During glioblastoma surgery, delineation of the brain tumour margins remains difficult especially since infiltrated and normal tissues have the same visual appearance. This problematic constitutes our research interest. We developed a fibre-optical fluorescence probe for spectroscopic and time domain measurements. First measurements of endogenous tissue fluorescence were performed on fresh and fixed rat tumour brain slices. Spectral characteristics, fluorescence redox ratios and fluorescence lifetime measurements were analysed. Fluorescence information collected from both, lifetime and spectroscopic experiments, appeared promising for tumour tissue discrimination. Two photon measurements were performed on the same fixed tissue. Different wavelengths are used to acquire two-photon excitation-fluorescence of tumorous and healthy sites.

Growing interest in optical instruments for biomedical applications has increased the use of optically calibrated phantoms. Often associated with tissue modeling, phantoms allow the characterization of optical devices for clinical purposes. Fluorescent gel phantoms have been developed, mimicking optical properties of healthy and tumorous brain tissues. Specific geometries of dedicated molds offer multiple-layer phantoms with variable thicknesses and monolayer phantoms with cylindrical inclusions at various depths and diameters. Organic chromophores are added to allow fluorescence spectroscopy. These phantoms are designed to be used with 405 nm as the excitation wavelength. This wavelength is then adapted to excite large endogenous molecules. The benefits of these phantoms in understanding fluorescence tissue analysis are then demonstrated. In particular, detectability aspects as a function of geometrical and optical parameters are presented and discussed.

Intraoperative localization of malignant tissues labeled with positron radiotracers opens up new prospects to improve the efficiency of cancer surgery. Because Silicon Photomultipliers (SiPM) introduced a breakthrough for the development of miniaturized imaging devices, we are currently designing two intraoperative beta probes based on this technology: a light imaging device with a small field of view (~5cm2) to perform tumor localization and post-operative control of the surgical cavity, and a miniaturized counting probe to guide in real time the excision of the tumor lesion. The first step of our project was focused on the characterization and optimization of SiPM devices as photodetectors for intraoperative beta detection. We studied the influence of temperature and bias voltage on the thermal and correlated noises and photon detection efficiency of different SiPM devices. The impact of these two parameters on the overall beta sensitivity was quantified as a function of the intensity of the scintillation light following a simple physical model. According to the results of this comprehensive study, the optimization of the detection head design of the two intraoperative probes was studied using Monte Carlo simulations. Detailed description of the simulation study as well as the performance characterization of the first prototypes will be presented at the conference.

Glioblastoma are brain tumors currently incurable, however, optimized treatment gives better prognosis and quality of life. In case of surgical treatment, there is still need to help surgeons to determine whether a tissue is tumorous or not. Within the framework of the design of a new autofluorescence probe for this issue, optically calibrated gel phantoms have been developed using "tumorous" inclusions in a "healthy" environment. Depending on "tumor" shape, size and localization, the sensitivity of the probe is evaluated. The probe sensitivity for fluorescence spectroscopy will be presented. The probe configuration is also taken into account and compared to simulated results.

The complete resection of the brain tumour is crucial to the patient life quality and prognosis. An autofluorescence probe aiming at helping the surgeon to improve the completeness of the removal is being developed. Autofluorescence spectroscopy is a promising approach to define whether the tissue is cancerous or not. First ex vivo measurements have been realised on an animal model. After tumorous cell injection in rat brain, autofluorescence intensity is revealed from the extracted brain. These autofluorescence data are compared to results from a histological analysis of same brains. First indicators are identified that may have the ability to differentiate tumorous and healthy tissues.

