GATE Monte Carlo approach to heterogeneity dose distribution in small fields used in radiation therapy.

The Accurate dosage prediction in Radiation Therapy is challenging, prompting a need for precision beyond conventional clinical Treatment Planning Systems (TPS). Monte Carlo-based methods are sought for their superior accuracy. The aim of this study is to compare dose distributions between the ACUROS algorithm and the GATE platform in various tissue densities and field sizes, focusing on smaller fields. This study was initiated with a homogeneous validation of the TrueBeam STX system, using measurements obtained from the Centre Hospitalier Interregional Edith Cavell (CHIREC) in Brussels. The validation compared dosimetric functions (Percentage Depth Dose (PDD), Dose profile (DP) and Collimator scatter fraction (CSF)) employing the GAMMA index with a 2% / 2 mm criterion tolerance. Following this, heterogeneous studies examined dose distributions between the ACUROS algorithm and the GATE platform in various tissue densities and field sizes, with a specific focus on smaller fields. Simulations were conducted using both platforms on chest phantoms with heterogeneous slabs representing bone, lung, and heart, each housing a central tumor. The impact of electronic equilibrium on tumors for different small field sizes was evaluated. Results showed a remarkable 99% agreement between measurements and GATE calculations in the homogeneous validation of the TrueBeam STX system. However, in heterogeneous studies, ACUROS consistently overestimated lung doses by up to 8% compared to GATE simulation, especially evident with a flattening filter and smaller beam sizes at density interfaces. This highlights significant dose estimation discrepancies between ACUROS and GATE, emphasizing the need for precise calculations. The findings support exploring Monte Carlo-based methods for enhanced accuracy in Radiation Therapy treatment planning.

Thermal assisted alkaline pretreatment of rice husk for enhanced biomass deconstruction and enzymatic saccharification: Physico-chemical and structural characterization.

Thermal assisted alkaline pretreatment (TAAP) of rice husk (RH) was investigated to facilitate enzymatic saccharification by enhancing the enzyme accessibility to cellulosic components. Statistically guided experiments based on the Box-Behnken design involving four factors viz. biomass loading, particle size, NaOH loading and reaction time was considered for optimization. The maximum sugar yield of 371 mg g-1 biomass was obtained at optimized pretreatment condition [biomass loading (10% w/w), particle size (0.25-0.625 mm), NaOH loading (2% w/w), and reaction time (40 min)]. The TAAP of RH resulted in the efficient removal of lignin (14.9-54% (w/w)) with low hemicellulose solubilization [10.7-33.1% (w/w)] and with a simultaneous increase in cellulose concentration [32.65-51.65% (w/w)]. The SEM analysis indicated increased porosity and biomass disruption during TAAP. The FTIR analysis showed progressive removal of noncellulosic constituents, and XRD analysis revealed an increase in cellulose crystallinity post-TAAP indicating the effectiveness of pretreatment.

Composite lymphomas: Experience from a tertiary cancer center in Kerala, South India.

OBJECTIVES: Composite tumors are defined as tumors in which there are two different intermixed histologic types. Our objective was to study the clinical and pathologic features of five cases of composite lymphoma. MATERIALS AND METHODS: Our study included five patients of composite lymphoma diagnosed over a period of 5 years. Clinical presentation, hematological parameters including peripheral smear, bone marrow aspirate, and histopathological examination of lymph node including immunohistochemistry (IHC) were studied. Treatment and follow-up details were also noted. RESULTS: All the five cases were in the adult age group ranging from 44 to 72 years. All the cases were composite follicular lymphoma (FL) and mixed cellularity classical Hodgkin lymphoma (CHL). Diagnosis in all cases was suspected on morphology by identification of distinct neoplastic follicles in FL and classic Reed-Sternberg cells in CHL and confirmed by IHC. CONCLUSION: Although rare, composite lymphomas should be kept in mind. Careful histopathological examination of lymph node with identification of distinct morphological features along with IHC helps to arrive at the definitive diagnosis.

Computed tomography angiography planning identifies the target vessel for optimum infarct location and improves clinical outcome in alcohol septal ablation for hypertrophic obstructive cardiomyopathy.

AIMS: Alcohol septal ablation (ASA) is an established treatment option in hypertrophic obstructive cardiomyopathy (HOCM). ASA is ineffective in some: inaccurate infarct and inability to identify a vessel contribute. We aimed to improve accuracy of infarct using CT angiography guidance and provide a more predictable and satisfactory outcome. METHODS AND RESULTS: Twenty-one successive patients with symptomatic LVOT obstruction refractory to medication underwent CT angiography planning to guide ASA. CT was performed using a dual-source CT system. Alcohol was delivered to the artery identified from CT: in 17/21 this was a sub-branch of a septal artery, in 2/21 the septal vessel was identified from the circumflex artery. Peak gradient improved from 98 (IQR 89.50-111.50) mmHg to 14 (IQR 8.50-22) mmHg (p=0.003). Systolic anterior motion (SAM) improved in 18/20 patients. NYHA class improved by ≥1 in 18/20. Peak VO2 improved from 79.19% of predicted value (±14.01) to 91.62% (±12.02) predicted (p<0.0001). Success at the first procedure is greater with CT guidance, 17/20 vs. 50/75 with traditional methods (pre-CT guidance) (p=0.02); 9/20 had six-month CMR with target septum infarct in all. ASA-related RBBB reduced from 62% to 13% (p=0.0004). CONCLUSIONS: CT angiography planning improves localisation of infarct and procedural success at the first attempt in ASA when compared to traditional methods. Follow-up to six months suggests a symptomatic, functional and haemodynamic improvement.

