the deflated state of the balloon fig3 and 4 illustrate a configuration of radiopaque markings 22 coupled to gastric balloon 28 to form a geometrical pattern such as a grid in accordance with an embodiment of the present invention in some embodiments of the present invention the markings comprise a plurality of spots as illustrated in fig3 and 4 as shown in fig3 balloon 28 is in an inflated state radiopaque markings 22 are aligned along latitude and longitude lines of balloon 28 and are generally straight due to the distention of the inflated balloon fig4 correspondingly represents a deflated state of gastric balloon 28 in which radiopaque markings 22 form wavy lines due to the shrinking of the balloon it is to be appreciated that other aspects of radiopaque marking 22 may change in addition to or instead of the straight versus wavy shape of the markings for example the distance between different aspects of the radiopaque markings e g lines or spots decreases in response to deflation of gastric balloon 28 reference is now made to fig5 and 6 which are schematic illustrations of gastric balloon 28 in the stomach 26 of the patient in respective inflated and deflated states in accordance with an embodiment of the present invention gastric balloon 28 is oriented within stomach 26 such that an anchor 30 coupled to the distal end of gastric balloon 28 is disposed within the antrum 32 in the embodiment shown radiopaque markings 22 comprise dashed lines interspersed with short gaps and function generally as described hereinabove to indicate the level of inflation.