NCT07221825 · Washington University School of Medicine
Low-Count Quantitative SPECT for Men Treated With Radium-223
What this study is about
Internal radiotherapies (radiolabeled molecules that are systemically administered and localize to sites of disease) provide cancer-ablating doses to diseased cells while sparing adjacent normal tissues.
View original scientific description
Internal radiotherapies (radiolabeled molecules that are systemically administered and localize to sites of disease) provide cancer-ablating doses to diseased cells while sparing adjacent normal tissues. \[223Ra\]RaCl2 (Xofigo) is the first FDA-approved alpha-particle emitting radiopharmaceutical therapy (αRPT), providing a survival benefit for men with bone metastatic castration-resistant prostate cancer. Systemically administered radiotherapies distribute throughout the patient, accumulating to unknown levels at sites of disease and in radiosensitive vital organs. The whole-body distribution means that absorbed doses in the patient extend far beyond a pre-defined treatment field. There is a lack of information about αRPT distribution and localization, and this confounds treatment monitoring, complicates dose and schedule personalization, and impedes drug development. Single-photon emission computed tomography (SPECT) imaging offers a mechanism to quantify uptake; however, αRPT administered activities are significantly lower than those used with diagnostic procedures, which presents a challenge for quantitation with conventional methods. Preliminary research shows that low-count quantitative SPECT (LC-QSPECT) imaging demonstrates reliable quantitation of regional uptake for αRPTs. The purpose of this study is to demonstrate the feasibility, tolerability and performance of LC-QSPECT imaging.
Interventions
DEVICE
Low-count quantitative single-photon emission computed tomography imaging
LC-QSPECT scans will be performed between 6 and 36 hours after administration of Xofigo during Cycles 1 and 3.
Primary outcome measures
Spearman's correlation coefficient between the LC-QSPECT estimated uptake in the lesions and intestine with ex vivo activity sampling
Time frame: Through collection of ex vivo sample (estimated to be 3 months)
The investigators will assess if the correlation (in absolute magnitude) ≥ 0.60 between the tissue and SPECT data against a low correlation of \< 0.2 based on 1-sided normal test at a 5% level.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- - Patients:
- Histologically or cytologically confirmed castration-resistant prostate cancer with symptomatic bone metastases.
- Minimum detectable skeletal lesion count of 3.
- Eligible to receive Xofigo.
- At least 18 years of age.
- ECOG performance status ≤ 3.
- Ability to understand and willingness to sign an IRB-approved written informed consent document. Legally authorized representatives may sign and give informed consent on behalf of study participants.
Exclusion criteria
- - Patients:
- Predominant visceral metastatic disease.
- Prior or concurrent malignancy whose natural history has the potential to interfere with the safety or efficacy assessment of the investigational regimen. Patients with prior or concurrent malignancy that does NOT meet that definition are eligible for this trial
- Uncontrolled intercurrent illness including, but not limited to: ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, or cardiac arrhythmia.
- Concurrent alternative radiopharmaceuticals
- Inability to maintain stationary supine pose for 45-60 minutes Eligibility Criteria - Physicians:
- Medical Oncologist or Radiation Oncologist at Siteman Cancer Center.
- Treating patients with prostate cancer.
- Willing to complete Physician Questionnaire during participation.
Where
- St Louis, Missouri
Collaborators
National Institute for Biomedical Imaging and Bioengineering (NIBIB)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 21, 2026 · Source of record for eligibility and locations