Objective:To explore the in vitro radiation levels and in vivo neutron activation after patients receiving boron neutron capture therapy (BNCT). Methods:Totally 29 BNCT treatments were performed for 21 patients with head and neck and brain cancer using the NeuPex accelerator-based boron neutron capture therapy (AB-BNCT) system in Xiamen Humanity Hospital from October, 2022 to April, 2024. The ambient dose equivalent rate around the patients was measured with an X/gamma dose rate survey meter. The gamma radiation dose rates were measured at 0, 0.5, 1.0, and 2.0 m from the irradiation position, at 0, 0.5, 1.0, and 2.0 m from the opposite side of the irradiation position, and at the navel and the affected knee, respectively. Meanwhile, a portable high-purity germanium gamma spectrometer was used to measure the spectrum of activated nuclides in the bodies of patients who had underwent the treatment, and the types of radionuclides generated by neutron activation during each BNCT treatment were analyzed.Results:The radionuclides 24Na, 38Cl, and 49Ca were mainly produced in the bodies of patients treated with BNCT. 20 minutes after BNCT treatment, the ambient dose equivalent rate at a distance of 1.0 m from the irradiation position was lower than 2.5 μSv/h. Conclusions:The dose delivered to the staff and family members by the patients undergoing BNCT is relatively low, and the resulting radiation risk is low. According to the ALARA principle, it is recommended that certain control actions be taken for patients having received BNCT treatment to minimize the exposure doses of both patients and staff as much as possible.

Objective:To explore the in vitro radiation levels and in vivo neutron activation after patients receiving boron neutron capture therapy (BNCT). Methods:Totally 29 BNCT treatments were performed for 21 patients with head and neck and brain cancer using the NeuPex accelerator-based boron neutron capture therapy (AB-BNCT) system in Xiamen Humanity Hospital from October, 2022 to April, 2024. The ambient dose equivalent rate around the patients was measured with an X/gamma dose rate survey meter. The gamma radiation dose rates were measured at 0, 0.5, 1.0, and 2.0 m from the irradiation position, at 0, 0.5, 1.0, and 2.0 m from the opposite side of the irradiation position, and at the navel and the affected knee, respectively. Meanwhile, a portable high-purity germanium gamma spectrometer was used to measure the spectrum of activated nuclides in the bodies of patients who had underwent the treatment, and the types of radionuclides generated by neutron activation during each BNCT treatment were analyzed.Results:The radionuclides 24Na, 38Cl, and 49Ca were mainly produced in the bodies of patients treated with BNCT. 20 minutes after BNCT treatment, the ambient dose equivalent rate at a distance of 1.0 m from the irradiation position was lower than 2.5 μSv/h. Conclusions:The dose delivered to the staff and family members by the patients undergoing BNCT is relatively low, and the resulting radiation risk is low. According to the ALARA principle, it is recommended that certain control actions be taken for patients having received BNCT treatment to minimize the exposure doses of both patients and staff as much as possible.