[Elemental imaging using laser-induced breakdown spectroscopy: latest medical applications]

Fluorescent Neutron Track Detectors for Boron-10 Microdistribution Measurement in BNCT: A Feasibility Study

Boron Neutron-Capture Therapy (BNCT) is a form of radiation therapy that relies on the highly localized and enhanced biological effects of the 10B neutron capture (BNC) reaction products to selectively kill cancer cells. The efficacy of BNCT is, therefore, strongly dependent on the 10B spatial microdistribution at a subcellular level. Fluorescent Nuclear Track Detectors (FNTDs) could be a promising technology for measuring 10B microdistribution. They allow the measurement of the tracks of charged particles, and their biocompatibility allows cell samples to be deposited and grown on their surfaces. If a layer of borated cells is deposited and irradiated by a neutron field, the energy deposited by the BNC products and their trajectories can be measured by analyzing the corresponding tracks. This allows the reconstruction of the position where the measured particles were generated, hence the microdistribution of 10B. With respect to other techniques developed to measure 10B microdistribution, FNTDs would be a non-destructive, biocompatible, relatively easy-to-use, and accessible method, allowing the simultaneous measurement of the 10B microdistribution, the LET of particles, and the evolution of the related biological response on the very same cell sample. An FNTD was tested in three irradiation conditions to study the feasibility of FNTDs for BNCT applications. The FNTD allowed the successful measurement of the correct alpha particle range and mean penetration depth expected for all the radiation fields employed. This work proved the feasibility of FNTD in reconstructing the tracks of the alpha particles produced in typical BNCT conditions, thus the 10B microdistribution. Further experiments are planned at the University of Pavia's LENA (Applied Nuclear Energy Laboratory) to test the final set-up coupling the FNTD with borated cell samples.

Relationship between Occupational Exposure to Airborne Nanoparticles, Nanoparticle Lung Burden and Lung Diseases

The biomonitoring of nanoparticles in patients’ broncho-alveolar lavages (BAL) could allow getting insights into the role of inhaled biopersistent nanoparticles in the etiology/development of some respiratory diseases. Our objective was to investigate the relationship between the biomonitoring of nanoparticles in BAL, interstitial lung diseases and occupational exposure to these particles released unintentionally. We analyzed data from a cohort of 100 patients suffering from lung diseases (NanoPI clinical trial, ClinicalTrials.gov Identifier: NCT02549248) and observed that most of the patients showed a high probability of exposure to airborne unintentionally released nanoparticles (>50%), suggesting a potential role of inhaled nanoparticles in lung physiopathology. Depending on the respiratory disease, the amount of patients likely exposed to unintentionally released nanoparticles was variable (e.g., from 88% for idiopathic pulmonary fibrosis to 54% for sarcoidosis). These findings are consistent with the previously performed mineralogical analyses of BAL samples that suggested (i) a role of titanium nanoparticles in idiopathic pulmonary fibrosis and (ii) a contribution of silica submicron particles to sarcoidosis. Further investigations are necessary to draw firm conclusions but these first results strengthen the array of presumptions on the contribution of some inhaled particles (from nano to submicron size) to some idiopathic lung diseases.