A miniature confocal Raman probe for endoscopic use

Raman spectroscopy is a powerful tool for studying biochemical changes in the human body. We describe a miniature, confocal fibre optic probe intended to fit within the instrument channel of a standard medical endoscope. This probe has been optimized for the study of the carcinogenesis process of oesophageal malignancy. The optical design and fabrication of this probe is described including the anisotropic wet etching technique used to make silicon motherboards and jigs. Example spectra of PTFE reference samples are shown. Spectra with acquisition times as low as 2 s from resected oesophageal tissue are presented showing identifiable biochemical changes from various pathologies.

Analysis of boron-10 in soft tissue by dynamic secondary ion mass spectrometry

We report here a preliminary study in which dynamic secondary ion mass spectrometry (SIMS) has provided images of boron-10 (10B) in biological tissue as used in research into boron neutron capture therapy. Cultured tumour cells incubated in media containing known concentrations of a 10B-containing compound, p-boronophenylalanine (BPA), and intracranial tumour tissue from animals previously injected with BPA were analysed by an in-house constructed SIMS. Investigations were conducted in positive secondary ion detection mode using a 25-keV, 5-nA gallium primary ion source. For calibration purposes, tissue standards were also analysed and their boron-to-carbon signal ratios correlated to bulk boron concentrations measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Ion maps of 10B, 12C, 23Na and 39K showing gross tissue and cell features were acquired. SIMS and ICP-AES standard measurements were in good agreement. Tissue regions with high or low 10B concentrations were identified along with 10B hotspots in normal brain areas. Cultured cells revealed the intracellular localization of 10B. SIMS is capable of producing images showing the distribution of 10B at p.p.m. levels in cells and in normal and tumour-bearing brain tissue.