Three-dimensional culture of human breast cancer cells, with DNA stained blue and a protein in the cell surface membrane stained green. Image created by Tom Misteli, Ph.D., and Karen Meaburn, Ph.D. at the NIH IRP.

A new type of scan has been used to visualise regions of breast tumours that are active with magnetising molecules in research funded by Cancer Research UK. Published in the Proceedings of the National Academy of Sciences, the work used carbon-13 hyperpolarised imaging to monitor breast cancer, allowing not only visualising the tumour as a whole, but details of its internal metabolic state as well.

Breast cancer is the most common cancer in the UK, with more than 20,000 cases per year. Current methods to diagnose breast cancer include a mammogram, ultrasound, biopsy, and MRI. Some of these methods fail to give a clear picture about the whole tumour environment, such as a biopsy which may only include cells from one region that may be distinctly different from another. The new method could help doctors decide which treatment would be best for each patient and help in fully understanding the tumour.

The researchers used hyperpolarised carbon-13 pyruvate, an isotope-labelled form of the naturally occurring molecule pyruvate which is converted into lactate during energy metabolism. To create an injectable solution, the carbon-13 pyruvate was cooled to -272°C and exposed to extremely strong magnetic fields and microwave radiation, making it “hyperpolarised” and then thawed into a solution.

Seven patients from Addenbrooke’s Hospital with various types and grades of breast cancer were tested before they had received any treatment. The hyperpolarised solution together with an MRI scan revealed how fast pyruvate was being metabolised by the cancer cells, and increased the signal strength by 10,000 times so they were easily visible. Tumour cells metabolise pyruvate to lactate much quicker than healthy cells, allowing the cancer cells to be visualised first through the MRI scan.

The carbon-13 hyperpolarised imaging technique could determine the aggressiveness of the tumour, the size, and the type. Areas of the tumour with metabolic variations revealed the “topography” of the tumour, showing which parts were most similar to each other.

The researchers now aim to trial this scan in more patients and see if it works as a better detection method than others currently used, as well as aid in informing treatment decisions in hospitals.