We develop and demonstrate a simple shape-based approach for diffuse optical tomographic reconstruction of coagulative lesions generated during interstitial photothermal therapy (PTT) of the prostate. The shape-based reconstruction assumes a simple ellipsoid shape, matching the general dimensions of a cylindrical diffusing fiber used for light delivery in current clinical studies of PTT in focal prostate cancer. The specific requirement is to accurately define the border between the photothermal lesion and native tissue as the photothermal lesion grows, with an accuracy of ? 1 ?? mm , so treatment can be terminated before there is damage to the rectal wall. To demonstrate the feasibility of the shape-based diffuse optical tomography reconstruction, simulated data were generated based on forward calculations in known geometries that include the prostate, rectum, and lesions of varying dimensions. The only source of optical contrast between the lesion and prostate was increased scattering in the lesion, as is typically observed with coagulation. With noise added to these forward calculations, lesion dimensions were reconstructed using the shape-based method. This approach for reconstruction is shown to be feasible and sufficiently accurate for lesions that are within 4 mm from the rectal wall. The method was also robust for irregularly shaped lesions.
Conventional Sources of energy are depleting at an alarming rate which give us unconventional resources as an only option for energy source. Unconventional sources of energy like Shale gas, Tight gas, Coal bed methane are difficult to exploit as compared to the conventional sources of energy. Hydraulic Fracturing is the well stimulation technique used for exploitation and production of these unconventional resources. Foam fracturing is the the most opted stimulation technique for low permeability shallow wells because of its reduced damage potential to reactive and sensitive formations. This research paper discusses about the evaluation of attempt made to develop an eco-friendly CO2 foam based fracturing fluid which can be used at HPHT conditions for shale reservoirs by Grafting Copolymerization. The graft copolymer was developed by free radical polymerization of Gum Acacia (GA) and Lactic acid (LA) by using Potassium Persulphate (KPS) as an initiator and its characterization was done by FESEM and FTIR analysis. Then, the grafted copolymer (GA-g-LA) was processed with CO2 foam based fracturing fluid as an additive. Lecithin is used to emulsify brine and liquid CO2. The effect of graft copolymer was on rheology and stability of the formulated foam based fracturing fluid is evaluated as a function of surfactant concentration. The results are compared with the conventional foam based fracturing fluids. The results showed that grafted copolymer has increased the stability of the formulated fracturing fluid at high temperatures. Use of grafted copolymer results in higher viscosity and proppant carrying capacity which is beneficial for HPHT fracturing conditions. The results of the core flood studies was evaluated on a shale sample to determine its return permeabilty and it was comparable to non-foam based fracturing fluid.
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