skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Numerical characterization of a tomographic system for online dose measurements in Boron Neutron Capture Therapy

Abstract

A tomographic system for online dose measurements in Boron Neutron Capture Therapy (BNCT) based on the measurement of a specific 478 keV {gamma}-ray emitted after the neutron capture in boron is being developed. In the present work we study by means of Monte Carlo numerical simulations the effects of the finite spatial resolution and the limited number of counts, i. e. the statistical noise, on the reconstructed image contrast of numerical phantoms. These phantoms, of simple geometry, mimic the tumor (specific) and the normal tissue (non specific) boron concentrations. The simulated projection data were reconstructed using the expectation-maximization maximum-likelihood algorithm. These studies will help in the improvement of BNCT dosimetry.

Authors:
; ;  [1];  [2];  [1];  [2];  [2];  [1];  [2];  [2]
  1. Escuela de Ciencia y Tecnologia (UNSAM), San Martin, Buenos Aires (Argentina)
  2. (Argentina)
Publication Date:
OSTI Identifier:
21054821
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 884; Journal Issue: 1; Conference: 6. Latin American symposium on nuclear physics and applications, Iguazu (Argentina), 3-7 Oct 2005; Other Information: DOI: 10.1063/1.2710586; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALGORITHMS; BORON 11 TARGET; CAPTURE; COMPUTERIZED SIMULATION; COMPUTERIZED TOMOGRAPHY; DOSES; DOSIMETRY; GAMMA RADIATION; KEV RANGE; MAXIMUM-LIKELIHOOD FIT; MONTE CARLO METHOD; NEOPLASMS; NEUTRON CAPTURE THERAPY; NEUTRON REACTIONS; NEUTRON SOURCES; PHANTOMS; PHOTON EMISSION; SPATIAL RESOLUTION