The survival outcome of patients suffering from gliomas is directly linked to the complete surgical resection of the tumour. To help the surgeons to delineate precisely the boundaries of the tumour, we developed an intraoperative positron probe with background noise rejection capability. The probe was designed to be directly coupled to the excision tool such that detection and removal of the radiolabelled tumours could be simultaneous. The device consists of two exchangeable detection heads composed of clear and plastic scintillating fibres. Each head is coupled to an optic fibre bundle that exports the scintillating light to a photodetection and processing electronic module placed outside the operative wound. The background rejection method is based on a real-time subtraction technique. The measured probe sensitivity for (18)F was 1.1 cps kBq(-1) ml(-1) for the small head and 3.4 cps kBq(-1) ml(-1) for the large head. The mean spatial resolution was 1.6 mm FWHM on the detector surface. The gamma-ray rejection efficiency measured by realistic brain phantom modelling of the surgical cavity was 99.4%. This phantom also demonstrated the ability of the probe to detect tumour discs as small as 5 mm in diameter (20 mg) for tumour-to-background ratios higher than 3:1 and with an acquisition time around 4 s at each scanning step. These results indicate that our detector could be a useful complement to existing techniques for the accurate excision of brain tumour tissue and more generally to improve the efficiency of radio-guided cancer surgery.

Autofluorescence spectroscopy from brain tissue may help to discriminate cancerous from healthy tissue. The characteristics of our probe are studied on phantoms and confronted to Monte Carlo simulations. Geometrical origins of fluorescence light are evaluated.

Designing the scintillation module of a mini gamma camera requests good understanding of how the scintillation light signal spreads within the crystal and how photons are finally collected on the PMT. For a given scintillation process, the key parameters are the geometry of the crystal, its optical coating and the interface between the crystal and the PMT. In order to optimize the design of our gamma camera TReCam, we studied the shape of the spatial distribution of the scintillation light for different values and combinations of these key parameters. Our approach was to produce computer simulations, for which the optical simulation transport software DETECT2000 was used. Three major parameters were investigated: optical coatings for the crystal (aluminum, Teflon, corner cube retro-reflectors), the thickness of the crystal (ranging from 1 mm up to 5 mm) and the interfaces (air, optical grease). In addition to the FWHM of the light spot distribution, specific figures of merit were implemented to further characterize photon spreading. In order to evaluate the influence of these parameters on the imaging performances of the TReCam, the whole scintillation module (including the PMT) was also simulated with GATE v4.0.0 based on GEANT 4.9.1.p02. It appears that the best configuration is a 5 mm thick LaBr3:Ce crystal plate covered on the top with Teflon optical coating coupled optically with a PMT.

Fluorescence spectroscopy of endogenous emission of brain tumors, in particular glioblastoma multiforme, will be used for intraoperative localization of brain tumor margins. Our future surgeon's probe aims to discriminate tumor from normal brain tissues using beta and autofluorescence detection at the same time. Within this study we have implemented C6 glioma cells into rat brains to analyze the endogenous fluorescence of tumor and normal rat brain tissue. Systematic differences have been observed when comparing the autofluorescence spectra obtained from white and grey matters: both the fluorescence intensity and the shape of the spectra differ. These results were obtained by means of a 2-fiber probe, one used to guide the laser to the tissue, the other for fluorescence light collection. Excitation light was delivered by a 405 nm picosecond laser and fluorescence detection was realized by a CCD-camera. In parallel we have developed brain phantoms allowing systematic analysis of fiber - sample geometries. Based on gelatin gels, they include silica particles with 235 and 329 nm diameters to simulate the diffusion characteristics of the tissue, ink for the absorption characteristics of the tissue and organic dyes like Rhodamin B to replace biofluorophores.

Multicapillary electrophoresis continues to see improvements in speed, robustness, and reliability. This paper reports on our work on two components belonging to a multicapillary sequencer developed in our group. Injection of the DNA samples into the capillaries was optimized to make it reproducible and to reduce the amount of sample volume required. An alternative laser illumination of the capillaries was also developed. Light intensity in the capillaries was increased as a result of a step-by-step scanning of the laser and the use of microlenses in front of the capillaries.

The present work aims a new medical probe for surgeons devoted to brain cancers, in particular glioblastoma multiforme. Within the last years, our group has started the development of a new intra-operative beta imaging probe. More recently, we initiated an alternative approach: an autofluorescence probe that has the same purpose namely the differentiation of normal from tumoral brain tissue delivering complementary information and that can avoid radiation to patient and surgeon. By means of a dedicated epi-fluorescence design and of specific fiber optic probes relative signal amplitude and spectral shape measurements are envisaged to distinguish normal and cancerous tissue by analyzing fluorophores like NADH, lipopigments and porphyrins. The autofluorescence spectra are recorded in the 475-635 nm range with a low resolution spectrometer. Intrinsic wavelength resolution is of the order of 5 nm. Different samples have been analyzed to validate our new detection system and to allow a first configuration of the future medical fluorescence probe. First results from the tissue measurements are shown. C6 tumoral cell implantation in rat brain permits first indication for discrimination of cancerous from healthy tissue.

