Which method of examining the bladder can be done using a lighted tube?

Cystoscopy is the method of examining the bladder using a lighted tube, which is known as a cystoscope. This procedure allows a healthcare provider to visualize the interior of the bladder and the urethra. During a cystoscopy, the tube is inserted through the urethra and into the bladder, enabling direct observation as well as the possibility of performing biopsies or other interventions if necessary.

In contrast, ultrasound, CT scans, and X-rays involve imaging technology to create visual representations of internal structures without the direct visual access provided by a cystoscope. Ultrasound uses sound waves, CT scans employ X-rays and computer technology, and X-rays utilize a form of radiation to capture images. Therefore, these methods do not involve the insertion of a lighted tube for direct examination.