THERANOSTICS is a concept combining Therapy and Diagnosis. When Chlorophyll is exposed to blue light it fluoresces a bright red colour. This slide is a photo of a bladder tumour using a cystoscope. White light shows an indistinct tumour in the bladder wall. The blue light photo shows an accurate picture of the size and shape of the cancer. This enables accurate placement of the PDT red light. The technique is also useful in ensuring that the complete tumour is excised at surgery, leaving no cancer cell behind.