# Energy-independent single photon molecular imaging technology

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2022 · $670,337

## Abstract

Project Summary (Abstract)
Nuclear molecular imaging techniques such as positron emission tomography (PET) and single photon emission
computed tomography (SPECT) have become important imaging modalities in the diagnosis and management
of human diseases. Solid-state radiation detectors such as cadmium zinc telluride (CZT) have been developed
for the detection of high-energy photons (x-ray and gamma-ray) including medical imaging systems by replacing
more commonly used scintillation crystals (e.g., NaI or CsI) and photomultiplier tubes (PMTs). SPECT is a very
mature noninvasive molecular imaging technology with many radiopharmaceuticals evaluated for many different
medical conditions. However, its low detection efficiency and lack of 3D dynamic-imaging capability are mainly
pointed out as disadvantages; thus there have been numerous efforts to replace all existing SPECT radiotracers
with PET counterparts. SPECT brings much more flexibility in production of radiopharmaceuticals, and labeling
biologically interesting molecules with 99mTc for SPECT imaging costs much less than production of PET
radionuclides such as 18F using a medical cyclotron and labeling with 18F. However, the availability of many
SPECT radiotracers in fact sometimes acts against the viability of SPECT technology because different SPECT
radiotracers that emit different energies of photons (roughly in the range of 70 keV – 350 keV) require change of
collimators sometimes multiple times even during the same day in the clinical setting. Collimators not only limit
the detection efficiency, but also hamper an efficient management of clinical imaging. With the previous funding
support under “Transforming Biomedicine at the Interface of the Life and Physical Sciences (R01)” (PAR-10-
141) which no longer exists, we developed a completely new SPECT technology that is based on high energy
resolution CZT, redesigned and successfully fabricated application-specific integrated circuit (ASIC), and
innovative collimator design that can cover a broad range of radionuclide emission energies. For this new grant
application, we propose to bring in another very important system design innovation while further developing and
manufacturing a prototype test system in that system design. The system innovation we are proposing is to have
a variable aperture (i.e., small detector modules moving radially in and out) ring geometry so that we can image
subjects within the field of view in high resolution (close proximity) in all possible angular positions. This design
will also allow fast 3D dynamic imaging capability with no or almost no rotation (a few degrees). In order to
achieve the goals defined above, we have the following specific aims: 1) To complete the variable aperture ring
SPECT design using extensive Monte Carlo simulations; 2) To develop new ASICs to be combined with our
small-pitch (1.6 mm) and modular CZT cameras that were developed by us recently. The new ASICs will allow
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## Key facts

- **NIH application ID:** 10072053
- **Project number:** 5R01EB026331-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Yonggang Cui
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $670,337
- **Award type:** 5
- **Project period:** 2018-04-01 → 2024-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10072053

## Citation

> US National Institutes of Health, RePORTER application 10072053, Energy-independent single photon molecular imaging technology (5R01EB026331-04). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/10072053. Licensed CC0.

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