Optical tecnology developments in biomedicine: history, current and future

Biomedical optics is a rapidly emerging field for medical imaging and diagnostics. This paper reviews several biomedical optical technologies that have been developed and translated for either clinical or pre-clinical applications. Specifically, we focus on the following technologies: 1) near-infrared spectroscopy and tomography, 2) optical coherence tomography, 3) fluorescence spectroscopy and imaging, and 4) optical molecular imaging. There representative biomedical applications are also discussed here

Handheld tumor scanner for breast cancer detection

Poster presented at Biomedical Technology Showcase 2006, Philadelphia, PA. Retrieved 18 Aug 2006 from http://www.biomed.drexel.edu/new04/Content/Biomed_Tech_Showcase/Poster_Presentations/Chance.pdf.The amplitude cancellation of in-phase and out of phase of dual source single detector showed remarkable sensitivity to localize small object such as breast tumor with positional accuracy of millimeters. The system design of low frequency, battery operated, mini handheld scanner based the principle of amplitude cancellation is introduced, and performance is evaluated on the phantom simulated the optical properties of tissue and tumor. Some clinical test results are shown

Discrepancy between cardiorespiratory system and skeletal muscle in elite cyclists after hypoxic training

BACKGROUND: The purpose of this study was to determine the effects of hypoxic training on the cardiorespiratory system and skeletal muscle among well-trained endurance athletes in a randomized cross-over design. METHODS: Eight junior national level competitive cyclists were separated into two groups; Group A trained under normoxic condition (21% O(2)) for 2 hours/day, 3 days/week for 3 weeks while Group B used the same training protocol under hypoxic condition (15% O(2)). After 3 weeks of each initial training condition, five weeks of self-training under usual field conditions intervened before the training condition was switched from NT to HT in Group A, from HT to NT in Group B. The subjects were tested at sea level before and after each training period. O(2 )uptake ([Image: see text] O(2)), blood samples, and muscle deoxygenation were measured during bicycle exercise test. RESULTS AND DISCUSSION: No changes in maximal workload, arterial O(2 )content, [Image: see text] O(2 )at lactate threshold and [Image: see text] O(2max )were observed before or after each training period. In contrast, deoxygenation change during submaximal exercise in the vastus lateralis was significantly higher at HT than NT (p < 0.01). In addition, half time of oxygenation recovery was significantly faster after HT (13.2 ± 2.6 sec) than NT (18.8 ± 2.7 sec) (p < 0.001). CONCLUSIONS: Three weeks of HT may not give an additional performance benefit at sea level for elite competitive cyclists, even though HT may induce some physiological adaptations on muscle tissue level

Characterizing the metabolic heterogeneity in human breast cancer xenografts by 3D high resolution fluorescence imaging

Abstract We previously reported that tumor mitochondrial redox state and its heterogeneity distinguished between the aggressive and the indolent breast cancer xenografts, suggesting novel metabolic indices as biomarkers for predicting tumor metastatic potential. Additionally, we reported that the identified redox biomarkers successfully differentiated between the normal breast tissue and the cancerous breast tissue from breast cancer patients. The aim of the present study was to further characterize intratumor heterogeneity by its distribution of mitochondrial redox state and glucose uptake pattern in tumor xenografts and to further investigate the metabolic heterogeneity of the clinical biopsy samples. We employed the Chance redox scanner, a multi-section cryogenic fluorescence imager to simultaneously image the intratumor heterogeneity in the mitochondrial redox state and glucose uptake at a high spatial resolution (down to 50 × 50 × 20 μm3). The mitochondrial redox state was determined by the ratio of the intrinsic fluorescence signals from reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavoproteins (Fp including FAD, i.e., flavin adenine dinucleotide), and the glucose uptake was measured using a near-infrared fluorescent glucose-analogue, pyropheophorbide 2-deoxyglucosamide (Pyro-2DG). Significant inter- and intratumor metabolic heterogeneity were observed from our imaging data on various types of breast cancer xenografts. The patterns and degrees of heterogeneity of mitochondrial redox state appeared to relate to tumor size and metastatic potential. The glucose uptake was also heterogeneous and generally higher in tumor peripheries. The oxidized and reduced regions mostly corresponded with the lower and the higher pyro-2DG uptake, respectively. However, there were some regions where the glucose uptake did not correlate with the redox indices. Pronounced glucose uptake and high NADH were observed in certain localized areas within the tumor necrotic regions, indicative of the existence of viable cells which was also supported by the H&E staining. Significant heterogeneity of the redox state indices was also observed in clinical specimens of breast cancer patients. As abnormal metabolism including the Warburg effect (high glycolysis) plays important roles in cancer transformation and progression, our observations that reveal the 3D intratumor metabolic heterogeneity as a characteristic feature of breast tumors are of great importance for understanding cancer biology and developing diagnostic and therapeutic methods