Schwannoma base tongue: Case report and review of literature.

Schwannomas are benign peripheral nerve sheath tumors. These are rare in the oral cavity (1%). The most common site of involvement in oral cavity is the tongue. Posterior third of tongue is not frequently involved. The aim of this paper is to present a case report of base tongue schwannoma and review literature of this rare tumor. Data from literature were analyzed for age, gender, presenting symptom, size at presentation, and surgical approach. We report a case of 26 year-old male who presented with swelling posterior 1/3rd tongue and change in quality of voice. He was evaluated for the same with MR and incision biopsy and was planned for surgery. Surgery was abandoned at a district hospital due to difficulty in intubation. At our center he underwent fibro optic bronchoscopy guided intubation followed by general anesthesia. He underwent excision of mass using left paramedian lip spitting approach with mandibulotomy and mandibular swing. Tumor was excised in toto. His postoperative recovery was uneventful. Literature review between 2001 and 2012 was done. 15 cases of base tongue schwannoma were identified. The most common age group involved was between 30-40 years. There was a slightly higher incidence in females. All patients were symptomatic at presentation. Most common complaints were related to swallowing and throat pain. Most patients underwent transoral excision of the tumor.

Optimization of enzymatic clarification of sapodilla juice: a statistical perspective.

Response surface methodology (RSM) was employed to establish optimum conditions for enzymatic clarification of sapodilla juice. Polygalacturonase obtained from Streptomyces lydicus had been purified to homogeneity and was used for the treatment. The independent variables were temperature (30-45 degrees C), enzyme concentration (0.5-1.5 U), and treatment time (30-90 min), whose effects on viscosity and clarity of the juice were evaluated using a Box-Behnken design. Significant regression models describing the changes of viscosity and clarity with respect to the independent variables were obtained, with the coefficient of determination, R (2) , greater than 0.8. Based on response surfaces and contour plots, the optimum conditions for clarifying sapodilla juice were enzyme concentration 1.15 U, incubation temperature 34 degrees C, and incubation time 70 min.

Evaluation of alpha-galactosidase biosynthesis by Streptomyces griseoloalbus in solid-state fermentation using response surface methodology.

AIM: The present study was aimed at evaluating the effects of the three crucial factors, galactose concentration, inoculum size and moisture content, on alpha-galactosidase production by the filamentous actinobacterium Streptomyces griseoloalbus in solid-state fermentation. METHODS AND RESULTS: Central Composite design was adopted to derive a statistical model for the optimization of fermentation conditions. Maximum alpha-galactosidase yield (117 U g(-1) of dry fermented substrate) was obtained when soya bean flour supplemented with 1.5% galactose and with initial moisture content of 40% was inoculated with 1.9 x 10(6) CFU g(-1) initial dry substrate. CONCLUSIONS: The model was valid and could result in considerably enhanced enzyme yield. SIGNIFICANCE AND IMPACT OF THE STUDY: The results indicated a cost effective method for the production of alpha-galactosidase using soya bean flour. This is the first report on exploitation of the potential of filamentous bacterium for the production of alpha-galactosidase, an enzyme having versatile applications.

Evaluation of fungal culture filtrate containing chitinase as a biocontrol agent against Helicoverpa armigera.

AIMS: To evaluate the biocontrol efficacy of culture filtrate containing chitinase from Trichoderma harzianum against Heliothis. METHODS AND RESULTS: T. harzianum was cultured by submerged fermentation using colloidal chitin as sole carbon source. The ability of the culture filtrate to hydrolyse colloidal chitin indicated the presence of chitinase as one of its components. Biocontrol assay on Heliothis showed that the culture filtrate is a potent antifeedant as it reduced the feeding rate and body weight of the larvae. It reduced the successful pupation and increased larval and pupal mortality in a dosage-dependent manner when applied topically. The highest mortalities (70%) were recorded for groups treated with 2000 U ml(-1) chitinase activity. The percentage of adult emergence was zero for the highest chitinase concentration (2000 U ml(-1)) tried. CONCLUSIONS: The studies showed that the culture filtrate containing chitinase from T. harzianum is capable of negatively affecting the growth and metamorphosis of Heliothis larvae. SIGNIFICANCE AND IMPACT OF THE STUDY: In view of the need for safer and environmentally friendly pest management tools, the present study could help in the development of enzyme-based biopesticides against Heliothis.