(*) Summary: Boron neutron capture therapy (BNCT), a binary treatment modality that can potentially irradiate tumor tissue within cellular dimensions, is critically dependent on the preferential delivery of boron-10 to individual neoplastic cells. CR-39 track-etch detectors have been used for obtaining boron-10 thermal neutron capture induced images of biological, including human lung previously perfused with  boron-10 PA, samples. Thermal neutrons production by means of a photo-neutron converter installed in front of the head of clinical linear accelerators is the method recently developed in Italy within the PhoNeS (Photo Neutron Source) project and is already tested at several hospital LINACs (Trieste, Roma, Como, Torino, Rionero in Vulture, Campobasso, Salisburgo, Aviano). Such a method was applied for the present study at the Torino Molinette Elekta SLIT 25 MV e-linac with the PhoNeS converter since December 2007.  Several biological samples from a resected lung lobe in a patient with adenocarcinoma, prepared by the clinical and biological units, have been positioned between couples of CR39 layers (37 x 13 x 1 cubic mm in size) within the PhoNeS cavity and irradiated with thermal neutrons. After etching the CR39 layers, 2h in NaOH (6N) at 90 degrees Celsius, approximately 10 µm diameter holes, corresponding to α and lithium-7 products of neutron capture by boron-10, are clearly observed with the microscope. A specific sideways illumination procedure has allowed the recording of digital photographic camera high-resolution images, which are made available for comparison with histological ones and the determination of boron-10 concentrations. Since the effectiveness of BNCT depends on the selective incorporation of boron-10 in order to optimize treatment plans, two different analytical methods for monitoring concentrations and intracellular distribution of boron in healthy cells and cancerous cells have been employed.

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(**) Biodata: Dr. Rachel Ibhade Obed, PhD, is a Junior Associate of the ICTP in the Applied Physics Scientific Section, Medical Physics. She is a Lecturer in the Department of Physics, University of Ibadan, Nigeria. She is also an Adjunct Lecturer at the National Institute for Radiation Protection and Research (NIRPR) in Ibadan. She was also an associate staff of the defunct Federal Radiation Protection Service (FRPS) in Nigeria for 7 years and was involved in radiation monitoring of many medical and industrial establishments. She was the Medical Physicist in the Department of Radiotherapy, University College Hospital Ibadan from August 1996 to September 1997. She has attended many IAEA training workshops and also had a 3-month IAEA fellowship award for training in Radiation Protection in Medical Physics tenable in the United Kingdom in 2001. She is the newly elected Honourable Treasurer of the Science Association of Nigeria (SAN) and belongs to many learned societies both locally and internationally. Currently she works to ensure radiation protection of patients in diagnostic radiology and radiotherapy in Nigeria. Amongst her duties also is to ensure radiation protection of the general public through her vast research works in environmental radioactivity such as soil radioactivity concentration levels in relation to cancer incidence in Nigeria, measurements of radon in drinking water and indoor radon in dwellings and workplaces in Nigeria using CR-39 track etch detectors. She has published 10 international papers in the area of radiation protection of patients and the general public and has supervised many undergraduate and postgraduate (M.Sc., PGDRP, MRP, MPhil/PhD and PhD) students. Her main interest is in imaging techniques and patient dosimetry in diagnostic radiology and radiotherapy.