The Experimental Assessment Of Build Up Factor And Attenuation Coefficient Of Brass Compensator Applied In Intensity-Modulated Radiation Therapy (Imrt) For 6mv Photon Beam

Introduction: Recent compensators are commonly applied in IMRT. The precise properties of applied compensators such as thickness, attenuation coefficient and build up factor are intensively important for IMRT calculations. Method: The brass compensator used for 6 MV photon beam was studied to estimate the relative effect of thickness and field size on IMRT calculations. Various field size together with several compensator thicknesses were examined. Result: The average reduction of effective attenuation coefficient (EAC), for the fields of 10×10 cm2 to 20×20 cm2, was 9.94%. By increasing the field size, EAC was decreased. The major reduction of EAC due to increasing field size was found to be 9.62%. The build up factor was increased by 2% to 21.8% respect to field size and compensator thickness. Also, the build up factor was increased by adding up the thickness. The rate of changes ranged from 24% to 48 %.Conclusion: The compensator thickness and field size are significantly important to calculate the effective attenuation coefficient and build up facto

Hematoporphyrin encapsulated polymeric nanomicelles for photodynamically treatment of cancer

Nowadays, developements in nanotechnology have leeds an increased application of this newborn technology in cancer treatment. In this study, a stabilized micelle was developed to load HpD in order to be used in photodynamic treatment of cancer in an animal model. To construct micelles, Pluronic P-105 was used and stabilized to encapsulate HpD. This process includes a 24 h polymerization in which the first 3.5 h was in the presence of N[2] purge and was continued at 65[degree]C. In this reaction, NNDEA and benzoil peroxide [BP] were used for stabilization of micelles and initiation of reaction, respectively. DLS analysis of micelles revealed that the size of them before and after drug encapsulation was 14 nm and 23.5 nm, respectively. To assess drug loading, drug standard curve was obtained and its loading was obtained as 2 mg/ml. To extract free drug from complex, it was dialyzed against water and its stability profile was measured up to one month which was more than 80%. According to obtained results, this complex could be used to reduce side effects in photodynamic therapy. Besides, according to tumor characteristics and physical properties of micelles, it is possible to enhance drug release and uptake at tumor site