An interventional study of [18F]AlF-FAPI-74 PET/CT and [18F]AlF-FAPI-74 PET/CT in Endometriosis, Deep Infiltrating Endometriosis and Women, sponsored by Universitaire Ziekenhuizen KU Leuven. Recruiting at 1 site in Belgium. Open to female participants aged 18 Years to 64 Years. Per ClinicalTrials.gov, last updated 2026-10-19.
Sponsored by Universitaire Ziekenhuizen KU Leuven · Not applicable, Interventional, and Diagnostic
The goal of this clinical trial is to learn whether [18F]AlF-FAPI-74 PET/CT can help detect endometriosis in adult women who are already scheduled for laparoscopy due to suspicion of deep infiltrating endometriosis or superficial peritoneal endometriosis. The main aims are: (i) How well does [18F]AlF-FAPI-74 PET/CT identify endometriosis lesions compared with findings during laparoscopy? (ii) Can PET/CT identify additional lesions that may not be seen on ultrasound or MRI? (iii) Can ultra-high-resolution NeuroEXPLORER PET/CT improve the detection of small lesions compared with standard PET/CT? Participants will: (i) Receive an intravenous injection of [18F]AlF-FAPI-74 followed by a PET/CT scan before their planned laparoscopy. (ii) Undergo their planned laparoscopy, during which PET findings will be compared with the surgical findings and where tissue is removed with laboratory analysis. (iii) Optionally undergo an additional NeuroEXPLORER PET/CT scan after the same tracer injection. (iv) Optionally undergo a second [18F]AlF-FAPI-74 PET/CT if participants started gonadotropin-releasing hormone (GnRH) treatment after their first scan to investigate whether tracer uptake in endometriosis lesions changes during treatment.
925 studies on the registry are indexed under Endometriosis; 264 are open to participants now.
This study's planned enrollment of 64 is close to the median of 65 across 539 interventional studies indexed under Endometriosis.
Browse Endometriosis studies →Universitaire Ziekenhuizen KU Leuven is the lead sponsor of 958 studies on the registry; 263 are open to participants now.
Of its 5 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
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Exclusion Criteria:
Diagnostic Test: [18F]AlF-FAPI-74 PET/CT
Diagnostic Test: [18F]AlF-FAPI-74 PET/CT
A \[18F\]AlF-FAPI-74 PET/CT will be performed at UZ Leuven before the participant's planned laparoscopy. Participants are required to fast for 4 hours before tracer administration but water is allowed. An intravenous line will be placed and \[18F\]AlF-FAPI-74 will be administered in one bolus (3.5 MBq/kg). PET/CT acquisition will start after 60 minutes. The CT will be a low dose CT with oral contrast. If there are no contraindications, 20 mg Buscopan may be administered shortly before imaging to reduce bowel movement. Participants may optionally undergo an additional NeuroEXPLORER PET/CT scan on the same day after the same \[18F\]AlF-FAPI-74 administration, so no second tracer injection is required. Participants who start treatment with a GnRH (ant)agonist after their first scan may undergo a second \[18F\]AlF-FAPI-74 PET/CT to investigate changes in tracer uptake during hormonal treatment. Participants will be monitored for adverse events related to study procedures.
A \[18F\]AlF-FAPI-74 PET/CT will be performed at UZ Leuven before the participant's planned laparoscopy. Participants are required to fast for 4 hours before tracer administration but water is allowed. An intravenous line will be placed and \[18F\]AlF-FAPI-74 will be administered in one bolus (3.5 MBq/kg). PET/CT acquisition will start after 60 minutes. The CT will be a low dose CT with oral contrast. If there are no contraindications, 20 mg Buscopan may be administered shortly before imaging to reduce bowel movement. Participants may optionally undergo an additional NeuroEXPLORER PET/CT scan on the same day after the same \[18F\]AlF-FAPI-74 administration, so no second tracer injection is required. Participants will be monitored for adverse events related to study procedures.
Evaluate diagnostic performance of [18F]AlF-FAPI-74 PET/CT as a non-invasive tool to diagnose deep infiltrating endometriosis and/or superficial peritoneal endometriosis, in comparison with laparoscopic findings in women with suspected endometriosis
Correlating the locations of endometriotic lesions on \[18F\]AlF-FAPI-74 PET/CT and the locations of endometriotic lesions detected during laparoscopy.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Frequency of serious adverse device effects (SADEs) related to NeuroEXPLORER PET/CT
The number of participants experiencing one or more serious adverse device effects (SADEs) during NeuroEXPLORER PET/CT will be recorded.
