Reference systems for the determination of 10B through autoradiography images: Application to a melanoma experimental model

The amount of 10B in tissue samples may be determined by measuring the track density in the autoradiography image produced on a nuclear track detector. Different systems were evaluated as reference standards to be used for a quantitative evaluation of boron concentration. The obtained calibration curves were applied to evaluate the concentration of 10B in melanoma tumour of NIH nude mice after a biodistribution study. The histological features observed in the tissue sections were accurately reproduced by the autoradiography images.Fil: Portu, Agustina Mariana. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carpano, M.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Dagrosa, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Nievas, S.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Pozzi, E.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Thorp, S.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Cabrini, R.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Liberman, S.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Saint Martin, María Laura Gisela. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

From nuclear track characterization to machine learning based image classification in neutron autoradiography for boron neutron capture therapy

Knowledge of the 10B microdistribution is of great relevance in BNCT studies. Since 10B concentration assesment through neutron autoradiography depends on the correct quantification of tracks in a nuclear track detector, image acquisition and processing conditions should be controlled and verified, in order to obtain accurate results to be applied in the frame of BNCT. With this aim, an image verification process was proposed, based on parameters extracted from the quantified nuclear tracks. Track characterization was performed by selecting a set of morphological and pixel-intensity uniformity parameters from the quantified objects (area, diameter, roundness, aspect ratio, heterogeneity and clumpiness). Their distributions were studied, leading to the observation of varying behaviours in images generated by different samples and acquisition conditions. The distributions corresponding to samples coming from the BNC reaction showed similar attributes in each analyzed parameter, proving to be robust to the experimental process, but sensitive to light and focus conditions. Considering those observations, a manual feature extraction was performed as a pre-processing step. A Support Vector Machine (SVM) and a fully dense Neural Network (NN) were optimized, trained, and tested. The final performance metrics were similar for both models: 93%-93% for the SVM, vs 94%-95% for the NN in accuracy and precision respectively. Based on the distribution of the predicted class probabilities, the latter had a better capacity to reject inadequate images, so the NN was selected to perform the image verification step prior to quantification. The trained NN was able to correctly classify the images regardless of their track density. The exhaustive characterization of the nuclear tracks provided new knowledge related to the autoradiographic images generation. The inclusion of machine learning in the analysis workflow proves to optimize the boron determination process and paves the way for further applications in the field of boron imaging.Fil: Viglietti, Julia S.. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Departamento de Radiobiología; ArgentinaFil: Espain, Maria Sol. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Departamento de Radiobiología; ArgentinaFil: Díaz, Rodrigo Fernando. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología. Centro Internacional de Estudios Avanzados; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Ciencias Fisicas. - Universidad Nacional de San Martin. Instituto de Ciencias Fisicas.; ArgentinaFil: Nieto, Luis Agustin. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología. Centro Internacional de Estudios Avanzados; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Ciencias Fisicas. - Universidad Nacional de San Martin. Instituto de Ciencias Fisicas.; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Szewc, Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Cincinnati; Estados UnidosFil: Bernardi, Guillermo Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Rodríguez, Luis M.. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fregenal, Daniel Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Saint Martin, María Laura Gisela. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Departamento de Radiobiología; ArgentinaFil: Portu, Agustina Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Departamento de Radiobiología; Argentin

