Neutron capture therapy (NCT) is a noninvasive therapeutic modality for treating locally invasive malignant tumors such as primary brain tumors and recurrent head and neck cancer.
It is a two step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope that has a high propensity or cross section (σ) to capture slow neutrons. The cross section of the capture agent is many times greater than that of the other elements present in tissues such as hydrogen, oxygen, and nitrogen. In the second step, the patient is radiated with epithermal neutrons, which after losing energy as they penetrate tissue, are absorbed by the capture agent which subsequently emits high-energy charged particles, thereby resulting in a biologically destructive nuclear reaction.
All of the clinical experience to date with NCT is with the non-radioactive isotope boron-10, and this is known as boron neutron capture therapy (BNCT).
A boron delivery system with high therapeutic efficiency and low adverse effects is crucial for a successful boron neutron capture therapy (BNCT).
Boron cluster-containing redox nanoparticles (BNPs) are promising for enhancing the BNCT performance 1).
Of the 180 patients with malignant brain tumors whom we treated with boron neutron capture therapy (BNCT) since 1968, only one (0.56%) developed multiple radiation-induced meningiomas. The parasagittal meningioma that had received 42Gy (w) for BNCT showed more rapid growth on Gd-enhanced MRI scans and more atypical features on histopathologic studies than the temporal convexity tumor that had received 20Gy (w). Long-term follow up MRI studies are necessary in long-survivors of malignant brain tumors treated by BNCT 3).