Chemists at the US National Cancer Institute (NCI), Bethesda, US, have developed a nano-sized dendrimer-based MRI agent they say could reduce the trauma associated with breast cancer surgery.

Chemists at the US National Cancer Institute (NCI), Bethesda, US, have developed a nano-sized dendrimer-based MRI agent they say could reduce the trauma associated with breast cancer surgery.

As with traditional MRI agents, this newcomer is injected into or around the tumour site. Where it differs is that the dendrimer-based agent, developed by a team led by Martin Brechbiel, section chief of the Radioimmune and Inorganic Chemistry Section at the NCI’s Radiation Oncology Branch, provides a ’unique visualisation’ of the lymph nodes associated with breast cancer. The spread of cancer to the lymph nodes is strongly linked to prognosis with likely removal of diseased nodes.

Current MRI compounds are small molecules, but this agent uses a series of dendrimer complexes to carry the magnetic signal. Some of these dendrimers can carry up to 256 ions of gadolinium, a common MRI magnetic signal.

’If it’s a small molecule you cannot see it with great resolution,’ said Brechbiel. ’It’s a very faint picture and then it’s all gone.’ But with the dendrimer complex, he claims, you get a clearer image with much improved resolution which lasts longer, offering the potential for serial MRI. A second round of imaging the next day can reveal how the cancer is developing.

Brechbiel has only tested the system on a mouse model, and is now looking for an industrial partner to help out with the hundred thousand dollars or more required to take this to clinical trials.

The potential advantages are clear, he says: ’Having a picture before you go into the operating room, a 3D image.’ Such an image could significantly improve a surgeon’s precision. ’Half an inch may save somebody a little extra trauma, and recovery time and the after effects of micro-dissection,’ Brechbiel told Chemistry World.

Bea Perks/Philadelphia, US