Citation Formats

Minsky, D. M., Valda, A. A., Somacal, H., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, Burlon, A. A., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, Fundacion J.B. Sauberan, Kreiner, A. J., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, and CONICET. Numerical characterization of a tomographic system for online dose measurements in Boron Neutron Capture Therapy. United States: N. p., 2007. Web. doi:10.1063/1.2710586.
Minsky, D. M., Valda, A. A., Somacal, H., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, Burlon, A. A., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, Fundacion J.B. Sauberan, Kreiner, A. J., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, & CONICET. Numerical characterization of a tomographic system for online dose measurements in Boron Neutron Capture Therapy. United States. doi:10.1063/1.2710586.
Minsky, D. M., Valda, A. A., Somacal, H., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, Burlon, A. A., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, Fundacion J.B. Sauberan, Kreiner, A. J., Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires, and CONICET. Mon . "Numerical characterization of a tomographic system for online dose measurements in Boron Neutron Capture Therapy". United States. doi:10.1063/1.2710586.
@article{osti_21054821,
title = {Numerical characterization of a tomographic system for online dose measurements in Boron Neutron Capture Therapy},
author = {Minsky, D. M. and Valda, A. A. and Somacal, H. and Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires and Burlon, A. A. and Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires and Fundacion J.B. Sauberan and Kreiner, A. J. and Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires and CONICET},
abstractNote = {A tomographic system for online dose measurements in Boron Neutron Capture Therapy (BNCT) based on the measurement of a specific 478 keV {gamma}-ray emitted after the neutron capture in boron is being developed. In the present work we study by means of Monte Carlo numerical simulations the effects of the finite spatial resolution and the limited number of counts, i. e. the statistical noise, on the reconstructed image contrast of numerical phantoms. These phantoms, of simple geometry, mimic the tumor (specific) and the normal tissue (non specific) boron concentrations. The simulated projection data were reconstructed using the expectation-maximization maximum-likelihood algorithm. These studies will help in the improvement of BNCT dosimetry.},
doi = {10.1063/1.2710586},
journal = {AIP Conference Proceedings},
number = 1,
volume = 884,
place = {United States},
year = {Mon Feb 12 00:00:00 EST 2007},
month = {Mon Feb 12 00:00:00 EST 2007}
}
  • 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 I) the dosimetry group from the Americas, represented by MIT, visited the clinical centers at Studsvik (Sweden), VTT Espoo (Finland), and the Nuclear Research Institute (NRI) at Rez (Czech Republic). 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 inmore » 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 {mu}g g{sup -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.« less
  • Purpose of paper is to confirm the feasibility of acquisition of three dimensional single photon emission computed tomography image from boron neutron capture therapy using Monte Carlo simulation. Prompt gamma ray (478 keV) was used to reconstruct image with ordered subsets expectation maximization method. From analysis of receiver operating characteristic curve, area under curve values of three boron regions were 0.738, 0.623, and 0.817. The differences between length of centers of two boron regions and distance of maximum count points were 0.3 cm, 1.6 cm, and 1.4 cm.
  • Purpose: To analyze the dose-volume histogram (DVH) of head-and-neck tumors treated with boron neutron capture therapy (BNCT) and to determine the advantage of the intra-arterial (IA) route over the intravenous (IV) route as a drug delivery system for BNCT. Methods and Materials: Fifteen BNCTs for 12 patients with recurrent head-and-neck tumors were included in the present study. Eight irradiations were done after IV administration of boronophenylalanine and seven after IA administration. The maximal, mean, and minimal doses given to the gross tumor volume were assessed using a BNCT planning system. Results: The results are reported as median values with themore » interquartile range. In the IA group, the maximal, mean, and minimal dose given to the gross tumor volume was 68.7 Gy-Eq (range, 38.8-79.9), 45.0 Gy-Eq (range, 25.1-51.0), and 13.8 Gy-Eq (range, 4.8-25.3), respectively. In the IV group, the maximal, mean, and minimal dose given to the gross tumor volume was 24.2 Gy-Eq (range, 21.5-29.9), 16.4 Gy-Eq (range, 14.5-20.2), and 7.8 Gy-Eq (range, 6.8-9.5), respectively. Within 1-3 months after BNCT, the responses were assessed. Of the 6 patients in the IV group, 2 had a partial response, 3 no change, and 1 had progressive disease. Of 4 patients in the IA group, 1 achieved a complete response and 3 a partial response. Conclusion: Intra-arterial administration of boronophenylalanine is a promising drug delivery system for head-and-neck BNCT.« less
  • The study of the radiobiology of boron neutron capture therapy is based on the cellular level dosimetry of boron-10's thermal neutron capture reaction {sup 10}B(n,{alpha}){sup 7}Li, in which one 1.47 MeV helium-4 ion and one 0.84 MeV lithium-7 ion are spawned. Because of the chemical preference of boron-10 carrier molecules, the dose is heterogeneously distributed in cells. In the present work, the (scaled) dose point kernel of boron-11 decay, called {sup 11}B-DPK, was calculated by GEANT4 Monte Carlo simulation code. The DPK curve drops suddenly at the radius of 4.26 {mu}m, the continuous slowing down approximation (CSDA) range of amore » lithium-7 ion. Then, after a slight ascending, the curve decreases to near zero when the radius goes beyond 8.20 {mu}m, which is the CSDA range of a 1.47 MeV helium-4 ion. With the DPK data, S values for nuclei and cells with the boron-10 on the cell surface are calculated for different combinations of cell and nucleus sizes. The S value for a cell radius of 10 {mu}m and a nucleus radius of 5 {mu}m is slightly larger than the value published by Tung et al. [Appl. Radiat. Isot. 61, 739-743 (2004)]. This result is potentially more accurate than the published value since it includes the contribution of a lithium-7 ion as well as the alpha particle.« less
  • Boron neutron capture therapy (BNCT) was proposed for untreatable colorectal liver metastases. Employing an experimental model of liver metastases in rats, we recently demonstrated that BNCT mediated by boronophenylalanine (BPA-BNCT) at 13 Gy prescribed to tumor is therapeutically useful at 3-week follow-up. The aim of the present study was to evaluate dose–response at 5-week follow-up, based on retrospective dose assessment in individual rats. BDIX rats were inoculated with syngeneic colon cancer cells DHD/K12/TRb. Tumor-bearing animals were divided into three groups: BPA-BNCT (n = 19), Beam only (n = 8) and Sham (n = 7) (matched manipulation, no treatment). For eachmore » rat, neutron flux was measured in situ and boron content was measured in a pre-irradiation blood sample for retrospective individual dose assessment. For statistical analysis (ANOVA), individual data for the BPA-BNCT group were pooled according to absorbed tumor dose, BPA-BNCT I: 4.5–8.9 Gy and BPA-BNCT II: 9.2–16 Gy. At 5 weeks post-irradiation, the tumor surface area post-treatment/pre-treatment ratio was 12.2 +/- 6.6 for Sham, 7.8 +/- 4.1 for Beam only, 4.4 +/- 5.6 for BPA-BNCT I and 0.45 +/- 0.20 for BPA-BNCT II; tumor nodule weight was 750 +/- 480 mg for Sham, 960 +/- 620 mg for Beam only, 380 +/- 720 mg for BPA-BNCT I and 7.3 +/- 5.9 mg for BPA-BNCT II. The BPA-BNCT II group exhibited statistically significant tumor control with no contributory liver toxicity. Potential threshold doses for tumor response and significant tumor control were established at 6.1 and 9.2 Gy, respectively.« less