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Study on Using Fluoroestradiol F-18 PET/CT for Detecting Endometriosis in Patients with Pain

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a condition called endometriosis, which is a disease where tissue similar to the lining inside the uterus grows outside of it, often causing pain and sometimes infertility. The study will use a new diagnostic tool called [18F]-FES PET/CT, which is a type of imaging test that helps doctors see how tissues in the body are functioning. This tool uses a special substance called fluoroestradiol F-18 to help detect and understand the characteristics of endometriosis lesions, which are the areas of abnormal tissue growth.

The purpose of the study is to explore how effective this new imaging method is in identifying and characterizing endometriosis lesions, especially in relation to the pain experienced by patients. Participants in the study will undergo this imaging test, and the results will be compared to other methods like MRI to see how well it works. The study will also look at how the findings from the imaging relate to the level of pain and other characteristics of the lesions.

Throughout the study, participants will have the [18F]-FES PET/CT scan, and the information gathered will help researchers understand more about endometriosis and how to better diagnose it. The study aims to provide insights that could lead to improved ways of detecting and managing this condition in the future.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes verifying age, pain levels, and previous surgical treatment for endometriosis.

    Eligibility criteria include being over 18 years old, having a pain score of 4 or higher on the visual analog scale (VAS), and having undergone surgery for endometriosis.

  2. Step 2

    Preparation for imaging

    Before the imaging procedure, a preoperative magnetic resonance imaging (MRI) is reviewed to ensure it is suitable for the study.

    The imaging procedure is scheduled to occur mid-cycle to align with the study requirements.

  3. Step 3

    Administration of diagnostic tool

    The diagnostic tool used in this study is a solution called EstroTep 500 MBq/mL, which contains the active substance fluoroestradiol f-18.

    This solution is administered through an intravenous injection, which means it is injected directly into a vein.

  4. Step 4

    Imaging procedure

    After the injection, a positron emission tomography/computed tomography (PET/CT) scan is performed. This imaging technique helps in detecting and characterizing endometriosis lesions.

    The scan evaluates the presence of hypermetabolism in lesions, which is an indicator of increased activity in the tissue.

  5. Step 5

    Analysis of results

    The primary focus is on characterizing the hypermetabolism of lesions by analyzing the standardized uptake value (SUV).

    Secondary analyses include examining the lesions using immunohistochemistry (IHC) and in situ hybridization to understand the intensity and type of receptor expressed in each lesion.

  6. Step 6

    Comparison and evaluation

    The sensitivity of the [18F]-FES PET/CT scan is compared to that of the MRI in diagnosing both superficial and deep endometriosis lesions.

    The study also evaluates the degree of association between the intensity of the [18F] SUV and the expression of estrogen receptors, as well as the intensity of pain experienced.

Who can join the trial?

8 criteria

  • Patients must have **endometriosis**, a condition where tissue similar to the lining inside the uterus grows outside of it.
  • Patients experiencing **pain** with a **Visual Analogue Scale (VAS)** score of **4 or higher**. The VAS is a tool used to measure pain intensity.
  • Patients with a VAS score **less than 4** who are being treated for endometriosis due to **infertility**.
  • Patients must be **over 18 years old**.
  • Patients must provide **informed consent**, meaning they understand the study and agree to participate.
  • Patients must have had a **preoperative MRI** (Magnetic Resonance Imaging) that does not prevent them from having a **[18F]-FES PET/CT** scan, which is a type of imaging test.
  • Patients must be **operated on mid-cycle**, which refers to the middle of their menstrual cycle.
  • Patients must be a member of a **Social Security scheme**.

Who cannot join the trial?

3 criteria

  • Participants must be female.
  • Participants must be within a specific age range, typically adults.
  • Participants should not be part of a vulnerable population, which means they should not be in a situation where they are unable to make decisions for themselves.
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Investigated drugs

[18F]-FES PET/CT is a special imaging tool used in this clinical trial to help doctors see and understand endometriosis lesions better. Endometriosis is a condition where tissue similar to the lining inside the uterus grows outside of it, causing pain and other symptoms. This tool uses a small amount of a radioactive substance to create detailed pictures of the inside of the body. By using this imaging method, doctors hope to detect and describe the endometriosis lesions more accurately, which can help in understanding the connection between these lesions and the pain experienced by patients. This can lead to better diagnosis and treatment planning for those suffering from endometriosis.

What is already known about the treatment

[18F]-FES PET/CT – This is a diagnostic tool used in the form of a PET/CT scan, which involves injecting a small amount of a radioactive substance into the body to help visualize certain conditions. Currently, it is being studied for its effectiveness in detecting and characterizing endometriosis lesions, a condition where tissue similar to the lining inside the uterus grows outside of it, often causing pain. The main therapeutic indication for this tool is to assist in diagnosing endometriosis by highlighting areas of concern during imaging. At the molecular level, the radioactive substance binds to estrogen receptors, which are often present in endometriosis tissue, allowing doctors to see these areas more clearly on the scan. This tool falls under the pharmacological classification of diagnostic radiopharmaceuticals.

Investigated diseases

Endometriosis – Endometriosis is a condition where tissue similar to the lining inside the uterus, called endometrium, starts to grow outside the uterus. This tissue can be found on the ovaries, fallopian tubes, and the outer surface of the uterus, as well as other organs in the pelvis. The misplaced tissue continues to act as it normally would, thickening, breaking down, and bleeding with each menstrual cycle. However, because this tissue has no way to exit the body, it becomes trapped, leading to inflammation and the formation of scar tissue and adhesions. Over time, this can cause pain, especially during menstruation, and may lead to fertility problems. The severity of symptoms can vary, with some individuals experiencing mild discomfort and others suffering from severe pain.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-520637-24-00Protocol codeRC31/23/0622Estimated enrolment20 patientsSponsorCentre Hospitalier Universitaire De Toulouse

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