A shielding design for an accelerator-based neutron source for boron neutron capture therapy

Hawk, Andrew E.; Blue, T.E.; Woollard, J

doi:10.1016/j.apradiso.2004.05.038

Cited by 9 publications

(3 citation statements)

References 7 publications

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“…Some research regarding the installation accelerator based NCT facilities at hospitals are made. 31,32 Compared to reactors, the dose rate will be lower but the irradiation time will still be acceptable especially for the use in restenosis where the total dose is low compared to other applications.…”

Section: Discussionmentioning

confidence: 99%

Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy

et al. 2005

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Restenosis is a major problem after balloon angioplasty and stent implantation. The aim of this study is to introduce gadolinium neutron capture brachytherapy (GdNCB) as a suitable modality for treatment of stenosis. The utility of GdNCB in intravascular brachytherapy (IVBT) of stent stenosis is investigated by using the GEANT4 and MCNP4B Monte Carlo radiation transport codes. To study capture rate, Kerma, absorbed dose and absorbed dose rate around a Gd-containing stent activated with neutrons, a 30 mm long, 5 mm diameter gadolinium foil is chosen. The input data is a neutron spectrum used for clinical neutron capture therapy in Studsvik, Sweden. Thermal neutron capture in gadolinium yields a spectrum of high-energy gamma photons, which due to the build-up effect gives an almost flat dose delivery pattern to the first 4 mm around the stent. The absorbed dose rate is 1.33 Gy/min, 0.25 mm from the stent surface while the dose to normal tissue is in order of 0.22 Gy/min, i.e., a factor of 6 lower. To spare normal tissue further fractionation of the dose is also possible. The capture rate is relatively high at both ends of the foil. The dose distribution from gamma and charge particle radiation at the edges and inside the stent contributes to a nonuniform dose distribution. This will lead to higher doses to the surrounding tissue and may prevent stent edge and in-stent restenosis. The position of the stent can be verified and corrected by the treatment plan prior to activation. Activation of the stent by an external neutron field can be performed days after catherization when the target cells start to proliferate and can be expected to be more radiation sensitive. Another advantage of the nonradioactive gadolinium stent is the possibility to avoid radiation hazard to personnel.

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Section: Discussionmentioning

confidence: 99%

Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy

et al. 2005

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“…Also, there are documents dealing with the design and optimization of the BNCT treatment rooms considering appropriate radiation shielding owing to the fact that protecting the facility personnel and the general public from radiation exposure is a primary safety concern in radiation therapies. The shields may be designed for choosing appropriate materials and their dimensions and geometries, the monitoring window for the patient position, the maze, and the entrance door of the room 21 , 24 – 27 .…”

Section: Introductionmentioning

confidence: 99%

Using ANN for thermal neutron shield designing for BNCT treatment room

Rasouli,

Yahyaee,

Masoudi

2024

Sci Rep

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Occupational radiation protection should be applied to the design of treatment rooms for various radiation therapy techniques, including BNCT, where escaping particles from the beam port of the beam shaping assembly (BSA) may reach the walls or penetrate through the entrance door. The focus of the present study is to design an alternative shielding material, other than the conventional material of lead, that can be considered as the material used in the door and be able to effectively absorb the BSA neutrons which have slowed down to the thermal energy range of $$< 1$$ < 1 eV after passing through the walls and the maze of the room. To this aim, a thermal neutron shield, composed of polymer composite and polyethylene, has been simulated using the Geant4 Monte Carlo code. The neutron flux and dose values were predicted using an artificial neural network (ANN), eliminating the need for time-consuming Monte Carlo simulations in all possible suggestions. Additionally, this technique enables simultaneous optimization of the parameters involved, which is more effective than the traditional sequential and separate optimization process. The results indicated that the optimized shielding material, chosen through ANN calculations that determined the appropriate thickness and weight percent of its compositions, can decrease the dose behind the door to lower than the allowable limit for occupational exposure. The stability of ANN was tested by considering uncertainties with the Gaussian distributions of random numbers to the testing data. The results are promising as they indicate that ANNs could be used as a reliable tool for accurately predicting the dosimetric results, providing a drastically powerful alternative approach to the time-consuming Monte Carlo simulations.

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“…Compared with nuclear reactors based neutron source, accelerators based neutron source is more suitable to be used in hospitals [21][22][23][24]. For instance, accelerators based neutron source with 1.9-2.8 MeV and 10-30 mA proton beam by 7 Li(p,n) 7 Be nuclear reaction are used for Boron Neutron Capture Therapy (BNCT) [7,25,26] aiming at human cancer treatment, such as Nagoya University Accelerator-driven Neutron Source [1].…”

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confidence: 99%

Influence mechanism of lithium surface oxidation on neutron yield of lithium target for accelerator-based neutron source

Wang,

Sun,

Yang

et al. 2024

J. Inst.

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Lithium is generally adopted as the target to generate epithermal neutrons based on 7Li(p,n)7Be nuclear reaction for the application of accelerator-based boron neutron capture therapy (AB-BNCT). The stability of neutron yields and neutron energy spectrum are key factors for the therapeutic effects of the AB-BNCT. Owing to the active chemical properties of lithium, the surface oxidation formation of lithium may influence the soundness of the target system and the stability of neutron yields. Experimental and simulation methods were performed for a better understanding of the passivation layer formation after air exposure and the influence of the passivation layer on the neutron yield and energy spectrum. On one hand, X-ray photoelectron spectroscopy was adopted to study the chemical states of lithium after air exposure. On the other hand, particle and heavy ion transport code system (PHITS) was used to evaluate the effect of surface chemical states variation on neutron yield and energy spectrum. The simulation results indicate that the formation of Li2O with a thickness of 2 μm could mainly influence the neutron yields at the neutron emission angle of 20–90° with a maximum reduction of ∼ 10.4%.

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A shielding design for an accelerator-based neutron source for boron neutron capture therapy

Cited by 9 publications

References 7 publications

Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy

Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy

Using ANN for thermal neutron shield designing for BNCT treatment room

Influence mechanism of lithium surface oxidation on neutron yield of lithium target for accelerator-based neutron source

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