A H BEDDOE, PhD, FIPEM, FACPSEM. Medical Physics Directorate, Queen Elizabeth Hospital, Birmingham, B15 2TH, UK. One of the main teach-in sessions at ...
T he British Journal of Radiology, 70 (1997), 665–667
Boron neutron capture therapy A H BEDDOE, PhD, FIPEM, FACPSEM Medical Physics Directorate, Queen Elizabeth Hospital, Birmingham, B15 2TH, UK
One of the main teach-in sessions at Radiology UK 1996, held in Birmingham, concerned the revival of a novel modality on the radiotherapy scene, boron neutron capture therapy (BNCT). In principle BNCT enables a therapeutic gain to be achieved over conventional photon therapy, provided one can first ensure that tumours take up more of a boron-rich compound than the surrounding healthy tissues immediately prior to thermal or epithermal neutron irradiation. Naturallyoccurring 10B has a very high affinity for thermal neutrons, having a thermal neutron cross-section of 3838 barns for the 10B(n, a) 7Li reaction. The short range particles which result (alpha particles and lithium nuclei) constitute very high LET radiation, potentially lethal to any cells in which the reaction occurs. The clinical potential of BNCT centres primarily around the treatment of glioblastoma multiforme. There are approximately 4000 cases of high grade astrocytoma in the UK per annum with prognoses of around 36 months in younger patients and around 12 months in the elderly. The available data suggest that conventional radiotherapy improves both disease free survival and overall survival [1] and that there is increased benefit from increased dose [2]. The rationale for choosing BNCT is that dose to the tumour can be increased without exceeding normal tissue tolerance. The treatment could also potentially benefit cerebral melanoma and tumour types for which local control is currently a problem, for example locally advanced pelvic tumours and melanoma. The efficacy of treatment of course depends (or will depend) on getting appropriate levels of boronated compounds to all parts of the tumour while achieving a relatively low concentration in the blood. Since the radiation exposure is localized to the neutron capture site (range
