# Nanoparticle CT Contrast Agent for New Capabilities in Tumor Detection, Staging, and Therapy Planning and Response

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2022 · $710,090

## Abstract

PROJECT SUMMARY/ABSTRACT
Our long-term goal is to revolutionize the effectiveness of oncologic imaging for millions of Americans. Accurate
and early detection of liver tumors and their associated vascular anatomy is critical for tumor staging, pre-surgical
planning, and treatment monitoring. Unfortunately, with currently available contrast agents, computed
tomography (CT) only shows a sensitivity of 60% for liver tumors <1 cm in diameter, even in modern studies with
PET/CT. Available CT contrast agents are severely limited by poor liver and vascular enhancement, particularly
for larger patients, and renal and allergic-type contraindications. Obesity is associated with higher risk of cancer
mortality, yet current CT agents perform particularly poorly at the high-kVp CT settings needed to image such
patients. All current CT agents use iodine, which loses up to 50% of its signal at high kVp. These so-called
“extravascular extracellular” agents equilibrate rapidly between the intravascular and interstitial fluid, and hence
provide a “washed out” appearance of critical structures. These small-molecule contrast agents are unable to
quantify angiogenesis, which is a universal characteristic of tumors that correlates with aggressiveness.
Unfortunately, prior experimental CT blood-pool contrast agents that can quantify angiogenesis have not been
translated to clinical use in part due to slow bioelimination, complex synthetic processes, or toxicity. We
developed a scalable process to produce a tantalum oxide nanoparticle contrast agent (TaCZ1) of prototype size
(3.1 nm) that provides outstanding blood pool contrast, superior liver enhancement, and rapid renal clearance
with no observable kidney pathology. However, reduction in the viscosity and osmolality of TaCZ is desirable to
broaden its potential clinical value. Our Specific Aims are to 1) Increase TaCZ particle size to reduce osmolality
and viscosity and improve imaging benefits; 2) Demonstrate TaCZ safety in preparation for clinical translation
as a contrast agent; and 3) Show the agent's superior detection, characterization, and treatment monitoring of
liver tumors. At project conclusion, we will have completed a major step toward clinical translation of a
transformative tantalum-based blood-pool CT contrast agent, defined the ideal nanoparticle size for excellent
safety, rapid renal clearance, and outstanding CT liver tumor imaging, and assessed this agent for primary and
metastatic liver tumor detection, characterization, and treatment response.

## Key facts

- **NIH application ID:** 10415833
- **Project number:** 5R01CA226868-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** BENJAMIN M YEH
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $710,090
- **Award type:** 5
- **Project period:** 2019-05-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10415833

## Citation

> US National Institutes of Health, RePORTER application 10415833, Nanoparticle CT Contrast Agent for New Capabilities in Tumor Detection, Staging, and Therapy Planning and Response (5R01CA226868-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10415833. Licensed CC0.

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