An adult outpatient arrives for voiding cystourethrography after recurrent UTIs. Contrast fills the bladder via catheter, and the radiologist asks for voiding images of the urethra in progress. The table is fluoroscopic with spot imaging capability. Which imaging action best completes the cystourethrography evaluation of the urethra?

The correct action succeeds because urethral evaluation requires contrast actively distending the lumen under physiologic voiding pressure, and right posterior oblique positioning rotates the urethra clear of bony overlap to profile caliber, stricture, valves, or dilation while timed spot images capture peak flow on the fluoroscopic table. An anteroposterior voiding view of the urethra preserves timing and intent but fails by projection geometry because the beam superimposes urethral segments and hides subtle narrowing visible only in profile. A right posterior oblique voiding view directed to bladder reflux preserves timing and positioning but fails by anatomic target because reflux assessment centers on the bladder and ureterovesical junctions rather than urethral luminal detail requested here. A right posterior oblique voiding view with the catheter left in situ preserves timing, position, and target but fails by technique because the catheter stents the lumen, masks pathology, creates artifactual defects, and prevents normal flow dynamics, so the catheter must be removed after filling. For examinations, remember voiding means exposure during active urine flow, not during filling or after drainage, and oblique urethral profiling is distinct from a bladder reflux series. Practically, confirm catheter removal, coach sustained voiding in the requested obliquity, and acquire labeled spot images at initiation, full stream, and near-completion to document the entire urethra.