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Abstract: To introduce our experience of treating locally and regionally recurrent head and neck cancer patients with BNCT at Tsing Hua Open-Pool Reactor in Taiwan, 12 patients (M/F=10/2, median age 55.5 Y/O) were enrolled and 11 received two fractions of treatment. Fractionated BNCT at 30-day interval with adaptive planning according to changed T/N ratios was feasible, effective and safe for selected recurrent head and neck cancer in this trial. [Copyright &y& Elsevier]

Abstract: Various quality control (QC) and quality assurance (QA) procedures of the boron neutron capture therapy (BNCT) beam at the Tsing Hua Open-pool Reactor (THOR) are established to ensure beam availability and quality. The QC/QA methods mainly employ foil activation and paired ionization chambers, respectively, for beam intensity check and dose assessment. Beam intensity is monitored on-line by using three dead-time corrected fission chambers. In addition to the periodic QC/QA activities regarding beam quality and the monitoring system, the quick QC/QA performed in an all-in-one phantom will be executed less than 70min before the clinical treatment to guarantee beam quality. The QC/QA procedures have been gradually established and the actual performance satisfied the preset criteria defined for the BNCT facility at THOR. [Copyright &y& Elsevier]

Abstract: This paper aims to evaluate the performance of the source description of the THOR BNCT beam via different measurement techniques in different phantoms. The measurement included (1) the absolute reaction rate measurement of a set of triple activation foils, (2) the neutron and gamma-ray dose rates measured using the paired ionization chamber method, and (3) the relative reaction rate distributions obtained using the indirect neutron radiography. Three source descriptions, THOR-Y09, surface source file RSSA, and THOR-50C, were tested. The comparison results concluded that THOR-Y09 is a well-tested source description not only for neutron components, but also for gamma-ray component. [Copyright &y& Elsevier]

Abstract: A refined dose assessment method has been used now in the THOR BNCT facility, which takes into account more delicate corrections, carefully handled calibration factors, and the spectrum- and kerma-weighted kt value. The refined method solved the previous problem of negative derived neutron dose in phantom at deeper positions. With the improved dose assessment, the calculated and measured gamma-ray dose rates match perfectly in a 15×15×15cm3 PMMA phantom. [Copyright &y& Elsevier]

Hepatoma is the second leading cause of cancer death worldwide. Due to the poor outcomes of patients with late diagnosis, newer treatments for hepatoma are still needed. As an emerging therapy, boron neutron capture therapy (BNCT) may be an effective solution in hepatoma management. In this study, boric acid (BA) was used as the boron drug for in vivo analysis of action mechanism. The N1S1 single liver tumor-bearing rat and the VX2 multifocal liver tumor-bearing rabbit models were used to investigate the retention status of BA in the tumor regions during BNCT. The autoradiographic examination showed BA can localize specifically not only in the hepatoma cells but also in tumor blood vessels. Our findings indicate that superior hepatoma targeting could be achieved in BA-mediated BNCT, which supports BA to be a suitable boron drug for BNCT for hepatoma. • Boric acid (BA) was used as the boron drug for BNCT for hepatoma. • BA can be specifically retained in the tumor cells and tumor vasculature in the liver tumor-bearing animal models. • A high boron dose could be selectively achieved in the hepatoma regions during BA-mediated BNCT. [ABSTRACT FROM AUTHOR]

Abstract: The GAFCHROMIC® EBT2 dosimetry film has been studied as a rapid QC/QA tool for 2D dose profile mapping in the BNCT beam at THOR. The pixel values of the EBT2 film image were converted to the 2D dose profile using a dose calibration curve obtained by 6-MV X-ray. The reproducibility of the 2D dose profile measured using the EBT2 film in the PMMA phantom was preliminarily found to be acceptable with uncertainties within about ±2 to ±3.5%. It is found that the EBT2 measured dose profile consisted of both gamma-ray components and neutron contributions. Therefore, the dose profile measured using the EBT2 film is significantly different from the neutron flux profile measured using the indirect neutron radiography method. Further study of the influence of neutrons to the response of the EBT2 film is indispensible for the absolute dose profile determination in a BNCT beam. [Copyright &y& Elsevier]

The whole picture of the BNCT facility at Tsing Hua Open-pool Reactor will be presented which consists of the following aspects: the construction project, the beam quality, routine operations including the QA program for the beam delivery, determination of boron-10 concentration in blood, T/N ratio, and the clinical affairs including the patient recruit procedure and the patient irradiation procedure. The facility is positioned to serve for conducting clinical trials, emergent (compassionate) treatments, and R&D works. • THOR has gone into critical since 1961. • THOR facility is the only reactor-based facility still clinically active. • We have accomplished two clinical trials for recurrent head and neck cancer. • 26 patients have been treated with 9 CRs and 4 survivals. • THOR BNCT facility is open to the BNCT community all around the world. [ABSTRACT FROM AUTHOR]

Abstract: This study aims to measure the two-dimensional (2D) neutron spatial distribution inside a cubic and a head PMMA phantom for the purpose of further comparison with the treatment planning. The measurements were made by using the indirect neutron radiography (INR), which utilized a thin copper foil and the imaging plate. The developed image provides satisfactory spatial resolution and very low statistical error (< 1%). As to the time cost, the whole procedure normally takes less than 3h. The result shows that the indirect neutron radiography can be a quick and reliable method to provide a 2D neutron spatial distribution inside a phantom. [Copyright &y& Elsevier]

Abstract: This paper aims to measure the spectra of HB11 (high flux reactor, HFR) and the Tsing Hua open-pool reactor (THOR) boron neutron capture therapy (BNCT) beams by multiple activation foils. The self-shielding corrections were made with the aid of MCNP calculations. The initial spectra were adjusted by a sophisticated process named coarse-scaling adjustment using SAND-EX, which can adjust a given coarse-group spectrum into a fine-group structure, i.e. 640 groups, with excellent continuity. The epithermal neutron flux of the THOR beam is about three times of HB11. The thermal neutron flux, boron and gold reaction rates along the central axis of a PMMA phantom are calculated for both adjusted spectra for comparison. [Copyright &y& Elsevier]