introduction polymer gel dosimeters offer a practical solution to 3d dose verification for conventional radiotherapy as well as intensity-modulated and stereotactic radiotherapy. in this study, egsnrc calculated and pagat polymer gel dosimeter measured dose profiles from single shot irradiation with 18 mm collimator of gamma knife in homogeneous and inhomogeneous phantoms were compared with eac...

The traditional microdosimetric approach uses observables such as the distribution of lineal energy deposition, y, and the specific energy deposition, z, to describe radiation quality with respect to damage in biological systems. A problem is, however, that there is no obvious link from purely physical observables to resulting biological effect. In recent developments, however, microdosimetric ...

Introduction:   Radiotherapy with or without surgery plays an important role in the treatment of patients with esophageal cancer. In the treatment planning of esophageal cancer, usually normal lung volume was observed in the treatment fields and probably received high radiation dose. The incidence of radiation pneumonitis (RP) after radiotherapy (RT) for sensitive organ of lu...

background: craniospinal radiotherapy faces technical challenges which are due to the sensitivity of the location in which the gross tumor is, and to organs at risk around planning target volume. using modern treatment planning systems causes a reduction in the complexities of the treatment techniques. the most effective method to assess the dosimetric accuracy and the validity of the software ...

Nasopharyngeal tumors are commonly treated with intensity-modulated radiotherapy techniques. For photon dose calculations, problems related to loss of lateral electronic equilibrium exist when small fields are used. The anisotropic analytical algorithm (AAA) implemented in Varian Eclipse was developed to replace the pencil beam convolution (PBC) algorithm for more accurate dose prediction in an...

Current estimation of radiation dose from computed tomography (CT) scans on patients has relied on the measurement of Computed Tomography Dose Index (CTDI) in standard cylindrical phantoms, and calculations based on mathematical representations of "standard man". Radiation dose to both adult and pediatric patients from a CT scan has been a concern, as noted in recent reports. The purpose of thi...

The combination of radiotherapy treatments and breast reconstruction, using temporary tissue expanders, generates several concerns due to the presence of a magnetic valve inside the radiation field. The objective of this work is to evaluate a radiotherapy treatment planning for a patient using a tissue expander. Isodose curve maps, obtained using radiochromic films, were compared to the ones ca...

the objective of this study was to determine and compare cystatin c changes before and after radiotherapy in patients with stomach cancer who were candidate for radiotherapy. this study was conducted as a prospective cohort one. eighteen patients with definite diagnosis of stomach cancer under treatment by radiotherapy who presented to radiotherapy-oncology center of imam hossein hospital, tehr...