Time frame: From enrollment until laparoscopy (up to 1 month after the last NeuroEXPLORER PET/CT)
Sensitivity, specificity, positive and negative predictive value and accuracy of [18F]AlF-FAPI-74 PET/CT for detecting endometriosis
Sensitivity, specificity, positive predictive value, negative predictive value, accuracy of \[18F\]AlF-FAPI-74 PET/CT in detecting endometriotic lesions using laparoscopic findings as the reference standard.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Semi-quantitative uptake measurements
Semi-quantitative uptake measurements (maximal standardized uptake value (SUVmax), average SUV (SUVmean), peak SUV (SUVpeak) of endometriotic lesions on \[18F\]AlF-FAPI-74 PET/CT.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Lesion-to-background uptake values
Endometriotic lesion-to-background uptake values (SUV lesion divided by SUV background) for \[18F\]AlF-FAPI-74 PET/CT, using following background organs: liver, lung, gluteus muscle, mediastinal bloodpool, bowel, bone marrow (L4 if no abnormal uptake).
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
FAP-positive endometriotic burden
Total FAP-positive endometriotic burden, defined as the sum of the volumes of all lesions deemed to be endometriotic in nature.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Additional lesions after unblinding
Number of additional endometriotic lesions recorded after unblinding of the surgeon during laparoscopy.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of MRI for detecting endometriosis
Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MRI in detecting endometriotic lesions, in patients in which MRI is available, and comparison with \[18F\]AlF-FAPI-74 PET/CT, laparoscopy and if available ultrasound.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ultrasound for detecting endometriosis
Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ultrasound in detecting endometriotic lesions, in patients in which ultrasound is available, and comparison with \[ 18F\]AlF-FAPI-74 PET/CT, laparoscopy and if available MRI.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Number of participants with a change in clinical management following review of [18F]AlF-FAPI-74 PET/CT findings
The number and proportion of participants with a change in planned clinical management attributable to the \[18F\]AlF-FAPI-74 PET/CT findings, as documented by the treating clinical team, will be recorded. The type of management change will also be documented.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Patient-reported responses to a study-specific questionnaire on the psychological impact of [18F]AlF-FAPI-74 PET/CT
Psychological impact of the \[18F\]AlF-FAPI-74 PET/CT procedure will be assessed using a study-specific questionnaire completed before and after the scan procedure. The questionnaire evaluates e.g. anxiety, concerns about the procedure, discomfort, or personnel. Responses will be scored according to the predefined questionnaire scoring system.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Intra- and interreader agreement for detection and localization of endometriosis lesions on [18F]AlF-FAPI-74 PET/CT
Two PET readers will independently identify and localize suspicious endometriosis lesions on \[18F\]AlF-FAPI-74 PET/CT. Intra- and interobserver agreement will be determined using the GWET agreement coefficient (AC) or intraclass correlation coefficients (ICC).
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Adverse events
Adverse events associated with \[18F\]AlF-FAPI-74 PET/CT.
Time frame: From tracer administration until 30 days after tracer administration
FAP IHC correlation
Correlation of \[18F\]AlF-FAPI-74 biodistribution with FAP tissue expression as measured by immunohistochemistry (IHC).
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Change in [18F]AlF-FAPI-74 PET/CT findings after initiation of GnRH therapy
Evolution of \[18F\]AlF-FAPI-74 PET/CT scans in patients initiating GnRH-agonist or GnRH-antagonist medication and receiving 2 \[18F\]AlF-FAPI-74 PET/CT (prior and post initiation of GnRH-agonist or GnRH-antagonist medication): (i) number of lesion; (ii) uptake; (iii) endometriotic lesion-to-background value; (iv) correlation with laparoscopy and if available MRI and/or ultrasound.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Frequency of adverse device effects (ADEs) associated with NeuroEXPLORER PET/CT
The number of participants experiencing one or more adverse device effects (ADEs) during NeuroEXPLORER PET/CT will be recorded.
Time frame: From enrollment until laparoscopy (up to 1 month after the last NeuroEXPLORER PET/CT)
Patient Reported Outcome Measures (PROM) to capture the perspective and satisfaction of the NeuroEXPLORER PET/CT
Patient Reported Outcome Measures (PROM) to capture the perspective and satisfaction of the NeuroEXPLORER PET/CT. This will be scored on a 0-10 Likert scale on the dimensions of "Investigation smoothness", "satisfaction with the scanning procedure" and "comfortable positioning during the examination".
Time frame: From enrollment until laparoscopy (up to 1 month after the last NeuroEXPLORER PET/CT)
Number of endometriotic lesions detected on NeuroEXPLORER PET/CT compared with standard [18F]AlF-FAPI-74 PET/CT
The number of endometriotic lesions detected on NeuroEXPLORER PET/CT will be compared with the number detected on the corresponding standard \[18F\]AlF-FAPI-74 PET/CT acquisition obtained after the same tracer injection. Results will be summarized descriptively.
Time frame: From enrollment until laparoscopy (up to 1 month after the last [18F]AlF-FAPI-74 PET/CT)
Documents are hosted by the registry — open the source record to download them.
Plan to share: No
Started Sep 2026 (actual). Primary completion is estimated for Aug 2029, 35 months after the start.
Of 193 non-industry interventional studies with no phase under Endometriosis, half reached primary completion within 24 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 44. This study's planned 35 months is above that.
Counting every sponsor, half of 208 studies reached it within 25 months; a quarter within 13 and three quarters within 44.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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