Patent ID: 8500660

Claim:
A method of measuring the size of a gastric lumen of patient, the method comprising: providing a system comprising: a circuit external to a banding device and to the patient, the circuit comprising a first coiled conductor, a tunable frequency generator, and a spectrum analyzer, wherein the circuit is tunable to allow a resonant frequency, wherein the frequency generator generates a current in the first coiled conductor, wherein size of the gastric lumen is determined by a change in resonant frequencies measured by the spectrum analyzer in the first coiled conductor when in the presence of a second coiled conductor in the gastric banding device, and wherein the size of the gastric lumen is determined without modifying the gastric banding device; tuning the circuit external to the banding device to a first resonant frequency in the absence of the patient; recording the first resonant frequency; positioning the second coiled conductor near the patient; tuning the circuit external to the banding device to a second resonant frequency in the presence of the patient after the patient has swallowed a water solution; and calculating the size of the gastric lumen based on the difference between the first resonant frequency and the second resonant frequency.