Breast CancerREPOSE-BreastNCT07883460
Improving Combined PET/CT and MRI of the Breast Using Dedicated Breast Positioning and Image Registration
A study testing Prone Breast PET/CT Acquisition in people with Breast Cancer and Breast - Female, run by Universität Münster at 1 site in Germany.
Trial summary
The goal of this clinical trial is to improve the combined use of PET/CT and MRI for imaging of the breast. PET/CT and MRI are usually performed in different body positions, which can change the shape and position of the breast and make it difficult to accurately align findings between the two examinations. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Breast Cancer, Breast - Female
- What is being tested?
- Prone Breast PET/CT Acquisition
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteGermany
- Study dates
- 6 Oct 2026to 30 Sep 2027
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Female sex
- Clinically indicated PET/CT and PET/MRI of the breast
- Histologically confirmed breast cancer
Who cannot join
- Age under 18 years
- Pregnancy
- Lack of capacity to provide informed consent
- Possible conception within the previous 14 days
- Inability to remain still in the prone position for approximately 10 minutes
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Germany1 site
Department of Nuclear Medicine, University Hospital Münster
Münster, North Rhine-Westphalia, 48149
Philippe Brüggemann, Dr. med., +4925183 ext. 47362, nuklearmedizin@ukmuenster.de
About this study
Official title: Development and Validation of a Multimodal, Non-Rigid Registration Method for Hybrid Imaging of the Breast
The goal of this clinical trial is to improve the combined use of PET/CT and MRI for imaging of the breast. PET/CT and MRI are usually performed in different body positions, which can change the shape and position of the breast and make it difficult to accurately align findings between the two examinations.
The main questions this study aims to answer are:
Read more
Can dedicated breast positioning during PET/CT reduce differences in breast shape and position compared with MRI?
Can image registration methods further improve the alignment of PET/CT and MRI images of the breast?
How accurately can findings seen on PET/CT be transferred to the corresponding location on MRI?
Participants in this study are breast cancer patients who are already scheduled to undergo PET/CT and PET/MRI as part of their clinical care. As part of the study, they will undergo an additional low-dose CT scan and an additional PET acquisition in a dedicated prone breast position. The additional PET images will be acquired using the tracer that has already been administered for the clinically indicated PET examination; no additional tracer injection is required.
The imaging data will then be used to develop and evaluate different methods for aligning PET/CT and MRI images of the breast.
The study does not investigate a new drug or treatment.
Read the detailed description
PET/CT and MRI provide complementary functional and anatomical information for breast imaging. However, direct spatial integration of separately acquired PET/CT and MRI datasets is limited by differences in patient positioning and the resulting deformation of the breast. Routine PET/CT is generally performed in the supine position, whereas dedicated breast MRI is acquired in the prone position with the breasts positioned within a breast coil. These differences can lead to substantial spatial discrepancies between corresponding findings.
REPOSE-Breast investigates a combined acquisition- and registration-based approach to reduce these discrepancies. The study includes patients who are already scheduled to undergo both PET/CT and PET/MRI as part of their clinical diagnostic work-up.
As part of the study, participants undergo an additional low-dose CT acquisition and an additional PET acquisition in a dedicated prone breast position. The additional PET acquisition uses the radiotracer that has already been administered for the clinically indicated PET examination; no additional tracer injection is required. The study-specific prone acquisition is intended to reduce positioning-related differences between PET/CT and MRI before subsequent image registration is performed.
The acquired PET/CT and MRI datasets will then be spatially aligned using several registration approaches of increasing methodological complexity. These include rigid registration, simple deformable registration, diffeomorphic deformable registration, and a biomechanical registration approach incorporating tissue deformation.
Anatomical information derived from CT and MRI is used to support the registration process and its validation. The resulting transformations will be applied to the corresponding imaging data to assess how accurately anatomical and functional findings can be transferred between PET/CT and MRI.
The overall aim is to determine whether the combination of dedicated prone breast positioning and non-rigid image registration can improve the spatial integration of separately acquired PET/CT and MRI datasets. This approach is intended to facilitate more reliable assignment of PET findings to the corresponding anatomical structures on MRI without requiring simultaneous PET/MRI acquisition.
- Conditions
- Breast Cancer, Breast - Female
- Being tested
- Prone Breast PET/CT Acquisition
- Keywords
- Breast Imaging, Positron Emission Tomography Computed Tomography, Hybrid Imaging, Breast Positioning, Prone Breast Imaging, Non-Rigid Image Registration, Deformable Image Registration, Multimodal Imaging Image Registration, Magnetic Resonance Imaging
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Prone Breast PET/CT AcquisitionDiagnostic test
Participants undergo an additional PET acquisition and a low-dose CT acquisition in a dedicated prone breast position using a breast-specific positioning setup. The study-specific imaging procedure takes approximately 6-10 minutes. The PET acquisition is performed after the clinically indicated radiotracer administration and does not require an additional tracer injection. The study-specific acquisition is designed to reduce differences in breast shape and position between PET/CT and prone breast MRI and to provide image data for subsequent multimodal image registration.
| Study group | Role | What they receive |
|---|---|---|
| Additional Prone Breast PET/CT Acquisition | Experimental | Participants undergo an additional PET acquisition and a low-dose CT scan in a dedicated prone breast position. The PET acquisition uses the radiotracer already administered for the clinically indicated PET examination; no additional tracer injection is required. The study-specific acquisition is performed to reduce positioning-related differences between PET/CT and breast MRI and to provide image data for subsequent multimodal image registration. Receives: Diagnostic Test: Prone Breast PET/CT Acquisition |
What is being measured
The primary outcome is the main question the study is designed to answer.
