BACKGROUND: The detection of a leakage in the system of the adjustable silicone gastric band (ASGB) may be difficult. Gastrografin injection into the port should be avoided because it acts like a glue and blocks the system. METHODS: A syringe containing saline and a syringe containing Thallium-201 chloride is connected to the 4-way stopcock which is connected to the needle. The needle is pushed into the port. The position is confirmed by injection and aspiration of saline. 2 ml of TL-201 chloride (74 MBp) is injected to locate the leakage in the system with planar images with a gamma camera (Elscint SP 6), 30 min, 2, 3, and 24 h after injection. RESULTS: The original ASGB was provided with an injection reservoir which, in our series, was found to be leaking in four cases (3%). CONCLUSIONS: Our technique for adjustment and leak detection appears to be simple and effective. Band-related problems such as reservoir leak should disappear with improvement of the material.