The precise delineation and excision of brain tumor extent allows to improve survival outcome and quality of life of surgically treated patients. In order to refine the resection of gliomas, we are developing a novel intraoperative probe specifically dedicated to the localization of residual tumor after the bulk has been excised. The probe, built around clear and plastic scintillating fibers, was designed to detect positrons emitted from radiolabeled brain tissue in order to discriminate more specifically neoplastic from normal tissues. The probe was also built to be directly coupled to the excision tool leading to simultaneous detection and removal of tumor. We report here performances of the first radio-isotopic configuration of the intraoperative probe which consists of a detection head composed of eight detection elements held around the excision tool in a closed packed annular arrangement. This head is coupled to an optic fiber bundle that exports the scintillating light to a multi-channel photomultiplier tube. The gamma ray background generated by the annihilation of beta+ in tissues is eliminated by a real-time subtraction method. The detector exhibits a beta sensitivity of 139 cps/kBq and a gamma ray rejection efficiency of 99.5%. The ability of the probe to detect residual lesions was evaluated with a realistic brain phantom representing the surgical cavity and the boundaries of the tumor. We showed that lesions as small as 5 mm in diameter can be detected for tumor to normal tissue uptake ratios of fluorinated tracers greater than 3.5. This ratio is achieved with radiopharmaceuticals like 18F-FET or 18F-choline. These promising results suggest that the features of our system are compatible with in situ localization of residual radiolabeled tumors.

489 Objectives: The removal of residual lesions is one of the key procedures in cancer staging to improve prognosis and quality of life of surgically treated patients. We are developing a novel intraoperative probe specifically dedicated to the localization brain tumor remnants after the bulk has been excised. The probe, built around clear and plastic scintillating fibers, was designed to detect β-emitting radiotracer and laser-induced fluorescence simultaneously to discriminate more specifically neoplastic from normal tissues. The probe was also built to be directly coupled to the excision tool in order to detect and remove lesions at onces. Methods: The first prototype of the beta probe consists of 8 detection elements held around the excision tool in a closed packed annular arrangement. This detection head is coupled to an fiber bundle that exports the scintillating light to a multi-channel photomultiplier connected to a 64-channel electronic ASIC. The γ ray background generated by the annihilation of β+ in tissue is eliminated by a real-time subtraction method. Results: The probe exhibits a β sensitivity of 140 cps/kBq and a γ ray rejection efficiency of 99.5 %. Its ability to detect residual lesions was evaluated with a brain phantom simulating the boundaries of the tumor. We showed that lesions as small as 5 mm can be detected for tumor-to-normal tissue uptake ratios of the fluorinated tracer greater than 3.5. Conclusions: Following these promising results, a second prototype based on two exchangeable heads composed of 12 and 28 detection elements was developed. Overall performances of this new probe will be presented. Preliminary evaluation of the surgical probe on a primate model will be also reported and discussed.

The present work aims a new medical probe for surgeons devoted to brain cancers, in particular glioblastoma multiforme. Within the last years, our group has started the development of a new intraoperative beta imaging probe. More recently, we took an alternative approach for the same application: a fluorescence probe. In both cases the purpose is to differentiate normal from tumor brain tissue.In a first step, we developed set-ups capable to measure autofluorescence. They are based on a dedicated epi-fluorescence design and on specific fiber optic probes. Relative signal amplitude, spectral shape and fluorescence lifetime measurements are foreseen to distinguish normal and cancer tissue by analyzing fluorophores like NADH, lipopigments and porphyrines. The autofluorescence spectra are recorded in the 460-640 nm range with a low resolution spectrometer. For lifetime measurements a fast detector (APD) is used together with a TCSPC-carte. Intrinsic wavelength- and time-re solutions are a few nm and 200 ps, respectively. Different samples have been analyzed to validate our new detection system and to allow a first configuration of our medical fluorescence probe. First results from the tissue measurements are shown.

