CTX: Cy5.5 bioconjugate which is a combination of chlorotoxin and a fluorescent material named, Cy5.5 was used by Researchers at Seattle Children’s Hospital Research Institute and Fred Hutchinson Cancer Research Center to demarcate cancer cells from the surrounding normal cells. This gives surgeons a better chance of removing all of the cancerous cells without injuring the surrounding healthy tissue. CTX: Cy5.5 is a fluorescent molecule emitting photons in the near infrared spectrum and hence can be visualized in the operating room with the aid of infrared glasses. Studies in mouse models have shown that Cy5.5 can identify tumors with as few as 2000 cancer cells, making it 500 times more sensitive than MRI. Treated animals exhibited no neurologic or behavioral deficits, and postmortem studies revealed no evidence of neuropathy. In 2015 clinical trials were beginning of this tumour "paint" technique.