6 research outputs found
Re-localisation of microscopic lesions in their macroscopic context for surgical instrument guidance
Optical biopsies interrogate microscopic structure in vivo with a 2mm diameter miniprobe
placed in contact with the tissue for detection of lesions and assessment of disease
progression. After detection, instruments are guided to the lesion location for a new optical
interrogation, or for treatment, or for tissue excision during the same or a future examination.
As the optical measurement can be considered as a point source of information at the surface
of the tissue of interest, accurate guidance can be difficult. A method for re-localisation of the
sampling point is, therefore, needed.
The method presented in this thesis has been developed for biopsy site re-localisation
during a surveillance examination of Barrett’s Oesophagus. The biopsy site, invisible
macroscopically during conventional endoscopy, is re-localised in the target endoscopic
image using epipolar lines derived from its locations given by the tip of the miniprobe visible
in a series of reference endoscopic images. A confidence region can be drawn around the relocalised
biopsy site from its uncertainty that is derived analytically. This thesis also presents
a method to improve the accuracy of the epipolar lines derived for the biopsy site relocalisation
using an electromagnetic tracking system.
Simulations and tests on patient data identified the cases when the analytical
uncertainty is a good approximation of the confidence region and showed that biopsy sites
can be re-localised with accuracies better than 1mm. Studies on phantom and on porcine
excised tissue demonstrated that an electromagnetic tracking system contributes to more
accurate epipolar lines and re-localised biopsy sites for an endoscope displacement greater
than 5mm. The re-localisation method can be applied to images acquired during different
endoscopic examinations. It may also be useful for pulmonary applications. Finally, it can be
combined with a Magnetic Resonance scanner which can steer cells to the biopsy site for
tissue treatment
Diffuse Reflectance Spectroscopy to Quantify In Vivo Tissue Optical Properties: Applications in Human Epithelium and Subcutaneous Murine Colon Cancer
Colorectal cancer is the 4th most common and 2nd deadliest cancer. Problems exist with predicting which patients will respond best to certain therapy regimens. Diffuse reflectance spectroscopy has been suggested as a candidate to optically monitor a patient’s early response to therapy and has been received favorably in experimentally managing other cancers such as breast and skin. In this dissertation, two diffuse reflectance spectroscopy probes were designed: one with a combined high-resolution microendoscopy modality, and one that was optimized for acquiring data from subcutaneous murine tumors. For both probes, percent errors for estimating tissue optical properties (reduced scattering coefficient and absorption coefficient) were less than 5% and 10%, respectively. Then, studies on tissue-simulating phantoms were performed to test probe sensitivity and to serve as testing platforms for investigators in biomedical optics. Next, the diffuse reflectance spectroscopy probe was applied to subcutaneous murine colon tumors (n=61) undergoing either antibody immunotherapy or standard 5-fluorouracil chemotherapy. Mice treated with a combination of these therapies showed reduced tumor growth compared to saline control, isotype control, immunotherapy, and chemotherapy groups (p\u3c0.001, \u3c0.001, \u3c0.001, and 0.046, respectively) 7 days post-treatment. Additionally, at 7 days post-treatment, oxyhemoglobin, a marker currently being explored as a functional prognostic cancer marker, trended to increase in immunotherapy, chemotherapy, and combination therapy groups compared to controls (p=0.315, 0.149, and 0.190). Also of interest, an oxyhemoglobin flare (averageincrease of 1.44x from baseline, p=0.03 compared to controls) was shown in tumors treated with chemotherapy, indicating that diffuse reflectance spectroscopy may be useful as a complimentary tool to monitor early tumor therapeutic response in colon cancer. However, subject-to-subject variability was high and studies correlating survival to early oxyhemoglobin flares are suggested
XXIV congreso anual de la sociedad española de ingenierÃa biomédica (CASEIB2016)
En la presente edición, más de 150 trabajos de alto nivel cientÃfico van a ser presentados en 18 sesiones paralelas y 3 sesiones de póster, que se centrarán en áreas relevantes de la IngenierÃa Biomédica. Entre las sesiones paralelas se pueden destacar la sesión plenaria Premio José MarÃa Ferrero Corral y la sesión de Competición de alumnos de Grado en IngenierÃa Biomédica, con la participación de 16 alumnos de los Grados en IngenierÃa Biomédica a nivel nacional.
El programa cientÃfico se complementa con dos ponencias invitadas de cientÃficos reconocidos internacionalmente, dos mesas redondas con una importante participación de sociedades cientÃficas médicas y de profesionales de la industria de tecnologÃa médica, y dos actos sociales que permitirán a los participantes acercarse a la historia y cultura valenciana. Por primera vez, en colaboración con FENIN, seJane Campos, R. (2017). XXIV congreso anual de la sociedad española de ingenierÃa biomédica (CASEIB2016). Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/79277EDITORIA