نتایج جستجو برای: isodose curves
تعداد نتایج: 93941 فیلتر نتایج به سال:
A gynaecological applicator consisting of a metallic intra-uterine tube with a plastic vaginal applicator and an HDR Ir-192 source have been simulated with MCNP5 (Monte Carlo code). A solid phantom has been designed to perform measurements around the applicator with radiochromic films. The isodose curves obtained are compared with curves calculated with the F4MESH tally of MCNP5 with a good agr...
Brachytherapy plays an important role in the definitive treatment of cervical cancers by radiotherapy. In the present study, we investigated whether sliding-window intensity-modulated radiation therapy (IMRT) can achieve a pear-shaped distribution with a similar sharp dose falloff identical to that of brachytherapy. The computed tomography scans of a tandem and ovoid patient were pushed to both...
Craniospinal is known as the method to kill cancer within a wide radiation area, starting from cranial spinal nervous system. In case, has spread through fluid of cerebro spinalis, such medulloblastoma. We carried out research determine isodose curve in medulloblastoma craniospinal patients and DVH (Dose Volume Histogram) statistic OAR (Organ at Risk) by using 3D-CRT radiotherapy technique. To ...
background: in radiation therapy, the sparing of normal tissues can be performed using either multi-leaf collimators or cerrobend blocks. the current work focuses on the physical characteristics of cerrobend blocks including attenuation coefficient, effective penumbra width and isodose curves undulation in penumbral regions. materials and methods: all measurements were performed using a dual en...
Introduction: Inclusion of inhomogeneities such as air-filled cavities in the head and neck treatment fields may result in potential dosimetric disagreement which was caused by electronic disequilibrium. Most of treatments planning systems (TPS) are not able to predict dose distribution of inhomogeneous regions accurately. EBT2 films are used frequently in radiotherapy quality ass...
The high density and atomic number of hip prostheses for patients undergoing pelvic radiotherapy challenge our ability to accurately calculate dose. A new clinical dose calculation algorithm, Monte Carlo, will allow accurate calculation of the radiation transport both within and beyond hip prostheses. The aim of this research was to investigate, for both phantom and patient geometries, the capa...
Background: Monte Carlo determination of TG-43 brachytherapy dosimetry parameters and dose distribution calculation for 131Cs source model CS-1 are presented in this study. Materials and Methods: The dose distribution was calculated around the 131Cs Model CS-1 located in the center of 30 cm ×30 cm ×30 cm water, and soft tissue phantoms cube using MCNP code by Monte Carlo method. The percentage ...
Introduction: Because of small size of the beamlets in IMRT, physical penumbra is one of the important dosimetric parameters and small changes in the penumbra will have a great impact on the results. The physical penumbra width is defined as the lateral distance between two specified isodose curves at a specified depth of phantom. In this study, after demonstrating the inconsi...
Background: Monte Carlo and experimental relative dose determination in a water phantom, due to a high dose rate (HDR) 192Ir source is presented for real energy spectrum and monochromatic at 356 keV. Materials and Methods: The dose distribution has been calculated around the 192Ir located in the center of 30 cm ×30 cm ×30 cm water phantom using MCNP4C code by Monte Carlo method. Relati...
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