Abstract
AB008. Optical density analysis in autoradiographic images for the study of preferential boron uptake in broncho-vascular tree and its effects on lung dosimetry
María Sol Espain1,2, Agustina Mariana Portu1,2, Marcela Alejandra Garabalino2, María Silvina Olivera2, Gustavo Alberto Santa Cruz2, Verónica Andrea Trivillin1,2, Paula Ramos2, Ana Mailén Dattoli Viegas1,2, Andrea Monti Hughes1,2, Sergio Ferraris3, Guillermo Belerenian3, Fernando Lange3, Gisela Saint Martin2, Emiliano César Cayetano Pozzi2, Paula Curotto2, Silvia Inés Thorp2, Amanda Elena Schwint1,2, Sara Josefina González1,2
1National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina;
2Department of Radiobiology, National Atomic Energy Commission (CNEA), Buenos Aires, Argentina;
3Center of Research and Development of Integral Models (CIDME), Maimonides University, Buenos Aires, Argentina
Correspondence to: María Sol Espain, B.Sc. in Physics. National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina; Department of Radiobiology, National Atomic Energy Commission (CNEA), Av. Gral. Paz 1499, B1650 Villa Maipú, Buenos Aires, Argentina. Email: msolespain@gmail.com; solespain@cnea.gob.ar.
Background: The lung is the most frequent site of metastasis for many types of tumors, and for some types of cancer, it is the only site of metastatic lesions. In Argentina, a multi-institutional project has been established to assess the feasibility of applying boron neutron capture therapy (BNCT) ex-situ to the treatment of patients with multiple lung metastases, seeking to deliver a therapeutic dose to tumor tissue without exceeding the radiotolerance of the normal lung. The procedure consists of boron infusion and irradiation of the explanted organ followed by surgical reimplant, which requires the perfusion of the organ with a preservation solution. Within this context, the validity of the ovine model as an adequate human surrogate has been established. The objective of this work was to characterize the microdistribution of boron between broncho-vascular and alveolar regions in an ovine lung model and to determine how this heterogeneity affects photon-equivalent dose estimates for an ex-situ BNCT protocol.
Methods: During a new boron biodistribution study of a normal sheep where boronophenylalanine (BPA)-fructose complex (350 mg/kg) was infused, lung samples were extracted for boron determination. Inductively coupled plasma optical emission spectroscopy (ICP-OES) measurements were carried out, and sections of normal lung were processed to obtain autoradiographic images using polycarbonate as nuclear track detector (NTD). The sample-detector assemblies were irradiated with a high fluence (1013 n/cm2) and etched for 4 min. This allowed for the analysis of the collective optical effect of nuclear tracks using optical density (OD) as the end point.
Results: The analysis revealed a preferential uptake of BPA in the broncho-vascular tree at the microscopic level. OD measurements were performed in order to quantify this trend, as it could explain potential vascular damage in normal lung after BNCT. Regions of interest were delimited in the histological images, and the OD in each of them was calculated in the corresponding autoradiographies. These results showed that the broncho-vascular tree captures almost twice as much boron as the alveolar region. The same relation was observed in both pre- and post-perfusion lung samples, indicating that the uptake differences are not a consequence of the conservation process. The impact of these findings on the dosimetry of a potential BNCT ex-situ clinical setting was assessed.
Conclusions: Photon equivalent dose in each tissue structure was determined by initially considering the boron concentration of the alveolar region and then using the boron concentration relative to the broncho-vascular tree. This analysis revealed that the percentage variances in the estimated dose in the organ voxels could reach up to 60%, with an average of 30%.
Keywords: Neutron autoradiography; lung; boron microdistribution
Acknowledgments
None.
Funding: The manuscript was funded by Investigación y Desarrollo en BNCT Para el Tratamiento de Nuevas Patologías [PIP 2014–2016 GI (2014–2016)].
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tro.amegroups.com/article/view/10.21037/tro-25-ab008/coif). M.S.E. and A.M.D.V. are employees of the National Scientific and Technical Research Council (CONICET). M.A.G., M.S.O., G.A.S.C., P.R., G.S.M., E.C.C.P., P.C., and S.I.T. are employees of the National Atomic Energy Commission of Argentina (CNEA). A.M.P., V.A.T., A.M.H., A.E.S., and S.J.G. are employees of both CONICET and CNEA. The other authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The animal study protocol was approved by the Maimonides University Institutional Committee for the Use and Care of Experimental Animals (CICUAE, Resolution No. 39/11 - REPORT N 4/12).
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the noncommercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
doi: 10.21037/tro-25-ab008
Cite this abstract as: Espain MS, Portu AM, Garabalino MA, Olivera MS, Santa Cruz GA, Trivillin VA, Ramos P, Dattoli Viegas AM, Monti Hughes A, Ferraris S, Belerenian G, Lange F, Martin GS, Pozzi ECC, Curotto P, Thorp SI, Schwint AE, González SJ. AB008. Optical density analysis in autoradiographic images for the study of preferential boron uptake in broncho-vascular tree and its effects on lung dosimetry. Ther Radiol Oncol 2025;9:AB008.
