Determining a methodology of dosimetric quality assurance for commercially available accelerator-based boron neutron capture therapy system (original) (raw)
Related papers
Dose Analysis of In Vitro and In Vivo Test for Boron Neutron Capture Therapy (BNCT)
ASEAN Journal on Science and Technology for Development, 2018
The purpose of this study was to determine the in vitro and in vivo doses of boron neutron capture cancer therapy (BNCT) using the SHIELD-HIT12A program. To be able to determine the recoil energy, the research was conducted using the Monte Carlo method. Running data obtained the value of ionization activity and recoil lost. The results showed that in vitro and in vivo doses of BNCT for soft tissue irradiation had a value of 0.312 × 10-2 Sv, which is safe and does not harm healthy body tissue around the cancer cells because it is below the threshold of 1.5 Rem or 15 × 10-3 Sv, in accordance with the provisions of the upper value permitted by the International Commission on Radiation Protection in 1966. While the comparative targets are water, the optimal target absorption dose was obtained at concentrations of 3.232 × 10-3 Gy. The dose of carbon equivalent in water with the type of thermal neutron radiation was 16.16 × 10-3 Sv; this dose is classified as unsafe.
Iranian Journal of Radiation Research, 2014
Background: The aim of this work was to establish how well gel dosimeters performed, as subsƟ tutes for brain Ɵ ssue compared with standard phantom materials such as water, polymethyl-methacrylate (or PMMA), A150 plasƟ c and TE- liquid phantom material for dosimetry of neutron beams in boron neutron capture therapy. Materials and Methods: Thermal neutron fluence, photon dose and epithermal neutron dose distribuƟ ons were computed for the epithermal neutron beam of the opƟ mized linac based BNCT. Results: Amongst all invesƟ gated phantom materials, TE-liquid was shown to be a beƩ er subsƟ tute for brain Ɵ ssue than other phantom materials. The differences between TE- liquid and brain at the depth of 6.1 cm for thermal neutron fluence, gamma dose and epithermal neutron dose distribuƟ ons was calculated 2.80%, 2.40% and -13.87% , respecƟ vely. In comparison with the other gel dosimeters, LMD2 provided a beƩ er simulaƟ on of radiaƟ on transport in the brain. It's results differed fr...
Medical Physics, 2005
An international collaboration was organized to undertake a dosimetry exchange to enable the future combination of clinical data from different centers conducting neutron capture therapy trials. As a first step ͑Part I͒ the dosimetry group from the Americas, represented by MIT, visited the clinical centers at Studsvik ͑Sweden͒, VTT Espoo ͑Finland͒, and the Nuclear Research Institute ͑NRI͒ at Rez ͑Czech Republic͒. A combined VTT/NRI group reciprocated with a visit to MIT. Each participant performed a series of dosimetry measurements under equivalent irradiation conditions using methods appropriate to their clinical protocols. This entailed in-air measurements and dose versus depth measurements in a large water phantom. Thermal neutron flux as well as fast neutron and photon absorbed dose rates were measured. Satisfactory agreement in determining absorbed dose within the experimental uncertainties was obtained between the different groups although the measurement uncertainties are large, ranging between 3% and 30% depending upon the dose component and the depth of measurement. To improve the precision in the specification of absorbed dose amongst the participants, the individually measured dose components were normalized to the results from a single method. Assuming a boron concentration of 15 g g −1 that is typical of concentrations realized clinically with the boron delivery compound boronophenylalanine-fructose, systematic discrepancies in the specification of the total biologically weighted dose of up to 10% were apparent between the different groups. The results from these measurements will be used in future to normalize treatment plan calculations between the different clinical dosimetry protocols as Part II of this study.
Dosimetry and dose planning in boron neutron capture therapy : Monte Carlo studies
2012
Boron neutron capture therapy (BNCT) is a biologically targeted radiotherapy modality. So far, 249 cancer patients have received BNCT at the Finnish Research Reactor 1 (FiR 1) in Finland. The effectiveness and safety of radiotherapy are dependent on the radiation dose delivered to the tumor and healthy tissues, and on the accuracy of the doses. At FiR 1, patient dose calculations are performed with the Monte Carlo (MC) -based treatmentplanning system (TPS), Simulation Environment for Radiotherapy Applications (SERA). Initially, BNCT was applied to head and neck cancer, brain tumors, and malignant melanoma. To evaluate the applicability of the new target tumors for BNCT, calculation dosimetry studies are needed. So far, clinical BNCT has been performed with the neutrons from a nuclear reactor, while an accelerator based neutron sources applicable for hospital operation would be preferable. In this thesis, BNCT patient dose calculation practice in Finland was evaluated against referen...
Dose prescription in boron neutron capture therapy
International Journal of Radiation Oncology*Biology*Physics, 1994
Purpose: The purpose of this paper is to address some aspects of the many considerations that need to go into a dose prescription in boron neutron capture therapy (BNCT) for brain tumors; and to describe some methods to incorporate knowledge from animal studies and other experiments into the process of dose prescription. Materials and Methods: Previously, an algorithm to estimate the normal tissue tolerance to mixed high and low linear energy transfer (LET) radiations in BNCT was proposed. We have developed mathematical formulations and computational methods to represent this algorithm. Generalized models to fit the central axis dose rate components for an epithermal neutron field were also developed. These formulations and beam fitting models were programmed into spreadsheets to simulate two treatment techniques which are expected to be used in BNCT: a two-field bilateral scheme and a single-field treatment scheme. Parameters in these spreadsheets can be varied to represent the fractionation scheme used, the r"B microdistribution in normal tissue, and the ratio of t"B in tumor to normal tissue. Most of these factors have to be determined for a given neutron field and "B compound combination from large animal studies. The spreadsheets have been programmed to integrate all of the treatment-related information and calculate the location along the central axis where the normal tissue tolerance is exceeded first. This information is then used to compute the maximum treatment time allowable and the maximum tumor dose that may be delivered for a given BNCT treatment. Results and Conclusion: The effect of different treatment variables on the treatment time and tumor dose has been shown to be very significant. It has also been shown that the location of D,,, shifts significantly, depending on some of the treatment variables-mainly the fractionation scheme used. These results further emphasize the fact that dose prescription in BNCT is very complicated and nonintuitive. The physician prescribing the dose would need to rely on some method, like the one developed here, to come up with an appropriate dose prescription.
