Neutron capture therapy of cancer

Neutron Capture Therapy of Cancer is a non-invasive radiotherapy treatment used to manage malignant tumors. This therapy utilizes the nuclear capture and fission reactions that occur when a non-radioactive isotope, boron-10, is irradiated with low energy thermal neutrons to produce high-energy alpha particles and lithium-7 nuclei.

History

The concept of Neutron Capture Therapy (NCT) was first proposed in 1936 by Locher. The development of nuclear reactors in the 1950s provided a source of neutrons, and the first clinical trials were conducted in the 1950s and 1960s. However, due to the lack of suitable boron delivery agents and the difficulty in achieving a therapeutic ratio, these early trials were not successful.

Mechanism

In Neutron Capture Therapy, a compound containing boron-10 is injected into the patient's bloodstream. The compound is designed to accumulate preferentially in tumor cells. The patient is then irradiated with thermal neutrons. The boron-10 in the tumor absorbs the neutrons and undergoes a nuclear reaction, producing high-energy alpha particles and lithium-7 nuclei. These particles have a very short range in tissue, so they deliver a high dose of radiation to the tumor cells, while sparing the surrounding healthy tissue.

Clinical Applications

Neutron Capture Therapy has been used to treat several types of cancer, including glioblastoma, melanoma, and head and neck cancer. The therapy is particularly effective for tumors that are resistant to conventional radiation therapy or are located in areas that are difficult to treat with surgery.

Challenges and Future Directions

Despite its potential, Neutron Capture Therapy is not widely used, due to the need for a nuclear reactor to produce the thermal neutrons. However, research is ongoing to develop alternative neutron sources, such as accelerator-based systems. In addition, new boron delivery agents are being developed to improve the selectivity and efficacy of the therapy.