We present a spatiotemporally integrated formulation of the optimal fractionation problem using the standard log-linear-quadratic survival model. Our objective is to choose a fluencemap and a number of fractions so as to maximize the biological effect of tumor dose averaged over its voxels subject to maximum dose, mean dose, and dose-volume constraints for various normal tissues. Constrains are...

OBJECTIVE To measure setup error of head and neck neoplasm in radiotherapy and discuss over effects of error on physical dose acting on target region and organs at risk of nasopharynx cancer (NPC) patients treated with intensity modulated radiation therapy (IMRT). METHODS A total of 152 patients who developed head and neck neoplasm and received IMRT were randomly selected. Through comparing d...

Although many methods exist for intensity modulated radiotherapy (IMRT) fluence map optimization for crisp data, based on clinical practice, some of the involved parameters are fuzzy. In this paper, the best fluence maps for an IMRT procedure were identifed as a solution of an optimization problem with a quadratic objective function, where the prescribed target dose vector was fuzzy. First, a d...

We have investigated the feasibility of using a set of multiple MOSFETs in conjunction with the mobile MOSFET wireless dosimetry system, to perform a comprehensive and efficient quality assurance (QA) of IMRT plans. Anatomy specific MOSFET configurations incorporating 5 MOSFETs have been developed for a specially designed IMRT dosimetry phantom. Kilovoltage cone beam computed tomography (kV CBC...

Two-dimensional conventional radiotherapy (2D-CRT) and intensity-modulated radiotherapy (IMRT) are effective for control of nasopharyngeal carcinoma (NPC). The purpose of this study was to compare the quality of life (QoL) of stage II NPC patients treated with 2D-CRT versus IMRT. We conducted a cross-sectional study of 106 patients with stage II NPC treated with 2D-CRT (n = 47) versus IMRT (n =...

Inter- and intra-leaf transmission and head scatter can play significant roles in intensity modulated radiation therapy (IMRT)-based treatment deliveries. In order to accurately calculate the dose in the IMRT planning process, it is therefore important that the detailed geometry of the multi-leaf collimator (MLC), in addition to other components in the accelerator treatment head, be accurately ...

purpose: the aim of this study was to test the in vitro sensitivity of lymphocytes of patients with head and neck cancer against gamma irradiation and also to find out if the frequencies of chromosomal aberrations correlate with side effects of radiotherapy. patients and methods : peripheral blood of 101 patients with head and neck cancer was collected before the onset of radiotherapy, cultured...

background and aims. head and neck tumors are the most common complaints of people referring to different medical sections, especially in children. the aim of this study was to evaluate the prevalence of these tumors in children less than 12 years of age to provide a better perspective for future studies. materials and methods. all the files in department of pathology at tabriz pediatric hospit...

background: it is suggested that various forms of tobacco use have some effects on diverse sites of head and neck to develop cancer. material and methods: the study examines data for oral cancer in male subjects, collected from the population registered in cancer registry during the year 2007- 2008. all the data collected were entered into the spreadsheets. the statistical package for social sc...

conclusions most patients are referred for restaging and demonstrate evidence of regional or distant metastasis with significant value for further treatment planning. providing insurance coverage and familiarizing referring physicians about appropriate indications of this relatively new diagnostic modality will be to the best interest of head and neck cancer patients in long term. methods we re...