The blood-brain barrier has long been an obstacle for doctors trying to treat brain diseases.
Because little can get through this barrier, it is frustratingly difficult for doctors to treat tumours and brain diseases because life-saving drugs can't enter brain cells.
Hall is a mother, grandmother and business owner who recently learned that the benign brain tumour she has lived with for eight years had begun to grow quickly and was malignant.
Doctors can use chemotherapy to treat what is left behind after surgery, but only about 25 per cent of the drugs reach