Genentech and Roche’s cancer drug Avastin can help find tumors as well as treat them, scientists said on Wednesday.

After tagging the antibody drug with a radioactive tracer and injecting it into mice, researchers found it successfully targeted cancer cells and this enabled them to produce well-defined images of tumors during scanning.

When compared with images of the same tumors taken using standard imaging, the Avastin images were better and also showed up tumors in earlier stages and at smaller sizes.

The research was presented at a EORTC-NCI-AACR conference on cancer in Geneva by Zheng Jim Wang, director of molecular imaging at privately owned company MPI Research Inc and an assistant professor at the University of Texas Health Science Center at San Antonio.

Scientists need to confirm their discovery in further studies and clinical trials but Wang hopes the new technique will eventually help doctors detect and diagnose tumors at earlier stages, improving treatment outcomes.

Avastin or bevacizumab — a blockbuster treatment used mainly in bowel cancer — is a so-called targeted therapy that works by starving tumors of blood supply. It had sales of 4.1 billion Swiss francs ($3.6 billion) last year.

Wang said it was possible that other targeted cancer therapies could be used for imaging in a similar way, but this depended on the type and biological distribution of the drug.