Indonesian Journal of Physics and Nuclear Applications, 2018
This research was aimed at discovering the optimum concentration of Boron-10 in concentrations range 20 µgram/gram until 35 µgram/gram with Boron Neutron Capture Therapy (BNCT) methods and the shortest time irradiation for cancer therapy. The research about dose analysis of Boron Neutron Capture Therapy (BNCT) to the brain cancer (Glioblastoma Multiform) using MCNPX-Code with a neutron source from Collimated Thermal Column Kartini Research Nuclear has been conducted. This research was a simulation-based experiment using MCNPX, and the data was arranged on a graph using OriginPro 8. The modelling was performed with the brain that contains cancer tissue as a target and the reactor as a radiation source. The variations of Boron concentrations in this research was on 20, 25, 30 and 35 μg/gram tumours. The outputs of MCNP were neutron scattering dose, gamma ray dose and neutron flux from the reactor. Neutron flux was used to calculate the doses of alpha, proton and gamma rays produced by...
Applied Radiation and Isotopes, 2019
The current methodology for determining the biological effect of Boron Neutron Capture Therapy (BNCT) has recently been questioned, and a more accurate framework based in the photon isoeffective dose has been proposed. In this work we derive a first order approximation to this quantity than can be easily evaluated even from limited data, as is the current situation in the radiobiology of BNCT. This procedure removes the main drawbacks of the current method and it is based on new weighting factors that, as a difference with the previously used, are true constants (dose independent). In addition to this, we apply the formalism to allow the comparison to a fractionated conventional radiotherapy treatment, for which there is a lot of knowledge from clinical practice. As an application, the photon isoeffective dose of a BNCT treatment for a brain tumor is estimated. An excel sheet used for these calculations is also provided as supplementary material and can be used also with user-provided input data for the estimation of the photon isoeffective dose for comparison with conventional radiotherapy, both to single and fractionated treatments.
Brain
Boron neutron capture therapy (BNCT) is a form of radiation therapy mediated by the short-range (less than 10 fim) energetic alpha ( 4 He) and lithium-7 ( 7 Li) ionizing particles that result from the prompt disintegration by slow neutrons of the stable-(nonradioactive) nucleus boron-10 ( 10 B). Recent advances in radiobiological and toxicological evaluation of tumour-affirutive boron-containing drugs and in optimization of the energies of neutrons in the incident beam have spurred interest in BNCT. This article presents a history of BNCT that emphasizes studies in the USA. A new dosimetric analysis of the 1959-1961 clinical trials of BNCT at Brookhaven National Laboratory is also presented. This analysis yields an acute radiation dose tolerance limit estimate of -10 Gy-Eq to the capillary endothelium of human basal ganglia from BNCT. (Gy-Eq: Gray-equivalent, or relative biological effectiveness of a radiation component multiplied by the physical dose of the component (Gy), summed over the component kinds of radiation.)
Dose Homogeneity in Boron Neutron Capture Therapy Using an Epithermal Neutron Beam
Radiation Research, 1995
Simulation models based on the neutron and photon Monte Carlo code MCNP were used to study the therapeutic possibilities of the HB11 epithermal neutron beam at the High Flux Reactor in Petten. Irradiations were simulated in two types of phantoms filled with water or tissue-equivalent material for benchmark treatment planning calculations. In a cuboid phantom the influence of different field sizes on the thermal-neutron-induced dose distribution was investigated. Various shapes of collimators were studied to test their efficacy in optimizing the thermal-neutron distribution over a planning target volume and healthy tissues. Using circular collimators of 8, 12 and 15 cm diameter it was shown that with the 15-cm field a relatively larger volume within 85% of the maximum neutron-induced dose was obtained than with the 8-or 12-cmdiameter field. However, even for this large field the maximum diameter of this volume was 7.5 cm. In an ellipsoid head phantom the neutron-induced dose was calculated assuming the skull to contain 10 ppm '0B, the brain 5 ppm 10B and the tumor 30 ppm '1B. It was found that with a single 15-cm-diameter circular beam a very inhomogeneous dose distribution in a typical target volume was obtained. Applying two equally weighted opposing 15-cmdiameter fields, however, a dose homogeneity within ?10% in this planning target volume was obtained. The dose in the surrounding healthy brain tissue is 30% at maximum of the dose in the center of the target volume. Contrary to the situation for the 8-cm field, combining four fields of 15 cm diameter gave no large improvement of the dose homogeneity over the target volume or a lower maximum dose in the healthy brain. Dose-volume histograms were evaluated for the planning target volume as well as for the healthy brain to compare different irradiation techniques, yielding a graphical confirmation of the above conclusions. Therapy with BNCT on brain tumors must be performed either with an 8-cm four-field irradiation or with two opposing 15or 12-cm fields to obtain an optimal dose distribution. @