Boron Neutron Capture Therapy

Boron Neutron Capture Therapy. Each year more than half a million of people in the world contract brain tumors and about 2000 die from the disease. Treatment of a brain tumor is one of the most challenging of cancer cases because of the site of the malignant growth, which makes surgical excision difficult and often impossible. Likewise, conventional radiation therapy using X-ray or y- rays from outside the skull is seldom effective.

An ingenious approach to this problem is called boron neutron capture therapy (BNCT). This technique brings together two components, each of which separately has minimal harmful effects on the cells. This first approach uses a compound containing stable boron isotope that can be concentrated in tumor cells. The second component is a beam of low energy neutrons. Upon capturing a neutron, the following nuclear reaction takes place.

The recoiling alpha particle and the lithium nucleus together carry about 3.8x10^-13 J of energy. Because these high energy particles are confined to just a few nana meters; about the cell of a cell, they can perfectly destroy tumor cells without damaging the surrounding tissues. Ionizing radiation like X-rays requires oxygen to produce reactive hydroxyl and superoxide radicals to enhance their biological effectiveness. However, a rapidly expanding tumor frequently depletes its blood supply and hence also the oxygen content. BNCT does not require oxygen and therefore does not suffer from this limitation. BNCT is currently an active research area involving collaboration of chemists, nuclear physicists and physicians.