# Ultra-high sensitivity, high spatial resolution single photon emission tomography using mechanical flux manipulation.

> **NIH NIH R41** · PRECISION SENSING, LLC · 2021 · $251,896

## Abstract

The goal of this project is to develop both hardware and software to demonstrate the ground breaking capabilities
of a new single photon radionuclide (SPR) imaging technique with the potential for >1000 times gain in sensitivity
and >100 times gain in volumetric spatial resolution compared to clinical SPECT imaging using parallel-hole
collimators. We refer to our new imaging methodology as mechanical flux manipulation (MFM). MFM utilizes
high resolution pixelated detectors, high bandwidth data acquisition electronics and a novel image reconstruction
methodology utilizing detector flux information to achieve target performance goals of >50% detection efficiency
for photons impinging an MFM detector and <2 mm reconstructed image resolution. MFM is a SPR tomographic
imaging technique. The two main features that differentiate MFM from traditional SPECT are collimator-less
detectors and the use of flux-probability distributions versus line of response (LOR) counts to reconstruct images.
MFM rejects the notion that the direction of every detected photon must be known in order to accurately
reconstruct images from a single photon radionuclide emitting object. Instead, MFM collects flux information on
a crystal by crystal basis and records how the flux to each crystal is altered by moving a mechanical attenuator
(MA) between the emission object and the detector. Using flux information, the incident direction of each detected
photon is not required for image reconstruction. MFM is further differentiated from SPECT in that it uses fully 3D
image reconstruction rather than stacks of 2D data. While MFM will support general single photon tomographic
imaging protocols, the focus of this Phase I proposal is to demonstrate feasibility for human brain imaging.
This project is consists of three specific aims. The first aim is to extend and validate the SimSET Monte Carlo
simulation tool to simulate an MFM scanner including real-world effects. The main component of this extension
is to be able to simulate continuous MA motion. An additional sub-aim is to fabricate a prototype MA assembly
and fully functional pixelated detector panel to collect experimental data with which to validate the SimSET Monte
Carlo software tools. The second aim of the project is to expand the MFM image reconstruction software to 3D
and to incorporate all corrections to support quantitative imaging. Extending to fully 3D image reconstruction will
require significantly more computing resources and optimization of the algorithms so that the code can run
efficiently. One of the sub-aims is to implement the reconstruction software using GPU processors. The third aim
is to use the validated Monte Carlo tools from specific aim 1 and the fully 3D image reconstruction code
developed in aim 2 to optimize the design of a MFM imaging system for high resolution human brain imaging.
After successful completion of this project, we will seek additional funding to build a prototype MFM system to
support <2...

## Key facts

- **NIH application ID:** 10323609
- **Project number:** 1R41EB032275-01
- **Recipient organization:** PRECISION SENSING, LLC
- **Principal Investigator:** Larry Pierce
- **Activity code:** R41 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $251,896
- **Award type:** 1
- **Project period:** 2021-09-15 → 2023-09-14

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10323609

## Citation

> US National Institutes of Health, RePORTER application 10323609, Ultra-high sensitivity, high spatial resolution single photon emission tomography using mechanical flux manipulation. (1R41EB032275-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10323609. Licensed CC0.

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