Standard white light cystoscopy is used in the diagnosis and monitoring of bladder cancer. A cystoscope is a specialised endoscope allowing for direct visual inspection. The cystoscope is inserted through the urethra into the bladder, and the pictures generated by the integrated camera are transmitted onto a nearby video screen. Most cystoscopes have extra tubes to guide other instruments for taking a biopsy of a bladder tumor or removal of superficial bladder tumors.
Blue light cystoscopy
When performing blue-light cystoscopy, the bladder of the patient is instilled with a diagnostic drug one hour before the procedure. The drug contains a substance that is quickly taken up by the cancerous cells , and is transformed. The transformed substance will light up red when illuminated with blue light. When performing the cystoscopy the cystoscope contains both a white and blue light source, so the doctor can switch between them. When the doctor switches on the blue light, the tumor cells light up red, and the unaffected part of the bladder will remain blue.
The inside of a bladder with the diagnostic product. To the left you can see what it looks like in standard white light, and to the right with the blue light switched on.