Evaluate the Distribution and Dynamic Behavior of TH-SC01 Cells in Vivo in Patients With Perianal Fistula

This study is evaluating a cell therapy called TH-SC01 — made from stem cells — to treat perianal fistulas (abnormal tunnels near the anus) in people with Crohn's disease or complex perianal fistulas. The study also uses special PET/CT imaging to track where the cells go in the body after injection. **You may be eligible if...** - You have been diagnosed with Crohn's disease or a complex perianal fistula for at least 6 months - You have an active fistula with 1–2 internal openings and up to 3 external openings - Your Crohn's disease is active in the fistula area but not causing severe bowel symptoms - You have previously tried antibiotics, immune-modifying drugs, anti-TNF biologics, or other biologics without adequate improvement - You are not planning to have children during the trial **You may NOT be eligible if...** - You have an active infection - You have a large abscess (more than 2 cm) near the fistula - You have severe rectal or anal narrowing or active rectal inflammation - You have received systemic steroids in the past 4 weeks - You have liver or kidney function problems beyond acceptable limits - You have had or have cancer - You have had a stem cell therapy previously - You have had major surgery or serious trauma in the past 6 months - You are pregnant or breastfeeding - You cannot undergo PET/CT scanning Talk to your doctor to see if this trial is right for you.