Target Registration Error After Multimodal Breast Image Registration
Target Registration Error (TRE) will be used to quantify the spatial accuracy of registration between corresponding breast imaging datasets. TRE will be calculated as the distance in mm between predefined corresponding anatomical or imaging reference points after registration. Lower TRE values indicate greater registration accuracy. Registration performance will be assessed for datasets acquired in different body positions and for datasets acquired in comparable prone breast positions.
Measured: Up to 4 months after completion of imaging acquisition for each participant
Mean Three-Dimensional Structural Similarity Index (3D-SSIM) Between Registered PET Datasets
Structural similarity between the registered PET datasets acquired as part of PET/CT and PET/MRI will be assessed using the three-dimensional Structural Similarity Index (3D-SSIM), implemented in Python using the scikit-image library. The index provides a dimensionless measure of similarity in spatial image patterns, with higher values indicating greater structural similarity and a value of 1 representing perfect similarity. The 3D-SSIM will be calculated within the registered breast image volume for each registration approach and acquisition setting to assess registration performance and the effect of comparable breast positioning on registration quality.
Measured: Up to 4 months after completion of imaging acquisition for each participant
Secondary outcomes (4)
Absolute Difference in SUVmax After Image Deformation
The maximum standardized uptake value (SUVmax) will be measured in corresponding regions of the original PET dataset and the PET dataset after application of the calculated deformation field. The absolute difference in SUVmax between the original and deformed datasets will be calculated to quantify changes in quantitative PET information introduced by image deformation. The mean absolute difference in SUVmax will be compared across registration methods and patient positioning conditions to assess the robustness of the registration approaches and whether reduced positioning differences improve quantitative stability.
Measured: Up to 4 months after completion of imaging acquisition for each participant
Absolute Difference in SUVmean After Image Deformation
The mean standardized uptake value (SUVmean) will be measured in corresponding regions of the original PET dataset and the PET dataset after application of the calculated deformation field. The absolute difference in SUVmean between the original and deformed datasets will be calculated to quantify changes in quantitative PET information introduced by image deformation. The mean absolute difference in SUVmean will be compared across registration methods and patient positioning conditions to assess the robustness of the registration approaches and whether reduced positioning differences improve quantitative stability.
Measured: Up to 4 months after completion of imaging acquisition for each participant
Absolute Difference in SUVpeak After Image Deformation
The peak standardized uptake value (SUVpeak) will be measured in corresponding regions of the original PET dataset and the PET dataset after application of the calculated deformation field. The absolute difference in SUVpeak between the original and deformed datasets will be calculated to quantify changes in quantitative PET information introduced by image deformation. The mean absolute difference in SUVpeak will be compared across registration methods and patient positioning conditions to assess the robustness of the registration approaches and whether reduced positioning differences improve quantitative stability.
Measured: Up to 4 months after completion of imaging acquisition for each participant
Absolute Difference in SUVmax-Based Tumor-to-Background Ratio After Image Deformation
The tumor-to-background ratio based on maximum standardized uptake value (TBRmax) will be calculated in corresponding regions of the original PET dataset and the PET dataset after application of the calculated deformation field. The absolute difference in TBRmax between the original and deformed datasets will be calculated to quantify changes in quantitative PET contrast introduced by image deformation. The mean absolute difference in TBRmax will be compared across registration methods and patient positioning conditions to assess the robustness of the registration approaches and whether reduced positioning differences improve quantitative stability.
Measured: Up to 4 months after completion of imaging acquisition for each participant
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Oct 2026
- Study start6 Oct 2026 (estimated)
- Primary completion30 Sep 2027 (estimated)
- Study completion30 Sep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universität Münster
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Philippe Brüggemann, Universität Münster
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07883460
- Sponsor's protocol ID
- 2026-294-f-S
- Other IDs
- BR2126605, ZD 3-22464/2026-014-G
- Acronym
- REPOSE-Breast
- Status last verified
- Oct 2026
- First submitted
- 2 Oct 2026
- Last updated
- 20 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Pseudonymized imaging data and associated study data may be shared with designated external research collaborators involved in the development and evaluation of image registration methods within the scope of this study. Subject to the participants' informed consent, data may also be shared with future research collaborators for related methodological research purposes. Any data sharing will be limited to the purposes permitted by the study documents and applicable data protection requirements. No unrestricted public release of individual participant data is planned.