Once the entire mucosal surface has been examined and all tumors and abnormal-appearing areas have been identified, the cystoscope is removed in exchange for a resectoscope (using the 30-degree lens). Most resectoscopes have a large enough diameter to permit continuous flow and suction of irrigation fluid, which both improves visualization and stabilizes the bladder wall. The resectoscope is connected to an energy source that is applied to the bladder mucosa through a resection loop. The surgeon performs thumb movements to advance or retract the loop across the mucosal surface, while the application of energy is controlled with a foot pedal. Resection should begin with removal of the tumor’s superficial exophytic portions, followed by removal of its deeper layers, until bands of detrusor fibers can be visualized. For smaller tumors, a single sweep of the loop may be adequate. To permit accurate staging, it is imperative that enough tissue be obtained to capture the muscularis propria.