# LABELED THYMIDINE--DEVELOPMENT AS A PET IMAGING AGENT

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 1988 · $90,559

## Abstract

Our overall goal is to use Positron emission tomography (PET) to
develop an understanding of the response of cancers to therapy
using non-invasive quantitative imaging of biochemistry.  PET
must be combined with the appropriate positron-labeled compound
in order to measure the metabolic pathway of interest.  11C-
thymidine (labeled in the methyl position) is a PET imaging agent
which has the potential for quantitating DNA synthesis in vivo.
Our ongoing studies (including those funded by this grant)
demonstrate that PET imaging with 11C-thymidine (TdR) is
feasible.  We have already addressed a number of the problems
associated with interpreting the PET images of 11C-TdR including
the contributions to TdR metabolism of intracellular pools,
reutilization and degradation.  This proposal addresses areas of
research needed to gain further insight into the biochemistry and
kinetics of TdR metabolism.  These studies are needed to assist in
converting the simple measurement of time-dependent tissue
radioisotope concentration obtained by the tomograph into
quantitative measurements of cellular proliferation.  In our effort
to test the hypothesis that the measurement of TdR uptake will
be useful in the quantitation of tumor growth, we will address the
following problems:  1) In order to interpret PET images one must
know the amount of labeled precursor delivered to the tumor.
Therefore, we will develop techniques and models which will
account for the proportion of native TdR compound remaining in
the circulation.  We will also study the first pass extraction of
TdR and the distribution of the metabolites of TdR.  2)
Refinement of the kinetic models of TdR metabolism is needed.
The data we are accumulating with PET will be fitted using
compartmental, graphical and sliding segment modeling
approaches.  We will compare the results of the kinetic models to
direct measurements of the incorporation of TdR into DNA at
biopsy.  3) Validation of the measurements made with PET is
essential.  This will be done in dogs with metastatic lymphoma,
where biopsy specimens will be analyzed using a number of
cellular and biochemical techniques for correlation with the PET
measurements.  The ultimate goal of our group is to develop an
understanding of the response of cancer to therapy using 11C-TdR
and PET.  In order to make meaningful measurements of cellular
proliferation using 11C-TdR and PET we need to produce detailed
biochemical and kinetic models of TdR metabolism.

## Key facts

- **NIH application ID:** 3178701
- **Project number:** 2R01CA039566-05
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **SAM.gov UEI:** HD1WMN6945W6
- **Principal Investigator:** Anthony Frank Shields
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $90,559
- **Award type:** 2
- **Project period:** 1988-01-01 → 1991-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3178701

## Citation

> US National Institutes of Health, RePORTER application 3178701, LABELED THYMIDINE--DEVELOPMENT AS A PET IMAGING AGENT (2R01CA039566-05). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3178701. Licensed CC0.

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