from time-of-flight PET emission scan data using advanced
image reconstruction. The PET-enabled high energy gamma-ray “CT” image is then combined with the X-ray
(low-energy: ≤140 keV) CT scan in PET/CT to produce a pair of dual-energy CT images. The goal of this
proposal is to develop the feasibility of the proposed method and demonstrate its proof-of-concept use for
imaging fat and calcification. We propose three specific aims to fulfill the goal in three years. Aim 1: To develop
a statistically efficient image reconstruction method for PET-enabled gamma-ray CT. Aim 2: To measure the
quantitative accuracy of PET-enabled gamma-ray CT using phantom studies with traditional PET transmission
scan as the reference. Aim 3: To develop a PET-enabled dual-energy CT approach for quantitative analysis of
material composition and validate it using phantom experiments. Successful completion of this project will
establish the feasibility of a novel PET-enabled dual-energy CT (P-DECT) imaging method and make the
method ready for starting a clinical imaging trial.

## Key facts

- **NIH application ID:** 10075273
- **Project number:** 5R21EB027346-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Guobao Wang
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $196,250
- **Award type:** 5
- **Project period:** 2019-04-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10075273

## Citation

> US National Institutes of Health, RePORTER application 10075273, PET-enabled Dual-energy CT (5R21EB027346-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10075273. Licensed CC0.

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