UV-C radiation effect on nuclear tracks of different ions in polycarbonate

The neutron autoradiography technique was developed in our laboratory using polycarbonate nuclear track detectors, to qualitatively and quantitatively analyze boron distribution and concentration in biological samples from experimental models coming from Boron Neutron Capture Therapy research. Spatial resolution was later improved by generating an imprint of the biological sample (e.g. cellular culture, tissue sections) on the detector surface, which can be microscopically observed together with nuclear tracks originated by 10B capture products. This methodology was developed for polycarbonate detectors and involves UV-C light irradiation of the sample-detector assembly. The chemical etching process of the detector, usually performed to enlarge the nuclear tracks, also “reveals” the imprint of the sample. In this work we report a fading effect in nuclear tracks due to UV-C exposure. Significant differences in track density produced by alpha ions and Li recoils coming from the neutron capture reaction, 10B(n,α)7Li, were found between exposed and unexposed to UV-C light (254 nm wavelength) polycarbonate foils. A decreasing relation between track density and exposure time to UV-C radiation could also be observed for these ions. To analyze the effect produced by UV-C radiation on nuclear tracks of different ions, polycarbonate detectors irradiated with 7Li, 12C, 16O, 32S, 127I, 197Au beams and air degraded alpha particles from a241Am source were also studied. A wavelength dependent photodegradation mechanism affecting the polycarbonate detector would be altering the nuclear tracks development in different ways, according to ion damage characteristics.Fil: Saint Martin, María Laura Gisela. Universidad Nacional de San Martín. Instituto Sabato; ArgentinaFil: Portu, Agustina Mariana. Comisión Nacional de Energía Atómica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia de Radiobiología (Centro Atómico Constituyentes); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ibarra, M. L.. Comisión Nacional de Energía Atómica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia de Radiobiología (Centro Atómico Constituyentes); Argentina. Universidad Nacional de San Martín; ArgentinaFil: Alurralde, Martín Alejo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Instituto Sabato; Argentina. Comisión Nacional de Energía Atómica; Argentin

A facility for the study of Single Event Effects in the TANDAR accelerator

Semiconductor devices used in space applications suffer degradation due to the space radiation environment, which affects their electric parameters, eventually reducing the in-orbit lifetime. This relatively slow behavior is due to cumulative total dose effects. On the other hand, radiation can destroy information or even damage electronic parts of the device in a sudden way. These processes are known as Single Event Effects (SEE). Heavy ion beams from electrostatic tandem or other accelerators can be used to test and characterize the response of the electronics to SEE. Two conditions are necessary for this purpose: to use very low fluxes of only a few hundred to hundreds of thousand particles/(cm2·s), and to browse over a wide Linear Energy Transfer (LET) interval by changing the energy and/or the type of the impinging particles. In this work we describe the facility developed at the Argentine tandem accelerator (Tandar) to study SEE, and especially the fabrication and use of a perforated Ta foil to reduce the beam current to the required values. The determination of the resulting beam uniformity over the area of irradiation is also reported. The system has been tested by a SEE experiment on a webcam sensor.Fil: Ibarra, M. L.. Comisión Nacional de Energía Atómica; ArgentinaFil: Portu, Agustina Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Saint Martin, María Laura Gisela. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de San Martín. Instituto Sabato; ArgentinaFil: Barrera, Marcela Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Filevich, Alberto. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alurralde, M.. Universidad Nacional de San Martín. Instituto Sabato; Argentina. Comisión Nacional de Energía Atómica; Argentin

Assessing advantages of sequential boron neutron capture therapy (BNCT) in an oral cancer model with normalized blood vessels

Background. We previously demonstrated the therapeutic success of sequential boron neutron capture therapy (SeqBNCT) in the hamster cheek pouch oral cancer model. It consists of BPA-BNCT followed by GB-10-BNCT 24 or 48 hours later. Additionally, we proved that tumor blood vessel normalization with thalidomide prior to BPA-BNCT improves tumor control. The aim of the present study was to evaluate the therapeutic efficacy and explore potential boron microdistribution changes in Seq-BNCT preceded by tumor blood vessel normalization. Material and Methods. Tumor bearing animals were treated with thalidomide for tumor blood vessel normalization, followed by Seq-BNCT (ThSeq-BNCT) or Seq-Beam Only (ThSeq-BO) in the window of normalization. Boron microdistribution was assessed by neutron autoradiography. Results. ThSeq-BNCT induced overall tumor response of 100%, with 87 (4)% complete tumor response. No cases of severe mucositis in dose-limiting precancerous tissue were observed. Differences in boron homogeneity between tumors pre-treated and not pre-treated with thalidomide were observed. Conclusion. ThSeq-BNCT achieved, for the first time, response in all treated tumors. Increased homogeneity in tumor boron microdistribution is associated to an improvement in tumor control