Surgery is considered as the primary therapeutic procedure for gliomas and several recent clinical studies have shown that total tumor resection is directly associated with longer survival when compared to subtotal resection. In order to refine the resection in the boundaries of gliomas, we are developing an intraoperative probe specifically dedicated to the localization of residual tumor labeled with positron emitters. The probe is designed to be compact and electrically safe in order to be directly coupled to the excision tool leading to simultaneous detection and removal of tumor tissues. It is built with clear and plastic scintillating fibers held in a closed packed annular arrangement ensheathing the excision tool. The annihilation gamma ray background is eliminated by a real-time subtraction method. Validation of the technical choice and optimization of the probe geometry were performed by preliminary measurements and Monte Carlo simulations based on the MCNP-4C code and an anthropomorphic brain phantom. The theoretical probe sensitivity was found to be 82 cps/muCi/ml with a gamma ray rejection efficiency of 99.6%. The expected minimum radiotracer detectable concentration for tumors labeled with 18 F-FET was 0.10 muCi/ml. When compared to the 0.29 muCi/ml average concentration in the bulk of the tumor, this result demonstrate the potential ability of the probe to define more accurately the extent of brain tumor resection

Since the introduction of systemic adjuvant chemotherapy (ACT) and endocrine therapy in the early 1970s, the determination of risk of recurrence and death from breast cancer became a critical piece of information in the selection of the optimal postoperative treatment strategy.Classical histopathological prognostic factors included tumor size, regional lymph node metastases and number of axillary nodes involved, tumor grade, presence of lymphovascular invasion, and, more recently, estrogen receptor (ER) and progesterone receptor status, measurement of proliferative activity (S-phase fraction, mitotic index, Ki-67), and HER2 overexpression/amplification.As isolated factors, they have limited predictive ability in the case of individual patients.For that reason, prognostic indices were developed.The most successful is Adjuvant!Online, an online nomogram developed by Peter Ravdin.This nomogram incorporates tumor size, axillary nodal status, tumor grade, ER status, age and comorbidity.The nomogram will provide an assessment of recurrence and mortality rates at 10 years, including deaths due to comorbid conditions.In addition, the nomogram also calculates relative and absolute benefit from various adjuvant interventions: tamoxifen, aromatase inhibitors, and first-generation, secondgeneration and third-generation ACT regimens.The prognostic and predictive value of this nomogram has been externally validated, with a margin of error ≤1%.Over the past decade, high-throughput technologies have been developed based on gene expression profiling.These include between two and a couple of hundred genes, and have the ability to separate patients with excellent outcomes from those with higher risk.One of these prognostic profiles has been externally validated and is currently undergoing testing for clinical utility in a large, multicenter, prospective randomized trial (MINDACT).Another approach was based on prospectively identifying a set of genes from the literature and from the results of gene expression profiling.Mathematical modeling then led to the selection of 16 genes related to cell proliferation, ER-driven genes, HER2 and proteases, as well as five 'housekeeping' genes (OncotypeDx).This assay is based on RT-PCR, is reproducible and applicable to archival, paraffin-embedded material, and has been shown to predict prognosis in patients with lymph-nodenegative, ER-positive primary breast cancer.Further testing indicated that the assay might also predict sensitivity to tamoxifen, or firstgeneration adjuvant chemotherapy.This assay is also under evaluation for clinical utility in a large, multicenter, prospective randomized trial (TailoRx).Whether these multigene predictors of prognosis will have greater utility than Adjuvant!Online remains to be determined.In the meantime, exploratory analyses are ongoing to identify reliable predictors of response to individual drugs and modern combination drug regimens.These are expected to lead to individualized selection of treatment, or personalized medicine.

Capillary electrophoresis is still widely used for DNA sequencing. The quality of the replaceable sieving matrix is a key area for massive sequencing with regard to speed and efficiency. The T25 polymer has been tested extensively and compared to poly(N,N-dimethylacrylamide) (PDMA). In terms of peak resolution, both polymers perform similarly. On the other hand, the run time is much shorter with the T25 polymer.