Monte Carlo Study Of Dose In Boron Neutron Capture Therapy For Non-Small Cell Lung Cancer

Boron neutron capture therapy(BNCT)is a radiation therapy combining characteristics of targeting and heavy ion therapy.It has a unique advantage for treating non-small cell lung cancer.However,the influence of the key parameters of BNCT on the treatment of non-small cell lung cancer requires further study,and radiation dose optimization needs to be developed to improve the feasibility of treatment and ensure the radiation safety of patients.In this study,based on the Chinese Radiation Phantom-Male and Monte Carlo software MCNP5,the impacts of neutron source and boron concentration on different types of non-small cell lung cancer(NSCLC)were studied to acquire appropriate treatment conditions.Then,neutron source multi-field irradiation and the addition of skin protection layer were proposed and studied.The main research contents and achievements are as follows:1)To study the feasibility of BNCT for diffuse non-small cell lung cancer,the effects of accelerator neutron source and reactor neutron source on the BNCT dosimetry were studied.The results showed that both neutron sources could treat this type of NSCLC,but the accelerator neutron source was more suitable.The effects of two boron concentration models on the BNCT dosimetry was studied.The results showed that dose rate of lung cancer and healthy organs increased with the increase of boron concentration.BNCT could be treated when 30 ppm of boron concentration in lung cancer and the ratio of boron concentration to healthy tissue was greater than 2.5: 1.Considering the future development and application of BNCT in China,we studied the dosimetry of Neuboron neutron source in BNCT of diffuse non-small cell lung cancer.The results show that under the suitable concentration of boron,BNCT could be performed.2)To study the feasibility of BNCT for different types of local non-small cell lung cancer,the effects of accelerator neutron source and reactor neutron source on the different locations of NSCLC were studied.The results revealed that the accelerator neutron source and reactor neutron source are suitable for shallow and deep tumor,respectively.The dosimetry of Neuboron neutron source in BNCT of different volumes of tumors in different phantoms were studied.The results show that the larger the tumor volume is,the longer the treatment time is,and the dose uniformity of the tumor decreased.Neuboron neutron source is more suitable for the treatment of adult population and small volume lung cancer;The dosimetry of Neuboron neutron source in BNCT of different locations of tumors were studied,the results show that deep tumors require longer treatment time,and the healthy organs received more dose when BNCT of deep tumor.3)To optimize the dose of local non-small cell lung cancer,a multi-field irradiation method and a skin protection layer method were proposed.The effects of the three-dimensional arrangement of neutron source and the weight of radiation time on dose optimization and treatment time were studied.The results showed that the neutron source irradiation method could effectively reduce the absorbed dose and improve the uniformity of tumor dose.The effects of different skin protection schemes on dose optimization and treatment time were studied.The results showed that 0.6 cm thick lithium carbonate material for skin protection layer reduced the 42% of skin dose,and effectively improved the feasibility of BNCTfor local NSCLC.In this paper,we found the specific neutron sources and boron concentration conditions required for the BNCT of different types of lung cancer,such as diffuse NSCLC and localized NSCLC of different sizes and locations.Innovatively proposed multi-Irradiation scheme and skin protection layer scheme to optimize the BNCT dose.Above study could provide a reference for the future judgment of feasibility of BNCT for NSCLC and the optimization of radiation dose and protection.