An Experimental Study of the Effect of Rock/Fluid Interaction on Resistivity Logs during CO₂Sequestration in Carbonate Rocks

Accurate laboratory measurements and analysis of electrical properties of core samples are a prerequisite step to the evaluation of oil and gas reserves. In recent times, this evaluation technique has been adopted in carbon dioxide sequestration projects for estimating and monitoring carbon dioxide (CO2) accumulation in saline aquifers. Several papers have reported laboratory success in the use of resistivity measurements to monitor the flow and also estimate the volume of CO2 plume in geological formations. Such laboratory experiments did not capture the effect of CO2 -brine-rock interaction (CBRI) on saturation estimation. The possibility of a change in value resistivity due to CO2/brine/rock interactions, and the possible effect on CO2 monitoring and estimation are of immediate interest here. Preliminary results of an ongoing research work showed that a much longer experiment time accommodates CO2-brine-rock interaction which ultimately lead to change in rock resistivity. We hereby present the electrical behavior of carbonates to CO2/ brine/rock interaction during prolonged CO2 sequestration and the effect on saturation estimation. This electrical behavior and its possible effect on CO2 monitoring and estimation are discussed.

Dosimetric Comparison between Conventional 2D and 3D Conformal Radiotherapy in the Treatment of Intact Breast Cancer

Background: Radiotherapy (RT) techniques after Conservative Breast Surgery (CBS) vary. Three Dimension (3D) planning allows for better plan optimization compared to 2 Dimension (2D) plans and also allowing for creating Dose Volume Histograms (DVHs) for both Planning Target Volume (PTV) and Organs at Risk (OAR). Patients and Methods: Twenty consecutive patients with CBS planned for whole breast and supraclavicular (SCV) RT at the National Cancer Institute (NCI), Egypt between January and June 2016 were included in this study. All patients were planned clinically in 2D fashion with no more than 2 cm of ipsilateral lung allowed in the tangential fields “Limited 2D” (Limit-2D) then Target and OAR volumes were drawn according to the Radiation Therapy Oncology Group (RTOG) guidelines and 3D plans and a central slice PTV-based 2D plan, “Modified 2D” (Mod-2D), were performed in the same Computerized Tomography (CT) slices for each patient. Mono-Iso-Centeric technique (MIT) was used in 3D plans. DVH parameters were used to compare the three plans. Results: In 3D plans, compared to Limit-2D, coverage improved for the intact breast (V95% = 95% versus (Vs) 69%, p = 0.036) and SCVPTV (V90% = 90% Vs 65%, p = 0.01). The breast and SCV V 107%, V112% and Dmax were better with 3D plan however not statistical significant (NS). Junctional hot spots were 120% and 107% in the Limit-2D and 3D plans respectively (p = 0.04). The dose to the heart, mean (333 Vs 491 cGy), V10 (5% Vs 10%) and V20 (3% Vs 7%), Ipsilateral lung V20 (19% Vs 26%), and contra lateral breast D-max (205 Vs 462 cGy) were higher in 3D plans however NS, and the dose to the cord was the same. Comparison between 3D and Mod-2D showed better OAR sparing with 3D with mean heart dose (491 cGy Vs 782 cGy, p = 0.025) and Ipsilateral lung V20 (26% Vs 32%, p = 0.07% with statistically comparable target coverage. Conclusion: This study demonstrated that application of 3D plan using MIT improves coverage of breast and SCVPTVs with minimizing hot spot at the junctional area if compared with Limit-2D plans with comparable dose to OAR. When compared with Mod-2D plans, 3D plans not only had better target coverage but also better sparing of OAR, the latter was statistically significant.

A Clinic-Epidemilogical Study of Cases of Locally Advanced Non Small Cell Lung Cancer (NSCLC) That Received Radiotherapy at NCI Cairo in the Period from 2001-2010

Purpose: This work was to study the clinic-epidemiological characteristics of patients with locally advanced NCSLC and to analyze their prognostic factors and also the results of different treatment modalities for local control and their effect on overall survival (OAS). Materials and Methods: This is a retrospective study including 121 patients with primary locally advanced NSCLC diagnosed between 2001 and 2010 at the radiotherapy department , National Cancer Institute, Cairo University, Egypt. Results: The study showed significant correlation between the tumor size 60, moderately differentiated tumors G2 and treatment outcomes;better locoregional control and better survival rates. On the opposite side poorly differentiated tumors G3, tumor size > 7 cm had the worst locoregional control and survival rates. The study also showed significant statistical correlation between treatment modality, locoregional control and survival rates. Patients who were treated by either concommitent chemo-radiotherapy or sequential chemo-radiotherapy had better local control compared to other patients who were treated by radical radiotherapy, and they also had the best survival rates among all the other treatment groups. The average 6 months OAS rates for all studied patients were 60.3% while 12 months survival rates were 38.8%. The median OAS was 7 months. Conclusions: From the present study, we concluded that concomitant chemo-radiotherapy is the treatment of choice for locally advanced non small cell lung cancer;also we concluded that better performance status and higher hemoglobin levels have better treatment outcome in these cases.